package handlers

import (
	"net/http"
	"sort"
	"strconv"
	"time"

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

// 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))
}

type PricingHandler struct {
	db             *gorm.DB
	pricingService *pricing.Service
	alertService   *alerts.Service
	componentRepo  *repository.ComponentRepository
	priceRepo      *repository.PriceRepository
	statsRepo      *repository.StatsRepository
}

func NewPricingHandler(
	db *gorm.DB,
	pricingService *pricing.Service,
	alertService *alerts.Service,
	componentRepo *repository.ComponentRepository,
	priceRepo *repository.PriceRepository,
	statsRepo *repository.StatsRepository,
) *PricingHandler {
	return &PricingHandler{
		db:             db,
		pricingService: pricingService,
		alertService:   alertService,
		componentRepo:  componentRepo,
		priceRepo:      priceRepo,
		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,
	})
}

type ComponentWithCount struct {
	models.LotMetadata
	QuoteCount int64 `json:"quote_count"`
}

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"),
		Search:    c.Query("search"),
		SortField: c.Query("sort"),
		SortDir:   c.Query("dir"),
	}

	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
	}

	// Get quote counts
	lotNames := make([]string, len(components))
	for i, comp := range components {
		lotNames[i] = comp.LotName
	}

	counts, _ := h.priceRepo.GetQuoteCounts(lotNames)

	// Combine components with counts
	result := make([]ComponentWithCount, len(components))
	for i, comp := range components {
		result[i] = ComponentWithCount{
			LotMetadata: comp,
			QuoteCount:  counts[comp.LotName],
		}
	}

	c.JSON(http.StatusOK, gin.H{
		"components": result,
		"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"`
	Coefficient float64            `json:"coefficient"`
	ManualPrice *float64           `json:"manual_price"`
	ClearManual bool               `json:"clear_manual"`
}

func (h *PricingHandler) UpdatePrice(c *gin.Context) {
	var req UpdatePriceRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	updates := map[string]interface{}{}

	// Update method if specified
	if req.Method != "" {
		updates["price_method"] = req.Method
	}

	// Update period days
	if req.PeriodDays >= 0 {
		updates["price_period_days"] = req.PeriodDays
	}

	// Update coefficient
	updates["price_coefficient"] = req.Coefficient

	// Handle manual price
	if req.ClearManual {
		updates["manual_price"] = nil
	} else if req.ManualPrice != nil {
		updates["manual_price"] = *req.ManualPrice
		// Also update current price immediately when setting manual
		updates["current_price"] = *req.ManualPrice
		updates["price_updated_at"] = time.Now()
	}

	err := h.db.Model(&models.LotMetadata{}).
		Where("lot_name = ?", req.LotName).
		Updates(updates).Error

	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Recalculate price if not using manual price
	if req.ManualPrice == nil {
		h.recalculateSinglePrice(req.LotName)
	}

	// Get updated component to return new price
	var comp models.LotMetadata
	h.db.Where("lot_name = ?", req.LotName).First(&comp)

	c.JSON(http.StatusOK, gin.H{
		"message":       "price updated",
		"current_price": comp.CurrentPrice,
	})
}

func (h *PricingHandler) recalculateSinglePrice(lotName string) {
	var comp models.LotMetadata
	if err := h.db.Where("lot_name = ?", lotName).First(&comp).Error; err != nil {
		return
	}

	// Skip if manual price is set
	if comp.ManualPrice != nil && *comp.ManualPrice > 0 {
		return
	}

	periodDays := comp.PricePeriodDays
	method := comp.PriceMethod
	if method == "" {
		method = models.PriceMethodMedian
	}

	// Get prices based on period
	var prices []float64
	if periodDays > 0 {
		h.db.Raw(`SELECT price FROM lot_log WHERE lot = ? AND date >= DATE_SUB(NOW(), INTERVAL ? DAY) ORDER BY price`,
			lotName, periodDays).Pluck("price", &prices)

		// If no prices in period, try all time
		if len(prices) == 0 {
			h.db.Raw(`SELECT price FROM lot_log WHERE lot = ? ORDER BY price`, lotName).Pluck("price", &prices)
		}
	} else {
		h.db.Raw(`SELECT price FROM lot_log WHERE lot = ? ORDER BY price`, lotName).Pluck("price", &prices)
	}

	if len(prices) == 0 {
		return
	}

	// Calculate price based on method
	var finalPrice float64
	switch method {
	case models.PriceMethodMedian:
		finalPrice = calculateMedian(prices)
	case models.PriceMethodAverage:
		finalPrice = calculateAverage(prices)
	default:
		finalPrice = calculateMedian(prices)
	}

	if finalPrice <= 0 {
		return
	}

	// Apply coefficient
	if comp.PriceCoefficient != 0 {
		finalPrice = finalPrice * (1 + comp.PriceCoefficient/100)
	}

	now := time.Now()
	// Only update price, preserve all user settings
	h.db.Model(&models.LotMetadata{}).
		Where("lot_name = ?", lotName).
		Updates(map[string]interface{}{
			"current_price":    finalPrice,
			"price_updated_at": now,
		})
}

func (h *PricingHandler) RecalculateAll(c *gin.Context) {
	// Set headers for SSE
	c.Header("Content-Type", "text/event-stream")
	c.Header("Cache-Control", "no-cache")
	c.Header("Connection", "keep-alive")

	// Get all components with their settings
	var components []models.LotMetadata
	h.db.Find(&components)
	total := int64(len(components))

	// Send initial progress
	c.SSEvent("progress", gin.H{"current": 0, "total": total, "status": "starting"})
	c.Writer.Flush()

	c.SSEvent("progress", gin.H{"current": 0, "total": total, "status": "processing", "updated": 0, "skipped": 0, "manual": 0, "errors": 0})
	c.Writer.Flush()

	// Process components individually to respect their settings
	var updated, skipped, manual, errors int
	now := time.Now()

	for i, comp := range components {
		// If manual price is set, use it
		if comp.ManualPrice != nil && *comp.ManualPrice > 0 {
			err := h.db.Model(&models.LotMetadata{}).
				Where("lot_name = ?", comp.LotName).
				Updates(map[string]interface{}{
					"current_price":    *comp.ManualPrice,
					"price_updated_at": now,
				}).Error
			if err != nil {
				errors++
			} else {
				manual++
			}
			goto sendProgress
		}

		// Calculate price based on component's individual settings
		{
			var basePrice *float64
			periodDays := comp.PricePeriodDays
			method := comp.PriceMethod
			if method == "" {
				method = models.PriceMethodMedian
			}

			// Build query based on period
			var query string
			var args []interface{}

			if periodDays > 0 {
				query = `SELECT price FROM lot_log WHERE lot = ? AND date >= DATE_SUB(NOW(), INTERVAL ? DAY) ORDER BY price`
				args = []interface{}{comp.LotName, periodDays}
			} else {
				query = `SELECT price FROM lot_log WHERE lot = ? ORDER BY price`
				args = []interface{}{comp.LotName}
			}

			var prices []float64
			h.db.Raw(query, args...).Pluck("price", &prices)

			// If no prices in period, try all time
			if len(prices) == 0 && periodDays > 0 {
				h.db.Raw(`SELECT price FROM lot_log WHERE lot = ? ORDER BY price`, comp.LotName).Pluck("price", &prices)
			}

			if len(prices) == 0 {
				skipped++
				goto sendProgress
			}

			// Calculate price based on method
			switch method {
			case models.PriceMethodMedian:
				median := calculateMedian(prices)
				basePrice = &median
			case models.PriceMethodAverage:
				avg := calculateAverage(prices)
				basePrice = &avg
			default:
				median := calculateMedian(prices)
				basePrice = &median
			}

			if basePrice == nil || *basePrice <= 0 {
				skipped++
				goto sendProgress
			}

			finalPrice := *basePrice

			// Apply coefficient
			if comp.PriceCoefficient != 0 {
				finalPrice = finalPrice * (1 + comp.PriceCoefficient/100)
			}

			// Update only price fields
			err := h.db.Model(&models.LotMetadata{}).
				Where("lot_name = ?", comp.LotName).
				Updates(map[string]interface{}{
					"current_price":    finalPrice,
					"price_updated_at": now,
				}).Error
			if err != nil {
				errors++
			} else {
				updated++
			}
		}

	sendProgress:
		// Send progress update every 50 components
		if (i+1)%50 == 0 || i == len(components)-1 {
			c.SSEvent("progress", gin.H{
				"current": updated + skipped + manual + errors,
				"total":   total,
				"updated": updated,
				"skipped": skipped,
				"manual":  manual,
				"errors":  errors,
				"status":  "processing",
			})
			c.Writer.Flush()
		}
	}

	// Update popularity scores
	h.statsRepo.UpdatePopularityScores()

	// Send completion
	c.SSEvent("progress", gin.H{
		"current": updated + skipped + manual + errors,
		"total":   total,
		"updated": updated,
		"skipped": skipped,
		"manual":  manual,
		"errors":  errors,
		"status":  "completed",
	})
	c.Writer.Flush()
}

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"})
}

type PreviewPriceRequest struct {
	LotName     string  `json:"lot_name" binding:"required"`
	Method      string  `json:"method"`
	PeriodDays  int     `json:"period_days"`
	Coefficient float64 `json:"coefficient"`
}

func (h *PricingHandler) PreviewPrice(c *gin.Context) {
	var req PreviewPriceRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	// Get component
	var comp models.LotMetadata
	if err := h.db.Where("lot_name = ?", req.LotName).First(&comp).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "component not found"})
		return
	}

	// Get all prices for calculations
	var allPrices []float64
	h.db.Raw(`SELECT price FROM lot_log WHERE lot = ? ORDER BY price`, req.LotName).Pluck("price", &allPrices)

	// Calculate median for all time
	var medianAllTime *float64
	if len(allPrices) > 0 {
		median := calculateMedian(allPrices)
		medianAllTime = &median
	}

	// Get quote count
	var quoteCount int64
	h.db.Model(&models.LotLog{}).Where("lot = ?", req.LotName).Count(&quoteCount)

	// Get last received price
	var lastPrice struct {
		Price *float64
		Date  *time.Time
	}
	h.db.Raw(`SELECT price, date FROM lot_log WHERE lot = ? ORDER BY date DESC, lot_log_id DESC LIMIT 1`, req.LotName).Scan(&lastPrice)

	// Calculate new price based on parameters (method, period, coefficient)
	method := req.Method
	if method == "" {
		method = "median"
	}

	var prices []float64
	if req.PeriodDays > 0 {
		h.db.Raw(`SELECT price FROM lot_log WHERE lot = ? AND date >= DATE_SUB(NOW(), INTERVAL ? DAY) ORDER BY price`,
			req.LotName, req.PeriodDays).Pluck("price", &prices)
		// Fall back to all time if no prices in period
		if len(prices) == 0 {
			prices = allPrices
		}
	} else {
		prices = allPrices
	}

	var newPrice *float64
	if len(prices) > 0 {
		var basePrice float64
		if method == "average" {
			basePrice = calculateAverage(prices)
		} else {
			basePrice = calculateMedian(prices)
		}

		if req.Coefficient != 0 {
			basePrice = basePrice * (1 + req.Coefficient/100)
		}
		newPrice = &basePrice
	}

	c.JSON(http.StatusOK, gin.H{
		"lot_name":        req.LotName,
		"current_price":   comp.CurrentPrice,
		"median_all_time": medianAllTime,
		"new_price":       newPrice,
		"quote_count":     quoteCount,
		"manual_price":    comp.ManualPrice,
		"last_price":      lastPrice.Price,
		"last_price_date": lastPrice.Date,
	})
}