feat: add stats page for admin

backend/gestion/handlers/stats.go

@@ -0,0 +1,150 @@
+package handlers
+
+import (
+	"gestion/db"
+	"net/http"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+type weekdayRow struct {
+	DOW   int `gorm:"column:dow"`
+	Count int `gorm:"column:count"`
+}
+
+type dayRow struct {
+	Day   time.Time `gorm:"column:day"`
+	Count int       `gorm:"column:count"`
+}
+
+type productRow struct {
+	ProductID  int     `gorm:"column:product_id"`
+	Name       string  `gorm:"column:name"`
+	Quantity   float64 `gorm:"column:total_quantity"`
+	OrderCount int     `gorm:"column:order_count"`
+	Revenue    float64 `gorm:"column:revenue"`
+}
+
+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 []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 []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,
+		}
+	}
+
+	// ── Top produits (quantité vendue, commandes terminées) ───────────────────
+	var prodRows []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 * ci.quantite)        AS revenue
+		FROM command_items ci
+		JOIN commandes c ON c.id = ci.command_id
+		WHERE c.status != 'cancelled'
+		GROUP BY ci.product_id, ci.produit
+		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,
+		}
+		if i == 0 {
+			topProductName = r.Name
+		}
+	}
+
+	// ── 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), 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,
+		"top_products": topProducts,
+	})
+}

backend/gestion/routes/routes.go

@@ -194,6 +194,11 @@ func SetupRoutes(router *gin.Engine, database *db.Database, geoService *services
 		adminGroupV2.POST("/categories", handlers.CreateCategory)
 		adminGroupV2.PUT("/categories/:id", handlers.UpdateCategory)
 		adminGroupV2.DELETE("/categories/:id", handlers.DeleteCategory)
+		// ============================================
+		// STATISTIQUES ADMIN
+		// ============================================
+		adminGroupV2.GET("/stats", handlers.GetAdminStats)
+
 		// ============================================
 		// COMMANDES - GESTION DE BASE
 		// ============================================