1;;; emms-bookmarks.el --- Bookmarks for Emms.
2
3;; Copyright (C) 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4
5;; Author: Yoni Rabkin <yrk@gnu.org>
6;; Keywords: emms, bookmark
7
8;; This file is part of EMMS.
9
10;; EMMS is free software; you can redistribute it and/or modify
11;; it under the terms of the GNU General Public License as published by
12;; the Free Software Foundation; either version 3, or (at your option)
13;; any later version.
14;;
15;; EMMS is distributed in the hope that it will be useful,
16;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18;; GNU General Public License for more details.
19;;
20;; You should have received a copy of the GNU General Public License
21;; along with EMMS; if not, write to the Free Software Foundation,
22;; Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
23
24;;; Commentary:
25;;
26;; You can use this to add ``temporal bookmarks'' (term by Lucas
27;; Bonnet) to your media files.  The interesting functions here are
28;; `emms-bookmarks-next', `emms-bookmarks-prev', `emms-bookmarks-add'
29;; (which pauses the player while you describe the bookmark) and
30;; `emms-bookmarks-clear'.  All of which do exactly what you think
31;; they do.
32
33;;; Code:
34
35
36;; dependencies
37(require 'emms)
38(require 'emms-playing-time)
39
40(defvar emms-bookmarks-prev-overshoot 5
41  "Time in seconds for skipping a previous bookmark.")
42
43(defun emms-bookmarks-reset (track)
44  "Remove all the bookmarks from TRACK."
45  (emms-track-set track 'bookmarks nil))
46
47(defun emms-bookmarks-straight-insertion-sort (item l acc)
48  "Insert ITEM into the already sorted L, ACC should be nil."
49  (if (null l)
50      (append acc (list item))
51    (cond ((< (cdr item) (cdr (car l))) (append acc (list item (car l)) (cdr l)))
52	  (t (emms-bookmarks-straight-insertion-sort item (cdr l) (append acc (list (car l))))))))
53
54(defun emms-bookmarks-get (track)
55  "Return the bookmark property from TRACK."
56  (emms-track-get track 'bookmarks))
57
58(defun emms-bookmarks-set (track desc time)
59  "Set bookmark property for TRACK, text DESC at TIME seconds."
60  (let ((old-bookmarks (emms-track-get track 'bookmarks))
61	(new-bookmarks nil))
62    (setq new-bookmarks (emms-bookmarks-straight-insertion-sort (cons desc time) old-bookmarks nil))
63    (emms-track-set track 'bookmarks new-bookmarks)))
64
65(defun emms-bookmarks-set-current (desc)
66  "Set bookmark property for the current track with text DESC."
67  (emms-bookmarks-set (emms-playlist-current-selected-track) desc emms-playing-time))
68
69(defun emms-bookmarks-search (time track test)
70  "Return a bookmark based on heuristics.
71
72TIME should be a reference point in seconds.
73TRACK should be an Emms track.
74TEST should be a numerical comparator predicate."
75  (let ((s (append (list (cons "time" time)) (copy-sequence (emms-bookmarks-get track)))))
76    (sort s #'(lambda (a b) (funcall test (cdr a) (cdr b))))
77    (while (not (= time (cdar s)))
78      (setq s (cdr s)))
79    (when (cdr s)
80      (car (cdr s)))))
81
82(defun emms-bookmarks-next-1 (time track)
83  "Return the bookmark after TIME for TRACK, otherwise return nil."
84  (emms-bookmarks-search time track #'<))
85
86(defun emms-bookmarks-prev-1 (time track)
87  "Return the bookmark before TIME for TRACK, otherwise return nil."
88  (emms-bookmarks-search (- time emms-bookmarks-prev-overshoot) track #'>))
89
90(defun emms-bookmarks-goto (search-f track failure-message)
91  "Seek the player to a bookmark.
92
93SEARCH-F should be a function which returns a bookmark.
94TRACK should be an Emms track.
95FAILURE-MESSAGE should be a string."
96  ;; note that when emms is paused then `emms-player-playing-p' => t
97  (when (not emms-player-playing-p)
98    (emms-start))
99  (let ((m (funcall search-f emms-playing-time track)))
100    (if m
101	(progn
102	  (emms-player-seek-to (cdr m))
103	  (message "%s" (car m)))
104      (message "%s" failure-message))))
105
106
107;; entry points
108
109(defun emms-bookmarks-next ()
110  "Seek to the next bookmark in the current track."
111  (interactive)
112  (emms-bookmarks-goto #'emms-bookmarks-next-1
113		       (emms-playlist-current-selected-track)
114		       "No next bookmark"))
115
116(defun emms-bookmarks-prev ()
117  "Seek to the previous bookmark in the current track."
118  (interactive)
119  (emms-bookmarks-goto #'emms-bookmarks-prev-1
120		       (emms-playlist-current-selected-track)
121		       "No previous bookmark"))
122
123(defmacro emms-bookmarks-with-paused-player (&rest body)
124  "Eval BODY with player paused."
125  `(progn
126     (when (not emms-player-paused-p) (emms-pause))
127     ,@body
128     (when emms-player-paused-p (emms-pause))))
129
130;; can't use `interactive' to promt the user here because we want to
131;; pause the player before the prompt appears.
132(defun emms-bookmarks-add ()
133  "Add a new bookmark to the current track.
134
135This function pauses the player while prompting the user for a
136description of the bookmark.  The function resumes the player
137after the prompt."
138  (interactive)
139  (emms-bookmarks-with-paused-player
140   (let ((desc (read-string "Description: ")))
141     (if (emms-playlist-current-selected-track)
142	 (emms-bookmarks-set-current desc)
143       (error "No current track to bookmark")))))
144
145(defun emms-bookmarks-clear ()
146  "Remove all the bookmarks from the current track."
147  (interactive)
148  (let ((this (emms-playlist-current-selected-track)))
149    (when this (emms-bookmarks-reset this))))
150
151(provide 'emms-bookmarks)
152
153;;; emms-bookmarks.el ends here
154