package ws

import (
	"log"
	"sync"
)

// Hub WebSocket连接池
type Hub struct {
	mu         sync.RWMutex
	clients    map[*Client]bool
	broadcast  chan []byte
	register   chan *Client
	unregister chan *Client

	// 按用户ID索引的客户端映射
	userClients map[string]map[*Client]bool
}

// NewHub 创建WebSocket Hub
func NewHub() *Hub {
	return &Hub{
		clients:     make(map[*Client]bool),
		broadcast:   make(chan []byte, 256),
		register:    make(chan *Client),
		unregister:  make(chan *Client),
		userClients: make(map[string]map[*Client]bool),
	}
}

// Run 启动Hub主循环
func (h *Hub) Run() {
	for {
		select {
		case client := <-h.register:
			h.mu.Lock()
			h.clients[client] = true

			// 用户索引
			if h.userClients[client.UserID] == nil {
				h.userClients[client.UserID] = make(map[*Client]bool)
			}
			h.userClients[client.UserID][client] = true
			h.mu.Unlock()

			log.Printf("[WS] 客户端连接: user=%s session=%s (当前连接数: %d)",
				client.UserID, client.SessionID, len(h.clients))

		case client := <-h.unregister:
			h.mu.Lock()
			if _, ok := h.clients[client]; ok {
				delete(h.clients, client)
				close(client.Send)

				// 清理用户索引
				if h.userClients[client.UserID] != nil {
					delete(h.userClients[client.UserID], client)
					if len(h.userClients[client.UserID]) == 0 {
						delete(h.userClients, client.UserID)
					}
				}
			}
			h.mu.Unlock()

			log.Printf("[WS] 客户端断开: user=%s session=%s (当前连接数: %d)",
				client.UserID, client.SessionID, len(h.clients))

		case message := <-h.broadcast:
			h.mu.RLock()
			for client := range h.clients {
				select {
				case client.Send <- message:
				default:
					// 客户端发送通道已满，跳过
					close(client.Send)
					delete(h.clients, client)
				}
			}
			h.mu.RUnlock()
		}
	}
}

// SendToUser 向指定用户的所有连接发送消息
func (h *Hub) SendToUser(userID string, message []byte) {
	h.mu.RLock()
	defer h.mu.RUnlock()

	if clients, ok := h.userClients[userID]; ok {
		for client := range clients {
			select {
			case client.Send <- message:
			default:
				// 跳过阻塞的客户端
			}
		}
	}
}

// SendToSession 向指定会话的连接发送消息
func (h *Hub) SendToSession(userID, sessionID string, message []byte) {
	h.mu.RLock()
	defer h.mu.RUnlock()

	if clients, ok := h.userClients[userID]; ok {
		for client := range clients {
			if client.SessionID == sessionID {
				select {
				case client.Send <- message:
				default:
				}
			}
		}
	}
}

// ClientCount 获取当前连接数
func (h *Hub) ClientCount() int {
	h.mu.RLock()
	defer h.mu.RUnlock()
	return len(h.clients)
}

// UserClientCount 获取指定用户的连接数
func (h *Hub) UserClientCount(userID string) int {
	h.mu.RLock()
	defer h.mu.RUnlock()
	if clients, ok := h.userClients[userID]; ok {
		return len(clients)
	}
	return 0
}