package handlers

import (
	"net/http"
	"sort"
	"strings"

	"git.mchus.pro/mchus/priceforge/internal/config"
	"git.mchus.pro/mchus/priceforge/internal/dbutil"
	"git.mchus.pro/mchus/priceforge/internal/models"
	"git.mchus.pro/mchus/priceforge/internal/repository"
	"git.mchus.pro/mchus/priceforge/internal/services"
	"git.mchus.pro/mchus/priceforge/internal/services/alerts"
	"git.mchus.pro/mchus/priceforge/internal/services/pricing"
	"git.mchus.pro/mchus/priceforge/internal/tasks"
	"github.com/gin-gonic/gin"
	"gorm.io/gorm"
)

const maxStockImportFileSize int64 = 25 * 1024 * 1024
const maxVendorMappingsCSVImportFileSize int64 = 10 * 1024 * 1024

// calculateMedian returns the median of a sorted slice of prices
func calculateMedian(prices []float64) float64 {
	if len(prices) == 0 {
		return 0
	}
	sort.Float64s(prices)
	n := len(prices)
	if n%2 == 0 {
		return (prices[n/2-1] + prices[n/2]) / 2
	}
	return prices[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))
}

// sortFloat64s sorts a slice of float64 in ascending order
func sortFloat64s(data []float64) {
	sort.Float64s(data)
}

type PricingHandler struct {
	db                    *gorm.DB
	pricingService        *pricing.Service
	alertService          *alerts.Service
	componentRepo         *repository.ComponentRepository
	componentService      *services.ComponentService
	priceRepo             *repository.PriceRepository
	statsRepo             *repository.StatsRepository
	stockImportService    *services.StockImportService
	vendorMapService      *services.VendorMappingService
	partnumberBookService *services.PartnumberBookService
	schedulerConfig       config.SchedulerConfig
	dbUsername            string
	taskManager           *tasks.Manager
}

func NewPricingHandler(
	db *gorm.DB,
	pricingService *pricing.Service,
	alertService *alerts.Service,
	componentRepo *repository.ComponentRepository,
	componentService *services.ComponentService,
	priceRepo *repository.PriceRepository,
	statsRepo *repository.StatsRepository,
	stockImportService *services.StockImportService,
	vendorMapService *services.VendorMappingService,
	partnumberBookService *services.PartnumberBookService,
	schedulerConfig config.SchedulerConfig,
	dbUsername string,
	taskManager *tasks.Manager,
) *PricingHandler {
	return &PricingHandler{
		db:                    db,
		pricingService:        pricingService,
		alertService:          alertService,
		componentRepo:         componentRepo,
		componentService:      componentService,
		priceRepo:             priceRepo,
		statsRepo:             statsRepo,
		stockImportService:    stockImportService,
		vendorMapService:      vendorMapService,
		partnumberBookService: partnumberBookService,
		schedulerConfig:       schedulerConfig,
		dbUsername:            dbUsername,
		taskManager:           taskManager,
	}
}

// queryLotPrices fetches prices from lot_log with timeout and retry
func (h *PricingHandler) queryLotPrices(lotName string, periodDays int) ([]float64, error) {
	var prices []float64
	query := dbutil.DefaultQueryTimeout(h.db)

	var err error
	if strings.HasSuffix(lotName, "*") {
		pattern := strings.TrimSuffix(lotName, "*") + "%"
		if periodDays > 0 {
			err = query.Execute(func(db *gorm.DB) error {
				return db.Raw(`SELECT price FROM lot_log WHERE lot LIKE ? AND date >= DATE_SUB(NOW(), INTERVAL ? DAY) ORDER BY price`,
					pattern, periodDays).Pluck("price", &prices).Error
			})
		} else {
			err = query.Execute(func(db *gorm.DB) error {
				return db.Raw(`SELECT price FROM lot_log WHERE lot LIKE ? ORDER BY price`, pattern).Pluck("price", &prices).Error
			})
		}
	} else {
		if periodDays > 0 {
			err = query.Execute(func(db *gorm.DB) error {
				return db.Raw(`SELECT price FROM lot_log WHERE lot = ? AND date >= DATE_SUB(NOW(), INTERVAL ? DAY) ORDER BY price`,
					lotName, periodDays).Pluck("price", &prices).Error
			})
		} else {
			err = query.Execute(func(db *gorm.DB) error {
				return db.Raw(`SELECT price FROM lot_log WHERE lot = ? ORDER BY price`, lotName).Pluck("price", &prices).Error
			})
		}
	}

	return prices, err
}

// queryMultipleLotPrices fetches prices from multiple lots with timeout and retry
func (h *PricingHandler) queryMultipleLotPrices(lotNames []string, periodDays int) ([]float64, error) {
	var prices []float64
	query := dbutil.DefaultQueryTimeout(h.db)

	var err error
	if periodDays > 0 {
		err = query.Execute(func(db *gorm.DB) error {
			return db.Raw(`SELECT price FROM lot_log WHERE lot IN ? AND date >= DATE_SUB(NOW(), INTERVAL ? DAY) ORDER BY price`,
				lotNames, periodDays).Pluck("price", &prices).Error
		})
	} else {
		err = query.Execute(func(db *gorm.DB) error {
			return db.Raw(`SELECT price FROM lot_log WHERE lot IN ? ORDER BY price`, lotNames).Pluck("price", &prices).Error
		})
	}

	return prices, err
}

// getMetaUsageMap returns a map of lot_name -> list of meta-articles that use this component
func (h *PricingHandler) getMetaUsageMap(lotNames []string) map[string][]string {
	result := make(map[string][]string)

	// Get all components with meta_prices
	var metaComponents []models.LotMetadata
	h.db.Where("meta_prices IS NOT NULL AND meta_prices != ''").Find(&metaComponents)

	// Build reverse lookup: which components are used in which meta-articles
	for _, meta := range metaComponents {
		sources := strings.Split(meta.MetaPrices, ",")
		for _, source := range sources {
			source = strings.TrimSpace(source)
			if source == "" {
				continue
			}

			// Handle wildcard patterns
			if strings.HasSuffix(source, "*") {
				prefix := strings.TrimSuffix(source, "*")
				for _, lotName := range lotNames {
					if strings.HasPrefix(lotName, prefix) && lotName != meta.LotName {
						result[lotName] = append(result[lotName], meta.LotName)
					}
				}
			} else {
				// Direct match
				for _, lotName := range lotNames {
					if lotName == source && lotName != meta.LotName {
						result[lotName] = append(result[lotName], meta.LotName)
					}
				}
			}
		}
	}

	return result
}

// expandMetaPrices expands meta_prices string to list of actual lot names.
// baseLot is always included as a source, then meta sources are added without duplicates.
func (h *PricingHandler) expandMetaPrices(metaPrices, baseLot string) []string {
	sources := strings.Split(metaPrices, ",")
	var result []string
	seen := make(map[string]bool)

	if baseLot != "" {
		result = append(result, baseLot)
		seen[baseLot] = true
	}

	for _, source := range sources {
		source = strings.TrimSpace(source)
		if source == "" {
			continue
		}

		if strings.HasSuffix(source, "*") {
			// Wildcard pattern - find matching lots
			prefix := strings.TrimSuffix(source, "*")
			var matchingLots []string
			h.db.Model(&models.LotMetadata{}).
				Where("lot_name LIKE ?", prefix+"%").
				Pluck("lot_name", &matchingLots)
			for _, lot := range matchingLots {
				if !seen[lot] {
					result = append(result, lot)
					seen[lot] = true
				}
			}
		} else if !seen[source] {
			result = append(result, source)
			seen[source] = true
		}
	}

	return result
}

// expandMetaPricesWithCache expands meta_prices using pre-loaded lot names (no DB queries).
// baseLot is always included as a source, then meta sources are added without duplicates.
func expandMetaPricesWithCache(metaPrices, baseLot string, allLotNames []string) []string {
	sources := strings.Split(metaPrices, ",")
	var result []string
	seen := make(map[string]bool)

	if baseLot != "" {
		result = append(result, baseLot)
		seen[baseLot] = true
	}

	for _, source := range sources {
		source = strings.TrimSpace(source)
		if source == "" {
			continue
		}

		if strings.HasSuffix(source, "*") {
			// Wildcard pattern - find matching lots from cache
			prefix := strings.TrimSuffix(source, "*")
			for _, lot := range allLotNames {
				if strings.HasPrefix(lot, prefix) && !seen[lot] {
					result = append(result, lot)
					seen[lot] = true
				}
			}
		} else if !seen[source] {
			result = append(result, source)
			seen[source] = true
		}
	}

	return result
}

func (h *PricingHandler) GetStats(c *gin.Context) {
	// Check if we're in offline mode
	if h.statsRepo == nil || h.alertService == nil {
		c.JSON(http.StatusOK, gin.H{
			"new_alerts_count":    0,
			"top_components":      []interface{}{},
			"trending_components": []interface{}{},
			"offline":             true,
		})
		return
	}

	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,
	})
}