JSPF loves export

backends/jspf/jspf.go

@@ -21,3 +21,104 @@ THE SOFTWARE.
 */
 
 package jspf
+
+import (
+	"encoding/json"
+	"os"
+	"time"
+
+	"github.com/spf13/viper"
+	"go.uploadedlobster.com/scotty/models"
+)
+
+type JspfBackend struct {
+	filePath   string
+	title      string
+	creator    string
+	identifier string
+}
+
+func (b JspfBackend) FromConfig(config *viper.Viper) models.Backend {
+	b.filePath = config.GetString("file-path")
+	b.title = config.GetString("title")
+	b.creator = config.GetString("username")
+	b.identifier = config.GetString("identifier")
+	return b
+}
+
+func (b JspfBackend) ImportLoves(loves []models.Love, oldestTimestamp time.Time) (models.ImportResult, error) {
+	result := models.ImportResult{
+		TotalCount:    len(loves),
+		ImportCount:   0,
+		LastTimestamp: oldestTimestamp,
+	}
+
+	tracks := make([]Track, 0, result.TotalCount)
+	for _, love := range loves {
+		if love.Created.Unix() > result.LastTimestamp.Unix() {
+			result.LastTimestamp = love.Created
+		}
+
+		extension := MusicBrainzTrackExtension{
+			AddedAt:            love.Created,
+			AddedBy:            love.UserName,
+			AdditionalMetadata: love.AdditionalInfo,
+			ArtistIdentifiers:  make([]string, len(love.ArtistMbids)),
+		}
+
+		for i, mbid := range love.ArtistMbids {
+			extension.ArtistIdentifiers[i] = "https://musicbrainz.org/artist/" + string(mbid)
+		}
+
+		if love.ReleaseMbid != "" {
+			extension.ReleaseIdentifier = "https://musicbrainz.org/release/" + string(love.ReleaseMbid)
+		}
+
+		track := Track{
+			Title:    love.TrackName,
+			Album:    love.ReleaseName,
+			Creator:  love.ArtistName(),
+			TrackNum: love.TrackNumber,
+			Extension: map[string]any{
+				"https://musicbrainz.org/doc/jspf#track": extension,
+			},
+		}
+
+		if love.RecordingMbid != "" {
+			track.Identifier = append(track.Identifier, "https://musicbrainz.org/recording/"+string(love.RecordingMbid))
+		}
+
+		tracks = append(tracks, track)
+
+		result.ImportCount += 1
+	}
+
+	err := b.writeJspf(tracks)
+	return result, err
+}
+
+func (b JspfBackend) writeJspf(tracks []Track) error {
+	playlist := Jspf{
+		Playlist: Playlist{
+			Title:      b.title,
+			Creator:    b.creator,
+			Identifier: b.identifier,
+			Date:       time.Now(),
+			Tracks:     tracks,
+		},
+	}
+
+	file, err := os.Create(b.filePath)
+	if err != nil {
+		return err
+	}
+
+	defer file.Close()
+	jspfJson, err := json.MarshalIndent(playlist, "", "\t")
+	if err != nil {
+		return err
+	}
+
+	_, err = file.Write(jspfJson)
+	return err
+}