package server

import (
	"net/http"
	"net/http/httputil"
	"net/url"

	"git.magicany.cc/black1552/gf-common/log"
	"github.com/gogf/gf/v2/net/ghttp"
	"github.com/gogf/gf/v2/os/gctx"
)

// BuildRequest 反向代理请求到指定主机
// 自动支持所有 HTTP 方法及 WebSocket 连接
func BuildRequest(r *ghttp.Request, host string) {
	targetURL, err := url.Parse(host)
	if err != nil {
		log.Error(gctx.New(), "parse target host error:", err)
		r.Response.WriteStatus(http.StatusInternalServerError)
		r.Response.Write([]byte("Invalid target host"))
		return
	}

	proxy := httputil.NewSingleHostReverseProxy(targetURL)

	// 自定义 Director 来设置目标 URL，保留原始请求的所有参数
	proxy.Director = func(req *http.Request) {
		req.URL.Scheme = targetURL.Scheme
		req.URL.Host = targetURL.Host
		req.URL.Path = r.URL.Path
		req.URL.RawQuery = r.URL.RawQuery
		// 保留原始 Host 头
		req.Host = r.Host
	}

	// 错误处理
	proxy.ErrorHandler = func(w http.ResponseWriter, req *http.Request, err error) {
		log.Error(gctx.New(), "proxy error:", err)
		w.WriteHeader(http.StatusBadGateway)
		w.Write([]byte("Bad Gateway"))
	}

	// ServeHTTP 会自动处理 WebSocket 升级和所有 HTTP 方法
	proxy.ServeHTTP(r.Response.Writer, r.Request)
}