// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package frontend

import (
	"io"
	"net/http"

	"golang.org/x/pkgsite/internal/log"
)

// playgroundURL is the playground endpoint used for share links.
const playgroundURL = "https://play.golang.org"

// handlePlay handles requests that mirror play.golang.org/share.
func (s *Server) handlePlay(w http.ResponseWriter, r *http.Request) {
	makeFetchPlayRequest(w, r, playgroundURL)
}

func httpErrorStatus(w http.ResponseWriter, status int) {
	http.Error(w, http.StatusText(status), status)
}

func makeFetchPlayRequest(w http.ResponseWriter, r *http.Request, pgURL string) {
	ctx := r.Context()
	if r.Method != http.MethodPost {
		httpErrorStatus(w, http.StatusMethodNotAllowed)
		return
	}
	req, err := http.NewRequest("POST", pgURL+"/share", r.Body)
	if err != nil {
		log.Errorf(ctx, "ERROR share error: %v", err)
		httpErrorStatus(w, http.StatusInternalServerError)
		return
	}
	req.Header.Set("Content-Type", "text/plain; charset=utf-8")
	req = req.WithContext(r.Context())
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		log.Errorf(ctx, "ERROR share error: %v", err)
		httpErrorStatus(w, http.StatusInternalServerError)
		return
	}
	copyHeader := func(k string) {
		if v := resp.Header.Get(k); v != "" {
			w.Header().Set(k, v)
		}
	}
	copyHeader("Content-Type")
	copyHeader("Content-Length")
	defer resp.Body.Close()
	w.WriteHeader(resp.StatusCode)
	if _, err := io.Copy(w, resp.Body); err != nil {
		log.Errorf(ctx, "ERROR writing shareId: %v", err)
	}
}