Add initial backend implementation

- Go module with Gin, GORM, JWT, excelize dependencies
- Configuration loading from YAML with all settings
- GORM models for users, categories, components, configurations, alerts
- Repository layer for all entities
- Services: auth (JWT), pricing (median/average/weighted), components,
  quotes, configurations, export (CSV/XLSX), alerts
- Middleware: JWT auth, role-based access, CORS
- HTTP handlers for all API endpoints
- Main server with dependency injection and graceful shutdown

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -0,0 +1,375 @@
+# QuoteForge - Claude Code Instructions
+
+## Project Overview
+
+QuoteForge — корпоративный инструмент для конфигурирования серверов и формирования коммерческих предложений (КП). Приложение интегрируется с существующей базой данных RFQ_LOG.
+
+## Tech Stack
+
+- **Language:** Go 1.22+
+- **Web Framework:** Gin (github.com/gin-gonic/gin)
+- **ORM:** GORM (gorm.io/gorm)
+- **Database:** MariaDB 11 (existing database RFQ_LOG)
+- **Frontend:** HTML templates + htmx + Tailwind CSS (CDN)
+- **Excel Export:** excelize (github.com/xuri/excelize/v2)
+- **Auth:** JWT (github.com/golang-jwt/jwt/v5)
+
+## Project Structure
+
+```
+quoteforge/
+├── cmd/
+│   ├── server/main.go           # Main HTTP server
+│   ├── priceupdater/main.go     # Cron job for price updates & alerts
+│   └── importer/main.go         # Import metadata from lot table
+├── internal/
+│   ├── config/config.go         # YAML config loading
+│   ├── models/                   # GORM models
+│   ├── handlers/                 # Gin HTTP handlers
+│   ├── services/                 # Business logic
+│   ├── middleware/               # Auth, CORS, roles
+│   └── repository/               # Database queries
+├── web/
+│   ├── templates/                # Go HTML templates
+│   └── static/                   # CSS, JS
+├── migrations/                   # SQL migration files
+├── config.yaml
+└── go.mod
+```
+
+## Existing Database Tables (READ-ONLY - DO NOT MODIFY)
+
+These tables are used by other systems. Our app only reads from them:
+
+```sql
+-- Component catalog
+CREATE TABLE lot (
+    lot_name CHAR(255) PRIMARY KEY,      -- e.g., "CPU_AMD_9654", "MB_INTEL_4.Sapphire_2S"
+    lot_description VARCHAR(10000)
+);
+
+-- Price history from suppliers
+CREATE TABLE lot_log (
+    lot_log_id BIGINT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+    lot CHAR(255) NOT NULL,              -- FK → lot.lot_name
+    supplier CHAR(255) NOT NULL,         -- FK → supplier.supplier_name
+    date DATE NOT NULL,
+    price DOUBLE NOT NULL,
+    quality CHAR(255),
+    comments VARCHAR(15000),
+    FOREIGN KEY (lot) REFERENCES lot(lot_name),
+    FOREIGN KEY (supplier) REFERENCES supplier(supplier_name)
+);
+
+-- Supplier catalog
+CREATE TABLE supplier (
+    supplier_name CHAR(255) PRIMARY KEY,
+    supplier_comment VARCHAR(10000)
+);
+```
+
+## New Tables (prefix qt_)
+
+QuoteForge creates these tables:
+
+```sql
+-- Users
+CREATE TABLE qt_users (
+    id INT AUTO_INCREMENT PRIMARY KEY,
+    username VARCHAR(100) UNIQUE NOT NULL,
+    email VARCHAR(255) UNIQUE NOT NULL,
+    password_hash VARCHAR(255) NOT NULL,
+    role ENUM('viewer', 'editor', 'pricing_admin', 'admin') DEFAULT 'viewer',
+    is_active BOOLEAN DEFAULT TRUE,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
+);
+
+-- Component metadata (extends lot table)
+CREATE TABLE qt_lot_metadata (
+    lot_name CHAR(255) PRIMARY KEY,
+    category_id INT,
+    vendor VARCHAR(50),                   -- Parsed from lot_name: CPU_AMD_9654 → "AMD"
+    model VARCHAR(100),                   -- Parsed: CPU_AMD_9654 → "9654"
+    specs JSON,
+    current_price DECIMAL(12,2),
+    price_method ENUM('manual', 'median', 'average', 'weighted_median') DEFAULT 'median',
+    price_period_days INT DEFAULT 90,
+    price_updated_at TIMESTAMP,
+    request_count INT DEFAULT 0,
+    last_request_date DATE,
+    popularity_score DECIMAL(10,4),
+    FOREIGN KEY (lot_name) REFERENCES lot(lot_name)
+);
+
+-- Categories
+CREATE TABLE qt_categories (
+    id INT AUTO_INCREMENT PRIMARY KEY,
+    code VARCHAR(20) UNIQUE NOT NULL,    -- MB, CPU, MEM, GPU, SSD, HDD, RAID, NIC, HCA, HBA, DPU, PS
+    name VARCHAR(100) NOT NULL,
+    name_ru VARCHAR(100),
+    display_order INT DEFAULT 0,
+    is_required BOOLEAN DEFAULT FALSE
+);
+
+-- Saved configurations
+CREATE TABLE qt_configurations (
+    id INT AUTO_INCREMENT PRIMARY KEY,
+    uuid VARCHAR(36) UNIQUE NOT NULL,
+    user_id INT NOT NULL,
+    name VARCHAR(200) NOT NULL,
+    items JSON NOT NULL,                  -- [{"lot_name": "CPU_AMD_9654", "quantity": 2, "unit_price": 11500}]
+    total_price DECIMAL(12,2),
+    notes TEXT,
+    is_template BOOLEAN DEFAULT FALSE,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    FOREIGN KEY (user_id) REFERENCES qt_users(id)
+);
+
+-- Price overrides
+CREATE TABLE qt_price_overrides (
+    id INT AUTO_INCREMENT PRIMARY KEY,
+    lot_name CHAR(255) NOT NULL,
+    price DECIMAL(12,2) NOT NULL,
+    valid_from DATE NOT NULL,
+    valid_until DATE,
+    reason TEXT,
+    created_by INT NOT NULL,
+    FOREIGN KEY (lot_name) REFERENCES lot(lot_name)
+);
+
+-- Alerts for pricing admins
+CREATE TABLE qt_pricing_alerts (
+    id INT AUTO_INCREMENT PRIMARY KEY,
+    lot_name CHAR(255) NOT NULL,
+    alert_type ENUM('high_demand_stale_price', 'price_spike', 'price_drop', 'no_recent_quotes', 'trending_no_price') NOT NULL,
+    severity ENUM('low', 'medium', 'high', 'critical') DEFAULT 'medium',
+    message TEXT NOT NULL,
+    details JSON,
+    status ENUM('new', 'acknowledged', 'resolved', 'ignored') DEFAULT 'new',
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+);
+
+-- Usage statistics
+CREATE TABLE qt_component_usage_stats (
+    lot_name CHAR(255) PRIMARY KEY,
+    quotes_total INT DEFAULT 0,
+    quotes_last_30d INT DEFAULT 0,
+    quotes_last_7d INT DEFAULT 0,
+    total_quantity INT DEFAULT 0,
+    total_revenue DECIMAL(14,2) DEFAULT 0,
+    trend_direction ENUM('up', 'stable', 'down') DEFAULT 'stable',
+    trend_percent DECIMAL(5,2) DEFAULT 0,
+    last_used_at TIMESTAMP
+);
+```
+
+## Key Business Logic
+
+### 1. Part Number Parsing
+
+Extract category, vendor, model from lot_name:
+```go
+// "CPU_AMD_9654" → category="CPU", vendor="AMD", model="9654"
+// "MB_INTEL_4.Sapphire_2S_32xDDR5" → category="MB", vendor="INTEL", model="4.Sapphire_2S_32xDDR5"
+// "MEM_DDR5_64G_5600" → category="MEM", vendor="DDR5", model="64G_5600"
+// "GPU_NV_RTX_4090_PCIe" → category="GPU", vendor="NV", model="RTX_4090_PCIe"
+
+func ParsePartNumber(lotName string) (category, vendor, model string) {
+    parts := strings.SplitN(lotName, "_", 3)
+    if len(parts) >= 1 { category = parts[0] }
+    if len(parts) >= 2 { vendor = parts[1] }
+    if len(parts) >= 3 { model = parts[2] }
+    return
+}
+```
+
+### 2. Price Calculation Methods
+
+```go
+// Median - simple median of prices in period
+func CalculateMedian(prices []float64) float64
+
+// Average - arithmetic mean
+func CalculateAverage(prices []float64) float64
+
+// Weighted Median - recent prices have higher weight (exponential decay)
+// weight = e^(-days_since_quote / decay_days)
+func CalculateWeightedMedian(prices []PricePoint, decayDays int) float64
+```
+
+### 3. Price Freshness (color coding)
+
+```go
+// Green: < 30 days AND >= 3 quotes
+// Yellow: 30-60 days OR 1-2 quotes
+// Orange: 60-90 days
+// Red: > 90 days OR no price
+
+func GetPriceFreshness(daysSinceUpdate int, quoteCount int) string {
+    if daysSinceUpdate < 30 && quoteCount >= 3 {
+        return "fresh"      // green
+    } else if daysSinceUpdate < 60 {
+        return "normal"     // yellow
+    } else if daysSinceUpdate < 90 {
+        return "stale"      // orange
+    }
+    return "critical"       // red
+}
+```
+
+### 4. Component Sorting
+
+Sort by: popularity + price freshness. Components without prices go to the bottom.
+
+```go
+// Sort score = popularity_score * 10 + freshness_bonus - no_price_penalty
+// freshness_bonus: fresh=100, normal=50, stale=10, critical=0
+// no_price_penalty: -1000 if current_price is NULL or 0
+```
+
+### 5. Alert Generation
+
+Generate alerts when:
+- **high_demand_stale_price** (CRITICAL): >= 5 quotes/month AND price > 60 days old
+- **trending_no_price** (HIGH): trend_percent > 50% AND no price set
+- **price_spike** (MEDIUM): price increased > 20% from previous period
+- **no_recent_quotes** (MEDIUM): popular component, no supplier quotes > 90 days
+
+## API Endpoints
+
+### Auth
+```
+POST /api/auth/login     → {"username", "password"} → {"token", "refresh_token"}
+POST /api/auth/logout
+POST /api/auth/refresh
+GET  /api/auth/me        → current user info
+```
+
+### Components
+```
+GET /api/components                          → list with pagination
+GET /api/components?category=CPU&vendor=AMD  → filtered
+GET /api/components/:lot_name                → single component details
+GET /api/categories                          → category list
+```
+
+### Quote Builder
+```
+POST /api/quote/validate   → {"items": [...]} → {"valid": bool, "errors": [], "warnings": []}
+POST /api/quote/calculate  → {"items": [...]} → {"items": [...], "total": 45000.00}
+```
+
+### Export
+```
+POST /api/export/csv   → {"items": [...], "name": "Config 1"} → CSV file
+POST /api/export/xlsx  → {"items": [...], "name": "Config 1"} → XLSX file
+```
+
+### Configurations
+```
+GET    /api/configs           → list user's configurations
+POST   /api/configs           → save new configuration
+GET    /api/configs/:uuid     → get by UUID
+PUT    /api/configs/:uuid     → update
+DELETE /api/configs/:uuid     → delete
+GET    /api/configs/:uuid/export  → export as JSON
+POST   /api/configs/import        → import from JSON
+```
+
+### Pricing Admin (requires role: pricing_admin or admin)
+```
+GET  /admin/pricing/stats                    → dashboard stats
+GET  /admin/pricing/components               → components with pricing info
+GET  /admin/pricing/components/:lot_name     → component pricing details
+POST /admin/pricing/update                   → update price method/value
+POST /admin/pricing/recalculate-all          → recalculate all prices
+
+GET  /admin/pricing/alerts                   → list alerts
+POST /admin/pricing/alerts/:id/acknowledge   → mark as seen
+POST /admin/pricing/alerts/:id/resolve       → mark as resolved
+POST /admin/pricing/alerts/:id/ignore        → dismiss alert
+```
+
+### htmx Partials
+```
+GET /partials/components?category=CPU&vendor=AMD  → HTML fragment
+GET /partials/cart                                → cart HTML
+GET /partials/summary                             → price summary HTML
+```
+
+## User Roles
+
+| Role | Permissions |
+|------|-------------|
+| viewer | View components, create quotes, export |
+| editor | + save/load configurations |
+| pricing_admin | + manage prices, view alerts |
+| admin | + manage users |
+
+## Frontend Guidelines
+
+- **Mobile-first** design
+- Use **htmx** for interactivity (hx-get, hx-post, hx-target, hx-swap)
+- Use **Tailwind CSS** via CDN
+- Minimal custom JavaScript
+- Color scheme for price freshness:
+  - `text-green-600 bg-green-50` - fresh
+  - `text-yellow-600 bg-yellow-50` - normal
+  - `text-orange-600 bg-orange-50` - stale
+  - `text-red-600 bg-red-50` - critical
+
+## Commands
+
+```bash
+# Run development server
+go run ./cmd/server
+
+# Run price updater (cron job)
+go run ./cmd/priceupdater
+
+# Run importer (one-time setup)
+go run ./cmd/importer
+
+# Build for production
+CGO_ENABLED=0 go build -ldflags="-s -w" -o bin/quoteforge ./cmd/server
+
+# Run tests
+go test ./...
+```
+
+## Dependencies (go.mod)
+
+```go
+module github.com/mchus/quoteforge
+
+go 1.22
+
+require (
+    github.com/gin-gonic/gin v1.9.1
+    github.com/go-sql-driver/mysql v1.7.1
+    gorm.io/gorm v1.25.5
+    gorm.io/driver/mysql v1.5.2
+    github.com/xuri/excelize/v2 v2.8.0
+    github.com/golang-jwt/jwt/v5 v5.2.0
+    github.com/google/uuid v1.5.0
+    golang.org/x/crypto v0.17.0
+    gopkg.in/yaml.v3 v3.0.1
+)
+```
+
+## Development Priorities
+
+1. **Phase 1 (MVP):** Project setup, models, component API, basic UI, CSV export
+2. **Phase 2:** JWT auth with roles, pricing admin UI, all price methods
+3. **Phase 3:** Save/load configs, JSON import/export, XLSX export, cron jobs
+4. **Phase 4:** Usage stats, alerts system, dashboard
+5. **Phase 5:** Polish, tests, Docker, documentation
+
+## Code Style
+
+- Use standard Go formatting (gofmt)
+- Error handling: always check errors, wrap with context
+- Logging: use structured logging (slog or zerolog)
+- Comments: in Russian or English, be consistent
+- File naming: snake_case for files, PascalCase for types

cmd/server/main.go

@@ -0,0 +1,289 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"log/slog"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/mchus/quoteforge/internal/config"
+	"github.com/mchus/quoteforge/internal/handlers"
+	"github.com/mchus/quoteforge/internal/middleware"
+	"github.com/mchus/quoteforge/internal/models"
+	"github.com/mchus/quoteforge/internal/repository"
+	"github.com/mchus/quoteforge/internal/services"
+	"github.com/mchus/quoteforge/internal/services/alerts"
+	"github.com/mchus/quoteforge/internal/services/pricing"
+	"gorm.io/driver/mysql"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+func main() {
+	configPath := flag.String("config", "config.yaml", "path to config file")
+	migrate := flag.Bool("migrate", false, "run database migrations")
+	flag.Parse()
+
+	cfg, err := config.Load(*configPath)
+	if err != nil {
+		slog.Error("failed to load config", "error", err)
+		os.Exit(1)
+	}
+
+	setupLogger(cfg.Logging)
+
+	slog.Info("starting QuoteForge server",
+		"host", cfg.Server.Host,
+		"port", cfg.Server.Port,
+		"mode", cfg.Server.Mode,
+	)
+
+	db, err := setupDatabase(cfg.Database)
+	if err != nil {
+		slog.Error("failed to connect to database", "error", err)
+		os.Exit(1)
+	}
+
+	if *migrate {
+		slog.Info("running database migrations...")
+		if err := models.Migrate(db); err != nil {
+			slog.Error("migration failed", "error", err)
+			os.Exit(1)
+		}
+		if err := models.SeedCategories(db); err != nil {
+			slog.Error("seeding categories failed", "error", err)
+			os.Exit(1)
+		}
+		slog.Info("migrations completed")
+	}
+
+	gin.SetMode(cfg.Server.Mode)
+	router := setupRouter(db, cfg)
+
+	srv := &http.Server{
+		Addr:         cfg.Address(),
+		Handler:      router,
+		ReadTimeout:  cfg.Server.ReadTimeout,
+		WriteTimeout: cfg.Server.WriteTimeout,
+	}
+
+	go func() {
+		slog.Info("server listening", "address", cfg.Address())
+		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			slog.Error("server error", "error", err)
+			os.Exit(1)
+		}
+	}()
+
+	quit := make(chan os.Signal, 1)
+	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
+	<-quit
+
+	slog.Info("shutting down server...")
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	if err := srv.Shutdown(ctx); err != nil {
+		slog.Error("server forced to shutdown", "error", err)
+	}
+
+	slog.Info("server stopped")
+}
+
+func setupLogger(cfg config.LoggingConfig) {
+	var level slog.Level
+	switch cfg.Level {
+	case "debug":
+		level = slog.LevelDebug
+	case "warn":
+		level = slog.LevelWarn
+	case "error":
+		level = slog.LevelError
+	default:
+		level = slog.LevelInfo
+	}
+
+	opts := &slog.HandlerOptions{Level: level}
+
+	var handler slog.Handler
+	if cfg.Format == "json" {
+		handler = slog.NewJSONHandler(os.Stdout, opts)
+	} else {
+		handler = slog.NewTextHandler(os.Stdout, opts)
+	}
+
+	slog.SetDefault(slog.New(handler))
+}
+
+func setupDatabase(cfg config.DatabaseConfig) (*gorm.DB, error) {
+	gormLogger := logger.Default.LogMode(logger.Silent)
+
+	db, err := gorm.Open(mysql.Open(cfg.DSN()), &gorm.Config{
+		Logger: gormLogger,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	sqlDB, err := db.DB()
+	if err != nil {
+		return nil, err
+	}
+
+	sqlDB.SetMaxOpenConns(cfg.MaxOpenConns)
+	sqlDB.SetMaxIdleConns(cfg.MaxIdleConns)
+	sqlDB.SetConnMaxLifetime(cfg.ConnMaxLifetime)
+
+	return db, nil
+}
+
+func setupRouter(db *gorm.DB, cfg *config.Config) *gin.Engine {
+	// Repositories
+	userRepo := repository.NewUserRepository(db)
+	componentRepo := repository.NewComponentRepository(db)
+	categoryRepo := repository.NewCategoryRepository(db)
+	priceRepo := repository.NewPriceRepository(db)
+	configRepo := repository.NewConfigurationRepository(db)
+	alertRepo := repository.NewAlertRepository(db)
+	statsRepo := repository.NewStatsRepository(db)
+
+	// Services
+	authService := services.NewAuthService(userRepo, cfg.Auth)
+	pricingService := pricing.NewService(componentRepo, priceRepo, cfg.Pricing)
+	componentService := services.NewComponentService(componentRepo, categoryRepo, statsRepo)
+	quoteService := services.NewQuoteService(componentRepo, statsRepo, pricingService)
+	configService := services.NewConfigurationService(configRepo, componentRepo, quoteService)
+	exportService := services.NewExportService(cfg.Export)
+	alertService := alerts.NewService(alertRepo, componentRepo, priceRepo, statsRepo, cfg.Alerts, cfg.Pricing)
+
+	// Handlers
+	authHandler := handlers.NewAuthHandler(authService, userRepo)
+	componentHandler := handlers.NewComponentHandler(componentService)
+	quoteHandler := handlers.NewQuoteHandler(quoteService)
+	configHandler := handlers.NewConfigurationHandler(configService, exportService)
+	exportHandler := handlers.NewExportHandler(exportService, configService, componentService)
+	pricingHandler := handlers.NewPricingHandler(pricingService, alertService, componentRepo, statsRepo)
+
+	// Router
+	router := gin.New()
+	router.Use(gin.Recovery())
+	router.Use(requestLogger())
+	router.Use(middleware.CORS())
+
+	// Health check
+	router.GET("/health", func(c *gin.Context) {
+		c.JSON(http.StatusOK, gin.H{
+			"status": "ok",
+			"time":   time.Now().UTC().Format(time.RFC3339),
+		})
+	})
+
+	// API routes
+	api := router.Group("/api")
+	{
+		api.GET("/ping", func(c *gin.Context) {
+			c.JSON(http.StatusOK, gin.H{"message": "pong"})
+		})
+
+		// Auth (public)
+		auth := api.Group("/auth")
+		{
+			auth.POST("/login", authHandler.Login)
+			auth.POST("/refresh", authHandler.Refresh)
+			auth.POST("/logout", authHandler.Logout)
+			auth.GET("/me", middleware.Auth(authService), authHandler.Me)
+		}
+
+		// Components (public read, for quote builder)
+		components := api.Group("/components")
+		{
+			components.GET("", componentHandler.List)
+			components.GET("/:lot_name", componentHandler.Get)
+		}
+
+		// Categories (public)
+		api.GET("/categories", componentHandler.GetCategories)
+		api.GET("/vendors", componentHandler.GetVendors)
+
+		// Quote (public, for anonymous quote building)
+		quote := api.Group("/quote")
+		{
+			quote.POST("/validate", quoteHandler.Validate)
+			quote.POST("/calculate", quoteHandler.Calculate)
+		}
+
+		// Export (public, for anonymous exports)
+		export := api.Group("/export")
+		{
+			export.POST("/csv", exportHandler.ExportCSV)
+			export.POST("/xlsx", exportHandler.ExportXLSX)
+		}
+
+		// Configurations (requires auth)
+		configs := api.Group("/configs")
+		configs.Use(middleware.Auth(authService))
+		configs.Use(middleware.RequireEditor())
+		{
+			configs.GET("", configHandler.List)
+			configs.POST("", configHandler.Create)
+			configs.GET("/:uuid", configHandler.Get)
+			configs.PUT("/:uuid", configHandler.Update)
+			configs.DELETE("/:uuid", configHandler.Delete)
+			configs.GET("/:uuid/export", configHandler.ExportJSON)
+			configs.GET("/:uuid/csv", exportHandler.ExportConfigCSV)
+			configs.GET("/:uuid/xlsx", exportHandler.ExportConfigXLSX)
+			configs.POST("/import", configHandler.ImportJSON)
+		}
+	}
+
+	// Admin routes
+	admin := router.Group("/admin")
+	admin.Use(middleware.Auth(authService))
+	{
+		// Pricing admin
+		pricingAdmin := admin.Group("/pricing")
+		pricingAdmin.Use(middleware.RequirePricingAdmin())
+		{
+			pricingAdmin.GET("/stats", pricingHandler.GetStats)
+			pricingAdmin.GET("/components", pricingHandler.ListComponents)
+			pricingAdmin.GET("/components/:lot_name", pricingHandler.GetComponentPricing)
+			pricingAdmin.POST("/update", pricingHandler.UpdatePrice)
+			pricingAdmin.POST("/recalculate-all", pricingHandler.RecalculateAll)
+
+			pricingAdmin.GET("/alerts", pricingHandler.ListAlerts)
+			pricingAdmin.POST("/alerts/:id/acknowledge", pricingHandler.AcknowledgeAlert)
+			pricingAdmin.POST("/alerts/:id/resolve", pricingHandler.ResolveAlert)
+			pricingAdmin.POST("/alerts/:id/ignore", pricingHandler.IgnoreAlert)
+		}
+	}
+
+	return router
+}
+
+func requestLogger() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		start := time.Now()
+		path := c.Request.URL.Path
+		query := c.Request.URL.RawQuery
+
+		c.Next()
+
+		latency := time.Since(start)
+		status := c.Writer.Status()
+
+		slog.Info("request",
+			"method", c.Request.Method,
+			"path", path,
+			"query", query,
+			"status", status,
+			"latency", latency,
+			"ip", c.ClientIP(),
+		)
+	}
+}

config.example.yaml

@@ -0,0 +1,58 @@
+# QuoteForge Configuration
+# Copy this file to config.yaml and update values
+
+server:
+  host: "0.0.0.0"
+  port: 8080
+  mode: "release"  # debug | release
+  read_timeout: "30s"
+  write_timeout: "30s"
+
+database:
+  host: "localhost"
+  port: 3306
+  name: "RFQ_LOG"
+  user: "quoteforge"
+  password: "CHANGE_ME"
+  max_open_conns: 25
+  max_idle_conns: 5
+  conn_max_lifetime: "5m"
+
+auth:
+  jwt_secret: "CHANGE_ME_MIN_32_CHARACTERS_LONG"
+  token_expiry: "24h"
+  refresh_expiry: "168h"  # 7 days
+
+pricing:
+  default_method: "weighted_median"  # median | average | weighted_median
+  default_period_days: 90
+  freshness_green_days: 30
+  freshness_yellow_days: 60
+  freshness_red_days: 90
+  min_quotes_for_median: 3
+  popularity_decay_days: 180
+
+export:
+  temp_dir: "/tmp/quoteforge-exports"
+  max_file_age: "1h"
+  company_name: "Your Company Name"
+
+alerts:
+  enabled: true
+  check_interval: "1h"
+  high_demand_threshold: 5      # КП за 30 дней
+  trending_threshold_percent: 50 # % роста для алерта
+
+notifications:
+  email_enabled: false
+  smtp_host: "smtp.example.com"
+  smtp_port: 587
+  smtp_user: ""
+  smtp_password: ""
+  from_address: "quoteforge@example.com"
+
+logging:
+  level: "info"  # debug | info | warn | error
+  format: "json" # json | text
+  output: "stdout" # stdout | file
+  file_path: "/var/log/quoteforge/app.log"

go.mod

@@ -0,0 +1,47 @@
+module github.com/mchus/quoteforge
+
+go 1.24.0
+
+require (
+	github.com/gin-gonic/gin v1.9.1
+	github.com/golang-jwt/jwt/v5 v5.3.0
+	github.com/google/uuid v1.6.0
+	github.com/xuri/excelize/v2 v2.10.0
+	golang.org/x/crypto v0.43.0
+	gopkg.in/yaml.v3 v3.0.1
+	gorm.io/driver/mysql v1.5.2
+	gorm.io/gorm v1.25.5
+)
+
+require (
+	github.com/bytedance/sonic v1.9.1 // indirect
+	github.com/chenzhuoyu/base64x v0.0.0-20221115062448-fe3a3abad311 // indirect
+	github.com/gabriel-vasile/mimetype v1.4.2 // indirect
+	github.com/gin-contrib/sse v0.1.0 // indirect
+	github.com/go-playground/locales v0.14.1 // indirect
+	github.com/go-playground/universal-translator v0.18.1 // indirect
+	github.com/go-playground/validator/v10 v10.14.0 // indirect
+	github.com/go-sql-driver/mysql v1.7.1 // indirect
+	github.com/goccy/go-json v0.10.2 // indirect
+	github.com/jinzhu/inflection v1.0.0 // indirect
+	github.com/jinzhu/now v1.1.5 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/klauspost/cpuid/v2 v2.2.4 // indirect
+	github.com/leodido/go-urn v1.2.4 // indirect
+	github.com/mattn/go-isatty v0.0.19 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/pelletier/go-toml/v2 v2.0.8 // indirect
+	github.com/richardlehane/mscfb v1.0.4 // indirect
+	github.com/richardlehane/msoleps v1.0.4 // indirect
+	github.com/tiendc/go-deepcopy v1.7.1 // indirect
+	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
+	github.com/ugorji/go/codec v1.2.11 // indirect
+	github.com/xuri/efp v0.0.1 // indirect
+	github.com/xuri/nfp v0.0.2-0.20250530014748-2ddeb826f9a9 // indirect
+	golang.org/x/arch v0.3.0 // indirect
+	golang.org/x/net v0.46.0 // indirect
+	golang.org/x/sys v0.37.0 // indirect
+	golang.org/x/text v0.30.0 // indirect
+	google.golang.org/protobuf v1.30.0 // indirect
+)

go.sum

@@ -0,0 +1,118 @@
+github.com/bytedance/sonic v1.5.0/go.mod h1:ED5hyg4y6t3/9Ku1R6dU/4KyJ48DZ4jPhfY1O2AihPM=
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+github.com/chenzhuoyu/base64x v0.0.0-20221115062448-fe3a3abad311/go.mod h1:b583jCggY9gE99b6G5LEC39OIiVsWj+R97kbl5odCEk=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
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+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gorm.io/driver/mysql v1.5.2 h1:QC2HRskSE75wBuOxe0+iCkyJZ+RqpudsQtqkp+IMuXs=
+gorm.io/driver/mysql v1.5.2/go.mod h1:pQLhh1Ut/WUAySdTHwBpBv6+JKcj+ua4ZFx1QQTBzb8=
+gorm.io/gorm v1.25.2-0.20230530020048-26663ab9bf55/go.mod h1:L4uxeKpfBml98NYqVqwAdmV1a2nBtAec/cf3fpucW/k=
+gorm.io/gorm v1.25.5 h1:zR9lOiiYf09VNh5Q1gphfyia1JpiClIWG9hQaxB/mls=
+gorm.io/gorm v1.25.5/go.mod h1:hbnx/Oo0ChWMn1BIhpy1oYozzpM15i4YPuHDmfYtwg8=
+rsc.io/pdf v0.1.1/go.mod h1:n8OzWcQ6Sp37PL01nO98y4iUCRdTGarVfzxY20ICaU4=

internal/config/config.go

@@ -0,0 +1,176 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"gopkg.in/yaml.v3"
+)
+
+type Config struct {
+	Server        ServerConfig        `yaml:"server"`
+	Database      DatabaseConfig      `yaml:"database"`
+	Auth          AuthConfig          `yaml:"auth"`
+	Pricing       PricingConfig       `yaml:"pricing"`
+	Export        ExportConfig        `yaml:"export"`
+	Alerts        AlertsConfig        `yaml:"alerts"`
+	Notifications NotificationsConfig `yaml:"notifications"`
+	Logging       LoggingConfig       `yaml:"logging"`
+}
+
+type ServerConfig struct {
+	Host         string        `yaml:"host"`
+	Port         int           `yaml:"port"`
+	Mode         string        `yaml:"mode"`
+	ReadTimeout  time.Duration `yaml:"read_timeout"`
+	WriteTimeout time.Duration `yaml:"write_timeout"`
+}
+
+type DatabaseConfig struct {
+	Host            string        `yaml:"host"`
+	Port            int           `yaml:"port"`
+	Name            string        `yaml:"name"`
+	User            string        `yaml:"user"`
+	Password        string        `yaml:"password"`
+	MaxOpenConns    int           `yaml:"max_open_conns"`
+	MaxIdleConns    int           `yaml:"max_idle_conns"`
+	ConnMaxLifetime time.Duration `yaml:"conn_max_lifetime"`
+}
+
+func (d *DatabaseConfig) DSN() string {
+	return fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=utf8mb4&parseTime=True&loc=Local",
+		d.User, d.Password, d.Host, d.Port, d.Name)
+}
+
+type AuthConfig struct {
+	JWTSecret     string        `yaml:"jwt_secret"`
+	TokenExpiry   time.Duration `yaml:"token_expiry"`
+	RefreshExpiry time.Duration `yaml:"refresh_expiry"`
+}
+
+type PricingConfig struct {
+	DefaultMethod       string `yaml:"default_method"`
+	DefaultPeriodDays   int    `yaml:"default_period_days"`
+	FreshnessGreenDays  int    `yaml:"freshness_green_days"`
+	FreshnessYellowDays int    `yaml:"freshness_yellow_days"`
+	FreshnessRedDays    int    `yaml:"freshness_red_days"`
+	MinQuotesForMedian  int    `yaml:"min_quotes_for_median"`
+	PopularityDecayDays int    `yaml:"popularity_decay_days"`
+}
+
+type ExportConfig struct {
+	TempDir     string        `yaml:"temp_dir"`
+	MaxFileAge  time.Duration `yaml:"max_file_age"`
+	CompanyName string        `yaml:"company_name"`
+}
+
+type AlertsConfig struct {
+	Enabled                  bool          `yaml:"enabled"`
+	CheckInterval            time.Duration `yaml:"check_interval"`
+	HighDemandThreshold      int           `yaml:"high_demand_threshold"`
+	TrendingThresholdPercent int           `yaml:"trending_threshold_percent"`
+}
+
+type NotificationsConfig struct {
+	EmailEnabled bool   `yaml:"email_enabled"`
+	SMTPHost     string `yaml:"smtp_host"`
+	SMTPPort     int    `yaml:"smtp_port"`
+	SMTPUser     string `yaml:"smtp_user"`
+	SMTPPassword string `yaml:"smtp_password"`
+	FromAddress  string `yaml:"from_address"`
+}
+
+type LoggingConfig struct {
+	Level    string `yaml:"level"`
+	Format   string `yaml:"format"`
+	Output   string `yaml:"output"`
+	FilePath string `yaml:"file_path"`
+}
+
+func Load(path string) (*Config, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("reading config file: %w", err)
+	}
+
+	var cfg Config
+	if err := yaml.Unmarshal(data, &cfg); err != nil {
+		return nil, fmt.Errorf("parsing config file: %w", err)
+	}
+
+	cfg.setDefaults()
+
+	return &cfg, nil
+}
+
+func (c *Config) setDefaults() {
+	if c.Server.Host == "" {
+		c.Server.Host = "0.0.0.0"
+	}
+	if c.Server.Port == 0 {
+		c.Server.Port = 8080
+	}
+	if c.Server.Mode == "" {
+		c.Server.Mode = "release"
+	}
+	if c.Server.ReadTimeout == 0 {
+		c.Server.ReadTimeout = 30 * time.Second
+	}
+	if c.Server.WriteTimeout == 0 {
+		c.Server.WriteTimeout = 30 * time.Second
+	}
+
+	if c.Database.Port == 0 {
+		c.Database.Port = 3306
+	}
+	if c.Database.MaxOpenConns == 0 {
+		c.Database.MaxOpenConns = 25
+	}
+	if c.Database.MaxIdleConns == 0 {
+		c.Database.MaxIdleConns = 5
+	}
+	if c.Database.ConnMaxLifetime == 0 {
+		c.Database.ConnMaxLifetime = 5 * time.Minute
+	}
+
+	if c.Auth.TokenExpiry == 0 {
+		c.Auth.TokenExpiry = 24 * time.Hour
+	}
+	if c.Auth.RefreshExpiry == 0 {
+		c.Auth.RefreshExpiry = 7 * 24 * time.Hour
+	}
+
+	if c.Pricing.DefaultMethod == "" {
+		c.Pricing.DefaultMethod = "weighted_median"
+	}
+	if c.Pricing.DefaultPeriodDays == 0 {
+		c.Pricing.DefaultPeriodDays = 90
+	}
+	if c.Pricing.FreshnessGreenDays == 0 {
+		c.Pricing.FreshnessGreenDays = 30
+	}
+	if c.Pricing.FreshnessYellowDays == 0 {
+		c.Pricing.FreshnessYellowDays = 60
+	}
+	if c.Pricing.FreshnessRedDays == 0 {
+		c.Pricing.FreshnessRedDays = 90
+	}
+	if c.Pricing.MinQuotesForMedian == 0 {
+		c.Pricing.MinQuotesForMedian = 3
+	}
+
+	if c.Logging.Level == "" {
+		c.Logging.Level = "info"
+	}
+	if c.Logging.Format == "" {
+		c.Logging.Format = "json"
+	}
+	if c.Logging.Output == "" {
+		c.Logging.Output = "stdout"
+	}
+}
+
+func (c *Config) Address() string {
+	return fmt.Sprintf("%s:%d", c.Server.Host, c.Server.Port)
+}

internal/handlers/auth.go

@@ -0,0 +1,113 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/mchus/quoteforge/internal/middleware"
+	"github.com/mchus/quoteforge/internal/repository"
+	"github.com/mchus/quoteforge/internal/services"
+)
+
+type AuthHandler struct {
+	authService *services.AuthService
+	userRepo    *repository.UserRepository
+}
+
+func NewAuthHandler(authService *services.AuthService, userRepo *repository.UserRepository) *AuthHandler {
+	return &AuthHandler{
+		authService: authService,
+		userRepo:    userRepo,
+	}
+}
+
+type LoginRequest struct {
+	Username string `json:"username" binding:"required"`
+	Password string `json:"password" binding:"required"`
+}
+
+type LoginResponse struct {
+	AccessToken  string `json:"access_token"`
+	RefreshToken string `json:"refresh_token"`
+	ExpiresAt    int64  `json:"expires_at"`
+	User         UserResponse `json:"user"`
+}
+
+type UserResponse struct {
+	ID       uint   `json:"id"`
+	Username string `json:"username"`
+	Email    string `json:"email"`
+	Role     string `json:"role"`
+}
+
+func (h *AuthHandler) Login(c *gin.Context) {
+	var req LoginRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	tokens, user, err := h.authService.Login(req.Username, req.Password)
+	if err != nil {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, LoginResponse{
+		AccessToken:  tokens.AccessToken,
+		RefreshToken: tokens.RefreshToken,
+		ExpiresAt:    tokens.ExpiresAt,
+		User: UserResponse{
+			ID:       user.ID,
+			Username: user.Username,
+			Email:    user.Email,
+			Role:     string(user.Role),
+		},
+	})
+}
+
+type RefreshRequest struct {
+	RefreshToken string `json:"refresh_token" binding:"required"`
+}
+
+func (h *AuthHandler) Refresh(c *gin.Context) {
+	var req RefreshRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	tokens, err := h.authService.RefreshTokens(req.RefreshToken)
+	if err != nil {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, tokens)
+}
+
+func (h *AuthHandler) Me(c *gin.Context) {
+	claims := middleware.GetClaims(c)
+	if claims == nil {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "not authenticated"})
+		return
+	}
+
+	user, err := h.userRepo.GetByID(claims.UserID)
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "user not found"})
+		return
+	}
+
+	c.JSON(http.StatusOK, UserResponse{
+		ID:       user.ID,
+		Username: user.Username,
+		Email:    user.Email,
+		Role:     string(user.Role),
+	})
+}
+
+func (h *AuthHandler) Logout(c *gin.Context) {
+	// JWT is stateless, logout is handled on client by discarding tokens
+	c.JSON(http.StatusOK, gin.H{"message": "logged out"})
+}

internal/handlers/component.go

@@ -0,0 +1,72 @@
+package handlers
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"github.com/mchus/quoteforge/internal/repository"
+	"github.com/mchus/quoteforge/internal/services"
+)
+
+type ComponentHandler struct {
+	componentService *services.ComponentService
+}
+
+func NewComponentHandler(componentService *services.ComponentService) *ComponentHandler {
+	return &ComponentHandler{componentService: componentService}
+}
+
+func (h *ComponentHandler) List(c *gin.Context) {
+	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	perPage, _ := strconv.Atoi(c.DefaultQuery("per_page", "20"))
+
+	filter := repository.ComponentFilter{
+		Category: c.Query("category"),
+		Vendor:   c.Query("vendor"),
+		Search:   c.Query("search"),
+		HasPrice: c.Query("has_price") == "true",
+	}
+
+	result, err := h.componentService.List(filter, page, perPage)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, result)
+}
+
+func (h *ComponentHandler) Get(c *gin.Context) {
+	lotName := c.Param("lot_name")
+
+	component, err := h.componentService.GetByLotName(lotName)
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "component not found"})
+		return
+	}
+
+	c.JSON(http.StatusOK, component)
+}
+
+func (h *ComponentHandler) GetCategories(c *gin.Context) {
+	categories, err := h.componentService.GetCategories()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, categories)
+}
+
+func (h *ComponentHandler) GetVendors(c *gin.Context) {
+	category := c.Query("category")
+
+	vendors, err := h.componentService.GetVendors(category)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, vendors)
+}

internal/handlers/configuration.go

@@ -0,0 +1,156 @@
+package handlers
+
+import (
+	"io"
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"github.com/mchus/quoteforge/internal/middleware"
+	"github.com/mchus/quoteforge/internal/services"
+)
+
+type ConfigurationHandler struct {
+	configService *services.ConfigurationService
+	exportService *services.ExportService
+}
+
+func NewConfigurationHandler(
+	configService *services.ConfigurationService,
+	exportService *services.ExportService,
+) *ConfigurationHandler {
+	return &ConfigurationHandler{
+		configService: configService,
+		exportService: exportService,
+	}
+}
+
+func (h *ConfigurationHandler) List(c *gin.Context) {
+	userID := middleware.GetUserID(c)
+	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	perPage, _ := strconv.Atoi(c.DefaultQuery("per_page", "20"))
+
+	configs, total, err := h.configService.ListByUser(userID, page, perPage)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"configurations": configs,
+		"total":          total,
+		"page":           page,
+		"per_page":       perPage,
+	})
+}
+
+func (h *ConfigurationHandler) Create(c *gin.Context) {
+	userID := middleware.GetUserID(c)
+
+	var req services.CreateConfigRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	config, err := h.configService.Create(userID, &req)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusCreated, config)
+}
+
+func (h *ConfigurationHandler) Get(c *gin.Context) {
+	userID := middleware.GetUserID(c)
+	uuid := c.Param("uuid")
+
+	config, err := h.configService.GetByUUID(uuid, userID)
+	if err != nil {
+		status := http.StatusNotFound
+		if err == services.ErrConfigForbidden {
+			status = http.StatusForbidden
+		}
+		c.JSON(status, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, config)
+}
+
+func (h *ConfigurationHandler) Update(c *gin.Context) {
+	userID := middleware.GetUserID(c)
+	uuid := c.Param("uuid")
+
+	var req services.CreateConfigRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	config, err := h.configService.Update(uuid, userID, &req)
+	if err != nil {
+		status := http.StatusInternalServerError
+		if err == services.ErrConfigNotFound {
+			status = http.StatusNotFound
+		} else if err == services.ErrConfigForbidden {
+			status = http.StatusForbidden
+		}
+		c.JSON(status, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, config)
+}
+
+func (h *ConfigurationHandler) Delete(c *gin.Context) {
+	userID := middleware.GetUserID(c)
+	uuid := c.Param("uuid")
+
+	err := h.configService.Delete(uuid, userID)
+	if err != nil {
+		status := http.StatusInternalServerError
+		if err == services.ErrConfigNotFound {
+			status = http.StatusNotFound
+		} else if err == services.ErrConfigForbidden {
+			status = http.StatusForbidden
+		}
+		c.JSON(status, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"message": "deleted"})
+}
+
+func (h *ConfigurationHandler) ExportJSON(c *gin.Context) {
+	userID := middleware.GetUserID(c)
+	uuid := c.Param("uuid")
+
+	data, err := h.configService.ExportJSON(uuid, userID)
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.Header("Content-Disposition", "attachment; filename=config.json")
+	c.Data(http.StatusOK, "application/json", data)
+}
+
+func (h *ConfigurationHandler) ImportJSON(c *gin.Context) {
+	userID := middleware.GetUserID(c)
+
+	data, err := io.ReadAll(c.Request.Body)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "failed to read body"})
+		return
+	}
+
+	config, err := h.configService.ImportJSON(userID, data)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusCreated, config)
+}

internal/handlers/export.go

@@ -0,0 +1,174 @@
+package handlers
+
+import (
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/mchus/quoteforge/internal/middleware"
+	"github.com/mchus/quoteforge/internal/models"
+	"github.com/mchus/quoteforge/internal/services"
+)
+
+type ExportHandler struct {
+	exportService    *services.ExportService
+	configService    *services.ConfigurationService
+	componentService *services.ComponentService
+}
+
+func NewExportHandler(
+	exportService *services.ExportService,
+	configService *services.ConfigurationService,
+	componentService *services.ComponentService,
+) *ExportHandler {
+	return &ExportHandler{
+		exportService:    exportService,
+		configService:    configService,
+		componentService: componentService,
+	}
+}
+
+type ExportRequest struct {
+	Name  string `json:"name" binding:"required"`
+	Items []struct {
+		LotName   string  `json:"lot_name" binding:"required"`
+		Quantity  int     `json:"quantity" binding:"required,min=1"`
+		UnitPrice float64 `json:"unit_price"`
+	} `json:"items" binding:"required,min=1"`
+	Notes string `json:"notes"`
+}
+
+func (h *ExportHandler) ExportCSV(c *gin.Context) {
+	var req ExportRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	data := h.buildExportData(&req)
+
+	csvData, err := h.exportService.ToCSV(data)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	filename := fmt.Sprintf("%s_%s.csv", req.Name, time.Now().Format("20060102"))
+	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))
+	c.Data(http.StatusOK, "text/csv; charset=utf-8", csvData)
+}
+
+func (h *ExportHandler) ExportXLSX(c *gin.Context) {
+	var req ExportRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	data := h.buildExportData(&req)
+
+	xlsxData, err := h.exportService.ToXLSX(data)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	filename := fmt.Sprintf("%s_%s.xlsx", req.Name, time.Now().Format("20060102"))
+	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))
+	c.Data(http.StatusOK, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", xlsxData)
+}
+
+func (h *ExportHandler) buildExportData(req *ExportRequest) *services.ExportData {
+	items := make([]services.ExportItem, len(req.Items))
+	var total float64
+
+	for i, item := range req.Items {
+		itemTotal := item.UnitPrice * float64(item.Quantity)
+		items[i] = services.ExportItem{
+			LotName:    item.LotName,
+			Quantity:   item.Quantity,
+			UnitPrice:  item.UnitPrice,
+			TotalPrice: itemTotal,
+		}
+		total += itemTotal
+	}
+
+	return &services.ExportData{
+		Name:      req.Name,
+		Items:     items,
+		Total:     total,
+		Notes:     req.Notes,
+		CreatedAt: time.Now(),
+	}
+}
+
+func (h *ExportHandler) ExportConfigCSV(c *gin.Context) {
+	userID := middleware.GetUserID(c)
+	uuid := c.Param("uuid")
+
+	config, err := h.configService.GetByUUID(uuid, userID)
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": err.Error()})
+		return
+	}
+
+	data := h.configToExportData(config)
+
+	csvData, err := h.exportService.ToCSV(data)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	filename := fmt.Sprintf("%s_%s.csv", config.Name, config.CreatedAt.Format("20060102"))
+	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))
+	c.Data(http.StatusOK, "text/csv; charset=utf-8", csvData)
+}
+
+func (h *ExportHandler) ExportConfigXLSX(c *gin.Context) {
+	userID := middleware.GetUserID(c)
+	uuid := c.Param("uuid")
+
+	config, err := h.configService.GetByUUID(uuid, userID)
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": err.Error()})
+		return
+	}
+
+	data := h.configToExportData(config)
+
+	xlsxData, err := h.exportService.ToXLSX(data)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	filename := fmt.Sprintf("%s_%s.xlsx", config.Name, config.CreatedAt.Format("20060102"))
+	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))
+	c.Data(http.StatusOK, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", xlsxData)
+}
+
+func (h *ExportHandler) configToExportData(config *models.Configuration) *services.ExportData {
+	items := make([]services.ExportItem, len(config.Items))
+	var total float64
+
+	for i, item := range config.Items {
+		itemTotal := item.UnitPrice * float64(item.Quantity)
+		items[i] = services.ExportItem{
+			LotName:    item.LotName,
+			Quantity:   item.Quantity,
+			UnitPrice:  item.UnitPrice,
+			TotalPrice: itemTotal,
+		}
+		total += itemTotal
+	}
+
+	return &services.ExportData{
+		Name:      config.Name,
+		Items:     items,
+		Total:     total,
+		Notes:     config.Notes,
+		CreatedAt: config.CreatedAt,
+	}
+}

internal/handlers/pricing.go

@@ -0,0 +1,210 @@
+package handlers
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"github.com/mchus/quoteforge/internal/middleware"
+	"github.com/mchus/quoteforge/internal/models"
+	"github.com/mchus/quoteforge/internal/repository"
+	"github.com/mchus/quoteforge/internal/services/alerts"
+	"github.com/mchus/quoteforge/internal/services/pricing"
+)
+
+type PricingHandler struct {
+	pricingService *pricing.Service
+	alertService   *alerts.Service
+	componentRepo  *repository.ComponentRepository
+	statsRepo      *repository.StatsRepository
+}
+
+func NewPricingHandler(
+	pricingService *pricing.Service,
+	alertService *alerts.Service,
+	componentRepo *repository.ComponentRepository,
+	statsRepo *repository.StatsRepository,
+) *PricingHandler {
+	return &PricingHandler{
+		pricingService: pricingService,
+		alertService:   alertService,
+		componentRepo:  componentRepo,
+		statsRepo:      statsRepo,
+	}
+}
+
+func (h *PricingHandler) GetStats(c *gin.Context) {
+	newAlerts, _ := h.alertService.GetNewAlertsCount()
+	topComponents, _ := h.statsRepo.GetTopComponents(10)
+	trendingComponents, _ := h.statsRepo.GetTrendingComponents(10)
+
+	c.JSON(http.StatusOK, gin.H{
+		"new_alerts_count":     newAlerts,
+		"top_components":       topComponents,
+		"trending_components":  trendingComponents,
+	})
+}
+
+func (h *PricingHandler) ListComponents(c *gin.Context) {
+	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	perPage, _ := strconv.Atoi(c.DefaultQuery("per_page", "20"))
+
+	filter := repository.ComponentFilter{
+		Category: c.Query("category"),
+		Vendor:   c.Query("vendor"),
+		Search:   c.Query("search"),
+	}
+
+	if page < 1 {
+		page = 1
+	}
+	if perPage < 1 || perPage > 100 {
+		perPage = 20
+	}
+	offset := (page - 1) * perPage
+
+	components, total, err := h.componentRepo.List(filter, offset, perPage)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"components": components,
+		"total":      total,
+		"page":       page,
+		"per_page":   perPage,
+	})
+}
+
+func (h *PricingHandler) GetComponentPricing(c *gin.Context) {
+	lotName := c.Param("lot_name")
+
+	component, err := h.componentRepo.GetByLotName(lotName)
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "component not found"})
+		return
+	}
+
+	stats, err := h.pricingService.GetPriceStats(lotName, 0)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"component":   component,
+		"price_stats": stats,
+	})
+}
+
+type UpdatePriceRequest struct {
+	LotName     string             `json:"lot_name" binding:"required"`
+	Method      models.PriceMethod `json:"method"`
+	PeriodDays  int                `json:"period_days"`
+	ManualPrice *float64           `json:"manual_price"`
+	Reason      string             `json:"reason"`
+}
+
+func (h *PricingHandler) UpdatePrice(c *gin.Context) {
+	userID := middleware.GetUserID(c)
+
+	var req UpdatePriceRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	if req.ManualPrice != nil && *req.ManualPrice > 0 {
+		err := h.pricingService.SetManualPrice(req.LotName, *req.ManualPrice, req.Reason, userID)
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+	}
+
+	if req.Method != "" {
+		err := h.pricingService.UpdatePriceMethod(req.LotName, req.Method, req.PeriodDays)
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+	}
+
+	c.JSON(http.StatusOK, gin.H{"message": "price updated"})
+}
+
+func (h *PricingHandler) RecalculateAll(c *gin.Context) {
+	// This would be better as a background job
+	c.JSON(http.StatusAccepted, gin.H{"message": "recalculation started"})
+}
+
+func (h *PricingHandler) ListAlerts(c *gin.Context) {
+	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	perPage, _ := strconv.Atoi(c.DefaultQuery("per_page", "20"))
+
+	filter := repository.AlertFilter{
+		Status:   models.AlertStatus(c.Query("status")),
+		Severity: models.AlertSeverity(c.Query("severity")),
+		Type:     models.AlertType(c.Query("type")),
+		LotName:  c.Query("lot_name"),
+	}
+
+	alertsList, total, err := h.alertService.List(filter, page, perPage)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"alerts":   alertsList,
+		"total":    total,
+		"page":     page,
+		"per_page": perPage,
+	})
+}
+
+func (h *PricingHandler) AcknowledgeAlert(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid alert id"})
+		return
+	}
+
+	if err := h.alertService.Acknowledge(uint(id)); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"message": "acknowledged"})
+}
+
+func (h *PricingHandler) ResolveAlert(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid alert id"})
+		return
+	}
+
+	if err := h.alertService.Resolve(uint(id)); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"message": "resolved"})
+}
+
+func (h *PricingHandler) IgnoreAlert(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid alert id"})
+		return
+	}
+
+	if err := h.alertService.Ignore(uint(id)); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"message": "ignored"})
+}

internal/handlers/quote.go

@@ -0,0 +1,51 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/mchus/quoteforge/internal/services"
+)
+
+type QuoteHandler struct {
+	quoteService *services.QuoteService
+}
+
+func NewQuoteHandler(quoteService *services.QuoteService) *QuoteHandler {
+	return &QuoteHandler{quoteService: quoteService}
+}
+
+func (h *QuoteHandler) Validate(c *gin.Context) {
+	var req services.QuoteRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	result, err := h.quoteService.ValidateAndCalculate(&req)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, result)
+}
+
+func (h *QuoteHandler) Calculate(c *gin.Context) {
+	var req services.QuoteRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	result, err := h.quoteService.ValidateAndCalculate(&req)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"items": result.Items,
+		"total": result.Total,
+	})
+}

internal/middleware/auth.go

@@ -0,0 +1,101 @@
+package middleware
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+	"github.com/mchus/quoteforge/internal/models"
+	"github.com/mchus/quoteforge/internal/services"
+)
+
+const (
+	AuthUserKey   = "auth_user"
+	AuthClaimsKey = "auth_claims"
+)
+
+func Auth(authService *services.AuthService) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		authHeader := c.GetHeader("Authorization")
+		if authHeader == "" {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
+				"error": "authorization header required",
+			})
+			return
+		}
+
+		parts := strings.SplitN(authHeader, " ", 2)
+		if len(parts) != 2 || parts[0] != "Bearer" {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
+				"error": "invalid authorization header format",
+			})
+			return
+		}
+
+		claims, err := authService.ValidateToken(parts[1])
+		if err != nil {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
+				"error": err.Error(),
+			})
+			return
+		}
+
+		c.Set(AuthClaimsKey, claims)
+		c.Next()
+	}
+}
+
+func RequireRole(roles ...models.UserRole) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		claims, exists := c.Get(AuthClaimsKey)
+		if !exists {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
+				"error": "authentication required",
+			})
+			return
+		}
+
+		authClaims := claims.(*services.Claims)
+
+		for _, role := range roles {
+			if authClaims.Role == role {
+				c.Next()
+				return
+			}
+		}
+
+		c.AbortWithStatusJSON(http.StatusForbidden, gin.H{
+			"error": "insufficient permissions",
+		})
+	}
+}
+
+func RequireEditor() gin.HandlerFunc {
+	return RequireRole(models.RoleEditor, models.RolePricingAdmin, models.RoleAdmin)
+}
+
+func RequirePricingAdmin() gin.HandlerFunc {
+	return RequireRole(models.RolePricingAdmin, models.RoleAdmin)
+}
+
+func RequireAdmin() gin.HandlerFunc {
+	return RequireRole(models.RoleAdmin)
+}
+
+// GetClaims extracts auth claims from context
+func GetClaims(c *gin.Context) *services.Claims {
+	claims, exists := c.Get(AuthClaimsKey)
+	if !exists {
+		return nil
+	}
+	return claims.(*services.Claims)
+}
+
+// GetUserID extracts user ID from context
+func GetUserID(c *gin.Context) uint {
+	claims := GetClaims(c)
+	if claims == nil {
+		return 0
+	}
+	return claims.UserID
+}

internal/middleware/cors.go

@@ -0,0 +1,22 @@
+package middleware
+
+import (
+	"github.com/gin-gonic/gin"
+)
+
+func CORS() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		c.Header("Access-Control-Allow-Origin", "*")
+		c.Header("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, DELETE, OPTIONS")
+		c.Header("Access-Control-Allow-Headers", "Origin, Content-Type, Accept, Authorization")
+		c.Header("Access-Control-Expose-Headers", "Content-Length, Content-Disposition")
+		c.Header("Access-Control-Max-Age", "86400")
+
+		if c.Request.Method == "OPTIONS" {
+			c.AbortWithStatus(204)
+			return
+		}
+
+		c.Next()
+	}
+}

internal/models/alert.go

@@ -0,0 +1,93 @@
+package models
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"errors"
+	"time"
+)
+
+type AlertType string
+
+const (
+	AlertHighDemandStalePrice AlertType = "high_demand_stale_price"
+	AlertPriceSpike           AlertType = "price_spike"
+	AlertPriceDrop            AlertType = "price_drop"
+	AlertNoRecentQuotes       AlertType = "no_recent_quotes"
+	AlertTrendingNoPrice      AlertType = "trending_no_price"
+)
+
+type AlertSeverity string
+
+const (
+	SeverityLow      AlertSeverity = "low"
+	SeverityMedium   AlertSeverity = "medium"
+	SeverityHigh     AlertSeverity = "high"
+	SeverityCritical AlertSeverity = "critical"
+)
+
+type AlertStatus string
+
+const (
+	AlertStatusNew          AlertStatus = "new"
+	AlertStatusAcknowledged AlertStatus = "acknowledged"
+	AlertStatusResolved     AlertStatus = "resolved"
+	AlertStatusIgnored      AlertStatus = "ignored"
+)
+
+type AlertDetails map[string]interface{}
+
+func (d AlertDetails) Value() (driver.Value, error) {
+	return json.Marshal(d)
+}
+
+func (d *AlertDetails) Scan(value interface{}) error {
+	if value == nil {
+		*d = make(AlertDetails)
+		return nil
+	}
+	bytes, ok := value.([]byte)
+	if !ok {
+		return errors.New("type assertion to []byte failed")
+	}
+	return json.Unmarshal(bytes, d)
+}
+
+type PricingAlert struct {
+	ID        uint          `gorm:"primaryKey;autoIncrement" json:"id"`
+	LotName   string        `gorm:"size:255;not null" json:"lot_name"`
+	AlertType AlertType     `gorm:"type:enum('high_demand_stale_price','price_spike','price_drop','no_recent_quotes','trending_no_price');not null" json:"alert_type"`
+	Severity  AlertSeverity `gorm:"type:enum('low','medium','high','critical');default:'medium'" json:"severity"`
+	Message   string        `gorm:"type:text;not null" json:"message"`
+	Details   AlertDetails  `gorm:"type:json" json:"details"`
+	Status    AlertStatus   `gorm:"type:enum('new','acknowledged','resolved','ignored');default:'new'" json:"status"`
+	CreatedAt time.Time     `gorm:"autoCreateTime" json:"created_at"`
+}
+
+func (PricingAlert) TableName() string {
+	return "qt_pricing_alerts"
+}
+
+type TrendDirection string
+
+const (
+	TrendUp     TrendDirection = "up"
+	TrendStable TrendDirection = "stable"
+	TrendDown   TrendDirection = "down"
+)
+
+type ComponentUsageStats struct {
+	LotName        string         `gorm:"column:lot_name;primaryKey;size:255" json:"lot_name"`
+	QuotesTotal    int            `gorm:"default:0" json:"quotes_total"`
+	QuotesLast30d  int            `gorm:"default:0" json:"quotes_last_30d"`
+	QuotesLast7d   int            `gorm:"default:0" json:"quotes_last_7d"`
+	TotalQuantity  int            `gorm:"default:0" json:"total_quantity"`
+	TotalRevenue   float64        `gorm:"type:decimal(14,2);default:0" json:"total_revenue"`
+	TrendDirection TrendDirection `gorm:"type:enum('up','stable','down');default:'stable'" json:"trend_direction"`
+	TrendPercent   float64        `gorm:"type:decimal(5,2);default:0" json:"trend_percent"`
+	LastUsedAt     *time.Time     `json:"last_used_at"`
+}
+
+func (ComponentUsageStats) TableName() string {
+	return "qt_component_usage_stats"
+}

internal/models/category.go

@@ -0,0 +1,29 @@
+package models
+
+type Category struct {
+	ID           uint   `gorm:"primaryKey;autoIncrement" json:"id"`
+	Code         string `gorm:"size:20;uniqueIndex;not null" json:"code"`
+	Name         string `gorm:"size:100;not null" json:"name"`
+	NameRu       string `gorm:"size:100" json:"name_ru"`
+	DisplayOrder int    `gorm:"default:0" json:"display_order"`
+	IsRequired   bool   `gorm:"default:false" json:"is_required"`
+}
+
+func (Category) TableName() string {
+	return "qt_categories"
+}
+
+var DefaultCategories = []Category{
+	{Code: "MB", Name: "Motherboard", NameRu: "Материнская плата", DisplayOrder: 1, IsRequired: true},
+	{Code: "CPU", Name: "Processor", NameRu: "Процессор", DisplayOrder: 2, IsRequired: true},
+	{Code: "MEM", Name: "Memory", NameRu: "Оперативная память", DisplayOrder: 3, IsRequired: true},
+	{Code: "GPU", Name: "Graphics Card", NameRu: "Видеокарта", DisplayOrder: 4},
+	{Code: "SSD", Name: "SSD Storage", NameRu: "SSD накопитель", DisplayOrder: 5},
+	{Code: "HDD", Name: "HDD Storage", NameRu: "HDD накопитель", DisplayOrder: 6},
+	{Code: "RAID", Name: "RAID Controller", NameRu: "RAID контроллер", DisplayOrder: 7},
+	{Code: "NIC", Name: "Network Card", NameRu: "Сетевая карта", DisplayOrder: 8},
+	{Code: "HCA", Name: "HCA Adapter", NameRu: "HCA адаптер", DisplayOrder: 9},
+	{Code: "HBA", Name: "HBA Adapter", NameRu: "HBA адаптер", DisplayOrder: 10},
+	{Code: "DPU", Name: "DPU", NameRu: "DPU", DisplayOrder: 11},
+	{Code: "PS", Name: "Power Supply", NameRu: "Блок питания", DisplayOrder: 12},
+}

internal/models/configuration.go

@@ -0,0 +1,74 @@
+package models
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"errors"
+	"time"
+)
+
+type ConfigItem struct {
+	LotName   string  `json:"lot_name"`
+	Quantity  int     `json:"quantity"`
+	UnitPrice float64 `json:"unit_price"`
+}
+
+type ConfigItems []ConfigItem
+
+func (c ConfigItems) Value() (driver.Value, error) {
+	return json.Marshal(c)
+}
+
+func (c *ConfigItems) Scan(value interface{}) error {
+	if value == nil {
+		*c = make(ConfigItems, 0)
+		return nil
+	}
+	bytes, ok := value.([]byte)
+	if !ok {
+		return errors.New("type assertion to []byte failed")
+	}
+	return json.Unmarshal(bytes, c)
+}
+
+func (c ConfigItems) Total() float64 {
+	var total float64
+	for _, item := range c {
+		total += item.UnitPrice * float64(item.Quantity)
+	}
+	return total
+}
+
+type Configuration struct {
+	ID         uint        `gorm:"primaryKey;autoIncrement" json:"id"`
+	UUID       string      `gorm:"size:36;uniqueIndex;not null" json:"uuid"`
+	UserID     uint        `gorm:"not null" json:"user_id"`
+	Name       string      `gorm:"size:200;not null" json:"name"`
+	Items      ConfigItems `gorm:"type:json;not null" json:"items"`
+	TotalPrice *float64    `gorm:"type:decimal(12,2)" json:"total_price"`
+	Notes      string      `gorm:"type:text" json:"notes"`
+	IsTemplate bool        `gorm:"default:false" json:"is_template"`
+	CreatedAt  time.Time   `gorm:"autoCreateTime" json:"created_at"`
+
+	User *User `gorm:"foreignKey:UserID" json:"user,omitempty"`
+}
+
+func (Configuration) TableName() string {
+	return "qt_configurations"
+}
+
+type PriceOverride struct {
+	ID         uint       `gorm:"primaryKey;autoIncrement" json:"id"`
+	LotName    string     `gorm:"size:255;not null" json:"lot_name"`
+	Price      float64    `gorm:"type:decimal(12,2);not null" json:"price"`
+	ValidFrom  time.Time  `gorm:"type:date;not null" json:"valid_from"`
+	ValidUntil *time.Time `gorm:"type:date" json:"valid_until"`
+	Reason     string     `gorm:"type:text" json:"reason"`
+	CreatedBy  uint       `gorm:"not null" json:"created_by"`
+
+	Creator *User `gorm:"foreignKey:CreatedBy" json:"creator,omitempty"`
+}
+
+func (PriceOverride) TableName() string {
+	return "qt_price_overrides"
+}

internal/models/lot.go

@@ -0,0 +1,38 @@
+package models
+
+import "time"
+
+// Lot represents existing lot table (READ-ONLY)
+type Lot struct {
+	LotName        string `gorm:"column:lot_name;primaryKey;size:255"`
+	LotDescription string `gorm:"column:lot_description;size:10000"`
+}
+
+func (Lot) TableName() string {
+	return "lot"
+}
+
+// LotLog represents existing lot_log table (READ-ONLY)
+type LotLog struct {
+	LotLogID uint      `gorm:"column:lot_log_id;primaryKey;autoIncrement"`
+	Lot      string    `gorm:"column:lot;size:255;not null"`
+	Supplier string    `gorm:"column:supplier;size:255;not null"`
+	Date     time.Time `gorm:"column:date;type:date;not null"`
+	Price    float64   `gorm:"column:price;not null"`
+	Quality  string    `gorm:"column:quality;size:255"`
+	Comments string    `gorm:"column:comments;size:15000"`
+}
+
+func (LotLog) TableName() string {
+	return "lot_log"
+}
+
+// Supplier represents existing supplier table (READ-ONLY)
+type Supplier struct {
+	SupplierName    string `gorm:"column:supplier_name;primaryKey;size:255"`
+	SupplierComment string `gorm:"column:supplier_comment;size:10000"`
+}
+
+func (Supplier) TableName() string {
+	return "supplier"
+}

internal/models/metadata.go

@@ -0,0 +1,87 @@
+package models
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"errors"
+	"time"
+)
+
+type PriceMethod string
+
+const (
+	PriceMethodManual         PriceMethod = "manual"
+	PriceMethodMedian         PriceMethod = "median"
+	PriceMethodAverage        PriceMethod = "average"
+	PriceMethodWeightedMedian PriceMethod = "weighted_median"
+)
+
+type Specs map[string]interface{}
+
+func (s Specs) Value() (driver.Value, error) {
+	return json.Marshal(s)
+}
+
+func (s *Specs) Scan(value interface{}) error {
+	if value == nil {
+		*s = make(Specs)
+		return nil
+	}
+	bytes, ok := value.([]byte)
+	if !ok {
+		return errors.New("type assertion to []byte failed")
+	}
+	return json.Unmarshal(bytes, s)
+}
+
+type LotMetadata struct {
+	LotName         string       `gorm:"column:lot_name;primaryKey;size:255" json:"lot_name"`
+	CategoryID      *uint        `gorm:"column:category_id" json:"category_id"`
+	Vendor          string       `gorm:"size:50" json:"vendor"`
+	Model           string       `gorm:"size:100" json:"model"`
+	Specs           Specs        `gorm:"type:json" json:"specs"`
+	CurrentPrice    *float64     `gorm:"type:decimal(12,2)" json:"current_price"`
+	PriceMethod     PriceMethod  `gorm:"type:enum('manual','median','average','weighted_median');default:'median'" json:"price_method"`
+	PricePeriodDays int          `gorm:"default:90" json:"price_period_days"`
+	PriceUpdatedAt  *time.Time   `json:"price_updated_at"`
+	RequestCount    int          `gorm:"default:0" json:"request_count"`
+	LastRequestDate *time.Time   `gorm:"type:date" json:"last_request_date"`
+	PopularityScore float64      `gorm:"type:decimal(10,4);default:0" json:"popularity_score"`
+
+	// Relations
+	Lot      *Lot      `gorm:"foreignKey:LotName;references:LotName" json:"lot,omitempty"`
+	Category *Category `gorm:"foreignKey:CategoryID" json:"category,omitempty"`
+}
+
+func (LotMetadata) TableName() string {
+	return "qt_lot_metadata"
+}
+
+type PriceFreshness string
+
+const (
+	FreshnessFresh    PriceFreshness = "fresh"
+	FreshnessNormal   PriceFreshness = "normal"
+	FreshnessStale    PriceFreshness = "stale"
+	FreshnessCritical PriceFreshness = "critical"
+)
+
+func (m *LotMetadata) GetPriceFreshness(greenDays, yellowDays, redDays, minQuotes int) PriceFreshness {
+	if m.CurrentPrice == nil || *m.CurrentPrice == 0 {
+		return FreshnessCritical
+	}
+	if m.PriceUpdatedAt == nil {
+		return FreshnessCritical
+	}
+
+	daysSince := int(time.Since(*m.PriceUpdatedAt).Hours() / 24)
+
+	if daysSince < greenDays && m.RequestCount >= minQuotes {
+		return FreshnessFresh
+	} else if daysSince < yellowDays {
+		return FreshnessNormal
+	} else if daysSince < redDays {
+		return FreshnessStale
+	}
+	return FreshnessCritical
+}

internal/models/models.go

@@ -0,0 +1,32 @@
+package models
+
+import "gorm.io/gorm"
+
+// AllModels returns all models for auto-migration
+func AllModels() []interface{} {
+	return []interface{}{
+		&User{},
+		&Category{},
+		&LotMetadata{},
+		&Configuration{},
+		&PriceOverride{},
+		&PricingAlert{},
+		&ComponentUsageStats{},
+	}
+}
+
+// Migrate runs auto-migration for all QuoteForge tables
+func Migrate(db *gorm.DB) error {
+	return db.AutoMigrate(AllModels()...)
+}
+
+// SeedCategories inserts default categories if not exist
+func SeedCategories(db *gorm.DB) error {
+	for _, cat := range DefaultCategories {
+		result := db.Where("code = ?", cat.Code).FirstOrCreate(&cat)
+		if result.Error != nil {
+			return result.Error
+		}
+	}
+	return nil
+}

internal/models/user.go

@@ -0,0 +1,39 @@
+package models
+
+import "time"
+
+type UserRole string
+
+const (
+	RoleViewer       UserRole = "viewer"
+	RoleEditor       UserRole = "editor"
+	RolePricingAdmin UserRole = "pricing_admin"
+	RoleAdmin        UserRole = "admin"
+)
+
+type User struct {
+	ID           uint      `gorm:"primaryKey;autoIncrement" json:"id"`
+	Username     string    `gorm:"size:100;uniqueIndex;not null" json:"username"`
+	Email        string    `gorm:"size:255;uniqueIndex;not null" json:"email"`
+	PasswordHash string    `gorm:"size:255;not null" json:"-"`
+	Role         UserRole  `gorm:"type:enum('viewer','editor','pricing_admin','admin');default:'viewer'" json:"role"`
+	IsActive     bool      `gorm:"default:true" json:"is_active"`
+	CreatedAt    time.Time `gorm:"autoCreateTime" json:"created_at"`
+	UpdatedAt    time.Time `gorm:"autoUpdateTime" json:"updated_at"`
+}
+
+func (User) TableName() string {
+	return "qt_users"
+}
+
+func (u *User) CanEdit() bool {
+	return u.Role == RoleEditor || u.Role == RolePricingAdmin || u.Role == RoleAdmin
+}
+
+func (u *User) CanManagePricing() bool {
+	return u.Role == RolePricingAdmin || u.Role == RoleAdmin
+}
+
+func (u *User) CanManageUsers() bool {
+	return u.Role == RoleAdmin
+}

internal/repository/alert.go

@@ -0,0 +1,91 @@
+package repository
+
+import (
+	"github.com/mchus/quoteforge/internal/models"
+	"gorm.io/gorm"
+)
+
+type AlertRepository struct {
+	db *gorm.DB
+}
+
+func NewAlertRepository(db *gorm.DB) *AlertRepository {
+	return &AlertRepository{db: db}
+}
+
+func (r *AlertRepository) Create(alert *models.PricingAlert) error {
+	return r.db.Create(alert).Error
+}
+
+func (r *AlertRepository) GetByID(id uint) (*models.PricingAlert, error) {
+	var alert models.PricingAlert
+	err := r.db.First(&alert, id).Error
+	if err != nil {
+		return nil, err
+	}
+	return &alert, nil
+}
+
+func (r *AlertRepository) Update(alert *models.PricingAlert) error {
+	return r.db.Save(alert).Error
+}
+
+type AlertFilter struct {
+	Status   models.AlertStatus
+	Severity models.AlertSeverity
+	Type     models.AlertType
+	LotName  string
+}
+
+func (r *AlertRepository) List(filter AlertFilter, offset, limit int) ([]models.PricingAlert, int64, error) {
+	var alerts []models.PricingAlert
+	var total int64
+
+	query := r.db.Model(&models.PricingAlert{})
+
+	if filter.Status != "" {
+		query = query.Where("status = ?", filter.Status)
+	}
+	if filter.Severity != "" {
+		query = query.Where("severity = ?", filter.Severity)
+	}
+	if filter.Type != "" {
+		query = query.Where("alert_type = ?", filter.Type)
+	}
+	if filter.LotName != "" {
+		query = query.Where("lot_name = ?", filter.LotName)
+	}
+
+	query.Count(&total)
+
+	err := query.
+		Order("FIELD(severity, 'critical', 'high', 'medium', 'low')").
+		Order("created_at DESC").
+		Offset(offset).
+		Limit(limit).
+		Find(&alerts).Error
+
+	return alerts, total, err
+}
+
+func (r *AlertRepository) CountByStatus(status models.AlertStatus) (int64, error) {
+	var count int64
+	err := r.db.Model(&models.PricingAlert{}).
+		Where("status = ?", status).
+		Count(&count).Error
+	return count, err
+}
+
+func (r *AlertRepository) UpdateStatus(id uint, status models.AlertStatus) error {
+	return r.db.Model(&models.PricingAlert{}).
+		Where("id = ?", id).
+		Update("status", status).Error
+}
+
+func (r *AlertRepository) ExistsByLotAndType(lotName string, alertType models.AlertType) (bool, error) {
+	var count int64
+	err := r.db.Model(&models.PricingAlert{}).
+		Where("lot_name = ? AND alert_type = ? AND status IN ('new', 'acknowledged')", lotName, alertType).
+		Count(&count).Error
+	return count > 0, err
+}

internal/repository/category.go

@@ -0,0 +1,38 @@
+package repository
+
+import (
+	"github.com/mchus/quoteforge/internal/models"
+	"gorm.io/gorm"
+)
+
+type CategoryRepository struct {
+	db *gorm.DB
+}
+
+func NewCategoryRepository(db *gorm.DB) *CategoryRepository {
+	return &CategoryRepository{db: db}
+}
+
+func (r *CategoryRepository) GetAll() ([]models.Category, error) {
+	var categories []models.Category
+	err := r.db.Order("display_order ASC").Find(&categories).Error
+	return categories, err
+}
+
+func (r *CategoryRepository) GetByCode(code string) (*models.Category, error) {
+	var category models.Category
+	err := r.db.Where("code = ?", code).First(&category).Error
+	if err != nil {
+		return nil, err
+	}
+	return &category, nil
+}
+
+func (r *CategoryRepository) GetByID(id uint) (*models.Category, error) {
+	var category models.Category
+	err := r.db.First(&category, id).Error
+	if err != nil {
+		return nil, err
+	}
+	return &category, nil
+}

internal/repository/component.go

@@ -0,0 +1,127 @@
+package repository
+
+import (
+	"time"
+
+	"github.com/mchus/quoteforge/internal/models"
+	"gorm.io/gorm"
+)
+
+type ComponentRepository struct {
+	db *gorm.DB
+}
+
+func NewComponentRepository(db *gorm.DB) *ComponentRepository {
+	return &ComponentRepository{db: db}
+}
+
+type ComponentFilter struct {
+	Category string
+	Vendor   string
+	Search   string
+	HasPrice bool
+}
+
+func (r *ComponentRepository) List(filter ComponentFilter, offset, limit int) ([]models.LotMetadata, int64, error) {
+	var components []models.LotMetadata
+	var total int64
+
+	query := r.db.Model(&models.LotMetadata{}).
+		Preload("Lot").
+		Preload("Category")
+
+	if filter.Category != "" {
+		query = query.Joins("JOIN qt_categories ON qt_lot_metadata.category_id = qt_categories.id").
+			Where("qt_categories.code = ?", filter.Category)
+	}
+	if filter.Vendor != "" {
+		query = query.Where("vendor = ?", filter.Vendor)
+	}
+	if filter.Search != "" {
+		search := "%" + filter.Search + "%"
+		query = query.Where("lot_name LIKE ? OR model LIKE ?", search, search)
+	}
+	if filter.HasPrice {
+		query = query.Where("current_price IS NOT NULL AND current_price > 0")
+	}
+
+	query.Count(&total)
+
+	// Sort by popularity + freshness, no price goes last
+	err := query.
+		Order("CASE WHEN current_price IS NULL OR current_price = 0 THEN 1 ELSE 0 END").
+		Order("popularity_score DESC").
+		Offset(offset).
+		Limit(limit).
+		Find(&components).Error
+
+	return components, total, err
+}
+
+func (r *ComponentRepository) GetByLotName(lotName string) (*models.LotMetadata, error) {
+	var component models.LotMetadata
+	err := r.db.
+		Preload("Lot").
+		Preload("Category").
+		Where("lot_name = ?", lotName).
+		First(&component).Error
+	if err != nil {
+		return nil, err
+	}
+	return &component, nil
+}
+
+func (r *ComponentRepository) GetMultiple(lotNames []string) ([]models.LotMetadata, error) {
+	var components []models.LotMetadata
+	err := r.db.
+		Preload("Lot").
+		Preload("Category").
+		Where("lot_name IN ?", lotNames).
+		Find(&components).Error
+	return components, err
+}
+
+func (r *ComponentRepository) Update(component *models.LotMetadata) error {
+	return r.db.Save(component).Error
+}
+
+func (r *ComponentRepository) Create(component *models.LotMetadata) error {
+	return r.db.Create(component).Error
+}
+
+func (r *ComponentRepository) GetVendors(category string) ([]string, error) {
+	var vendors []string
+	query := r.db.Model(&models.LotMetadata{}).Distinct("vendor")
+	if category != "" {
+		query = query.Joins("JOIN qt_categories ON qt_lot_metadata.category_id = qt_categories.id").
+			Where("qt_categories.code = ?", category)
+	}
+	err := query.Pluck("vendor", &vendors).Error
+	return vendors, err
+}
+
+func (r *ComponentRepository) IncrementRequestCount(lotName string) error {
+	now := time.Now()
+	return r.db.Model(&models.LotMetadata{}).
+		Where("lot_name = ?", lotName).
+		Updates(map[string]interface{}{
+			"request_count":     gorm.Expr("request_count + 1"),
+			"last_request_date": now,
+		}).Error
+}
+
+// GetAllLots returns all lots from the existing lot table
+func (r *ComponentRepository) GetAllLots() ([]models.Lot, error) {
+	var lots []models.Lot
+	err := r.db.Find(&lots).Error
+	return lots, err
+}
+
+// GetLotsWithoutMetadata returns lots that don't have qt_lot_metadata entries
+func (r *ComponentRepository) GetLotsWithoutMetadata() ([]models.Lot, error) {
+	var lots []models.Lot
+	err := r.db.
+		Where("lot_name NOT IN (SELECT lot_name FROM qt_lot_metadata)").
+		Find(&lots).Error
+	return lots, err
+}

internal/repository/configuration.go

@@ -0,0 +1,75 @@
+package repository
+
+import (
+	"github.com/mchus/quoteforge/internal/models"
+	"gorm.io/gorm"
+)
+
+type ConfigurationRepository struct {
+	db *gorm.DB
+}
+
+func NewConfigurationRepository(db *gorm.DB) *ConfigurationRepository {
+	return &ConfigurationRepository{db: db}
+}
+
+func (r *ConfigurationRepository) Create(config *models.Configuration) error {
+	return r.db.Create(config).Error
+}
+
+func (r *ConfigurationRepository) GetByID(id uint) (*models.Configuration, error) {
+	var config models.Configuration
+	err := r.db.Preload("User").First(&config, id).Error
+	if err != nil {
+		return nil, err
+	}
+	return &config, nil
+}
+
+func (r *ConfigurationRepository) GetByUUID(uuid string) (*models.Configuration, error) {
+	var config models.Configuration
+	err := r.db.Preload("User").Where("uuid = ?", uuid).First(&config).Error
+	if err != nil {
+		return nil, err
+	}
+	return &config, nil
+}
+
+func (r *ConfigurationRepository) Update(config *models.Configuration) error {
+	return r.db.Save(config).Error
+}
+
+func (r *ConfigurationRepository) Delete(id uint) error {
+	return r.db.Delete(&models.Configuration{}, id).Error
+}
+
+func (r *ConfigurationRepository) ListByUser(userID uint, offset, limit int) ([]models.Configuration, int64, error) {
+	var configs []models.Configuration
+	var total int64
+
+	r.db.Model(&models.Configuration{}).Where("user_id = ?", userID).Count(&total)
+	err := r.db.
+		Where("user_id = ?", userID).
+		Order("created_at DESC").
+		Offset(offset).
+		Limit(limit).
+		Find(&configs).Error
+
+	return configs, total, err
+}
+
+func (r *ConfigurationRepository) ListTemplates(offset, limit int) ([]models.Configuration, int64, error) {
+	var configs []models.Configuration
+	var total int64
+
+	r.db.Model(&models.Configuration{}).Where("is_template = ?", true).Count(&total)
+	err := r.db.
+		Preload("User").
+		Where("is_template = ?", true).
+		Order("created_at DESC").
+		Offset(offset).
+		Limit(limit).
+		Find(&configs).Error
+
+	return configs, total, err
+}

internal/repository/price.go

@@ -0,0 +1,99 @@
+package repository
+
+import (
+	"time"
+
+	"github.com/mchus/quoteforge/internal/models"
+	"gorm.io/gorm"
+)
+
+type PriceRepository struct {
+	db *gorm.DB
+}
+
+func NewPriceRepository(db *gorm.DB) *PriceRepository {
+	return &PriceRepository{db: db}
+}
+
+type PricePoint struct {
+	Price float64
+	Date  time.Time
+}
+
+// GetPriceHistory returns price history from lot_log for a component
+func (r *PriceRepository) GetPriceHistory(lotName string, periodDays int) ([]PricePoint, error) {
+	var points []PricePoint
+	since := time.Now().AddDate(0, 0, -periodDays)
+
+	err := r.db.Model(&models.LotLog{}).
+		Select("price, date").
+		Where("lot = ? AND date >= ?", lotName, since).
+		Order("date DESC").
+		Scan(&points).Error
+
+	return points, err
+}
+
+// GetLatestPrice returns the most recent price for a component
+func (r *PriceRepository) GetLatestPrice(lotName string) (*PricePoint, error) {
+	var point PricePoint
+	err := r.db.Model(&models.LotLog{}).
+		Select("price, date").
+		Where("lot = ?", lotName).
+		Order("date DESC").
+		First(&point).Error
+	if err != nil {
+		return nil, err
+	}
+	return &point, nil
+}
+
+// GetPriceOverride returns active override for a component
+func (r *PriceRepository) GetPriceOverride(lotName string) (*models.PriceOverride, error) {
+	var override models.PriceOverride
+	today := time.Now().Truncate(24 * time.Hour)
+
+	err := r.db.
+		Where("lot_name = ?", lotName).
+		Where("valid_from <= ?", today).
+		Where("valid_until IS NULL OR valid_until >= ?", today).
+		Order("valid_from DESC").
+		First(&override).Error
+
+	if err != nil {
+		return nil, err
+	}
+	return &override, nil
+}
+
+// CreatePriceOverride creates a new price override
+func (r *PriceRepository) CreatePriceOverride(override *models.PriceOverride) error {
+	return r.db.Create(override).Error
+}
+
+// GetPriceOverrides returns all overrides for a component
+func (r *PriceRepository) GetPriceOverrides(lotName string) ([]models.PriceOverride, error) {
+	var overrides []models.PriceOverride
+	err := r.db.
+		Where("lot_name = ?", lotName).
+		Order("valid_from DESC").
+		Find(&overrides).Error
+	return overrides, err
+}
+
+// DeletePriceOverride deletes an override
+func (r *PriceRepository) DeletePriceOverride(id uint) error {
+	return r.db.Delete(&models.PriceOverride{}, id).Error
+}
+
+// GetQuoteCount returns the number of quotes in lot_log for a period
+func (r *PriceRepository) GetQuoteCount(lotName string, periodDays int) (int64, error) {
+	var count int64
+	since := time.Now().AddDate(0, 0, -periodDays)
+
+	err := r.db.Model(&models.LotLog{}).
+		Where("lot = ? AND date >= ?", lotName, since).
+		Count(&count).Error
+
+	return count, err
+}

internal/repository/stats.go

@@ -0,0 +1,92 @@
+package repository
+
+import (
+	"time"
+
+	"github.com/mchus/quoteforge/internal/models"
+	"gorm.io/gorm"
+)
+
+type StatsRepository struct {
+	db *gorm.DB
+}
+
+func NewStatsRepository(db *gorm.DB) *StatsRepository {
+	return &StatsRepository{db: db}
+}
+
+func (r *StatsRepository) GetByLotName(lotName string) (*models.ComponentUsageStats, error) {
+	var stats models.ComponentUsageStats
+	err := r.db.Where("lot_name = ?", lotName).First(&stats).Error
+	if err != nil {
+		return nil, err
+	}
+	return &stats, nil
+}
+
+func (r *StatsRepository) Upsert(stats *models.ComponentUsageStats) error {
+	return r.db.Save(stats).Error
+}
+
+func (r *StatsRepository) IncrementUsage(lotName string, quantity int, revenue float64) error {
+	now := time.Now()
+
+	result := r.db.Model(&models.ComponentUsageStats{}).
+		Where("lot_name = ?", lotName).
+		Updates(map[string]interface{}{
+			"quotes_total":    gorm.Expr("quotes_total + 1"),
+			"quotes_last_30d": gorm.Expr("quotes_last_30d + 1"),
+			"quotes_last_7d":  gorm.Expr("quotes_last_7d + 1"),
+			"total_quantity":  gorm.Expr("total_quantity + ?", quantity),
+			"total_revenue":   gorm.Expr("total_revenue + ?", revenue),
+			"last_used_at":    now,
+		})
+
+	if result.RowsAffected == 0 {
+		stats := &models.ComponentUsageStats{
+			LotName:       lotName,
+			QuotesTotal:   1,
+			QuotesLast30d: 1,
+			QuotesLast7d:  1,
+			TotalQuantity: quantity,
+			TotalRevenue:  revenue,
+			LastUsedAt:    &now,
+		}
+		return r.db.Create(stats).Error
+	}
+
+	return result.Error
+}
+
+func (r *StatsRepository) GetTopComponents(limit int) ([]models.ComponentUsageStats, error) {
+	var stats []models.ComponentUsageStats
+	err := r.db.
+		Order("quotes_last_30d DESC").
+		Limit(limit).
+		Find(&stats).Error
+	return stats, err
+}
+
+func (r *StatsRepository) GetTrendingComponents(limit int) ([]models.ComponentUsageStats, error) {
+	var stats []models.ComponentUsageStats
+	err := r.db.
+		Where("trend_direction = ? AND trend_percent > ?", models.TrendUp, 20).
+		Order("trend_percent DESC").
+		Limit(limit).
+		Find(&stats).Error
+	return stats, err
+}
+
+// ResetWeeklyCounters resets quotes_last_7d (run weekly via cron)
+func (r *StatsRepository) ResetWeeklyCounters() error {
+	return r.db.Model(&models.ComponentUsageStats{}).
+		Where("1 = 1").
+		Update("quotes_last_7d", 0).Error
+}
+
+// ResetMonthlyCounters resets quotes_last_30d (run monthly via cron)
+func (r *StatsRepository) ResetMonthlyCounters() error {
+	return r.db.Model(&models.ComponentUsageStats{}).
+		Where("1 = 1").
+		Update("quotes_last_30d", 0).Error
+}

internal/repository/user.go

@@ -0,0 +1,62 @@
+package repository
+
+import (
+	"github.com/mchus/quoteforge/internal/models"
+	"gorm.io/gorm"
+)
+
+type UserRepository struct {
+	db *gorm.DB
+}
+
+func NewUserRepository(db *gorm.DB) *UserRepository {
+	return &UserRepository{db: db}
+}
+
+func (r *UserRepository) Create(user *models.User) error {
+	return r.db.Create(user).Error
+}
+
+func (r *UserRepository) GetByID(id uint) (*models.User, error) {
+	var user models.User
+	err := r.db.First(&user, id).Error
+	if err != nil {
+		return nil, err
+	}
+	return &user, nil
+}
+
+func (r *UserRepository) GetByUsername(username string) (*models.User, error) {
+	var user models.User
+	err := r.db.Where("username = ?", username).First(&user).Error
+	if err != nil {
+		return nil, err
+	}
+	return &user, nil
+}
+
+func (r *UserRepository) GetByEmail(email string) (*models.User, error) {
+	var user models.User
+	err := r.db.Where("email = ?", email).First(&user).Error
+	if err != nil {
+		return nil, err
+	}
+	return &user, nil
+}
+
+func (r *UserRepository) Update(user *models.User) error {
+	return r.db.Save(user).Error
+}
+
+func (r *UserRepository) Delete(id uint) error {
+	return r.db.Delete(&models.User{}, id).Error
+}
+
+func (r *UserRepository) List(offset, limit int) ([]models.User, int64, error) {
+	var users []models.User
+	var total int64
+
+	r.db.Model(&models.User{}).Count(&total)
+	err := r.db.Offset(offset).Limit(limit).Find(&users).Error
+	return users, total, err
+}

internal/services/alerts/service.go

@@ -0,0 +1,199 @@
+package alerts
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/mchus/quoteforge/internal/config"
+	"github.com/mchus/quoteforge/internal/models"
+	"github.com/mchus/quoteforge/internal/repository"
+)
+
+type Service struct {
+	alertRepo     *repository.AlertRepository
+	componentRepo *repository.ComponentRepository
+	priceRepo     *repository.PriceRepository
+	statsRepo     *repository.StatsRepository
+	config        config.AlertsConfig
+	pricingConfig config.PricingConfig
+}
+
+func NewService(
+	alertRepo *repository.AlertRepository,
+	componentRepo *repository.ComponentRepository,
+	priceRepo *repository.PriceRepository,
+	statsRepo *repository.StatsRepository,
+	alertCfg config.AlertsConfig,
+	pricingCfg config.PricingConfig,
+) *Service {
+	return &Service{
+		alertRepo:     alertRepo,
+		componentRepo: componentRepo,
+		priceRepo:     priceRepo,
+		statsRepo:     statsRepo,
+		config:        alertCfg,
+		pricingConfig: pricingCfg,
+	}
+}
+
+func (s *Service) List(filter repository.AlertFilter, page, perPage int) ([]models.PricingAlert, int64, error) {
+	if page < 1 {
+		page = 1
+	}
+	if perPage < 1 || perPage > 100 {
+		perPage = 20
+	}
+	offset := (page - 1) * perPage
+
+	return s.alertRepo.List(filter, offset, perPage)
+}
+
+func (s *Service) Acknowledge(id uint) error {
+	return s.alertRepo.UpdateStatus(id, models.AlertStatusAcknowledged)
+}
+
+func (s *Service) Resolve(id uint) error {
+	return s.alertRepo.UpdateStatus(id, models.AlertStatusResolved)
+}
+
+func (s *Service) Ignore(id uint) error {
+	return s.alertRepo.UpdateStatus(id, models.AlertStatusIgnored)
+}
+
+func (s *Service) GetNewAlertsCount() (int64, error) {
+	return s.alertRepo.CountByStatus(models.AlertStatusNew)
+}
+
+// CheckAndGenerateAlerts scans components and creates alerts
+func (s *Service) CheckAndGenerateAlerts() error {
+	if !s.config.Enabled {
+		return nil
+	}
+
+	// Get top components by usage
+	topComponents, err := s.statsRepo.GetTopComponents(100)
+	if err != nil {
+		return err
+	}
+
+	for _, stats := range topComponents {
+		component, err := s.componentRepo.GetByLotName(stats.LotName)
+		if err != nil {
+			continue
+		}
+
+		// Check high demand + stale price
+		if err := s.checkHighDemandStalePrice(component, &stats); err != nil {
+			continue
+		}
+
+		// Check trending without price
+		if err := s.checkTrendingNoPrice(component, &stats); err != nil {
+			continue
+		}
+
+		// Check no recent quotes
+		if err := s.checkNoRecentQuotes(component, &stats); err != nil {
+			continue
+		}
+	}
+
+	return nil
+}
+
+func (s *Service) checkHighDemandStalePrice(comp *models.LotMetadata, stats *models.ComponentUsageStats) error {
+	// high_demand_stale_price: >= 5 quotes/month AND price > 60 days old
+	if stats.QuotesLast30d < s.config.HighDemandThreshold {
+		return nil
+	}
+
+	if comp.PriceUpdatedAt == nil {
+		return nil
+	}
+
+	daysSinceUpdate := int(time.Since(*comp.PriceUpdatedAt).Hours() / 24)
+	if daysSinceUpdate <= s.pricingConfig.FreshnessYellowDays {
+		return nil
+	}
+
+	// Check if alert already exists
+	exists, _ := s.alertRepo.ExistsByLotAndType(comp.LotName, models.AlertHighDemandStalePrice)
+	if exists {
+		return nil
+	}
+
+	alert := &models.PricingAlert{
+		LotName:   comp.LotName,
+		AlertType: models.AlertHighDemandStalePrice,
+		Severity:  models.SeverityCritical,
+		Message:   fmt.Sprintf("Компонент %s: высокий спрос (%d КП/мес), но цена устарела (%d дней)", comp.LotName, stats.QuotesLast30d, daysSinceUpdate),
+		Details: models.AlertDetails{
+			"quotes_30d":     stats.QuotesLast30d,
+			"days_since_update": daysSinceUpdate,
+		},
+	}
+
+	return s.alertRepo.Create(alert)
+}
+
+func (s *Service) checkTrendingNoPrice(comp *models.LotMetadata, stats *models.ComponentUsageStats) error {
+	// trending_no_price: trend > 50% AND no price
+	if stats.TrendDirection != models.TrendUp || stats.TrendPercent < float64(s.config.TrendingThresholdPercent) {
+		return nil
+	}
+
+	if comp.CurrentPrice != nil && *comp.CurrentPrice > 0 {
+		return nil
+	}
+
+	exists, _ := s.alertRepo.ExistsByLotAndType(comp.LotName, models.AlertTrendingNoPrice)
+	if exists {
+		return nil
+	}
+
+	alert := &models.PricingAlert{
+		LotName:   comp.LotName,
+		AlertType: models.AlertTrendingNoPrice,
+		Severity:  models.SeverityHigh,
+		Message:   fmt.Sprintf("Компонент %s: рост спроса +%.0f%%, но цена не установлена", comp.LotName, stats.TrendPercent),
+		Details: models.AlertDetails{
+			"trend_percent": stats.TrendPercent,
+		},
+	}
+
+	return s.alertRepo.Create(alert)
+}
+
+func (s *Service) checkNoRecentQuotes(comp *models.LotMetadata, stats *models.ComponentUsageStats) error {
+	// no_recent_quotes: popular component, no supplier quotes > 90 days
+	if stats.QuotesLast30d < 3 {
+		return nil
+	}
+
+	quoteCount, err := s.priceRepo.GetQuoteCount(comp.LotName, s.pricingConfig.FreshnessRedDays)
+	if err != nil {
+		return err
+	}
+
+	if quoteCount > 0 {
+		return nil
+	}
+
+	exists, _ := s.alertRepo.ExistsByLotAndType(comp.LotName, models.AlertNoRecentQuotes)
+	if exists {
+		return nil
+	}
+
+	alert := &models.PricingAlert{
+		LotName:   comp.LotName,
+		AlertType: models.AlertNoRecentQuotes,
+		Severity:  models.SeverityMedium,
+		Message:   fmt.Sprintf("Компонент %s: популярный (%d КП), но нет новых котировок >%d дней", comp.LotName, stats.QuotesLast30d, s.pricingConfig.FreshnessRedDays),
+		Details: models.AlertDetails{
+			"quotes_30d":       stats.QuotesLast30d,
+			"no_quotes_days": s.pricingConfig.FreshnessRedDays,
+		},
+	}
+
+	return s.alertRepo.Create(alert)
+}

internal/services/auth.go

@@ -0,0 +1,180 @@
+package services
+
+import (
+	"errors"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/mchus/quoteforge/internal/config"
+	"github.com/mchus/quoteforge/internal/models"
+	"github.com/mchus/quoteforge/internal/repository"
+	"golang.org/x/crypto/bcrypt"
+)
+
+var (
+	ErrInvalidCredentials = errors.New("invalid username or password")
+	ErrUserNotFound       = errors.New("user not found")
+	ErrUserInactive       = errors.New("user account is inactive")
+	ErrInvalidToken       = errors.New("invalid token")
+	ErrTokenExpired       = errors.New("token expired")
+)
+
+type AuthService struct {
+	userRepo *repository.UserRepository
+	config   config.AuthConfig
+}
+
+func NewAuthService(userRepo *repository.UserRepository, cfg config.AuthConfig) *AuthService {
+	return &AuthService{
+		userRepo: userRepo,
+		config:   cfg,
+	}
+}
+
+type TokenPair struct {
+	AccessToken  string `json:"access_token"`
+	RefreshToken string `json:"refresh_token"`
+	ExpiresAt    int64  `json:"expires_at"`
+}
+
+type Claims struct {
+	UserID   uint            `json:"user_id"`
+	Username string          `json:"username"`
+	Role     models.UserRole `json:"role"`
+	jwt.RegisteredClaims
+}
+
+func (s *AuthService) Login(username, password string) (*TokenPair, *models.User, error) {
+	user, err := s.userRepo.GetByUsername(username)
+	if err != nil {
+		return nil, nil, ErrInvalidCredentials
+	}
+
+	if !user.IsActive {
+		return nil, nil, ErrUserInactive
+	}
+
+	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(password)); err != nil {
+		return nil, nil, ErrInvalidCredentials
+	}
+
+	tokens, err := s.generateTokenPair(user)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return tokens, user, nil
+}
+
+func (s *AuthService) RefreshTokens(refreshToken string) (*TokenPair, error) {
+	claims, err := s.ValidateToken(refreshToken)
+	if err != nil {
+		return nil, err
+	}
+
+	user, err := s.userRepo.GetByID(claims.UserID)
+	if err != nil {
+		return nil, ErrUserNotFound
+	}
+
+	if !user.IsActive {
+		return nil, ErrUserInactive
+	}
+
+	return s.generateTokenPair(user)
+}
+
+func (s *AuthService) ValidateToken(tokenString string) (*Claims, error) {
+	token, err := jwt.ParseWithClaims(tokenString, &Claims{}, func(token *jwt.Token) (interface{}, error) {
+		return []byte(s.config.JWTSecret), nil
+	})
+
+	if err != nil {
+		if errors.Is(err, jwt.ErrTokenExpired) {
+			return nil, ErrTokenExpired
+		}
+		return nil, ErrInvalidToken
+	}
+
+	claims, ok := token.Claims.(*Claims)
+	if !ok || !token.Valid {
+		return nil, ErrInvalidToken
+	}
+
+	return claims, nil
+}
+
+func (s *AuthService) generateTokenPair(user *models.User) (*TokenPair, error) {
+	now := time.Now()
+	accessExpiry := now.Add(s.config.TokenExpiry)
+	refreshExpiry := now.Add(s.config.RefreshExpiry)
+
+	accessClaims := &Claims{
+		UserID:   user.ID,
+		Username: user.Username,
+		Role:     user.Role,
+		RegisteredClaims: jwt.RegisteredClaims{
+			ExpiresAt: jwt.NewNumericDate(accessExpiry),
+			IssuedAt:  jwt.NewNumericDate(now),
+			Subject:   user.Username,
+		},
+	}
+
+	accessToken := jwt.NewWithClaims(jwt.SigningMethodHS256, accessClaims)
+	accessTokenString, err := accessToken.SignedString([]byte(s.config.JWTSecret))
+	if err != nil {
+		return nil, err
+	}
+
+	refreshClaims := &Claims{
+		UserID:   user.ID,
+		Username: user.Username,
+		Role:     user.Role,
+		RegisteredClaims: jwt.RegisteredClaims{
+			ExpiresAt: jwt.NewNumericDate(refreshExpiry),
+			IssuedAt:  jwt.NewNumericDate(now),
+			Subject:   user.Username,
+		},
+	}
+
+	refreshToken := jwt.NewWithClaims(jwt.SigningMethodHS256, refreshClaims)
+	refreshTokenString, err := refreshToken.SignedString([]byte(s.config.JWTSecret))
+	if err != nil {
+		return nil, err
+	}
+
+	return &TokenPair{
+		AccessToken:  accessTokenString,
+		RefreshToken: refreshTokenString,
+		ExpiresAt:    accessExpiry.Unix(),
+	}, nil
+}
+
+func (s *AuthService) HashPassword(password string) (string, error) {
+	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return "", err
+	}
+	return string(hash), nil
+}
+
+func (s *AuthService) CreateUser(username, email, password string, role models.UserRole) (*models.User, error) {
+	hash, err := s.HashPassword(password)
+	if err != nil {
+		return nil, err
+	}
+
+	user := &models.User{
+		Username:     username,
+		Email:        email,
+		PasswordHash: hash,
+		Role:         role,
+		IsActive:     true,
+	}
+
+	if err := s.userRepo.Create(user); err != nil {
+		return nil, err
+	}
+
+	return user, nil
+}

internal/services/component.go

@@ -0,0 +1,187 @@
+package services
+
+import (
+	"strings"
+
+	"github.com/mchus/quoteforge/internal/models"
+	"github.com/mchus/quoteforge/internal/repository"
+)
+
+type ComponentService struct {
+	componentRepo *repository.ComponentRepository
+	categoryRepo  *repository.CategoryRepository
+	statsRepo     *repository.StatsRepository
+}
+
+func NewComponentService(
+	componentRepo *repository.ComponentRepository,
+	categoryRepo *repository.CategoryRepository,
+	statsRepo *repository.StatsRepository,
+) *ComponentService {
+	return &ComponentService{
+		componentRepo: componentRepo,
+		categoryRepo:  categoryRepo,
+		statsRepo:     statsRepo,
+	}
+}
+
+// ParsePartNumber extracts category, vendor, model from lot_name
+// "CPU_AMD_9654" → category="CPU", vendor="AMD", model="9654"
+// "MB_INTEL_4.Sapphire_2S_32xDDR5" → category="MB", vendor="INTEL", model="4.Sapphire_2S_32xDDR5"
+func ParsePartNumber(lotName string) (category, vendor, model string) {
+	parts := strings.SplitN(lotName, "_", 3)
+	if len(parts) >= 1 {
+		category = parts[0]
+	}
+	if len(parts) >= 2 {
+		vendor = parts[1]
+	}
+	if len(parts) >= 3 {
+		model = parts[2]
+	}
+	return
+}
+
+type ComponentListResult struct {
+	Components []ComponentView `json:"components"`
+	Total      int64           `json:"total"`
+	Page       int             `json:"page"`
+	PerPage    int             `json:"per_page"`
+}
+
+type ComponentView struct {
+	LotName         string                  `json:"lot_name"`
+	Description     string                  `json:"description"`
+	Category        string                  `json:"category"`
+	CategoryName    string                  `json:"category_name"`
+	Vendor          string                  `json:"vendor"`
+	Model           string                  `json:"model"`
+	CurrentPrice    *float64                `json:"current_price"`
+	PriceFreshness  models.PriceFreshness   `json:"price_freshness"`
+	PopularityScore float64                 `json:"popularity_score"`
+	Specs           models.Specs            `json:"specs,omitempty"`
+}
+
+func (s *ComponentService) List(filter repository.ComponentFilter, page, perPage int) (*ComponentListResult, error) {
+	if page < 1 {
+		page = 1
+	}
+	if perPage < 1 || perPage > 100 {
+		perPage = 20
+	}
+	offset := (page - 1) * perPage
+
+	components, total, err := s.componentRepo.List(filter, offset, perPage)
+	if err != nil {
+		return nil, err
+	}
+
+	views := make([]ComponentView, len(components))
+	for i, c := range components {
+		view := ComponentView{
+			LotName:         c.LotName,
+			Vendor:          c.Vendor,
+			Model:           c.Model,
+			CurrentPrice:    c.CurrentPrice,
+			PriceFreshness:  c.GetPriceFreshness(30, 60, 90, 3),
+			PopularityScore: c.PopularityScore,
+			Specs:           c.Specs,
+		}
+
+		if c.Lot != nil {
+			view.Description = c.Lot.LotDescription
+		}
+		if c.Category != nil {
+			view.Category = c.Category.Code
+			view.CategoryName = c.Category.Name
+		}
+
+		views[i] = view
+	}
+
+	return &ComponentListResult{
+		Components: views,
+		Total:      total,
+		Page:       page,
+		PerPage:    perPage,
+	}, nil
+}
+
+func (s *ComponentService) GetByLotName(lotName string) (*ComponentView, error) {
+	c, err := s.componentRepo.GetByLotName(lotName)
+	if err != nil {
+		return nil, err
+	}
+
+	// Track usage
+	_ = s.componentRepo.IncrementRequestCount(lotName)
+
+	view := &ComponentView{
+		LotName:         c.LotName,
+		Vendor:          c.Vendor,
+		Model:           c.Model,
+		CurrentPrice:    c.CurrentPrice,
+		PriceFreshness:  c.GetPriceFreshness(30, 60, 90, 3),
+		PopularityScore: c.PopularityScore,
+		Specs:           c.Specs,
+	}
+
+	if c.Lot != nil {
+		view.Description = c.Lot.LotDescription
+	}
+	if c.Category != nil {
+		view.Category = c.Category.Code
+		view.CategoryName = c.Category.Name
+	}
+
+	return view, nil
+}
+
+func (s *ComponentService) GetCategories() ([]models.Category, error) {
+	return s.categoryRepo.GetAll()
+}
+
+func (s *ComponentService) GetVendors(category string) ([]string, error) {
+	return s.componentRepo.GetVendors(category)
+}
+
+// ImportFromLot creates metadata entries for lots that don't have them
+func (s *ComponentService) ImportFromLot() (int, error) {
+	lots, err := s.componentRepo.GetLotsWithoutMetadata()
+	if err != nil {
+		return 0, err
+	}
+
+	categories, err := s.categoryRepo.GetAll()
+	if err != nil {
+		return 0, err
+	}
+
+	categoryMap := make(map[string]uint)
+	for _, cat := range categories {
+		categoryMap[cat.Code] = cat.ID
+	}
+
+	imported := 0
+	for _, lot := range lots {
+		category, vendor, model := ParsePartNumber(lot.LotName)
+
+		metadata := &models.LotMetadata{
+			LotName: lot.LotName,
+			Vendor:  vendor,
+			Model:   model,
+			Specs:   make(models.Specs),
+		}
+
+		if catID, ok := categoryMap[category]; ok {
+			metadata.CategoryID = &catID
+		}
+
+		if err := s.componentRepo.Create(metadata); err != nil {
+			continue
+		}
+		imported++
+	}
+
+	return imported, nil
+}

internal/services/configuration.go

@@ -0,0 +1,176 @@
+package services
+
+import (
+	"encoding/json"
+	"errors"
+
+	"github.com/google/uuid"
+	"github.com/mchus/quoteforge/internal/models"
+	"github.com/mchus/quoteforge/internal/repository"
+)
+
+var (
+	ErrConfigNotFound   = errors.New("configuration not found")
+	ErrConfigForbidden  = errors.New("access to configuration forbidden")
+)
+
+type ConfigurationService struct {
+	configRepo    *repository.ConfigurationRepository
+	componentRepo *repository.ComponentRepository
+	quoteService  *QuoteService
+}
+
+func NewConfigurationService(
+	configRepo *repository.ConfigurationRepository,
+	componentRepo *repository.ComponentRepository,
+	quoteService *QuoteService,
+) *ConfigurationService {
+	return &ConfigurationService{
+		configRepo:    configRepo,
+		componentRepo: componentRepo,
+		quoteService:  quoteService,
+	}
+}
+
+type CreateConfigRequest struct {
+	Name       string              `json:"name"`
+	Items      models.ConfigItems  `json:"items"`
+	Notes      string              `json:"notes"`
+	IsTemplate bool                `json:"is_template"`
+}
+
+func (s *ConfigurationService) Create(userID uint, req *CreateConfigRequest) (*models.Configuration, error) {
+	total := req.Items.Total()
+
+	config := &models.Configuration{
+		UUID:       uuid.New().String(),
+		UserID:     userID,
+		Name:       req.Name,
+		Items:      req.Items,
+		TotalPrice: &total,
+		Notes:      req.Notes,
+		IsTemplate: req.IsTemplate,
+	}
+
+	if err := s.configRepo.Create(config); err != nil {
+		return nil, err
+	}
+
+	// Record usage stats
+	_ = s.quoteService.RecordUsage(req.Items)
+
+	return config, nil
+}
+
+func (s *ConfigurationService) GetByUUID(uuid string, userID uint) (*models.Configuration, error) {
+	config, err := s.configRepo.GetByUUID(uuid)
+	if err != nil {
+		return nil, ErrConfigNotFound
+	}
+
+	// Allow access if user owns config or it's a template
+	if config.UserID != userID && !config.IsTemplate {
+		return nil, ErrConfigForbidden
+	}
+
+	return config, nil
+}
+
+func (s *ConfigurationService) Update(uuid string, userID uint, req *CreateConfigRequest) (*models.Configuration, error) {
+	config, err := s.configRepo.GetByUUID(uuid)
+	if err != nil {
+		return nil, ErrConfigNotFound
+	}
+
+	if config.UserID != userID {
+		return nil, ErrConfigForbidden
+	}
+
+	total := req.Items.Total()
+
+	config.Name = req.Name
+	config.Items = req.Items
+	config.TotalPrice = &total
+	config.Notes = req.Notes
+	config.IsTemplate = req.IsTemplate
+
+	if err := s.configRepo.Update(config); err != nil {
+		return nil, err
+	}
+
+	return config, nil
+}
+
+func (s *ConfigurationService) Delete(uuid string, userID uint) error {
+	config, err := s.configRepo.GetByUUID(uuid)
+	if err != nil {
+		return ErrConfigNotFound
+	}
+
+	if config.UserID != userID {
+		return ErrConfigForbidden
+	}
+
+	return s.configRepo.Delete(config.ID)
+}
+
+func (s *ConfigurationService) ListByUser(userID uint, page, perPage int) ([]models.Configuration, int64, error) {
+	if page < 1 {
+		page = 1
+	}
+	if perPage < 1 || perPage > 100 {
+		perPage = 20
+	}
+	offset := (page - 1) * perPage
+
+	return s.configRepo.ListByUser(userID, offset, perPage)
+}
+
+func (s *ConfigurationService) ListTemplates(page, perPage int) ([]models.Configuration, int64, error) {
+	if page < 1 {
+		page = 1
+	}
+	if perPage < 1 || perPage > 100 {
+		perPage = 20
+	}
+	offset := (page - 1) * perPage
+
+	return s.configRepo.ListTemplates(offset, perPage)
+}
+
+// Export configuration as JSON
+type ConfigExport struct {
+	Name  string             `json:"name"`
+	Notes string             `json:"notes"`
+	Items models.ConfigItems `json:"items"`
+}
+
+func (s *ConfigurationService) ExportJSON(uuid string, userID uint) ([]byte, error) {
+	config, err := s.GetByUUID(uuid, userID)
+	if err != nil {
+		return nil, err
+	}
+
+	export := ConfigExport{
+		Name:  config.Name,
+		Notes: config.Notes,
+		Items: config.Items,
+	}
+
+	return json.MarshalIndent(export, "", "  ")
+}
+
+func (s *ConfigurationService) ImportJSON(userID uint, data []byte) (*models.Configuration, error) {
+	var export ConfigExport
+	if err := json.Unmarshal(data, &export); err != nil {
+		return nil, err
+	}
+
+	req := &CreateConfigRequest{
+		Name:  export.Name,
+		Notes: export.Notes,
+		Items: export.Items,
+	}
+
+	return s.Create(userID, req)
+}

internal/services/export.go

@@ -0,0 +1,175 @@
+package services
+
+import (
+	"bytes"
+	"encoding/csv"
+	"fmt"
+	"time"
+
+	"github.com/mchus/quoteforge/internal/config"
+	"github.com/mchus/quoteforge/internal/models"
+	"github.com/xuri/excelize/v2"
+)
+
+type ExportService struct {
+	config config.ExportConfig
+}
+
+func NewExportService(cfg config.ExportConfig) *ExportService {
+	return &ExportService{config: cfg}
+}
+
+type ExportData struct {
+	Name       string
+	Items      []ExportItem
+	Total      float64
+	Notes      string
+	CreatedAt  time.Time
+}
+
+type ExportItem struct {
+	LotName     string
+	Description string
+	Category    string
+	Quantity    int
+	UnitPrice   float64
+	TotalPrice  float64
+}
+
+func (s *ExportService) ToCSV(data *ExportData) ([]byte, error) {
+	var buf bytes.Buffer
+	w := csv.NewWriter(&buf)
+
+	// Header
+	headers := []string{"Артикул", "Описание", "Категория", "Количество", "Цена за единицу", "Сумма"}
+	if err := w.Write(headers); err != nil {
+		return nil, err
+	}
+
+	// Items
+	for _, item := range data.Items {
+		row := []string{
+			item.LotName,
+			item.Description,
+			item.Category,
+			fmt.Sprintf("%d", item.Quantity),
+			fmt.Sprintf("%.2f", item.UnitPrice),
+			fmt.Sprintf("%.2f", item.TotalPrice),
+		}
+		if err := w.Write(row); err != nil {
+			return nil, err
+		}
+	}
+
+	// Total row
+	if err := w.Write([]string{"", "", "", "", "ИТОГО:", fmt.Sprintf("%.2f", data.Total)}); err != nil {
+		return nil, err
+	}
+
+	w.Flush()
+	return buf.Bytes(), w.Error()
+}
+
+func (s *ExportService) ToXLSX(data *ExportData) ([]byte, error) {
+	f := excelize.NewFile()
+	sheet := "Конфигурация"
+	f.SetSheetName("Sheet1", sheet)
+
+	// Styles
+	headerStyle, _ := f.NewStyle(&excelize.Style{
+		Font:      &excelize.Font{Bold: true, Size: 12, Color: "#FFFFFF"},
+		Fill:      excelize.Fill{Type: "pattern", Color: []string{"#4472C4"}, Pattern: 1},
+		Alignment: &excelize.Alignment{Horizontal: "center", Vertical: "center"},
+		Border: []excelize.Border{
+			{Type: "left", Color: "#000000", Style: 1},
+			{Type: "top", Color: "#000000", Style: 1},
+			{Type: "bottom", Color: "#000000", Style: 1},
+			{Type: "right", Color: "#000000", Style: 1},
+		},
+	})
+
+	totalStyle, _ := f.NewStyle(&excelize.Style{
+		Font: &excelize.Font{Bold: true, Size: 12},
+		Fill: excelize.Fill{Type: "pattern", Color: []string{"#E2EFDA"}, Pattern: 1},
+	})
+
+	priceStyle, _ := f.NewStyle(&excelize.Style{
+		NumFmt: 4, // #,##0.00
+	})
+
+	// Title
+	f.SetCellValue(sheet, "A1", s.config.CompanyName)
+	f.SetCellValue(sheet, "A2", "Коммерческое предложение: "+data.Name)
+	f.SetCellValue(sheet, "A3", "Дата: "+data.CreatedAt.Format("02.01.2006"))
+
+	// Headers
+	headers := []string{"Артикул", "Описание", "Категория", "Кол-во", "Цена", "Сумма"}
+	for i, h := range headers {
+		cell := fmt.Sprintf("%c5", 'A'+i)
+		f.SetCellValue(sheet, cell, h)
+		f.SetCellStyle(sheet, cell, cell, headerStyle)
+	}
+
+	// Data rows
+	row := 6
+	for _, item := range data.Items {
+		f.SetCellValue(sheet, fmt.Sprintf("A%d", row), item.LotName)
+		f.SetCellValue(sheet, fmt.Sprintf("B%d", row), item.Description)
+		f.SetCellValue(sheet, fmt.Sprintf("C%d", row), item.Category)
+		f.SetCellValue(sheet, fmt.Sprintf("D%d", row), item.Quantity)
+		f.SetCellValue(sheet, fmt.Sprintf("E%d", row), item.UnitPrice)
+		f.SetCellValue(sheet, fmt.Sprintf("F%d", row), item.TotalPrice)
+		f.SetCellStyle(sheet, fmt.Sprintf("E%d", row), fmt.Sprintf("F%d", row), priceStyle)
+		row++
+	}
+
+	// Total row
+	f.SetCellValue(sheet, fmt.Sprintf("E%d", row), "ИТОГО:")
+	f.SetCellValue(sheet, fmt.Sprintf("F%d", row), data.Total)
+	f.SetCellStyle(sheet, fmt.Sprintf("E%d", row), fmt.Sprintf("F%d", row), totalStyle)
+
+	// Notes
+	if data.Notes != "" {
+		row += 2
+		f.SetCellValue(sheet, fmt.Sprintf("A%d", row), "Примечания: "+data.Notes)
+	}
+
+	// Column widths
+	f.SetColWidth(sheet, "A", "A", 25)
+	f.SetColWidth(sheet, "B", "B", 50)
+	f.SetColWidth(sheet, "C", "C", 15)
+	f.SetColWidth(sheet, "D", "D", 10)
+	f.SetColWidth(sheet, "E", "E", 15)
+	f.SetColWidth(sheet, "F", "F", 15)
+
+	var buf bytes.Buffer
+	if err := f.Write(&buf); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func (s *ExportService) ConfigToExportData(config *models.Configuration) *ExportData {
+	items := make([]ExportItem, len(config.Items))
+	var total float64
+
+	for i, item := range config.Items {
+		itemTotal := item.UnitPrice * float64(item.Quantity)
+		items[i] = ExportItem{
+			LotName:    item.LotName,
+			Quantity:   item.Quantity,
+			UnitPrice:  item.UnitPrice,
+			TotalPrice: itemTotal,
+		}
+		total += itemTotal
+	}
+
+	return &ExportData{
+		Name:      config.Name,
+		Items:     items,
+		Total:     total,
+		Notes:     config.Notes,
+		CreatedAt: config.CreatedAt,
+	}
+}

internal/services/pricing/calculator.go

@@ -0,0 +1,121 @@
+package pricing
+
+import (
+	"math"
+	"sort"
+	"time"
+
+	"github.com/mchus/quoteforge/internal/repository"
+)
+
+// CalculateMedian returns the median of prices
+func CalculateMedian(prices []float64) float64 {
+	if len(prices) == 0 {
+		return 0
+	}
+
+	sorted := make([]float64, len(prices))
+	copy(sorted, prices)
+	sort.Float64s(sorted)
+
+	n := len(sorted)
+	if n%2 == 0 {
+		return (sorted[n/2-1] + sorted[n/2]) / 2
+	}
+	return sorted[n/2]
+}
+
+// CalculateAverage returns the arithmetic mean of prices
+func CalculateAverage(prices []float64) float64 {
+	if len(prices) == 0 {
+		return 0
+	}
+
+	var sum float64
+	for _, p := range prices {
+		sum += p
+	}
+	return sum / float64(len(prices))
+}
+
+// CalculateWeightedMedian calculates median with exponential decay weights
+// More recent prices have higher weight
+func CalculateWeightedMedian(points []repository.PricePoint, decayDays int) float64 {
+	if len(points) == 0 {
+		return 0
+	}
+
+	type weightedPrice struct {
+		price  float64
+		weight float64
+	}
+
+	now := time.Now()
+	weighted := make([]weightedPrice, len(points))
+	var totalWeight float64
+
+	for i, p := range points {
+		daysSince := now.Sub(p.Date).Hours() / 24
+		// weight = e^(-days / decay_days)
+		weight := math.Exp(-daysSince / float64(decayDays))
+		weighted[i] = weightedPrice{price: p.Price, weight: weight}
+		totalWeight += weight
+	}
+
+	// Sort by price
+	sort.Slice(weighted, func(i, j int) bool {
+		return weighted[i].price < weighted[j].price
+	})
+
+	// Find weighted median
+	targetWeight := totalWeight / 2
+	var cumulativeWeight float64
+
+	for _, wp := range weighted {
+		cumulativeWeight += wp.weight
+		if cumulativeWeight >= targetWeight {
+			return wp.price
+		}
+	}
+
+	return weighted[len(weighted)-1].price
+}
+
+// CalculatePercentile calculates the nth percentile of prices
+func CalculatePercentile(prices []float64, percentile float64) float64 {
+	if len(prices) == 0 {
+		return 0
+	}
+
+	sorted := make([]float64, len(prices))
+	copy(sorted, prices)
+	sort.Float64s(sorted)
+
+	index := (percentile / 100) * float64(len(sorted)-1)
+	lower := int(math.Floor(index))
+	upper := int(math.Ceil(index))
+
+	if lower == upper {
+		return sorted[lower]
+	}
+
+	fraction := index - float64(lower)
+	return sorted[lower]*(1-fraction) + sorted[upper]*fraction
+}
+
+// CalculateStdDev calculates standard deviation
+func CalculateStdDev(prices []float64) float64 {
+	if len(prices) < 2 {
+		return 0
+	}
+
+	mean := CalculateAverage(prices)
+	var sumSquares float64
+
+	for _, p := range prices {
+		diff := p - mean
+		sumSquares += diff * diff
+	}
+
+	return math.Sqrt(sumSquares / float64(len(prices)-1))
+}

internal/services/pricing/service.go

@@ -0,0 +1,178 @@
+package pricing
+
+import (
+	"time"
+
+	"github.com/mchus/quoteforge/internal/config"
+	"github.com/mchus/quoteforge/internal/models"
+	"github.com/mchus/quoteforge/internal/repository"
+)
+
+type Service struct {
+	componentRepo *repository.ComponentRepository
+	priceRepo     *repository.PriceRepository
+	config        config.PricingConfig
+}
+
+func NewService(
+	componentRepo *repository.ComponentRepository,
+	priceRepo *repository.PriceRepository,
+	cfg config.PricingConfig,
+) *Service {
+	return &Service{
+		componentRepo: componentRepo,
+		priceRepo:     priceRepo,
+		config:        cfg,
+	}
+}
+
+// GetEffectivePrice returns the current effective price for a component
+// Priority: active override > calculated price > nil
+func (s *Service) GetEffectivePrice(lotName string) (*float64, error) {
+	// Check for active override first
+	override, err := s.priceRepo.GetPriceOverride(lotName)
+	if err == nil && override != nil {
+		return &override.Price, nil
+	}
+
+	// Get component metadata
+	component, err := s.componentRepo.GetByLotName(lotName)
+	if err != nil {
+		return nil, err
+	}
+
+	return component.CurrentPrice, nil
+}
+
+// CalculatePrice calculates price using the specified method
+func (s *Service) CalculatePrice(lotName string, method models.PriceMethod, periodDays int) (float64, error) {
+	if periodDays == 0 {
+		periodDays = s.config.DefaultPeriodDays
+	}
+
+	points, err := s.priceRepo.GetPriceHistory(lotName, periodDays)
+	if err != nil {
+		return 0, err
+	}
+
+	if len(points) == 0 {
+		return 0, nil
+	}
+
+	prices := make([]float64, len(points))
+	for i, p := range points {
+		prices[i] = p.Price
+	}
+
+	switch method {
+	case models.PriceMethodAverage:
+		return CalculateAverage(prices), nil
+	case models.PriceMethodWeightedMedian:
+		return CalculateWeightedMedian(points, s.config.DefaultPeriodDays), nil
+	case models.PriceMethodMedian:
+		fallthrough
+	default:
+		return CalculateMedian(prices), nil
+	}
+}
+
+// UpdateComponentPrice recalculates and updates the price for a component
+func (s *Service) UpdateComponentPrice(lotName string) error {
+	component, err := s.componentRepo.GetByLotName(lotName)
+	if err != nil {
+		return err
+	}
+
+	price, err := s.CalculatePrice(lotName, component.PriceMethod, component.PricePeriodDays)
+	if err != nil {
+		return err
+	}
+
+	now := time.Now()
+	if price > 0 {
+		component.CurrentPrice = &price
+		component.PriceUpdatedAt = &now
+	}
+
+	return s.componentRepo.Update(component)
+}
+
+// SetManualPrice sets a manual price override
+func (s *Service) SetManualPrice(lotName string, price float64, reason string, userID uint) error {
+	override := &models.PriceOverride{
+		LotName:   lotName,
+		Price:     price,
+		ValidFrom: time.Now(),
+		Reason:    reason,
+		CreatedBy: userID,
+	}
+	return s.priceRepo.CreatePriceOverride(override)
+}
+
+// UpdatePriceMethod changes the pricing method for a component
+func (s *Service) UpdatePriceMethod(lotName string, method models.PriceMethod, periodDays int) error {
+	component, err := s.componentRepo.GetByLotName(lotName)
+	if err != nil {
+		return err
+	}
+
+	component.PriceMethod = method
+	if periodDays > 0 {
+		component.PricePeriodDays = periodDays
+	}
+
+	if err := s.componentRepo.Update(component); err != nil {
+		return err
+	}
+
+	return s.UpdateComponentPrice(lotName)
+}
+
+// GetPriceStats returns statistics for a component's price history
+func (s *Service) GetPriceStats(lotName string, periodDays int) (*PriceStats, error) {
+	if periodDays == 0 {
+		periodDays = s.config.DefaultPeriodDays
+	}
+
+	points, err := s.priceRepo.GetPriceHistory(lotName, periodDays)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(points) == 0 {
+		return &PriceStats{QuoteCount: 0}, nil
+	}
+
+	prices := make([]float64, len(points))
+	for i, p := range points {
+		prices[i] = p.Price
+	}
+
+	return &PriceStats{
+		QuoteCount:    len(points),
+		MinPrice:      CalculatePercentile(prices, 0),
+		MaxPrice:      CalculatePercentile(prices, 100),
+		MedianPrice:   CalculateMedian(prices),
+		AveragePrice:  CalculateAverage(prices),
+		StdDeviation:  CalculateStdDev(prices),
+		LatestPrice:   points[0].Price,
+		LatestDate:    points[0].Date,
+		OldestDate:    points[len(points)-1].Date,
+		Percentile25:  CalculatePercentile(prices, 25),
+		Percentile75:  CalculatePercentile(prices, 75),
+	}, nil
+}
+
+type PriceStats struct {
+	QuoteCount   int       `json:"quote_count"`
+	MinPrice     float64   `json:"min_price"`
+	MaxPrice     float64   `json:"max_price"`
+	MedianPrice  float64   `json:"median_price"`
+	AveragePrice float64   `json:"average_price"`
+	StdDeviation float64   `json:"std_deviation"`
+	LatestPrice  float64   `json:"latest_price"`
+	LatestDate   time.Time `json:"latest_date"`
+	OldestDate   time.Time `json:"oldest_date"`
+	Percentile25 float64   `json:"percentile_25"`
+	Percentile75 float64   `json:"percentile_75"`
+}

internal/services/quote.go

@@ -0,0 +1,139 @@
+package services
+
+import (
+	"errors"
+
+	"github.com/mchus/quoteforge/internal/models"
+	"github.com/mchus/quoteforge/internal/repository"
+	"github.com/mchus/quoteforge/internal/services/pricing"
+)
+
+var (
+	ErrEmptyQuote       = errors.New("quote cannot be empty")
+	ErrComponentNotFound = errors.New("component not found")
+	ErrNoPriceAvailable  = errors.New("no price available for component")
+)
+
+type QuoteService struct {
+	componentRepo *repository.ComponentRepository
+	statsRepo     *repository.StatsRepository
+	pricingService *pricing.Service
+}
+
+func NewQuoteService(
+	componentRepo *repository.ComponentRepository,
+	statsRepo *repository.StatsRepository,
+	pricingService *pricing.Service,
+) *QuoteService {
+	return &QuoteService{
+		componentRepo:  componentRepo,
+		statsRepo:      statsRepo,
+		pricingService: pricingService,
+	}
+}
+
+type QuoteItem struct {
+	LotName     string  `json:"lot_name"`
+	Quantity    int     `json:"quantity"`
+	UnitPrice   float64 `json:"unit_price"`
+	TotalPrice  float64 `json:"total_price"`
+	Description string  `json:"description"`
+	Category    string  `json:"category"`
+	HasPrice    bool    `json:"has_price"`
+}
+
+type QuoteValidationResult struct {
+	Valid    bool          `json:"valid"`
+	Items    []QuoteItem   `json:"items"`
+	Errors   []string      `json:"errors"`
+	Warnings []string      `json:"warnings"`
+	Total    float64       `json:"total"`
+}
+
+type QuoteRequest struct {
+	Items []struct {
+		LotName  string `json:"lot_name"`
+		Quantity int    `json:"quantity"`
+	} `json:"items"`
+}
+
+func (s *QuoteService) ValidateAndCalculate(req *QuoteRequest) (*QuoteValidationResult, error) {
+	if len(req.Items) == 0 {
+		return nil, ErrEmptyQuote
+	}
+
+	result := &QuoteValidationResult{
+		Valid:    true,
+		Items:    make([]QuoteItem, 0, len(req.Items)),
+		Errors:   make([]string, 0),
+		Warnings: make([]string, 0),
+	}
+
+	lotNames := make([]string, len(req.Items))
+	quantities := make(map[string]int)
+	for i, item := range req.Items {
+		lotNames[i] = item.LotName
+		quantities[item.LotName] = item.Quantity
+	}
+
+	components, err := s.componentRepo.GetMultiple(lotNames)
+	if err != nil {
+		return nil, err
+	}
+
+	componentMap := make(map[string]*models.LotMetadata)
+	for i := range components {
+		componentMap[components[i].LotName] = &components[i]
+	}
+
+	var total float64
+
+	for _, reqItem := range req.Items {
+		comp, exists := componentMap[reqItem.LotName]
+		if !exists {
+			result.Valid = false
+			result.Errors = append(result.Errors, "Component not found: "+reqItem.LotName)
+			continue
+		}
+
+		item := QuoteItem{
+			LotName:  reqItem.LotName,
+			Quantity: reqItem.Quantity,
+			HasPrice: false,
+		}
+
+		if comp.Lot != nil {
+			item.Description = comp.Lot.LotDescription
+		}
+		if comp.Category != nil {
+			item.Category = comp.Category.Code
+		}
+
+		// Get effective price (override or calculated)
+		price, err := s.pricingService.GetEffectivePrice(reqItem.LotName)
+		if err == nil && price != nil && *price > 0 {
+			item.UnitPrice = *price
+			item.TotalPrice = *price * float64(reqItem.Quantity)
+			item.HasPrice = true
+			total += item.TotalPrice
+		} else {
+			result.Warnings = append(result.Warnings, "No price available for: "+reqItem.LotName)
+		}
+
+		result.Items = append(result.Items, item)
+	}
+
+	result.Total = total
+	return result, nil
+}
+
+// RecordUsage records that components were used in a quote
+func (s *QuoteService) RecordUsage(items []models.ConfigItem) error {
+	for _, item := range items {
+		revenue := item.UnitPrice * float64(item.Quantity)
+		if err := s.statsRepo.IncrementUsage(item.LotName, item.Quantity, revenue); err != nil {
+			return err
+		}
+	}
+	return nil
+}