package ffmpeg

import (
	"fmt"
	"io"
	"log"
	"os"
	"os/exec"
	"path"
	"strconv"
	"stream-poc2/model"
)

// EncodeChunk doesn't have the nicest function signature...
func EncodeChunk(profileSettings model.VideoProfileSettings, nativeHeight int, preset string, origSegmentPath string, writer io.Writer) error {
	ffmpegArgs := []string{
		"-nostdin", "-hide_banner", "-loglevel", "error",
	}

	if profileSettings.Resolution.Height != nativeHeight {
		// apply resize filter
		ffmpegArgs = append(ffmpegArgs,
			"-hwaccel", "cuda", "-hwaccel_output_format", "cuda",
			"-i", origSegmentPath,
			"-vf", fmt.Sprintf("scale_cuda=%d:%d", profileSettings.Resolution.Width, profileSettings.Resolution.Height),
		)
	} else {
		// just load the segment
		ffmpegArgs = append(ffmpegArgs,
			"-i", origSegmentPath,
		)
	}

	ffmpegArgs = append(ffmpegArgs,
		"-copyts",
		"-c:v", profileSettings.FFMpegCodec(),
	)
	if preset != "" {
		ffmpegArgs = append(ffmpegArgs,
			"-preset", preset,
		)
	}

	ffmpegArgs = append(ffmpegArgs,
		"-b:v", strconv.Itoa(profileSettings.AvgBitrate), "-maxrate", strconv.Itoa(profileSettings.MaxBitrate), "-bufsize", "1M",
		"-an", // <- no audio
		"-f", "mpegts", "-mpegts_copyts", "1",
		"-",
	)

	log.Println("exec ffmpeg args: ", ffmpegArgs)

	cmd := exec.Command("/usr/bin/ffmpeg", ffmpegArgs...)
	cmd.Stdout = writer
	cmd.Stderr = os.Stderr

	err := cmd.Run()
	if err != nil {
		log.Println("Failed to run:", err)
		return err
	}

	return nil
}

// MakeSegments has the ugliest function signature no the planet
func MakeSegments(filepath, outdir string, audioStreams []model.AudioStream) (string, []string, error) {
	segmentsVideoCSV := path.Join(outdir, "segments_video.csv")
	segmentsAudioCSV := make([]string, len(audioStreams))

	// do slicing
	ffmpegArgs := []string{
		"-nostdin", "-hide_banner", "-loglevel", "error",
		"-i", filepath,
		// video stream
		"-c:v", "copy", "-an",
		"-f", "ssegment", "-segment_format", "mpegts", "-segment_list", segmentsVideoCSV,
		"-segment_list_type", "csv", "-segment_time", strconv.Itoa(SlicerTargetDurationSec), path.Join(outdir, "video", "s%d.ts"),
	}

	for i, audioStream := range audioStreams {
		csvName := path.Join(outdir, fmt.Sprintf("segments_audio_%d.csv", audioStream.Index))
		segmentsAudioCSV[i] = csvName

		ffmpegArgs = append(ffmpegArgs,
			// audio streams (encode to mp3)
			"-vn", "-map", fmt.Sprintf("0:a:%d", i),
		)

		if audioStream.Codec != "mp3" {
			// mp3 always works
			// TODO: This does not update the stream info in the metadata !!!
			log.Println("Transcoding audio to mp3 for stream ", audioStream.Index)
			ffmpegArgs = append(ffmpegArgs,
				"-c:a", "libmp3lame", "-q:a", "0",
			)
		} else {
			log.Println("Not transcoding audio as it is already mp3 for stream ", audioStream.Index)
			ffmpegArgs = append(ffmpegArgs,
				"-c:a", "copy",
			)
		}

		ffmpegArgs = append(ffmpegArgs,
			"-f", "ssegment", "-segment_format", "mpegts", "-segment_list", csvName,
			"-segment_list_type", "csv", "-segment_time", strconv.Itoa(SlicerTargetDurationSec), path.Join(outdir, "audio", strconv.Itoa(audioStream.Index), "s%d.ts"),
		)
	}

	cmd := exec.Command("/usr/bin/ffmpeg", ffmpegArgs...)
	cmd.Stderr = os.Stderr

	err := cmd.Run()
	if err != nil {
		log.Println("failed to segment:", err)
		return "", nil, err
	}

	return segmentsVideoCSV, segmentsAudioCSV, nil
}