;;; emus.el --- Simple music player for Emacs.  -*- lexical-binding:t -*-

;; Author: Tim Vaughan <timv@ughan.xyz>
;; Version: 1.0
;; Keywords: multimedia
;; URL: http://github.com/tgvaughan/emus

;;; Commentary:

;; This is a simple package for playing audio from a local library
;; of audio files.

;;; Code:

;;; Customizations
;;

(defgroup emus nil
  "Simple music player for Emacs inspired by CMUS."
  :group 'multimedia)

(defcustom emus-directory "~/Music/"
  "Directory containing audio files for emus."
  :type '(string))

(defcustom emus-mpg123-program "mpg123"
  "Name of (and, optionally, path to) mpg123 binary."
  :type '(string))

;;; Library
;;

(defvar emus-library nil
  "Emus audio library.")

(defun emus-get-audio-files ()
  "Get all mp3 files in main emus directory."
  (directory-files-recursively emus-directory ".*\\.mp3"))

(defvar emus-tags nil)

(defun emus-update-tags ()
  "Get ID3 tags for given filename"
  (let ((proc (emus-get-process))
        (depth 0)
        (tagstr "")
        (filenames (emus-get-audio-files)))
    (setq emus-tags nil)
    (set-process-filter proc (lambda (proc string)
                               (setq tagstr (concat tagstr string))
                               (cond
                                ((string-suffix-p "}\n" string) (setq depth (- depth 1)))
                                ((string-suffix-p "{\n" string) (setq depth (+ depth 1))))
                               (when (and (= depth 0) (string-suffix-p "\n" string))
                                 (add-to-list 'emus-tags `(,(car filenames) ,tagstr))
                                 (setq tagstr "")
                                 (setq filenames (cdr filenames))
                                 (if filenames
                                     (emus-send-cmd "lp" (car filenames))
                                   (set-process-filter proc nil)))))
    (emus-send-cmd "lp" (car filenames))))

(defun emus-get-process ()
  "Return current or new mpg123 process."
  (let* ((emus-process-raw (get-process "emus-process"))
         (emus-process (if emus-process-raw
                           (if (process-live-p emus-process-raw)
                               emus-process-raw
                             (kill-process emus-process-raw)
                             nil))))
    (if emus-process
        emus-process
      (make-process :name "emus-process"
                    ;; :buffer (get-buffer-create "*emus-process*")
                    :command `(,emus-mpg123-program "-R")))))

(defun emus-send-cmd (cmd &rest args)
  (process-send-string (emus-get-process)
                       (concat
                        (seq-reduce (lambda (s1 s2) (concat s1 " " s2)) args cmd)
                        "\n")))

;;; Browser
;;

(defun emus-browse ()
  "Switch to *emus* audio library browser."
  (interactive)
  (switch-to-buffer "*emus*")
  (emus-mode))

(define-derived-mode emus-mode special-mode "Emus"
  "Major mode for EMUS music player.")

;;; Debugging

(defun emus-test ()
  (message (emus-get-file-tags "/Users/vaughant/Music/Floex_-_Zorya/Floex - Zorya - 01 Ursa Major.mp3")))

(defun emus-test-play ()
  (emus-send-cmd "lp" "/Users/vaughant/Music/Floex_-_Zorya/Floex - Zorya - 01 Ursa Major.mp3")
  (emus-send-cmd "silence")
  (emus-send-cmd "p"))


;;; emus.el ends here