scotty/backends/scrobblerlog.go

/*
Copyright © 2023 Philipp Wolfer <phw@uploadedlobster.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
package backends

import (
	"bufio"
	"encoding/csv"
	"errors"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/spf13/viper"
)

type ScrobblerLogBackend struct {
	filePath       string
	includeSkipped bool
}

func (b ScrobblerLogBackend) FromConfig(config *viper.Viper) Backend {
	b.filePath = config.GetString("file-path")
	b.includeSkipped = config.GetBool("include-skipped")
	return b
}

func (b ScrobblerLogBackend) ExportListens(oldestTimestamp time.Time) ([]Listen, error) {
	file, err := os.Open(b.filePath)
	if err != nil {
		return nil, err
	}

	defer file.Close()

	reader := bufio.NewReader(file)
	client, err := readHeader(reader)
	if err != nil {
		return nil, err
	}

	tsvReader := csv.NewReader(reader)
	tsvReader.Comma = '\t'
	// Row length is often flexible
	tsvReader.FieldsPerRecord = -1

	listens := make([]Listen, 0)
	for {
		// A row is:
		// artistName	releaseName	trackName	trackNumber	duration	rating	timestamp	recordingMbid
		row, err := tsvReader.Read()
		if err == io.EOF {
			break
		} else if err != nil {
			return nil, err
		}

		// fmt.Printf("row: %v\n", row)

		// We consider only the last field (recording MBID) optional
		if len(row) < 7 {
			line, _ := tsvReader.FieldPos(0)
			return nil, errors.New(fmt.Sprintf(
				"Invalid record in %s line %v", b.filePath, line))
		}

		rating := row[5]
		if !b.includeSkipped && rating == "S" {
			continue
		}

		listen, err := rowToListen(row, client)
		if err != nil {
			return nil, err
		}

		listens = append(listens, listen)
	}

	return listens, nil
}

func (b ScrobblerLogBackend) ImportListens(listens []Listen, oldestTimestamp time.Time) (ImportResult, error) {
	result := ImportResult{
		Count:         0,
		LastTimestamp: oldestTimestamp,
	}

	file, err := os.Create(b.filePath)
	if err != nil {
		return result, err
	}

	defer file.Close()

	err = writeHeader(file)
	if err != nil {
		return result, err
	}

	tsvWriter := csv.NewWriter(file)
	tsvWriter.Comma = '\t'

	for _, listen := range listens {
		result.Count += 1
		if listen.ListenedAt.Unix() > result.LastTimestamp.Unix() {
			result.LastTimestamp = listen.ListenedAt
		}

		// A row is:
		// artistName	releaseName	trackName	trackNumber	duration	rating	timestamp	recordingMbid
		rating := listen.AdditionalInfo["rockbox_rating"]
		if rating == "" {
			rating = "L"
		}
		tsvWriter.Write([]string{
			listen.ArtistName(),
			listen.ReleaseName,
			listen.TrackName,
			strconv.Itoa(listen.TrackNumber),
			strconv.Itoa(int(listen.Duration.Seconds())),
			rating,
			strconv.Itoa(int(listen.ListenedAt.Unix())),
			string(listen.RecordingMbid),
		})
	}

	tsvWriter.Flush()

	return result, nil
}

func readHeader(reader *bufio.Reader) (client string, err error) {
	// Skip header
	for i := 0; i < 3; i++ {
		line, _, err := reader.ReadLine()
		if err != nil {
			return client, err
		}

		if len(line) == 0 || line[0] != '#' {
			err = errors.New(fmt.Sprintf("Unexpected header (line %v)", i))
		} else {
			text := string(line)
			if i == 0 && !strings.HasPrefix(text, "#AUDIOSCROBBLER/1") {
				err = errors.New(fmt.Sprintf("Not a scrobbler log file"))
			}

			after, found := strings.CutPrefix(text, "#CLIENT/")
			if found {
				client = strings.Split(after, " ")[0]
			}
		}

		if err != nil {
			return client, err
		}
	}
	return client, nil
}

func writeHeader(writer io.Writer) error {
	headers := []string{
		"#AUDIOSCROBBLER/1.1\n",
		"#TZ/UNKNOWN\n",
		"#CLIENT/Rockbox sansaclipplus $Revision$\n",
	}
	for _, line := range headers {
		_, err := writer.Write([]byte(line))
		if err != nil {
			return err
		}
	}
	return nil
}

func rowToListen(row []string, client string) (Listen, error) {
	var listen Listen
	trackNumber, err := strconv.Atoi(row[3])
	if err != nil {
		return listen, err
	}

	duration, err := strconv.Atoi(row[4])
	if err != nil {
		return listen, err
	}

	timestamp, err := strconv.Atoi(row[6])
	if err != nil {
		return listen, err
	}

	listen = Listen{
		Track: Track{
			ArtistNames: []string{row[0]},
			ReleaseName: row[1],
			TrackName:   row[2],
			TrackNumber: trackNumber,
			Duration:    time.Duration(duration * int(time.Second)),
			AdditionalInfo: AdditionalInfo{
				"rockbox_rating": row[5],
				"media_player":   client,
			},
		},
		ListenedAt: time.Unix(int64(timestamp), 0),
	}

	if len(row) > 7 {
		listen.Track.RecordingMbid = MBID(row[7])
	}

	return listen, nil
}