Deezer export listens

backends/deezer/deezer.go

@@ -64,6 +64,74 @@ func (b *DeezerApiBackend) OAuth2Setup(token oauth2.TokenSource) error {
 	return nil
 }
 
+func (b *DeezerApiBackend) ExportListens(oldestTimestamp time.Time, results chan models.ListensResult, progress chan models.Progress) {
+	// Choose a high offset, we attempt to search the loves backwards starting
+	// at the oldest one.
+	offset := math.MaxInt32
+	perPage := MaxItemsPerGet
+
+	defer close(results)
+	defer close(progress)
+
+	p := models.Progress{Total: int64(perPage)}
+	var totalCount int
+
+out:
+	for {
+		result, err := b.client.UserHistory(offset, perPage)
+		if err != nil {
+			progress <- p.Complete()
+			results <- models.ListensResult{Error: err}
+			return
+		}
+
+		// The offset was higher then the actual number of tracks. Adjust the offset
+		// and continue.
+		if offset >= result.Total {
+			p.Total = int64(result.Total)
+			totalCount = result.Total
+			offset = result.Total - perPage
+			if offset < 0 {
+				offset = 0
+			}
+			continue
+		}
+
+		count := len(result.Tracks)
+		if count == 0 {
+			break out
+		}
+
+		listens := make(models.ListensList, 0, perPage)
+		for _, track := range result.Tracks {
+			listen := track.AsListen()
+			if listen.ListenedAt.Unix() > oldestTimestamp.Unix() {
+				listens = append(listens, listen)
+			} else {
+				totalCount -= 1
+				break
+			}
+		}
+
+		sort.Sort(listens)
+		results <- models.ListensResult{Listens: listens, Total: totalCount}
+		p.Elapsed += int64(count)
+		progress <- p
+
+		if offset <= 0 {
+			// This was the last request, no further results
+			break out
+		}
+
+		offset -= perPage
+		if offset < 0 {
+			offset = 0
+		}
+	}
+
+	progress <- p.Complete()
+}
+
 func (b *DeezerApiBackend) ExportLoves(oldestTimestamp time.Time, results chan models.LovesResult, progress chan models.Progress) {
 	// Choose a high offset, we attempt to search the loves backwards starting
 	// at the oldest one.
@@ -132,6 +200,15 @@ out:
 	progress <- p.Complete()
 }
 
+func (t Listen) AsListen() models.Listen {
+	love := models.Listen{
+		ListenedAt: time.Unix(t.Timestamp, 0),
+		Track:      t.Track.AsTrack(),
+	}
+
+	return love
+}
+
 func (t LovedTrack) AsLove() models.Love {
 	love := models.Love{
 		Created: time.Unix(t.AddedAt, 0),