;;; emms-mark.el --- mark track like dired

;; Copyright (C) 2006, 2007 Ye Wenbin
;;
;; Author: Ye Wenbin <wenbinye@163.com>
;; Keywords: 
;; X-URL: not distributed yet

;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, write to the Free Software
;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

;;; Commentary:

;; Provide mark operation to tracks

;; Put this file into your load-path and the following into your ~/.emacs:
;;   (require 'emms-mark)

;; To activate it for the current buffer only, do:
;;   (emms-mark-mode)

;; To make this the default EMMS mode, do:
;;   (setq emms-playlist-default-major-mode 'emms-mark-mode)

;;; Code:

(provide 'emms-mark)
(require 'emms)
(require 'emms-playlist-mode)
(eval-when-compile
  (require 'cl))

;;{{{  set new description-function
(defun emms-mark-track-description (track)
  "Return a description of the current track."
  (assert (not (eq (default-value 'emms-track-description-function)
                   'emms-mark-track-description))
          nil "Should never set emms-track-selection-function to be emms-mark-track-description.")
  (concat "  " (funcall (default-value 'emms-track-description-function)
                        track)))

(defun emms-mark-update-descriptions ()
  "Update the track descriptions in the current buffer."
  (emms-with-inhibit-read-only-t
   (save-excursion
     (goto-char (point-min))
     (emms-walk-tracks
       (emms-playlist-update-track)))))
;;}}}

;;{{{ functions to mark tracks
(defvar emms-mark-char ?*)
(defvar emms-mark-face-alist
  '((?* . font-lock-warning-face)
    (?\040 . emms-playlist-track-face)))

(defun emms-mark-track (&optional arg)
  (interactive "p")
  (or arg (setq arg 1))
  (let ((face (assoc-default emms-mark-char emms-mark-face-alist))
        buffer-read-only track)
    (save-excursion
      (beginning-of-line)
      (while (and (not (eobp))
                  (/= arg 0))
        (setq track (get-text-property (point) 'emms-track))
        (delete-char 1)
        (insert (emms-propertize (string emms-mark-char)
                                 'emms-track track))
        (backward-char 1)
        (if (> arg 0)
            ;; Propertizing forward...
            (put-text-property (point)
                               (progn (forward-line 1) (point))
                               'face face)
          ;; ... and backward
          (let ((start (save-excursion (end-of-line) (point))))
            (put-text-property (progn (beginning-of-line) (point))
                               start
                               'face face))
          (forward-line -1))
        (setq arg (if (> arg 0)
                      (1- arg)
                    (1+ arg)))))))

(defun emms-mark-unmark-track (&optional arg)
  (interactive "p")
  (let ((emms-mark-char ?\040))
    (emms-mark-track arg)))

(defun emms-mark-forward (arg)
  (interactive "p")
  (emms-mark-track arg)
  (forward-line arg))

(defun emms-mark-unmark-forward (arg)
  (interactive "p")
  (emms-mark-unmark-track arg)
  (forward-line arg))

(defun emms-mark-all ()
  (interactive)
  (save-excursion
    (goto-char (point-min))
    (emms-mark-track (count-lines (point-min) (point-max)))))

(defun emms-mark-unmark-all ()
  (interactive)
  (emms-mark-do-with-marked-track 'emms-mark-unmark-track))

(defun emms-mark-regexp (regexp arg)
  "Mark all tracks matching a regexp. A prefix argument means to
unmark them instead."
  (interactive
   (list
    (read-from-minibuffer (if current-prefix-arg
                              "Mark track match: "
                            "Unmark track match: "))
    current-prefix-arg))
  (let ((emms-mark-char (if arg ?\040 ?*)))
    (save-excursion
      (goto-char (point-min))
      (while (re-search-forward regexp nil t)
        (emms-mark-track 1)
        (forward-line 1)))))

(defun emms-mark-toggle ()
  (interactive)
  (save-excursion
    (goto-char (point-min))
    (let (buffer-read-only)
      (while (not (eobp))
        (if (eq ?\040 (following-char))
            (emms-mark-track)
          (emms-mark-unmark-track))
        (forward-line 1)))))

(defsubst emms-mark-has-markedp ()
  "Predicate whether the playlist has marked line"
  (save-excursion
    (goto-char (point-min))
    (re-search-forward (format "^[%c]" emms-mark-char) nil t)))

;;}}}

;;{{{ functions to operate marked tracks
(defun emms-mark-do-with-marked-track (func &optional move)
  "Call FUNC on every marked line in current playlist. The FUNC take
no argument, so if need the track in marked line, should use
`emms-playlist-track-at' to get it. The FUNC can also modify the
playlist buffer, such as delete the line. It is import for who want to
use this function, this function didn't move forward. So if FUNC don't
move forward, set the second parameter MOVE to non-nil. Otherwise, the
function will never exit the loop."
  (let ((regexp (format "^[%c]" emms-mark-char))
        (newfunc func))
    (if move
        (setq newfunc (lambda () (funcall func) (forward-line 1))))
    (save-excursion
      (goto-char (point-min))
      (while (re-search-forward regexp nil t)
        (backward-char 1)               ; move to beginning of line
        (funcall newfunc)))))

(defun emms-mark-mapcar-marked-track (func &optional move)
  "This function does the same thing as
`emms-mark-do-with-marked-track', the only difference is this function
collect the result of FUNC."
  (let ((regexp (format "^[%c]" emms-mark-char))
        result (newfunc func))
    (if move
        (setq newfunc (lambda () (let ((res (funcall func)))
                                   (forward-line 1) res))))
    (save-excursion
      (goto-char (point-min))
      (while (re-search-forward regexp nil t)
        (backward-char 1)               ; move to beginning of line
        (setq result (cons (funcall newfunc) result)))
      (nreverse result))))

(defun emms-mark-delete-marked-tracks ()
  (interactive)
  (emms-with-inhibit-read-only-t
   (emms-mark-do-with-marked-track
    (lambda nil (delete-region (point)
                               (progn (forward-line 1) (point)))))))

(defun emms-mark-kill-marked-tracks ()
  (interactive)
  (let (tracks buffer-read-only)
    (emms-mark-do-with-marked-track
     (lambda nil
       (setq tracks
             (concat tracks
                     (delete-and-extract-region (point)
                                                (progn (forward-line 1) (point)))))))
    (kill-new tracks)))

(defun emms-mark-copy-marked-tracks ()
  (interactive)
  (let (tracks)
    (emms-mark-do-with-marked-track
     (lambda nil
       (setq tracks
             (concat tracks
                     (buffer-substring (point)
                                       (progn (forward-line 1) (point)))))))
    (kill-new tracks)))
;;}}}

;;{{{ mode stuff
(defconst emms-mark-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "W" 'emms-mark-copy-marked-tracks)
    (define-key map "K" 'emms-mark-kill-marked-tracks)
    (define-key map "D" 'emms-mark-delete-marked-tracks)
    (define-key map "m" 'emms-mark-forward)
    (define-key map "u" 'emms-mark-unmark-forward)
    (define-key map "U" 'emms-mark-unmark-all)
    (define-key map "t" 'emms-mark-toggle)
    (define-key map "%m" 'emms-mark-regexp)
    map))

(defun emms-mark-mode ()
  "An EMMS major mode that allows tracks to be marked like dired.
\\{emms-mark-mode-map}"
  (interactive)
  (if (eq major-mode 'emms-mark-mode)
      ;; do nothing if we're already in emms-mark-mode
      nil

    ;; start emms-playlist-mode exactly once
    (unless (eq major-mode 'emms-playlist-mode)
      (emms-playlist-mode))

    ;; use inherited keymap
    (set-keymap-parent emms-mark-mode-map (current-local-map))
    (use-local-map emms-mark-mode-map)
    (setq major-mode 'emms-mark-mode
          mode-name "Emms-Mark")

    ;; show a blank space at beginning of each line
    (set (make-local-variable 'emms-track-description-function)
         'emms-mark-track-description)
    (emms-mark-update-descriptions)))

(defun emms-mark-mode-disable ()
  "Disable `emms-mark-mode' and return to `emms-playlist-mode'."
  (interactive)
  (if (not (eq major-mode 'emms-mark-mode))
      ;; do nothing if we're not in emms-mark-mode
      nil

    ;; call emms-playlist-mode, saving important variables
    (let ((selected emms-playlist-selected-marker))
      (emms-playlist-mode)
      (setq emms-playlist-selected-marker selected)
      (emms-playlist-mode-overlay-selected))

    ;; update display
    (emms-mark-update-descriptions)))
;;}}}

;;; emms-mark.el ends here