add monitor sync jobs and duplicate-safe qobuz updates

internal/qobuz/client.go

@@ -5,6 +5,7 @@ import (
 	"crypto/md5"
 	"encoding/hex"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -39,6 +40,8 @@ type Track struct {
 	Album    string
 }
 
+var ErrDuplicateTracks = errors.New("qobuz duplicate tracks")
+
 func NewClient(appID, appSecret string) *Client {
 	return &Client{
 		httpClient: &http.Client{Timeout: 30 * time.Second},
@@ -197,6 +200,7 @@ func (c *Client) AddTracksToPlaylist(ctx context.Context, playlistID int64, trac
 	if len(trackIDs) == 0 {
 		return nil
 	}
+	hadDuplicate := false
 	chunks := chunk(trackIDs, 100)
 	for _, ch := range chunks {
 		ids := make([]string, 0, len(ch))
@@ -210,9 +214,16 @@ func (c *Client) AddTracksToPlaylist(ctx context.Context, playlistID int64, trac
 
 		var out map[string]any
 		if err := c.postFormSigned(ctx, "/playlist/addTracks", form, &out); err != nil {
+			if isDuplicateConflictErr(err) {
+				hadDuplicate = true
+				continue
+			}
 			return err
 		}
 	}
+	if hadDuplicate {
+		return ErrDuplicateTracks
+	}
 	return nil
 }
 
@@ -366,6 +377,17 @@ func isSigError(err error) bool {
 	return strings.Contains(msg, "signature") || strings.Contains(msg, "request_sig")
 }
 
+func isDuplicateConflictErr(err error) bool {
+	if err == nil {
+		return false
+	}
+	msg := strings.ToLower(err.Error())
+	if !strings.Contains(msg, "duplicate track") {
+		return false
+	}
+	return strings.Contains(msg, "(409)") || strings.Contains(msg, `"code":409`) || strings.Contains(msg, "code: 409")
+}
+
 func md5Hex(s string) string {
 	h := md5.Sum([]byte(s))
 	return hex.EncodeToString(h[:])