Rockbox scrobbler.log listen reader

backends/scrobblerlog.go

@@ -22,6 +22,14 @@ THE SOFTWARE.
 package backends
 
 import (
+	"bufio"
+	"encoding/csv"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
 	"time"
 
 	"github.com/spf13/viper"
@@ -39,5 +47,124 @@ func (b ScrobblerLogBackend) FromConfig(config *viper.Viper) Backend {
 }
 
 func (b ScrobblerLogBackend) ExportListens(oldestTimestamp time.Time) ([]Listen, error) {
-	return nil, nil
+	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
+	}
+
+	csvReader := csv.NewReader(reader)
+	csvReader.Comma = '\t'
+	// Row length is often flexible
+	csvReader.FieldsPerRecord = -1
+
+	listens := make([]Listen, 0)
+	for {
+		// A row is:
+		// artistName	releaseName	trackName	trackNumber	duration	rating	timestamp	recordingMbid
+		row, err := csvReader.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, _ := csvReader.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 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 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),
+			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
 }