package middleware

import (
	"net/http"

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

// CORS 跨域中间件 (含安全头) — 白名单模式
func CORS(allowedOrigins []string) gin.HandlerFunc {
	return func(c *gin.Context) {
		origin := c.Request.Header.Get("Origin")

		// 白名单校验
		allowed := false
		if origin != "" {
			for _, o := range allowedOrigins {
				if o == origin {
					allowed = true
					break
				}
			}
		}

		// 仅对白名单中的 origin 设置 CORS 头
		if allowed {
			c.Header("Access-Control-Allow-Origin", origin)
			c.Header("Access-Control-Allow-Credentials", "true")
		}

		c.Header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, PATCH, OPTIONS")
		c.Header("Access-Control-Allow-Headers", "Origin, Content-Type, Authorization, X-Request-ID")
		c.Header("Access-Control-Max-Age", "86400")

		// 安全头
		c.Header("X-Content-Type-Options", "nosniff")
		c.Header("X-Frame-Options", "DENY")
		c.Header("X-XSS-Protection", "1; mode=block")
		c.Header("Referrer-Policy", "strict-origin-when-cross-origin")
		c.Header("Permissions-Policy", "camera=(), microphone=(), geolocation=()")
		c.Header("Content-Security-Policy", "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; connect-src 'self' https:; font-src 'self'; object-src 'none'")
		c.Header("Strict-Transport-Security", "max-age=31536000; includeSubDomains")

		// 预检请求
		if c.Request.Method == http.MethodOptions {
			c.AbortWithStatus(http.StatusNoContent)
			return
		}

		c.Next()
	}
}