progress shenanigan!

commands/copy/copy.go

@@ -194,7 +194,7 @@ func (c *CopyCommand) _transcode_file(file *types.File, trans_config *transcoder
 		log.Info().Str("file", new_filename).Msg("Transcoding File")
 	}
 
-	output, err := transcoder.Transcode(file, trans_config, dest_filepath)
+	output, err := transcoder.Transcode(file, trans_config, nil, dest_filepath)
 	if err != nil {
 		log.Fatal().Err(err).Str("output", output).Msg("Transcode Failed")
 	}

commands/transcode/transcode.go

@@ -95,7 +95,22 @@ func (c *TranscodeCommand) Run() {
 			output_file.Extension, transcode_config.FileExtension)
 	}
 
-	output, err := transcoder.Transcode(input_file, transcode_config, output_file.JoinPathTo())
+	progress_chan := make(chan string)
+	go func() {
+		for {
+			progress, isnt_closed := <-progress_chan
+			if isnt_closed {
+				log.Info().
+					Str("src", *c.Args.Source).
+					Str("progress", progress).
+					Msg("Transcoding")
+			} else {
+				return
+			}
+		}
+	}()
+
+	output, err := transcoder.Transcode(input_file, transcode_config, progress_chan, output_file.JoinPathTo())
 	if err != nil {
 		log.Fatal().Err(err).Str("output", output).Msg("Transcode Failed")
 	}

utils/transcoder/transcoder.go

@@ -1,10 +1,16 @@
 package transcoder
 
 import (
+	"bufio"
+	"encoding/json"
 	"errors"
 	"fmt"
+	"math"
+	"os"
 	"os/exec"
+	"strconv"
 	"strings"
+	"time"
 
 	"gitlab.com/ChaotiCryptidz/musicutil/types"
 )
@@ -29,7 +35,59 @@ func isNotEmptyString(x string) bool {
 	return true
 }
 
-func Transcode(file *types.File, config *TranscodeConfig, dest string) (string, error) {
+func progressDurationToMilliSeconds(duration string) int64 {
+	fields := strings.Split(strings.TrimSpace(duration), ":")
+	durationNs := int64(0)
+
+	h, _ := strconv.ParseInt(fields[0], 10, 64)
+	durationNs += int64(time.Hour) * h
+
+	m, _ := strconv.ParseInt(fields[1], 10, 64)
+	durationNs += int64(time.Minute) * m
+
+	s, _ := strconv.ParseFloat(fields[2], 64)
+	durationNs += int64(float64(time.Second) * s)
+
+	return time.Duration(durationNs).Milliseconds()
+}
+
+func getFileLengthMilliSeconds(filename string) (int64, error) {
+	type FFProbeFormat struct {
+		Duration string `json:"duration"`
+	}
+	type FFProbeOutput struct {
+		Format FFProbeFormat `json:"format"`
+	}
+
+	ffprobe_output_str, err := exec.Command(
+		"ffprobe",
+		"-v", "quiet",
+		"-print_format", "json",
+		"-show_format",
+		filename,
+	).Output()
+
+	if err != nil {
+		return 0, err
+	}
+
+	var ffprobe_output FFProbeOutput
+	err = json.Unmarshal([]byte(ffprobe_output_str), &ffprobe_output)
+	if err != nil {
+		return 0, err
+	} else {
+		duration_str := ffprobe_output.Format.Duration
+		duration_float, err := strconv.ParseFloat(duration_str, 64)
+		if err != nil {
+			return 0, err
+		}
+
+		duration_millis := int64(math.Round(duration_float * 1000))
+		return duration_millis, nil
+	}
+}
+
+func Transcode(file *types.File, config *TranscodeConfig, progress_chan chan string, dest string) (string, error) {
 	command_args := make([]string, 0)
 	command_args = append(command_args, "-y")
 	command_args = append(command_args, "-hide_banner")
@@ -69,11 +127,55 @@ func Transcode(file *types.File, config *TranscodeConfig, dest string) (string,
 
 	command_args = append(command_args, dest)
 
+	// Progress Shenanigans
+
+	if progress_chan != nil {
+		total_length_milliseconds, err := getFileLengthMilliSeconds(file.JoinPathTo())
+		if err != nil {
+			goto end
+		}
+
+		progress_temp_dir, err := os.MkdirTemp("", "*-musicutil_transcode_temp")
+		if err != nil {
+			goto end
+		}
+		defer os.RemoveAll(progress_temp_dir)
+
+		progress_filename := progress_temp_dir + "/progress.log"
+		progress_file, err := os.Create(progress_filename)
+		if err != nil {
+			goto end
+		}
+		defer os.Remove(progress_filename)
+
+		command_args = append(command_args, "-progress", progress_filename, "-nostats")
+
+		go func() {
+			reader := bufio.NewReader(progress_file)
+			for {
+				line, err := reader.ReadBytes('\n')
+				if err == nil {
+					if strings.HasPrefix(string(line), "out_time=") {
+						out_time := strings.TrimSuffix(strings.TrimPrefix(string(line), "out_time="), "\n")
+						out_time_ms := progressDurationToMilliSeconds(out_time)
+
+						progress_chan <- fmt.Sprintf("%0.2f%%", (float64(out_time_ms) / float64(total_length_milliseconds) * 100))
+					}
+				}
+			}
+		}()
+	}
+
+end:
 	cmd := exec.Command("ffmpeg", command_args...)
 	output, err := cmd.CombinedOutput()
 	if err != nil {
 		fmt.Println(output)
 		return string(output), errors.New("ffmpeg error")
 	}
+
+	if progress_chan != nil {
+		close(progress_chan)
+	}
 	return string(output), nil
 }