package api

import (
	"bytes"
	"fmt"
	"math"
	"net/http"
	"os/exec"
	"strconv"
	"strings"
)

func RegisterHlsEndpoints() {
	http.HandleFunc("/hls/index.m3u8", EndpointHlsM3U8)
}

/*
TODO: endpoint for clients to query a video's:
	video tracks,
	audio tracks,
	captions
Then add support to existing endpoints for specifiying these 3 options
*/

func EndpointHlsM3U8(w http.ResponseWriter, r *http.Request) {
	//TODO: clean up this mess
	options := strings.Split(strings.Split(strings.Replace(r.URL.String(), "%20", " ", -1), "?")[1], "&")

	//TODO: make the order of options not hardcoded
	libPathName := strings.TrimPrefix(options[0], "lib=")

	var lib Library

	for _, l := range Libraries {
		if l.PathName == libPathName {
			lib = l
			break
		}
	}

	filePath := lib.Path + strings.TrimPrefix(options[1], "path=")

	ffprobe := exec.Command(
		"ffprobe",
		"-v", "error",
		"-show_entries", "format=duration",
		"-of", "default=noprint_wrappers=1:nokey=1",
		filePath,
	)

	var ffprobeStdout bytes.Buffer
	ffprobe.Stdout = &ffprobeStdout

	err := ffprobe.Run()
	if err != nil {
		http.Error(w, "Internal server error", http.StatusInternalServerError)
		return
	}

	fileLenStr := strings.TrimSuffix(ffprobeStdout.String(), "\n")
	fileLenFloat, err := strconv.ParseFloat(fileLenStr, 64)
	if err != nil {
		http.Error(w, "Internal server error", http.StatusInternalServerError)
		return
	}
	fileLenFloat = math.Ceil(fileLenFloat/6.0) * 6.0
	fileLenInt := int(fileLenFloat)

	w.Header().Set("Content-Type", "application/vnd.apple.mpegurl")

	fmt.Fprintln(w, "#EXTM3U")
	fmt.Fprintln(w, "#EXT-X-VERSION:7")
	//TODO: make this configurable
	fmt.Fprintln(w, "#EXT-X-TARGETDURATION:6")
	fmt.Fprintln(w, "#EXT-X-MEDIA-SEQUENCE:0")

	for i := 0; i < fileLenInt/6; i++ {
		fmt.Fprintln(w, "#EXTINF:6.0,")
		fmt.Fprintf(w, "/hls/segment/%d.mp4?lib=%s&path=%s\n", i, lib.PathName, strings.TrimPrefix(options[1], "path="))
	}

	fmt.Fprintln(w, "#EXT-X-ENDLIST")
}