package middleware

import (
	"log"
	"strings"

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

// CORS CORS中间件
func CORS() gin.HandlerFunc {
	return func(c *gin.Context) {
		// 获取请求路径
		path := c.Request.URL.Path

		c.Header("Access-Control-Allow-Origin", "*")
		c.Header("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, DELETE, OPTIONS")
		// 添加 WebSocket 升级所需的头
		c.Header("Access-Control-Allow-Headers", "Origin, Content-Type, Accept, Authorization, Connection, Upgrade, Sec-WebSocket-Key, Sec-WebSocket-Version, Sec-WebSocket-Protocol, Sec-WebSocket-Extensions")
		c.Header("Access-Control-Expose-Headers", "Content-Length, Connection, Upgrade")
		c.Header("Access-Control-Allow-Credentials", "true")

		// 处理 WebSocket 升级请求的预检
		if c.Request.Method == "OPTIONS" {
			log.Printf("[CORS] OPTIONS 预检请求: %s", path)
			c.AbortWithStatus(204)
			return
		}

		// 针对 WebSocket 路径的特殊处理
		if path == "/ws" {
			connection := c.GetHeader("Connection")
			upgrade := c.GetHeader("Upgrade")
			log.Printf("[CORS] WebSocket 请求: Connection=%s, Upgrade=%s", connection, upgrade)

			// 检查是否是有效的 WebSocket 升级请求
			if strings.Contains(strings.ToLower(connection), "upgrade") && strings.ToLower(upgrade) == "websocket" {
				log.Printf("[CORS] 有效的 WebSocket 升级请求")
			} else {
				log.Printf("[CORS] 警告: 不是有效的 WebSocket 升级请求!")
			}
		}

		c.Next()
	}
}