package handlers

import (
	"encoding/json"
	"fmt"
	"gestion/db"
	"gestion/services"
	"log"
	"net/http"
	"strconv"
	"time"

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

// returnStaleOrUnavailable retourne le cache périmé avec le temps restant recalculé,
// ou {eta_available: false, message: "Aucune heure disponible"} si le cache est absent ou expiré.
func returnStaleOrUnavailable(commandID int, status string, etaData map[string]string) gin.H {
	if len(etaData) > 0 {
		if updatedAtStr, ok := etaData["updated_at"]; ok {
			var updatedAt int64
			fmt.Sscanf(updatedAtStr, "%d", &updatedAt)
			var etaMin int64
			if etaStr, ok2 := etaData["eta_minutes"]; ok2 {
				fmt.Sscanf(etaStr, "%d", &etaMin)
			}
			elapsed := int64(time.Since(time.Unix(updatedAt, 0)).Minutes())
			remaining := etaMin - elapsed
			if remaining > 0 {
				arrival := time.Now().Add(time.Duration(remaining) * time.Minute)
				log.Printf("📦 [ETA] Cache périmé utilisé - %d min restantes", remaining)
				return gin.H{
					"success":           true,
					"command_id":        commandID,
					"status":            status,
					"eta_minutes":       remaining,
					"estimated_arrival": arrival.Format("15:04"),
					"eta_available":     true,
				}
			}
		}
	}
	return gin.H{
		"success":       true,
		"command_id":    commandID,
		"status":        status,
		"eta_available": false,
		"message":       "Aucune heure disponible",
	}
}

func GetOrderETA(c *gin.Context) {
	database := c.MustGet("database").(*db.Database)
	geoService := c.MustGet("geoService").(*services.GeoService)

	// 1️⃣ AUTHENTIFICATION
	username, exists := c.Get("username")
	if !exists {
		log.Printf("❌ [ETA] Non authentifié")
		c.JSON(http.StatusUnauthorized, gin.H{
			"success": false,
			"error":   "Utilisateur non authentifié",
		})
		return
	}

	// 2️⃣ RÉCUPÉRER L'ID DE LA COMMANDE
	commandID, err := strconv.Atoi(c.Param("id"))
	if err != nil {
		log.Printf("❌ [ETA] ID invalide: %v", err)
		c.JSON(http.StatusBadRequest, gin.H{
			"success": false,
			"error":   "ID de commande invalide",
		})
		return
	}

	command, err := database.GetCommandByID(commandID)
	if err != nil {
		log.Printf("❌ [ETA] Commande %d non trouvée", commandID)
		c.JSON(http.StatusNotFound, gin.H{
			"success": false,
			"error":   "Commande non trouvée",
		})
		return
	}

	cmdUsername, _ := command["username"].(string)
	userRole := c.GetString("role")

	if userRole != "admin" {
		if userRole == "client" && cmdUsername != username.(string) {
			log.Printf("❌ [ETA] Accès refusé - commande appartient à %s", cmdUsername)
			c.JSON(http.StatusForbidden, gin.H{
				"success": false,
				"error":   "Vous n'avez pas accès à cette commande",
			})
			return
		}

		if userRole == "livreur" {
			livreurAssign, _ := command["livreur_assign"].(string)
			if livreurAssign != username.(string) {
				log.Printf("❌ [ETA] Accès refusé - livreur non assigné")
				c.JSON(http.StatusForbidden, gin.H{
					"success": false,
					"error":   "Vous n'avez pas accès à cette commande",
				})
				return
			}
		}
	}

	cmdStatus, _ := command["status"].(string)

	if cmdStatus == "livre" || cmdStatus == "delivered" || cmdStatus == "approved" {
		log.Printf("ℹ️ [ETA] Commande déjà %s - pas d'ETA applicable", cmdStatus)
		c.JSON(http.StatusOK, gin.H{
			"success":           true,
			"command_id":        commandID,
			"status":            cmdStatus,
			"message":           "La commande a déjà été livrée",
			"eta_available":     false,
			"estimated_arrival": "Livraison complétée",
		})
		return
	}

	if cmdStatus == "pending" || cmdStatus == "assigned" {
		log.Printf("⏳ [ETA] Commande %s - pas d'ETA disponible", cmdStatus)
		c.JSON(http.StatusOK, gin.H{
			"success":       true,
			"command_id":    commandID,
			"status":        cmdStatus,
			"eta_available": false,
			"message":       "En attente de démarrage de la livraison",
		})
		return
	}

	if cmdStatus == "arrived" {
		log.Printf("ℹ️ [ETA] Commande arrived - livreur déjà sur place")
		c.JSON(http.StatusOK, gin.H{
			"success":       true,
			"command_id":    commandID,
			"status":        cmdStatus,
			"eta_available": false,
			"message":       "Le livreur est arrivé à destination",
		})
		return
	}

	etaKey := fmt.Sprintf("command:eta:%d", commandID)
	etaData, err := db.Redis.HGetAll(db.RedisCtx, etaKey).Result()

	if err == nil && len(etaData) > 0 {
		// ETA existe, vérifier s'il est récent
		if updatedAtStr, ok := etaData["updated_at"]; ok {
			var updatedAt int64
			fmt.Sscanf(updatedAtStr, "%d", &updatedAt)

			timeSinceUpdate := time.Since(time.Unix(updatedAt, 0))
			if timeSinceUpdate < 30*time.Second {
				// Cache valide
				var etaMinutes int64
				if etaStr, ok := etaData["eta_minutes"]; ok {
					fmt.Sscanf(etaStr, "%d", &etaMinutes)
				}

				var arrivalTime int64
				if arrivalStr, ok := etaData["arrival_time"]; ok {
					fmt.Sscanf(arrivalStr, "%d", &arrivalTime)
				}

				log.Printf("✅ [ETA] Cache hit - ETA: %d min", etaMinutes)

				c.JSON(http.StatusOK, gin.H{
					"success":           true,
					"command_id":        commandID,
					"status":            cmdStatus,
					"eta_minutes":       etaMinutes,
					"estimated_arrival": time.Unix(arrivalTime, 0).Format("15:04"),
					"eta_available":     true,
					"with_traffic":      true,
					"livreur_assign":    command["livreur_assign"],
					"delivery_address":  command["adresse"],
				})
				return
			}
		}
	}

	log.Printf("🔄 [ETA] Cache miss ou expiré - Recalcul de l'ETA...")

	var destLat, destLon float64

	destCacheKey := fmt.Sprintf("command:destination:%d", commandID)
	destData, err := db.Redis.Get(db.RedisCtx, destCacheKey).Result()
	if err == nil && destData != "" {
		var coords struct {
			Lat float64 `json:"lat"`
			Lon float64 `json:"lon"`
		}
		if err := json.Unmarshal([]byte(destData), &coords); err == nil && coords.Lat != 0 && coords.Lon != 0 {
			destLat = coords.Lat
			destLon = coords.Lon
			log.Printf("📍 Destination depuis cache Redis: (%.6f, %.6f)", destLat, destLon)
		}
	}

	if destLat == 0 || destLon == 0 {
		if dLat, okLat := command["dest_latitude"].(float64); okLat && dLat != 0 {
			destLat = dLat
		}
		if dLon, okLon := command["dest_longitude"].(float64); okLon && dLon != 0 {
			destLon = dLon
		}
	}

	if destLat == 0 || destLon == 0 {
		log.Printf("⚠️ [ETA] Coordonnées destination manquantes - retour cache périmé ou message")
		c.JSON(http.StatusOK, returnStaleOrUnavailable(commandID, cmdStatus, etaData))
		return
	}

	// Récupérer position du livreur
	livreurAssign, _ := command["livreur_assign"].(string)
	if livreurAssign == "" {
		log.Printf("⚠️ [ETA] Aucun livreur assigné")
		c.JSON(http.StatusOK, gin.H{
			"success":       true,
			"command_id":    commandID,
			"status":        cmdStatus,
			"eta_available": false,
			"message":       "Aucune heure disponible",
		})
		return
	}

	toCoords := services.Coordinates{Latitude: destLat, Longitude: destLon}

	livreurLocation, gpsErr := geoService.GetDeliveryPersonLocation(livreurAssign)
	if gpsErr != nil {
		lastLat, lastLon, lastErr := database.GetLastDeliveryCoords(livreurAssign)
		if lastErr != nil || lastLat == 0 {
			log.Printf("⚠️ [ETA] Aucune position disponible pour %s", livreurAssign)
			c.JSON(http.StatusOK, returnStaleOrUnavailable(commandID, cmdStatus, etaData))
			return
		}
		livreurLocation = &services.Coordinates{Latitude: lastLat, Longitude: lastLon}
		log.Printf("📍 [ETA] Position depuis dernière livraison: (%.6f, %.6f)", lastLat, lastLon)
	}

	log.Printf("🛣️ [ETA] Calcul TomTom: (%.6f, %.6f) -> (%.6f, %.6f)",
		livreurLocation.Latitude, livreurLocation.Longitude, toCoords.Latitude, toCoords.Longitude)

	etaMinutes, distanceKm, err := services.GetETAWithTraffic(*livreurLocation, toCoords)
	if err != nil {
		log.Printf("⚠️ [ETA] TomTom failed, fallback local: %v", err)
		distanceKm = services.CalculateDistance(*livreurLocation, toCoords)
		etaMinutes = services.CalculateETA(distanceKm)
	}

	now := time.Now()
	arrivalTime := now.Add(time.Duration(etaMinutes) * time.Minute)

	etaCache := map[string]any{
		"command_id":   commandID,
		"eta_minutes":  etaMinutes,
		"updated_at":   now.Unix(),
		"arrival_time": arrivalTime.Unix(),
		"distance_km":  distanceKm,
		"with_traffic": err == nil,
	}

	db.Redis.HSet(db.RedisCtx, etaKey, etaCache)
	db.Redis.Expire(db.RedisCtx, etaKey, 4*time.Hour)

	log.Printf("✅ [ETA] SUCCESS - ETA: %d min, arrivée: %s", etaMinutes, arrivalTime.Format("15:04"))

	c.JSON(http.StatusOK, gin.H{
		"success":           true,
		"command_id":        commandID,
		"status":            cmdStatus,
		"eta_minutes":       etaMinutes,
		"distance_km":       fmt.Sprintf("%.2f", distanceKm),
		"estimated_arrival": arrivalTime.Format("15:04"),
		"eta_available":     true,
		"with_traffic":      err == nil,
		"livreur_assign":    livreurAssign,
		"delivery_address":  command["adresse"],
	})
}