package proxy

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

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

func NewReverseProxy(target string) gin.HandlerFunc {
	targetURL, err := url.Parse(target)
	if err != nil {
		log.Fatalf("invalid proxy target URL: %s, err: %v", target, err)
	}

	proxy := &httputil.ReverseProxy{
		Director: func(req *http.Request) {
			req.URL.Scheme = targetURL.Scheme
			req.URL.Host = targetURL.Host
			req.Host = targetURL.Host
		},
		ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
			log.Printf("[proxy] error: %v", err)
			w.WriteHeader(http.StatusBadGateway)
			_, _ = w.Write([]byte(`{"code":50200,"message":"service unavailable"}`))
		},
	}

	return func(c *gin.Context) {
		proxy.ServeHTTP(c.Writer, c.Request)
	}
}