package audio

import (
	"fmt"
	"io"
	"os"
	"time"

	"github.com/dhowden/tag"
	"github.com/tcolgate/mp3"
	settings "physick.ru/culture_exam/Settings"
)

type TrackMeta struct {
	Name string
	Author string
	Album string
	Location string
	Duration time.Duration
}

func GenerateMetadata(fileName string) (TrackMeta, error) {
	var fullPath = fmt.Sprintf("%s/%s", settings.Current.SongsLocation, fileName)
	var duration, error = GetSongDuration(fullPath)
	// If file doesn't exist that will be caught there
	if error != nil {
		return TrackMeta{}, error
	}
	var Artist, Title, Album, metaErr = GetInfo(fullPath)
	if metaErr != nil {
		return TrackMeta{}, metaErr
	}
	return TrackMeta {
		Name: Title,
		Author: Artist,
		Album: Album,
		Location: fullPath,
		Duration: duration,
	}, nil
}

func GetSongDuration(path string) (time.Duration, error) {
	var file, fopenErr = os.Open(path)
	if fopenErr != nil {
		return time.Duration(0), fopenErr
	}
	defer file.Close()

	var track = mp3.NewDecoder(file)
	var duration time.Duration
	var frame mp3.Frame
	var skipped = 0

	for {
		var err = track.Decode(&frame, &skipped)
		if err != nil {
			if err == io.EOF {
				break
			}
			return time.Duration(0), err
		}
		duration += frame.Duration()
	}
	return duration, nil
}

// Author - name - album
func GetInfo (filePath string) (string, string, string, error) {
	f, err := os.Open(filePath)
	if err != nil {
		return "", "", "", err
	}
	defer f.Close()
	m, err := tag.ReadFrom(f)
	if err != nil {
		return "", "", "", err
	}
	return m.Artist(), m.Title(), m.Album(), nil
}