feat: the library's folders are set in Admin › Library, and changing a folder moves its tracks with it, keeping their plays, likes and playlists (#6129)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/api/admin_library_folders.go

@@ -0,0 +1,111 @@
+package api
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"os"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/apierror"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/library"
+)
+
+// The library's folders (#6129): where the scan, the watcher and the import
+// look for music, set here rather than only by MINSTREL_LIBRARY_SCAN_PATHS.
+
+type libraryFolderView struct {
+	Path string `json:"path"`
+	// Present is whether the server can see the folder right now; a folder
+	// whose mount went away reads false here before anything else notices.
+	Present bool  `json:"present"`
+	Tracks  int64 `json:"tracks"`
+}
+
+type libraryFoldersView struct {
+	Folders []libraryFolderView `json:"folders"`
+	// Saved is false while the folders still come from
+	// MINSTREL_LIBRARY_SCAN_PATHS.
+	Saved bool `json:"saved"`
+	// Moved is how many tracks a save moved to a new folder.
+	Moved int64 `json:"moved,omitempty"`
+}
+
+func (h *handlers) libraryFolders(ctx context.Context) (libraryFoldersView, error) {
+	q := dbq.New(h.pool)
+	row, err := q.GetLibrarySettings(ctx)
+	if err != nil {
+		return libraryFoldersView{}, err
+	}
+	v := libraryFoldersView{Folders: []libraryFolderView{}, Saved: len(row.ScanPaths) > 0}
+	for _, root := range h.scanner.Roots() {
+		n, err := q.CountTracksUnder(ctx, root)
+		if err != nil {
+			return libraryFoldersView{}, err
+		}
+		info, statErr := os.Stat(root)
+		v.Folders = append(v.Folders, libraryFolderView{Path: root, Present: statErr == nil && info.IsDir(), Tracks: n})
+	}
+	return v, nil
+}
+
+// handleGetLibraryFolders implements GET /api/admin/library/folders.
+func (h *handlers) handleGetLibraryFolders(w http.ResponseWriter, r *http.Request) {
+	v, err := h.libraryFolders(r.Context())
+	if err != nil {
+		writeErrWithLog(w, h.logger, "admin library folders: get", apierror.Internal(err))
+		return
+	}
+	writeJSON(w, http.StatusOK, v)
+}
+
+type putLibraryFoldersBody struct {
+	Folders []struct {
+		Path string `json:"path"`
+		// Was is the folder this one replaces, whose files are now at Path;
+		// "" is a folder added.
+		Was string `json:"was"`
+	} `json:"folders"`
+}
+
+// handlePutLibraryFolders implements PUT /api/admin/library/folders.
+//
+// The whole list. A folder whose path changed moves its tracks with it, so
+// their plays, likes and playlists survive; one left out is no longer read,
+// and its tracks are marked missing by the next scan. After a save a scan
+// starts, to pick up anything the old folders did not hold.
+func (h *handlers) handlePutLibraryFolders(w http.ResponseWriter, r *http.Request) {
+	var body putLibraryFoldersBody
+	if !decodeBody(w, r, &body) {
+		return
+	}
+	if h.scanner == nil {
+		writeErr(w, apierror.Internal(errors.New("no scanner")))
+		return
+	}
+	changes := make([]library.RootChange, 0, len(body.Folders))
+	for _, f := range body.Folders {
+		changes = append(changes, library.RootChange{Path: f.Path, Was: f.Was})
+	}
+	res, err := h.scanner.SetRoots(r.Context(), changes)
+	if err != nil {
+		var re *library.RootsError
+		if errors.As(err, &re) {
+			writeErr(w, apierror.BadRequest("bad_folders", re.Error()))
+			return
+		}
+		writeErrWithLog(w, h.logger, "admin library folders: put", apierror.Internal(err))
+		return
+	}
+	if _, _, err := library.TryStartScan(context.Background(), h.pool, h.scanner, h.coverart,
+		h.logger.With("source", "library_folders"), h.scanCfg); err != nil {
+		h.logger.Warn("admin library folders: scan after save", "err", err)
+	}
+	v, err := h.libraryFolders(r.Context())
+	if err != nil {
+		writeErrWithLog(w, h.logger, "admin library folders: get", apierror.Internal(err))
+		return
+	}
+	v.Moved = res.Tracks
+	writeJSON(w, http.StatusOK, v)
+}