package websocket

import (
	"api-service/internal/config"
	"api-service/internal/database"
	"context"
	"database/sql"
	"encoding/json"
	"fmt"
	"sync"
	"time"
)

// Hub mengelola semua klien WebSocket
type Hub struct {
	// Konfigurasi
	config config.WebSocketConfig

	// Klien
	clients         map[*Client]bool
	clientsByID     map[string]*Client
	clientsByIP     map[string][]*Client
	clientsByStatic map[string]*Client

	// Ruangan
	rooms map[string]map[*Client]bool

	// Channel komunikasi
	broadcast    chan WebSocketMessage
	register     chan *Client
	unregister   chan *Client
	messageQueue chan WebSocketMessage

	// Sinkronisasi
	mu sync.RWMutex

	// Context
	ctx    context.Context
	cancel context.CancelFunc

	// Layanan eksternal
	dbService database.Service

	// Monitoring
	startTime    time.Time
	messageCount int64
	errorCount   int64
	activityLog  []ActivityLog
	activityMu   sync.RWMutex

	// Registry handler pesan
	messageRegistry *MessageRegistry
	broadcaster     *Broadcaster
}

// ActivityLog menyimpan log aktivitas
type ActivityLog struct {
	Timestamp time.Time `json:"timestamp"`
	Event     string    `json:"event"`
	ClientID  string    `json:"client_id"`
	Details   string    `json:"details"`
}

// DatabaseService mendefinisikan interface untuk layanan database
type DatabaseService interface {
	Health() map[string]interface{}
	//ListDBs() []string
	ListenForChanges(ctx context.Context, dbName string, channels []string, callback func(channel, payload string)) error
	NotifyChange(dbName, channel, payload string) error
	GetDB(name string) (*sql.DB, error)
	GetPrimaryDB(name string) (*sql.DB, error)
}

// Global database service instance
var (
	dbService database.Service
	once      sync.Once
)

// Initialize the database connection
func init() {
	once.Do(func() {
		dbService = database.New(config.LoadConfig())
		if dbService == nil {
			panic("Failed to initialize database connection")
		}
	})
}

// NewHub membuat hub baru dengan konfigurasi yang diberikan
func NewHub(config config.WebSocketConfig) *Hub {
	ctx, cancel := context.WithCancel(context.Background())

	hub := &Hub{

		config:          config,
		clients:         make(map[*Client]bool),
		clientsByID:     make(map[string]*Client),
		clientsByIP:     make(map[string][]*Client),
		clientsByStatic: make(map[string]*Client),
		rooms:           make(map[string]map[*Client]bool),
		broadcast:       make(chan WebSocketMessage, 1000),
		register:        make(chan *Client),
		unregister:      make(chan *Client),
		messageQueue:    make(chan WebSocketMessage, config.MessageQueueSize),
		ctx:             ctx,
		cancel:          cancel,
		dbService:       dbService,
		startTime:       time.Now(),
		activityLog:     make([]ActivityLog, 0, config.ActivityLogSize),
		messageRegistry: NewMessageRegistry(),
	}

	// Setup default message handlers
	// SetupDefaultHandlers(hub.messageRegistry)

	// Setup database change listeners
	hub.setupDatabaseListeners()

	return hub
}

// Run menjalankan loop utama hub
func (h *Hub) Run() {
	// Start queue workers
	for i := 0; i < h.config.QueueWorkers; i++ {
		go h.queueWorker(i)
	}

	for {
		select {
		case client := <-h.register:
			h.registerClient(client)

		case client := <-h.unregister:
			h.unregisterClient(client)

		case message := <-h.broadcast:
			h.messageCount++
			h.broadcastToClients(message)

		case <-h.ctx.Done():
			return
		}
	}
}

// queueWorker memproses pesan dari antrian
func (h *Hub) queueWorker(workerID int) {
	for {
		select {
		case message := <-h.messageQueue:
			h.broadcast <- message
		case <-h.ctx.Done():
			return
		}
	}
}

// registerClient mendaftarkan klien baru
func (h *Hub) registerClient(client *Client) {
	h.mu.Lock()
	defer h.mu.Unlock()

	// Register di peta klien utama
	h.clients[client] = true

	// Register berdasarkan ID
	h.clientsByID[client.ID] = client

	// Register berdasarkan ID statis
	if client.StaticID != "" {
		h.clientsByStatic[client.StaticID] = client
	}

	// Register berdasarkan IP
	if h.clientsByIP[client.IPAddress] == nil {
		h.clientsByIP[client.IPAddress] = make([]*Client, 0)
	}
	h.clientsByIP[client.IPAddress] = append(h.clientsByIP[client.IPAddress], client)

	// Register di ruangan
	if client.Room != "" {
		if h.rooms[client.Room] == nil {
			h.rooms[client.Room] = make(map[*Client]bool)
		}
		h.rooms[client.Room][client] = true
	}

	// Log aktivitas
	h.logActivity("client_connected", client.ID,
		fmt.Sprintf("IP: %s, Static: %s, Room: %s", client.IPAddress, client.StaticID, client.Room))
}

// unregisterClient menghapus klien
func (h *Hub) unregisterClient(client *Client) {
	h.mu.Lock()
	defer h.mu.Unlock()

	if _, ok := h.clients[client]; ok {
		// Hapus dari peta klien utama
		delete(h.clients, client)
		close(client.Send)

		// Hapus dari peta berdasarkan ID
		delete(h.clientsByID, client.ID)

		// Hapus dari peta berdasarkan ID statis
		if client.StaticID != "" {
			delete(h.clientsByStatic, client.StaticID)
		}

		// Hapus dari peta berdasarkan IP
		if ipClients, exists := h.clientsByIP[client.IPAddress]; exists {
			for i, c := range ipClients {
				if c == client {
					h.clientsByIP[client.IPAddress] = append(ipClients[:i], ipClients[i+1:]...)
					break
				}
			}
			// Jika tidak ada lagi klien dari IP ini, hapus entri IP
			if len(h.clientsByIP[client.IPAddress]) == 0 {
				delete(h.clientsByIP, client.IPAddress)
			}
		}

		// Hapus dari ruangan
		if client.Room != "" {
			if room, exists := h.rooms[client.Room]; exists {
				delete(room, client)
				if len(room) == 0 {
					delete(h.rooms, client.Room)
				}
			}
		}
	}

	// Log aktivitas
	h.logActivity("client_disconnected", client.ID,
		fmt.Sprintf("IP: %s, Duration: %v", client.IPAddress, time.Since(client.connectedAt)))

	client.cancel()
}

// broadcastToClients mengirim pesan ke klien yang sesuai
func (h *Hub) broadcastToClients(message WebSocketMessage) {
	h.mu.RLock()
	defer h.mu.RUnlock()

	if message.ClientID != "" {
		// Kirim ke klien tertentu
		if client, exists := h.clientsByID[message.ClientID]; exists {
			select {
			case client.Send <- message:
			default:
				go func() {
					h.unregister <- client
				}()
			}
		}
		return
	}

	// Periksa apakah ini pesan ruangan
	if message.Room != "" {
		if room, roomExists := h.rooms[message.Room]; roomExists {
			for client := range room {
				select {
				case client.Send <- message:
				default:
					go func(c *Client) {
						h.unregister <- c
					}(client)
				}
			}
		}
		return
	}

	// Broadcast ke semua klien
	for client := range h.clients {
		select {
		case client.Send <- message:
		default:
			go func(c *Client) {
				h.unregister <- c
			}(client)
		}
	}
}

// logActivity mencatat aktivitas
func (h *Hub) logActivity(event, clientID, details string) {
	h.activityMu.Lock()
	defer h.activityMu.Unlock()

	activity := ActivityLog{
		Timestamp: time.Now(),
		Event:     event,
		ClientID:  clientID,
		Details:   details,
	}

	h.activityLog = append(h.activityLog, activity)

	// Pertahankan hanya aktivitas terakhir sesuai konfigurasi
	if len(h.activityLog) > h.config.ActivityLogSize {
		h.activityLog = h.activityLog[1:]
	}
}

// GetConfig mengembalikan konfigurasi hub
func (h *Hub) GetConfig() config.WebSocketConfig {
	return h.config
}

// GetMessageRegistry mengembalikan registry pesan
func (h *Hub) GetMessageRegistry() *MessageRegistry {
	return h.messageRegistry
}

// RegisterChannel mengembalikan channel register untuk handler
func (h *Hub) RegisterChannel() chan *Client {
	return h.register
}

// GetStats mengembalikan statistik hub
func (h *Hub) GetStats() map[string]interface{} {
	h.mu.RLock()
	defer h.mu.RUnlock()

	return map[string]interface{}{
		"connected_clients": len(h.clients),
		"unique_ips":        len(h.clientsByIP),
		"static_clients":    len(h.clientsByStatic),
		"rooms":             len(h.rooms),
		"message_count":     h.messageCount,
		"error_count":       h.errorCount,
		"uptime":            time.Since(h.startTime).String(),
		"server_id":         h.config.ServerID,
		"timestamp":         time.Now().Unix(),
	}
}

// setupDatabaseListeners sets up database change listeners for real-time updates
func (h *Hub) setupDatabaseListeners() {
	// Listen for changes on retribusi table
	channels := []string{"data_changes"}

	err := h.dbService.ListenForChanges(h.ctx, "simrs_prod", channels, func(channel, payload string) {
		h.handleDatabaseChange(channel, payload)
	})

	if err != nil {
		h.logActivity("database_listener_error", "", fmt.Sprintf("Failed to setup listeners: %v", err))
	} else {
		h.logActivity("database_listener_started", "", "Database change listeners initialized")
	}
}

// handleDatabaseChange processes database change notifications
func (h *Hub) handleDatabaseChange(channel, payload string) {
	h.logActivity("database_change", "", fmt.Sprintf("Channel: %s, Payload: %s", channel, payload))

	// Parse the payload to determine what changed
	var changeData map[string]interface{}
	if err := json.Unmarshal([]byte(payload), &changeData); err != nil {
		h.logActivity("database_change_parse_error", "", fmt.Sprintf("Failed to parse payload: %v", err))
		return
	}

	// Create WebSocket message for broadcasting
	message := WebSocketMessage{
		Type:     DatabaseChangeMessage,
		Data:     changeData,
		ClientID: "",
		Room:     "data_updates", // Broadcast to data_updates room
	}

	// Broadcast the change to all connected clients in the data_updates room
	h.broadcast <- message
}

// GetDatabaseConnection returns a database connection for the specified database
func (h *Hub) GetDatabaseConnection(dbName string) (*sql.DB, error) {
	return h.dbService.GetDB(dbName)
}

// ExecuteDatabaseQuery executes a database query and returns results
func (h *Hub) ExecuteDatabaseQuery(dbName, query string, args ...interface{}) ([]map[string]interface{}, error) {
	db, err := h.GetDatabaseConnection(dbName)
	if err != nil {
		return nil, fmt.Errorf("failed to get database connection: %w", err)
	}

	ctx, cancel := context.WithTimeout(h.ctx, 30*time.Second)
	defer cancel()

	rows, err := db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("failed to execute query: %w", err)
	}
	defer rows.Close()

	columns, err := rows.Columns()
	if err != nil {
		return nil, fmt.Errorf("failed to get columns: %w", err)
	}

	var results []map[string]interface{}

	for rows.Next() {
		values := make([]interface{}, len(columns))
		valuePtrs := make([]interface{}, len(columns))
		for i := range values {
			valuePtrs[i] = &values[i]
		}

		if err := rows.Scan(valuePtrs...); err != nil {
			return nil, fmt.Errorf("failed to scan row: %w", err)
		}

		row := make(map[string]interface{})
		for i, col := range columns {
			val := values[i]
			if b, ok := val.([]byte); ok {
				val = string(b)
			}
			row[col] = val
		}
		results = append(results, row)
	}

	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("rows iteration error: %w", err)
	}

	return results, nil
}

// NotifyDatabaseChange sends a notification to the database for real-time updates
func (h *Hub) NotifyDatabaseChange(dbName, channel, payload string) error {
	return h.dbService.NotifyChange(dbName, channel, payload)
}