package handlers

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

	"github.com/gin-gonic/gin"
	"github.com/gorilla/websocket"
	"gorm.io/gorm"

	"ezops/internal/models"
)

var upgrader = websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool {
		return true // allow all origins in dev
	},
	ReadBufferSize:  1024,
	WriteBufferSize: 1024,
}

// WSMessage WebSocket消息结构
type WSMessage struct {
	Status int    `json:"status"` // 0=data, 1=resize
	Data   string `json:"data"`
	Cols   int    `json:"cols"`
	Rows   int    `json:"rows"`
}

// WebShellHandler WebShell处理器
type WebShellHandler struct {
	db      *gorm.DB
	clients sync.Map // serverID -> []*websocket.Conn
}

// NewWebShellHandler 创建WebShell处理器
func NewWebShellHandler(db *gorm.DB) *WebShellHandler {
	return &WebShellHandler{db: db}
}

// Terminal WebSocket终端连接
// @Summary WebShell终端
// @Description 通过WebSocket连接到服务器的SSH终端
// @Tags WebShell
// @Param id query int true "服务器ID"
// @Param cols query int false "终端列数"
// @Param rows query int false "终端行数"
// @Router /ws/terminal [get]
func (h *WebShellHandler) Terminal(c *gin.Context) {
	serverID := c.Query("id")
	if serverID == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "missing server id"})
		return
	}

	// Verify server exists
	var server models.Server
	if err := h.db.First(&server, serverID).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "server not found"})
		return
	}

	// Upgrade to WebSocket
	conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
	if err != nil {
		log.Printf("[WebShell] upgrade error: %v", err)
		return
	}
	defer conn.Close()

	log.Printf("[WebShell] connected to server %s (%s:%d)", server.Hostname, server.IP, server.Port)

	// Send welcome message
	welcome := WSMessage{
		Status: 0,
		Data:   "\r\n\x1b[32mEZOps WebShell\x1b[0m - Connected to " + server.Hostname + " (" + server.IP + ")\r\n",
	}
	conn.WriteJSON(welcome)

	// Demo mode: echo input back with a prompt
	// In production this would connect to actual SSH via crypto/ssh or a PTY bridge
	for {
		msgType, data, err := conn.ReadMessage()
		if err != nil {
			log.Printf("[WebShell] read error: %v", err)
			break
		}

		if msgType == websocket.TextMessage {
			var msg WSMessage
			if err := json.Unmarshal(data, &msg); err != nil {
				continue
			}

			switch msg.Status {
			case 0: // data
				// Process command input
				resp := WSMessage{Status: 0}
				switch msg.Data {
				case "\r", "\n":
					resp.Data = "\r\n[" + server.Hostname + " ~]$ "
				case "\u0003": // Ctrl+C
					resp.Data = "^C\r\n[" + server.Hostname + " ~]$ "
				case "\u0004": // Ctrl+D
					resp.Data = "\r\n\x1b[33mConnection closed.\x1b[0m\r\n"
					conn.WriteJSON(resp)
					goto done
				default:
					resp.Data = msg.Data // echo back
				}
				conn.WriteJSON(resp)

			case 1: // resize
				log.Printf("[WebShell] resize to cols=%d rows=%d", msg.Cols, msg.Rows)
			}
		}
	}

done:
	log.Printf("[WebShell] disconnected from server %s", server.Hostname)
}