Tests for reading / writing scrobbler log

backends/scrobblerlog/parser.go

@@ -0,0 +1,217 @@
+/*
+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 scrobblerlog
+
+import (
+	"bufio"
+	"encoding/csv"
+	"errors"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+	"time"
+
+	"go.uploadedlobster.com/scotty/models"
+)
+
+type ScrobblerLog struct {
+	Timezone string
+	Client   string
+	Listens  []models.Listen
+}
+
+func Parse(data io.Reader, includeSkipped bool) (ScrobblerLog, error) {
+	result := ScrobblerLog{
+		Listens: make([]models.Listen, 0),
+	}
+
+	reader := bufio.NewReader(data)
+	err := readHeader(reader, &result)
+	if err != nil {
+		return result, err
+	}
+
+	tsvReader := csv.NewReader(reader)
+	tsvReader.Comma = '\t'
+	// Row length is often flexible
+	tsvReader.FieldsPerRecord = -1
+
+	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 result, 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 result, errors.New(fmt.Sprintf(
+				"Invalid record in scrobblerlog line %v", line))
+		}
+
+		rating := row[5]
+		if !includeSkipped && rating == "S" {
+			continue
+		}
+
+		client := strings.Split(result.Client, " ")[0]
+		listen, err := rowToListen(row, client)
+		if err != nil {
+			return result, err
+		}
+
+		result.Listens = append(result.Listens, listen)
+	}
+
+	return result, nil
+}
+
+func Write(data io.Writer, log *ScrobblerLog) (lastTimestamp time.Time, err error) {
+	err = writeHeader(data, log)
+	if err != nil {
+		return
+	}
+
+	tsvWriter := csv.NewWriter(data)
+	tsvWriter.Comma = '\t'
+
+	for _, listen := range log.Listens {
+		if listen.ListenedAt.Unix() > lastTimestamp.Unix() {
+			lastTimestamp = listen.ListenedAt
+		}
+
+		// A row is:
+		// artistName	releaseName	trackName	trackNumber	duration	rating	timestamp	recordingMbid
+		rating, ok := listen.AdditionalInfo["rockbox_rating"].(string)
+		if !ok || 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
+}
+
+func readHeader(reader *bufio.Reader, log *ScrobblerLog) error {
+	// Skip header
+	for i := 0; i < 3; i++ {
+		line, _, err := reader.ReadLine()
+		if err != nil {
+			return 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"))
+			}
+
+			timezone, found := strings.CutPrefix(text, "#TZ/")
+			if strings.HasPrefix(text, "#TZ/") {
+				log.Timezone = timezone
+			}
+
+			client, found := strings.CutPrefix(text, "#CLIENT/")
+			if found {
+				log.Client = client
+			}
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func writeHeader(writer io.Writer, log *ScrobblerLog) error {
+	headers := []string{
+		"#AUDIOSCROBBLER/1.1\n",
+		"#TZ/" + log.Timezone + "\n",
+		"#CLIENT/" + log.Client + "\n",
+	}
+	for _, line := range headers {
+		_, err := writer.Write([]byte(line))
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func rowToListen(row []string, client string) (models.Listen, error) {
+	var listen models.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 = models.Listen{
+		Track: models.Track{
+			ArtistNames: []string{row[0]},
+			ReleaseName: row[1],
+			TrackName:   row[2],
+			TrackNumber: trackNumber,
+			Duration:    time.Duration(duration * int(time.Second)),
+			AdditionalInfo: models.AdditionalInfo{
+				"rockbox_rating": row[5],
+				"media_player":   client,
+			},
+		},
+		ListenedAt: time.Unix(int64(timestamp), 0),
+	}
+
+	if len(row) > 7 {
+		listen.Track.RecordingMbid = models.MBID(row[7])
+	}
+
+	return listen, nil
+}