// tofuproxy -- flexible HTTP/HTTPS proxy, TLS terminator, X.509 TOFU
//              manager, WARC/geminispace browser
// Copyright (C) 2021-2024 Sergey Matveev <stargrave@stargrave.org>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 3 of the License.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package rounds

import (
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"os/exec"

	"go.stargrave.org/tofuproxy/fifos"
)

const CmdDWebP = "dwebp"

func RoundTranscodeWebP(
	host string,
	resp *http.Response,
	w http.ResponseWriter,
	req *http.Request,
) (bool, error) {
	if resp.Header.Get("Content-Type") != "image/webp" {
		return true, nil
	}
	tmpFd, err := os.CreateTemp("", "tofuproxy.*.webp")
	if err != nil {
		log.Fatalln(err)
	}
	defer os.Remove(tmpFd.Name())
	defer tmpFd.Close()
	defer resp.Body.Close()
	if _, err = io.Copy(tmpFd, resp.Body); err != nil {
		log.Printf("Error during %s: %+v\n", req.URL, err)
		return false, err
	}
	tmpFd.Close()
	cmd := exec.Command(CmdDWebP, tmpFd.Name(), "-o", "-")
	data, err := cmd.Output()
	if err != nil {
		return false, err
	}
	w.Header().Add("Content-Type", "image/png")
	w.WriteHeader(http.StatusOK)
	w.Write(data)
	fifos.LogVarious <- fmt.Sprintf(
		"%s %s\tWebP transcoded to PNG", req.Method, req.URL,
	)
	return false, nil
}