;;; empc.el --- A simple elisp wrapper for mpd and mpc.

;;; Commentary:

;; 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, version 3.

;; 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, see <http://www.gnu.org/licenses/>.

;; This is a single window, single playlist, no thrills, bare-bones
;; mpc client for EMACS.

;;; Code:

(define-derived-mode empc-mode fundamental-mode "Empc")
(defvar empc-buffer-name "*empc*")
(defvar empc-search-initial-input "")

(defun empc ()
  "Create a new empc buffer. If it already exists switch to it."
  (interactive)
  (if (get-buffer empc-buffer-name)
      (set-window-buffer (selected-window) empc-buffer-name)
    (empc-create-playlist)))

(defun empc-create-playlist ()
  "Create the playlist buffer and set it to empc-mode."
  (get-buffer-create empc-buffer-name)
  (set-window-buffer (selected-window) empc-buffer-name)
  (with-current-buffer empc-buffer-name
    (empc-mode)
    (insert (shell-command-to-string "mpc playlist"))
    (rectangle-number-lines (point-min) (- (point-max) 1) 1 "%-5d ")
    (empc-finalize-buffer)))

(defun empc-finalize-buffer ()
  "Set some final settings for the empc buffer."
  (read-only-mode t)
  (toggle-truncate-lines t)
  (hl-line-mode t)
  (goto-char (point-min))
  (message "Hello :3"))

(defun empc-revert-playlist ()
  "Reread the playlist."
  (interactive)
  (when (y-or-n-p "Revert playlist buffer?" )
      (kill-buffer "*empc*")
      (empc)))

(defun empc-update-database ()
  "Run a databse update and revert the playlist buffer."
  (interactive)
  (when (y-or-n-p "Run database update?" )
    (shell-command-to-string "mpc clear && mpc update --wait  && mpc add /")
    (empc-revert-playlist)))
    
(defun empc-play-highlighted ()
  "Play the currently highlighted song."
  (interactive)
  (let ((pos (number-to-string (line-number-at-pos))))
    (shell-command-to-string (concat "mpc -q play " pos))
    (message (concat "Playing #" pos))))

(defun empc-search-playlist ()
  "Provide a jump box to search for specific songs."
  (interactive)
  (let* ((playlist
          (split-string
	   (with-current-buffer empc-buffer-name
	     (buffer-string))
	   "\n"))
         (song-id (completing-read "Song: " playlist nil t
				   empc-search-initial-input)))
    (shell-command-to-string (concat "mpc -q play "
				     (car (split-string song-id " "))))
    (empc-follow)))

(defun empc-follow ()
  "Recenter the currently played/paused song."
  (interactive)
  (goto-char (point-min))
  (forward-line (1- (string-to-number
		    (shell-command-to-string "mpc current -f %position%"))))
  (recenter))

(defmacro empc-generic-command (cmd quiet follow)
  "Macro to generate functions for simple mpc commands.
Call command CMD. If QUIET is non-nil print the mpc status
message. If FOLLOW is non-nil follow the currently playing song."
  `(defun ,(intern (concat "empc-" cmd)) ()
     "This function was generated by the empc-generic-command
     macro."
     (interactive)
     (shell-command (concat "mpc " (when ,quiet "-q ") ,cmd))
     (when ,follow (empc-follow))))

(defun empc-define-keymaps ()
  "Define keys in ‘empc-mode-map’."
  (setq empc-mode-map (make-sparse-keymap))
  (define-key empc-mode-map "\r" 'empc-play-highlighted)
  (define-key empc-mode-map "p" (empc-generic-command "toggle" t nil))
  (define-key empc-mode-map "n" (empc-generic-command "next" t t))
  (define-key empc-mode-map "b" (empc-generic-command "prev" t t))
  (define-key empc-mode-map "c" (empc-generic-command "seek +5" nil nil))
  (define-key empc-mode-map "x" (empc-generic-command "seek -5" nil nil))
  (define-key empc-mode-map "r" (empc-generic-command "random" nil nil))
  (define-key empc-mode-map "R" (empc-generic-command "repeat" nil nil))
  (define-key empc-mode-map "s" (empc-generic-command "single" nil nil))
  (define-key empc-mode-map "." (empc-generic-command "status" nil nil))
  (define-key empc-mode-map "+" (empc-generic-command "volume +5" nil nil))
  (define-key empc-mode-map "-" (empc-generic-command "volume -5" nil nil))
  (define-key empc-mode-map "f" 'empc-follow)
  (define-key empc-mode-map "g" 'empc-revert-playlist)
  (define-key empc-mode-map "U" 'empc-update-database)
  (define-key empc-mode-map "q" 'quit-window)
  (define-key empc-mode-map "j" 'empc-search-playlist))

(empc-define-keymaps)
(provide 'empc)

;;; empc.el ends here