package main

import (
	"log"
	"net/http"
	"os"
	"strconv"
	"strings"
	"sync"
	"time"

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

type ClubInstance struct {
	ClubID       string            `json:"club_id"`
	ClubName     string            `json:"club_name"`
	APIBaseURL   string            `json:"api_base_url"`
	LogoURL      string            `json:"logo_url"`
	City         string            `json:"city"`
	Country      string            `json:"country"`
	IsActive     bool              `json:"is_active"`
	Version      string            `json:"version"`
	Tags         map[string]string `json:"tags"`
	Features     []string          `json:"features"`
	LastSeen     time.Time         `json:"last_seen"`
	RegisteredAt time.Time         `json:"registered_at"`
}

type CentralDirectory struct {
	instances map[string]ClubInstance
	mutex     sync.RWMutex
	token     string
}

func NewCentralDirectory(token string) *CentralDirectory {
	return &CentralDirectory{
		instances: make(map[string]ClubInstance),
		token:     token,
	}
}

func (cd *CentralDirectory) HandleRegistration(c *gin.Context) {
	var payload ClubInstance
	if err := c.ShouldBindJSON(&payload); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid payload"})
		return
	}

	// Validate token
	if !cd.validateToken(c) {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "unauthorized"})
		return
	}

	// Validate required fields
	if payload.ClubID == "" || payload.ClubName == "" || payload.APIBaseURL == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "missing required fields: club_id, club_name, api_base_url"})
		return
	}

	cd.mutex.Lock()
	defer cd.mutex.Unlock()

	// Set registration time if not present
	if payload.RegisteredAt.IsZero() {
		payload.RegisteredAt = time.Now()
	}

	// Update or add instance
	if existing, exists := cd.instances[payload.ClubID]; exists {
		// Update existing instance but preserve registration time
		payload.RegisteredAt = existing.RegisteredAt
		cd.instances[payload.ClubID] = payload
		log.Printf("Updated club instance: %s (%s)", payload.ClubName, payload.ClubID)
	} else {
		cd.instances[payload.ClubID] = payload
		log.Printf("Registered new club instance: %s (%s)", payload.ClubName, payload.ClubID)
	}

	c.JSON(http.StatusOK, gin.H{
		"status":    "registered",
		"club_id":   payload.ClubID,
		"timestamp": payload.LastSeen,
	})
}

func (cd *CentralDirectory) HandleHeartbeat(c *gin.Context) {
	var payload map[string]interface{}
	if err := c.ShouldBindJSON(&payload); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid payload"})
		return
	}

	// Validate token
	if !cd.validateToken(c) {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "unauthorized"})
		return
	}

	clubID, ok := payload["club_id"].(string)
	if !ok {
		c.JSON(http.StatusBadRequest, gin.H{"error": "missing club_id"})
		return
	}

	cd.mutex.Lock()
	defer cd.mutex.Unlock()

	if instance, exists := cd.instances[clubID]; exists {
		instance.LastSeen = time.Now()
		if lastSeen, ok := payload["last_seen"].(string); ok {
			if parsed, err := time.Parse(time.RFC3339, lastSeen); err == nil {
				instance.LastSeen = parsed
			}
		}
		cd.instances[clubID] = instance
		c.JSON(http.StatusOK, gin.H{"status": "ok"})
	} else {
		c.JSON(http.StatusNotFound, gin.H{"error": "club not found"})
	}
}

func (cd *CentralDirectory) HandleListClubs(c *gin.Context) {
	search := c.Query("search")
	active := c.DefaultQuery("active", "true")
	limit := c.DefaultQuery("limit", "50")

	cd.mutex.RLock()
	defer cd.mutex.RUnlock()

	var results []ClubInstance
	for _, instance := range cd.instances {
		// Filter by active status
		if active == "true" && !instance.IsActive {
			continue
		}
		if active == "false" && instance.IsActive {
			continue
		}

		// Filter by search query
		if search != "" {
			query := strings.ToLower(search)
			if !strings.Contains(strings.ToLower(instance.ClubName), query) &&
				!strings.Contains(strings.ToLower(instance.City), query) &&
				!strings.Contains(strings.ToLower(instance.Country), query) {
				continue
			}
		}

		results = append(results, instance)
	}

	// Apply limit
	if len(results) > 0 {
		if limitInt := parseInt(limit); limitInt > 0 && limitInt < len(results) {
			results = results[:limitInt]
		}
	}

	c.JSON(http.StatusOK, results)
}

func (cd *CentralDirectory) HandleGetClub(c *gin.Context) {
	clubID := c.Param("id")

	cd.mutex.RLock()
	defer cd.mutex.RUnlock()

	instance, exists := cd.instances[clubID]
	if !exists {
		c.JSON(http.StatusNotFound, gin.H{"error": "club not found"})
		return
	}

	c.JSON(http.StatusOK, instance)
}

func (cd *CentralDirectory) HandleHealth(c *gin.Context) {
	cd.mutex.RLock()
	count := len(cd.instances)
	cd.mutex.RUnlock()

	c.JSON(http.StatusOK, gin.H{
		"status":    "ok",
		"timestamp": time.Now(),
		"instances": count,
		"service":   "myclub-directory",
	})
}

func (cd *CentralDirectory) HandleStats(c *gin.Context) {
	cd.mutex.RLock()
	defer cd.mutex.RUnlock()

	activeCount := 0
	featureCounts := make(map[string]int)
	countryCounts := make(map[string]int)

	for _, instance := range cd.instances {
		if instance.IsActive {
			activeCount++
		}

		for _, feature := range instance.Features {
			featureCounts[feature]++
		}

		if instance.Country != "" {
			countryCounts[instance.Country]++
		}
	}

	c.JSON(http.StatusOK, gin.H{
		"total_instances":  len(cd.instances),
		"active_instances": activeCount,
		"features":         featureCounts,
		"countries":        countryCounts,
		"timestamp":        time.Now(),
	})
}

func (cd *CentralDirectory) validateToken(c *gin.Context) bool {
	// Check Authorization header (same pattern as error system)
	authHeader := c.GetHeader("Authorization")
	if authHeader != "" {
		token := strings.TrimPrefix(authHeader, "Bearer ")
		return token == cd.token
	}

	// Check X-Ingest-Token header (same pattern as error system)
	tokenHeader := c.GetHeader("X-Ingest-Token")
	if tokenHeader != "" {
		return tokenHeader == cd.token
	}

	// Check X-Directory-Token header (fallback for direct access)
	directoryTokenHeader := c.GetHeader("X-Directory-Token")
	if directoryTokenHeader != "" {
		return directoryTokenHeader == cd.token
	}

	return false
}

func parseInt(s string) int {
	if i, err := strconv.Atoi(s); err == nil {
		return i
	}
	return 0
}

func setupRoutes(cd *CentralDirectory) *gin.Engine {
	r := gin.Default()

	// CORS middleware
	r.Use(func(c *gin.Context) {
		c.Header("Access-Control-Allow-Origin", "*")
		c.Header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
		c.Header("Access-Control-Allow-Headers", "Content-Type, Authorization, X-Directory-Token")

		if c.Request.Method == "OPTIONS" {
			c.AbortWithStatus(http.StatusNoContent)
			return
		}

		c.Next()
	})

	// API routes
	api := r.Group("/api/v1")
	{
		// Public endpoints
		api.GET("/clubs", cd.HandleListClubs)
		api.GET("/clubs/:id", cd.HandleGetClub)
		api.GET("/health", cd.HandleHealth)
		api.GET("/stats", cd.HandleStats)

		// Protected endpoints (require token)
		api.POST("/directory/register", cd.HandleRegistration)
		api.POST("/directory/heartbeat", cd.HandleHeartbeat)
	}

	// Root endpoint
	r.GET("/", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{
			"service":   "MyClub Central Directory",
			"version":   "1.0.0",
			"timestamp": time.Now(),
		})
	})

	r.NoRoute(func(c *gin.Context) {
		c.JSON(http.StatusNotFound, gin.H{"error": "endpoint not found"})
	})

	return r
}

func main() {
	port := os.Getenv("PORT")
	if port == "" {
		port = "8083"
	}

	token := os.Getenv("DIRECTORY_TOKEN")
	if token == "" {
		log.Fatal("DIRECTORY_TOKEN environment variable is required")
	}

	log.Printf("Starting MyClub Central Directory on port %s", port)

	cd := NewCentralDirectory(token)
	r := setupRoutes(cd)

	// Start cleanup goroutine to remove inactive instances
	go cd.cleanupInactiveInstances()

	if err := r.Run(":" + port); err != nil {
		log.Fatal("Failed to start server:", err)
	}
}

func (cd *CentralDirectory) cleanupInactiveInstances() {
	ticker := time.NewTicker(10 * time.Minute) // Check every 10 minutes
	defer ticker.Stop()

	for range ticker.C {
		cd.mutex.Lock()
		now := time.Now()
		for clubID, instance := range cd.instances {
			// Remove instances that haven't been seen for more than 1 hour
			if now.Sub(instance.LastSeen) > time.Hour {
				delete(cd.instances, clubID)
				log.Printf("Removed inactive club instance: %s (%s)", instance.ClubName, clubID)
			}
		}
		cd.mutex.Unlock()
	}
}