package ws

import (
	"encoding/json"
	"log"
	"net/http"
	"sync"
	"time"

	"github.com/gorilla/websocket"
)

var upgrader = websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool { return true },
}

type Client struct {
	Conn     *websocket.Conn
	UserID   uint
	TenantID uint
	Role     string
	Send     chan []byte
}

type Message struct {
	Type      string `json:"type"`
	SessionID uint   `json:"session_id"`
	Content   string `json:"content,omitempty"`
	FromID    uint   `json:"from_id,omitempty"`
	FromName  string `json:"from_name,omitempty"`
	TenantID  uint   `json:"tenant_id"`
	Seq       int    `json:"seq,omitempty"`
	Timestamp int64  `json:"timestamp"`
}

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

var DefaultHub = NewHub()

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

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

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

		case msg := <-h.broadcast:
			h.mu.RLock()
			for client := range h.clients {
				select {
				case client.Send <- msg:
				default:
					close(client.Send)
					delete(h.clients, client)
				}
			}
			h.mu.RUnlock()
		}
	}
}

func (h *Hub) BroadcastToTenant(tenantID uint, msg []byte) {
	h.mu.RLock()
	defer h.mu.RUnlock()
	for client := range h.clients {
		if client.TenantID == tenantID {
			select {
			case client.Send <- msg:
			default:
			}
		}
	}
}

func HandleWebSocket(c *Client) {
	conn := c.Conn

	go func() {
		ticker := time.NewTicker(30 * time.Second)
		defer ticker.Stop()
		for {
			select {
			case msg, ok := <-c.Send:
				if !ok {
					conn.WriteMessage(websocket.CloseMessage, []byte{})
					return
				}
				conn.SetWriteDeadline(time.Now().Add(10 * time.Second))
				if err := conn.WriteMessage(websocket.TextMessage, msg); err != nil {
					return
				}
			case <-ticker.C:
				conn.SetWriteDeadline(time.Now().Add(10 * time.Second))
				if err := conn.WriteMessage(websocket.PingMessage, nil); err != nil {
					return
				}
			}
		}
	}()

	for {
		_, msgBytes, err := conn.ReadMessage()
		if err != nil {
			break
		}

		var msg Message
		if err := json.Unmarshal(msgBytes, &msg); err != nil {
			continue
		}
		msg.TenantID = c.TenantID
		msg.FromID = c.UserID
		msg.Timestamp = time.Now().UnixMilli()

		reply, _ := json.Marshal(msg)
		DefaultHub.BroadcastToTenant(c.TenantID, reply)
	}
}

func Upgrade(w http.ResponseWriter, r *http.Request, userID, tenantID uint, role string) (*Client, error) {
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		return nil, err
	}
	client := &Client{
		Conn:     conn,
		UserID:   userID,
		TenantID: tenantID,
		Role:     role,
		Send:     make(chan []byte, 256),
	}
	DefaultHub.register <- client
	log.Printf("WebSocket 连接: user=%d tenant=%d", userID, tenantID)
	return client, nil
}