feat(music): add a delete-playlist command

- D in the playlist buffer deletes a saved playlist.
- Candidates span both m3u sources: local library and MPD dir.
- A typed yes/no confirms deletion.
- Deleting the loaded playlist's file clears its association.

2 files changed, 169 insertions, 1 deletions

diff --git a/modules/music-config.el b/modules/music-config.el
index 9b4dc149..78ea49d9 100644
--- a/modules/music-config.el
+++ b/modules/music-config.el
@@ -591,6 +591,21 @@ Returns the full path to the selected file, or nil if cancelled."
     (unless (string= choice "(Cancel)")
       (cdr (assoc choice m3u-files)))))
 
+(defun cj/music--delete-playlist-file (path)
+  "Delete the playlist file at PATH.
+Signals a `user-error' when PATH is nil or missing.  When the playlist
+buffer's associated file is PATH, the association is cleared (the in-memory
+queue is untouched).  Refreshes the radio metadata cache since an .m3u just
+left the roots."
+  (unless (and path (file-exists-p path))
+    (user-error "Playlist file does not exist: %s"
+                (if path (file-name-nondirectory path) "nil")))
+  (delete-file path)
+  (with-current-buffer (cj/music--ensure-playlist-buffer)
+    (when (equal cj/music-playlist-file path)
+      (setq cj/music-playlist-file nil)))
+  (cj/music--refresh-radio-name-map))
+
 ;;; Commands: add/select
 
 (defun cj/music--music-files-recursive (directory)
@@ -839,6 +854,23 @@ reloaded playlist keeps its display name and cover art."
     (message "Reloaded playlist: %s" name)))
 
 
+(defun cj/music-delete-playlist ()
+  "Delete an .m3u playlist file after strong confirmation.
+Candidates are the playlists `cj/music-playlist-load' offers -- every
+directory in `cj/music-m3u-roots' (the local library and MPD's playlist
+dir).  Deleting the loaded playlist's file keeps the in-memory queue but
+clears its file association."
+  (interactive)
+  (let ((file (cj/music--select-m3u-file "Delete playlist: ")))
+    (if (not file)
+        (message "Playlist deletion cancelled")
+      (unless (cj/confirm-strong (format "Delete playlist %s? "
+                                         (file-name-nondirectory file)))
+        (user-error "Aborted deleting playlist"))
+      (cj/music--delete-playlist-file file)
+      (message "Deleted playlist: %s" (file-name-nondirectory file)))))
+
+
 (defun cj/music-playlist-edit ()
   "Open the playlist's M3U file in other window, prompting to save if modified."
   (interactive)
@@ -1347,7 +1379,7 @@ The rule uses a resize-safe :align-to span, not a hardcoded character count."
      (funcall mode-indicator "x" "consume" cj/music-consume-mode) "\n"
      (propertize "Keys    " 'face 'cj/music-header-face)
      (propertize " : " 'face 'cj/music-header-face)
-     (propertize "a:add  c:clear  L:load  v:save  S:stop  SPC:pause  <>:skip  ↑↓:move  C-↑↓:reorder  q:dismiss"
+     (propertize "a:add  c:clear  L:load  v:save  D:delete  S:stop  SPC:pause  <>:skip  ↑↓:move  C-↑↓:reorder  q:dismiss"
                  'face 'cj/music-keyhint-face) "\n"
      (propertize "Radio   " 'face 'cj/music-header-face)
      (propertize " : " 'face 'cj/music-header-face)
@@ -1592,6 +1624,7 @@ unless fancy."
         ("c" . cj/music-playlist-clear)
         ("C" . cj/music-playlist-clear)
         ("L" . cj/music-playlist-load)
+        ("D" . cj/music-delete-playlist)
         ("E" . cj/music-playlist-edit)
         ("g" . cj/music-playlist-reload)
         ("v" . cj/music-playlist-save)
diff --git a/tests/test-music-config--delete-playlist-file.el b/tests/test-music-config--delete-playlist-file.el
new file mode 100644
index 00000000..ace51a4d
--- /dev/null
+++ b/tests/test-music-config--delete-playlist-file.el
@@ -0,0 +1,135 @@
+;;; test-music-config--delete-playlist-file.el --- Tests for playlist file deletion -*- coding: utf-8; lexical-binding: t; -*-
+;;
+;; Author: Craig Jennings <c@cjennings.net>
+;;
+;;; Commentary:
+;; Unit tests for cj/music--delete-playlist-file function.
+;; Tests the internal helper that removes a playlist's .m3u file,
+;; clears the playlist buffer's file association when it pointed at
+;; the deleted file, and refreshes the radio metadata cache.
+;;
+;; Test organization:
+;; - Normal Cases: Existing file is deleted
+;; - Boundary Cases: Association cleared only when it matches; cache refresh
+;; - Error Cases: Nil path, nonexistent path
+;;
+;;; Code:
+
+(require 'ert)
+(require 'testutil-general)
+
+;; Stub missing dependencies before loading music-config
+(defvar-keymap cj/custom-keymap
+  :doc "Stub keymap for testing")
+
+;; Add EMMS elpa directory to load path for batch testing
+(let ((emms-dir (car (file-expand-wildcards
+                      (expand-file-name "elpa/emms-*" user-emacs-directory)))))
+  (when emms-dir
+    (add-to-list 'load-path emms-dir)))
+
+(require 'emms)
+(require 'emms-playlist-mode)
+(require 'music-config)
+
+;;; Test helpers
+
+(defun test-delete-playlist--setup ()
+  "Create test base dir and ensure playlist buffer exists."
+  (cj/create-test-base-dir)
+  (let ((buf (get-buffer-create cj/music-playlist-buffer-name)))
+    (with-current-buffer buf
+      (emms-playlist-mode)
+      (setq emms-playlist-buffer-p t))
+    (setq emms-playlist-buffer buf)
+    buf))
+
+(defun test-delete-playlist--teardown ()
+  "Clean up test playlist buffer and temp files."
+  (when-let ((buf (get-buffer cj/music-playlist-buffer-name)))
+    (with-current-buffer buf
+      (setq cj/music-playlist-file nil))
+    (kill-buffer buf))
+  (cj/delete-test-base-dir))
+
+;;; Normal Cases
+
+(ert-deftest test-music-config--delete-playlist-file-normal-removes-file ()
+  "Normal: an existing playlist file is deleted from disk."
+  (test-delete-playlist--setup)
+  (unwind-protect
+      (let ((file (cj/create-temp-test-file-with-content
+                   "#EXTM3U\n/tmp/song.mp3\n" "playlist.m3u")))
+        (cj/music--delete-playlist-file file)
+        (should-not (file-exists-p file)))
+    (test-delete-playlist--teardown)))
+
+;;; Boundary Cases
+
+(ert-deftest test-music-config--delete-playlist-file-boundary-clears-matching-association ()
+  "Boundary: deleting the associated playlist file clears the association."
+  (test-delete-playlist--setup)
+  (unwind-protect
+      (let ((file (cj/create-temp-test-file-with-content
+                   "#EXTM3U\n" "playlist.m3u")))
+        (with-current-buffer (get-buffer cj/music-playlist-buffer-name)
+          (setq cj/music-playlist-file file))
+        (cj/music--delete-playlist-file file)
+        (with-current-buffer (get-buffer cj/music-playlist-buffer-name)
+          (should-not cj/music-playlist-file)))
+    (test-delete-playlist--teardown)))
+
+(ert-deftest test-music-config--delete-playlist-file-boundary-keeps-other-association ()
+  "Boundary: deleting a different file leaves the association untouched."
+  (test-delete-playlist--setup)
+  (unwind-protect
+      (let ((doomed (cj/create-temp-test-file-with-content
+                     "#EXTM3U\n" "doomed.m3u"))
+            (kept (cj/create-temp-test-file-with-content
+                   "#EXTM3U\n" "kept.m3u")))
+        (with-current-buffer (get-buffer cj/music-playlist-buffer-name)
+          (setq cj/music-playlist-file kept))
+        (cj/music--delete-playlist-file doomed)
+        (should (file-exists-p kept))
+        (with-current-buffer (get-buffer cj/music-playlist-buffer-name)
+          (should (equal cj/music-playlist-file kept))))
+    (test-delete-playlist--teardown)))
+
+(ert-deftest test-music-config--delete-playlist-file-boundary-refreshes-radio-cache ()
+  "Boundary: deletion clears the cached radio metadata."
+  (test-delete-playlist--setup)
+  (unwind-protect
+      (let ((file (cj/create-temp-test-file-with-content
+                   "#EXTM3U\n" "playlist.m3u")))
+        (setq cj/music--radio-metadata-cache '(("stale" . "entry")))
+        (cj/music--delete-playlist-file file)
+        (should-not cj/music--radio-metadata-cache))
+    (test-delete-playlist--teardown)))
+
+;;; Error Cases
+
+(ert-deftest test-music-config--delete-playlist-file-error-nil-path ()
+  "Error: nil path signals user-error."
+  (test-delete-playlist--setup)
+  (unwind-protect
+      (should-error (cj/music--delete-playlist-file nil) :type 'user-error)
+    (test-delete-playlist--teardown)))
+
+(ert-deftest test-music-config--delete-playlist-file-error-nonexistent-path ()
+  "Error: a path that does not exist signals user-error and touches nothing."
+  (test-delete-playlist--setup)
+  (unwind-protect
+      (let ((kept (cj/create-temp-test-file-with-content
+                   "#EXTM3U\n" "kept.m3u")))
+        (with-current-buffer (get-buffer cj/music-playlist-buffer-name)
+          (setq cj/music-playlist-file kept))
+        (should-error
+         (cj/music--delete-playlist-file
+          (expand-file-name "no-such.m3u" cj/test-base-dir))
+         :type 'user-error)
+        (with-current-buffer (get-buffer cj/music-playlist-buffer-name)
+          (should (equal cj/music-playlist-file kept))))
+    (test-delete-playlist--teardown)))
+
+(provide 'test-music-config--delete-playlist-file)
+;;; test-music-config--delete-playlist-file.el ends here