package handlers

import (
	"fmt"
	"gestion/db"
	"gestion/models"
	"net/http"

	"github.com/gin-gonic/gin"
)

var weekdayNames = []string{"Dimanche", "Lundi", "Mardi", "Mercredi", "Jeudi", "Vendredi", "Samedi"}

// GetAdminStats returns aggregated order & product statistics for the admin dashboard.
func GetAdminStats(c *gin.Context) {
	database := c.MustGet("database").(*db.Database)
	gdb := database.GDB

	// ── Commandes par jour de la semaine (all time, non annulées) ──────────────
	var wdRows []models.WeekdayRow
	gdb.Raw(`
		SELECT EXTRACT(DOW FROM created_at)::int AS dow, COUNT(*) AS count
		FROM commandes
		WHERE status != 'cancelled'
		GROUP BY dow
		ORDER BY dow
	`).Scan(&wdRows)

	byWeekday := make([]gin.H, 7)
	wdMap := make(map[int]int, len(wdRows))
	for _, r := range wdRows {
		wdMap[r.DOW] = r.Count
	}
	peakCount, peakWeekday := 0, ""
	for i := 0; i < 7; i++ {
		cnt := wdMap[i]
		byWeekday[i] = gin.H{"weekday": weekdayNames[i], "count": cnt}
		if cnt > peakCount {
			peakCount = cnt
			peakWeekday = weekdayNames[i]
		}
	}

	// ── Commandes par jour sur 30 jours ───────────────────────────────────────
	var dayRows []models.DayRow
	gdb.Raw(`
		SELECT DATE(created_at) AS day, COUNT(*) AS count
		FROM commandes
		WHERE created_at >= NOW() - INTERVAL '30 days'
		  AND status != 'cancelled'
		GROUP BY DATE(created_at)
		ORDER BY day
	`).Scan(&dayRows)

	byDay := make([]gin.H, len(dayRows))
	for i, r := range dayRows {
		byDay[i] = gin.H{
			"day":   r.Day.Format("2006-01-02"),
			"label": r.Day.Format("02/01"),
			"count": r.Count,
		}
	}

	// ── Revenus par jour sur 30 jours (commandes approuvées) ─────────────────
	var dayRevRows []models.DayRevenueRow
	gdb.Raw(`
		SELECT DATE(created_at) AS day, COALESCE(SUM(total_prix - COALESCE(referral_used, 0)), 0) AS revenue
		FROM commandes
		WHERE created_at >= NOW() - INTERVAL '30 days'
		  AND status = 'approved'
		GROUP BY DATE(created_at)
		ORDER BY day
	`).Scan(&dayRevRows)

	byDayRevenue := make([]gin.H, len(dayRevRows))
	for i, r := range dayRevRows {
		byDayRevenue[i] = gin.H{
			"day":     r.Day.Format("2006-01-02"),
			"label":   r.Day.Format("02/01"),
			"revenue": r.Revenue,
		}
	}

	// ── Commandes & revenus par heure (all time, non annulées) ───────────────
	var hourRows []models.HourRow
	gdb.Raw(`
		SELECT
			EXTRACT(HOUR FROM created_at)::int AS hour,
			COUNT(*)                           AS count,
			COALESCE(SUM(total_prix - COALESCE(referral_used, 0)), 0) AS revenue
		FROM commandes
		WHERE status != 'cancelled'
		GROUP BY hour
		ORDER BY hour
	`).Scan(&hourRows)

	hourMap := make(map[int]models.HourRow, len(hourRows))
	for _, r := range hourRows {
		hourMap[r.Hour] = r
	}
	byHour := make([]gin.H, 24)
	for h := 0; h < 24; h++ {
		r := hourMap[h]
		byHour[h] = gin.H{
			"hour":    h,
			"label":   fmt.Sprintf("%02dh", h),
			"count":   r.Count,
			"revenue": r.Revenue,
		}
	}

	// ── Top produits (quantité vendue, commandes terminées) ───────────────────
	var prodRows []models.ProductRow
	gdb.Raw(`
		SELECT
			ci.product_id,
			ci.produit                              AS name,
			SUM(ci.quantite)                        AS total_quantity,
			COUNT(DISTINCT ci.command_id)           AS order_count,
			SUM(ci.prix)              AS revenue,
			COALESCE(p.category, '')                AS category,
			COALESCE(cat.color, '#7c3aed')          AS category_color
		FROM command_items ci
		JOIN commandes c ON c.id = ci.command_id
		LEFT JOIN products p   ON p.id = ci.product_id
		LEFT JOIN categories cat ON cat.name = p.category
		WHERE c.status != 'cancelled'
		GROUP BY ci.product_id, ci.produit, p.category, cat.color
		ORDER BY total_quantity DESC
		LIMIT 15
	`).Scan(&prodRows)

	topProducts := make([]gin.H, len(prodRows))
	topProductName := ""
	for i, r := range prodRows {
		topProducts[i] = gin.H{
			"product_id":     r.ProductID,
			"name":           r.Name,
			"quantity":       r.Quantity,
			"order_count":    r.OrderCount,
			"revenue":        r.Revenue,
			"category":       r.Category,
			"category_color": r.CategoryColor,
		}
		if i == 0 {
			topProductName = r.Name
		}
	}

	// ── Répartition des doses/quantités par produit ───────────────────────────
	var qtyRows []models.QuantityBreakdownRow
	gdb.Raw(`
		SELECT
			ci.product_id,
			ci.produit                           AS product_name,
			ci.quantite                          AS quantity,
			COUNT(DISTINCT ci.command_id)        AS order_count,
			SUM(ci.quantite)                     AS total_sold,
			SUM(ci.prix)           AS revenue,
			COALESCE(cat.color, '#7c3aed')       AS category_color
		FROM command_items ci
		JOIN commandes c ON c.id = ci.command_id
		LEFT JOIN products p   ON p.id = ci.product_id
		LEFT JOIN categories cat ON cat.name = p.category
		WHERE c.status != 'cancelled'
		GROUP BY ci.product_id, ci.produit, ci.quantite, cat.color
		ORDER BY ci.product_id, COUNT(DISTINCT ci.command_id) DESC
	`).Scan(&qtyRows)

	type productGroup struct {
		ProductID     int
		Name          string
		CategoryColor string
		TotalOrders   int
		Quantities    []gin.H
	}
	var groups []productGroup
	groupIdx := map[int]int{}
	for _, r := range qtyRows {
		idx, ok := groupIdx[r.ProductID]
		if !ok {
			idx = len(groups)
			groups = append(groups, productGroup{
				ProductID:     r.ProductID,
				Name:          r.ProductName,
				CategoryColor: r.CategoryColor,
			})
			groupIdx[r.ProductID] = idx
		}
		groups[idx].TotalOrders += r.OrderCount
		groups[idx].Quantities = append(groups[idx].Quantities, gin.H{
			"quantity":    r.Quantity,
			"order_count": r.OrderCount,
			"total_sold":  r.TotalSold,
			"revenue":     r.Revenue,
		})
	}
	// Trier par total de commandes décroissant, garder 15 max
	for i := 0; i < len(groups)-1; i++ {
		for j := i + 1; j < len(groups); j++ {
			if groups[j].TotalOrders > groups[i].TotalOrders {
				groups[i], groups[j] = groups[j], groups[i]
			}
		}
	}
	if len(groups) > 15 {
		groups = groups[:15]
	}
	byQuantity := make([]gin.H, len(groups))
	for i, g := range groups {
		byQuantity[i] = gin.H{
			"product_id":     g.ProductID,
			"name":           g.Name,
			"category_color": g.CategoryColor,
			"total_orders":   g.TotalOrders,
			"quantities":     g.Quantities,
		}
	}

	// ── Résumé global ─────────────────────────────────────────────────────────
	var totalOrders int64
	var totalRevenue float64
	gdb.Raw(`SELECT COUNT(*) FROM commandes WHERE status != 'cancelled'`).Scan(&totalOrders)
	gdb.Raw(`SELECT COALESCE(SUM(total_prix - COALESCE(referral_used, 0)), 0) FROM commandes WHERE status = 'approved'`).Scan(&totalRevenue)

	avgPerDay := 0.0
	if totalOrders > 0 {
		// average over the last 30 days with data
		var activeDays int64
		gdb.Raw(`
			SELECT COUNT(DISTINCT DATE(created_at))
			FROM commandes
			WHERE created_at >= NOW() - INTERVAL '30 days' AND status != 'cancelled'
		`).Scan(&activeDays)
		if activeDays > 0 {
			var last30Count int64
			gdb.Raw(`
				SELECT COUNT(*) FROM commandes
				WHERE created_at >= NOW() - INTERVAL '30 days' AND status != 'cancelled'
			`).Scan(&last30Count)
			avgPerDay = float64(last30Count) / float64(activeDays)
		}
	}

	c.JSON(http.StatusOK, gin.H{
		"summary": gin.H{
			"total_orders":  totalOrders,
			"total_revenue": totalRevenue,
			"peak_weekday":  peakWeekday,
			"top_product":   topProductName,
			"avg_per_day":   avgPerDay,
		},
		"by_weekday":     byWeekday,
		"by_day_30":      byDay,
		"by_day_revenue": byDayRevenue,
		"by_hour":        byHour,
		"top_products":   topProducts,
		"by_quantity":    byQuantity,
	})
}