Command Line Music Setup with Python and mpv

# Maps a string such as 'The Beatles' to 'the-beatles'.
def toNeat(s):
  s = s.lower().replace("&","and")
  s = re.sub(r"[()\[\],.'\"\\\?\#/\!\$\:]", "", s)
  s = re.sub(r"[ \*\_]", "-", s)
  s = re.sub("-+", "-", s)
  search = re.search("[^0-9a-z\-\=]", s)
  if search:
    print("Error: Unrecognized character in '" + s + "'")
    sys.exit(-42)
  return s

Album1/Track A.mp3
Album1/Track B.mp3
Album1/Track C.mp3
Album2/Track D.mp3
Album2/Track E.mp3

track-a.mp3
track-b.mp3
track-c.mp3
track-d.mp3
track-e.mp3

Alpha 1.mp3 (Artist: Alpha, Title: 1)
Alpha 2.mp3 (Artist: Alpha, Title: 2)
Beta 1.mp3 (Artist: Beta, Title: 1)
KeepThisDir/1.mp3
KeepThisDir/2.mp3

alpha/1.mp3 (Artist: Alpha, Title: 1)
alpha/2.mp3 (Artist: Alpha, Title: 2)
beta/1.mp3 (Artist: Beta, Title: 1)
KeepThisDir/1.mp3
KeepThisDir/2.mp3

> music-organizer.py -h
usage: music-organizer.py [-h] [--delete-conflicts]
                          [--ignore-multiple-artists] [--collection]
                          [--artist]

Organizes a music collection using tag information. The directory format is
that the music collection consists of artist subdirectories, and there are 2
modes to operate on the entire collection or a single artist. All names are
made lowercase and separated by dashes for easier navigation in a Linux
filesystem.

optional arguments:
  -h, --help            show this help message and exit
  --delete-conflicts    If an artist has duplicate tracks with the same name,
                        delete them. Note this might always be best in case an
                        artist has multiple versions. To keep multiple
                        versions, fix the tag information.
  --ignore-multiple-artists
                        This script will prompt for confirmation if an artist
                        directory has songs with more than 2 different tags.
                        This flag disables the confirmation and won't perform
                        this check.
  --collection          Operate in 'collection' mode and run 'artist' mode on
                        every subdirectory.
  --artist              Operate in 'artist' mode and copy all songs to the
                        root of the directory and cleanly format the names to
                        be easily typed and navigated in a shell.

require 'os'
require 'io'
require 'string'


-- Helper function to execute a command and return the output as a string.
-- Reference: http://stackoverflow.com/questions/132397
function os.capture(cmd, raw)
  local f = assert(io.popen(cmd, 'r'))
  local s = assert(f:read('*a'))
  f:close()
  return string.sub(s, 0, -2) -- Use string.sub to trim the trailing newline.
end

-- Global variables for deleting/restoring the current track.
deleted_tmp = "/tmp/mpv-deleted"
last_deleted_track = ""

-- Delete the current track by moving it to the `deleted_tmp` location.
function delete_current_track()
  last_deleted_track = mp.get_property("path")
  os.execute("mv '" .. last_deleted_track .. "' '" .. deleted_tmp .. "'")
  print("'" .. last_deleted_track .. "' deleted.")
end

-- Restore the last deleted track.
-- This can be done to restore an arbitrary number of tracks by
-- using a queue rather than a single file.
function restore_prev_track()
  if last_deleted_track ~= "" then
    os.execute("mv '" .. deleted_tmp .. "' '" .. last_deleted_track .. "'")
    print("Successfully recovered '" .. last_deleted_track .. "'")
    last_deleted_track = ""
  else
    print("No track to recover.")
  end
end

-- Move the current track into a `good` directory.
function mark_good()
  last_deleted_track = mp.get_property("path")
  os.execute("mkdir -p good")
  os.execute("mv '" .. mp.get_property("path") .. "' '" .. "good" .. "'")
  print("Marked '" .. last_deleted_track .. "' as good.")
end

-- Get a field such as 'Artist' or 'Title' from the current track.
function get_current_track_field(field)
  return os.capture(
    'exiftool -json "' .. mp.get_property("path") ..
    '" | grep \'^ *"' .. field .. '\' ' ..
    ' | sed \'s/^ *"' .. field .. '": "\\(.*\\)",$/\\1/g\'; '
  )
end

-- Print the current track's artist and title in the following format.
--
-- [music] ---------------
-- [music] Title: Marche Slave
-- [music] Artist: Tchaikovsky
-- [music] ---------------
function print_info()
  local artist = get_current_track_field("Artist")
  local title = get_current_track_field("Title")
  print(string.rep("-", 15))
  print('Artist: ' .. artist)
  print('Title: ' .. title)
  print(string.rep("-", 15))
end

-- Display a prompt for user input in Linux or Mac using
-- zenity or CocoaDialog, which must be already installed.
uname = os.capture('uname')
function prompt_input(title)
  local val
  if uname == "Linux" then
    val = os.capture(
      'zenity --entry --title "' .. title .. '" --text ""'
    )
  elseif uname == "Darwin" then
    val = os.capture(
      '/Applications/CocoaDialog.app/Contents/MacOS/CocoaDialog ' ..
      'standard-inputbox ' ..
      '--title "' .. title .. '" ' ..
      '| tail -n 1'
    )
  end
  return val
end

-- Use zenity and mutt to share the current track's information with a friend.
-- This can be modified to send the message with any command-line email client
-- or used to interface directly with an SMTP server.
function share_info()
  local email = prompt_input("Email to share with?")
  if email == "" then
    print("Error: No email input.")
    return
  end
  local content = prompt_input("Optional message body?");
  local artist = get_current_track_field("Artist")
  local title = get_current_track_field("Title")
  local info = 'Hi, check out ' .. title .. ' by ' .. artist .. '.'
  print(email)
  print(info)
  os.capture("echo '" .. content .. "' | " ..
    "mutt -s '" .. info .. "'" .. " -- '" .. email .. "'")
end

-- Set key bindings.
mp.add_key_binding("d", "delete_current_track", delete_current_track)
mp.add_key_binding("r", "restore_prev_track", restore_prev_track)
mp.add_key_binding("g", "mark_good", mark_good)
mp.add_key_binding("i", "print_info", print_info)
mp.add_key_binding("s", "share", share_info)

# shellrc.sc
# Source this to add additional shell features for mpv.

alias mpvnova='mpv --no-video'
alias mpvshuf='mpvnova --shuffle --loop inf'
alias mpvp='mpvshuf --playlist'

playcurrentdir() {
  mpvp <(find "$PWD" -type f -follow)
}
alias pcd='playcurrentdir'

playdir() {
  if [[ $# == 0 ]]; then
    echo "playdir requires one or more directories on input."
  else
    if [[ $(uname) == "Linux" ]]; then READLINK=readlink;
    else READLINK=greadlink; fi
    mpvshuf --playlist <(find "$@" -type f -follow -exec $READLINK -f {} \;)
    unset READLINK
  fi
}
alias pd='playdir'