#!/usr/bin/python
#
# squeezify_playlists.py

"""Utility for converting M3U playlists to a format and location that
the SqueezeBox SlimServer groks.

Given: a directory hierarchy containing per-directory playlists, with
songs listed as relative filenames in each playlist.

Output: s single directory that contains versions of all those
playlists, with the songs listed as absolute filenames.
"""

__author__ = "Leo Breebaart <leo@lspace.org>"
__version__ = "1.0"
__date__ = "16 September 2006"
__license__ = "MIT License <http://www.opensource.org/licenses/mit-license.php>"

import sys
import os


def collect_playlists(directory):
    """ Traverse 'directory' and yield all the .m3u filenamess found.
    Files are detected based on the presence of a case-insensitive
    '.m3u' extension, and returned as full, absolute pathnames."""

    for root, dirs, files in os.walk(directory):
        for f in files:
            _, extension = os.path.splitext(f)
            if extension.lower() == ".m3u":
                yield os.path.abspath(os.path.join(root, f))


def store_playlist(filename, contents):
    """ Write 'contents' to 'filename', where 'contents' is a list of
    lines (newlines included)."""

    f = open(filename, "w")
    f.writelines(contents)
    f.close()


def convert_name(filename, targetdir):
    """ Returns a path that consists of the basename of 'filename'
    grafted onto 'targetdir':

    >>> convert_name('/a/b/c/d/joop.m3u', '/x/y/z')
    '/x/y/z/joop.m3u'

    """

    basename = os.path.basename(filename)
    return os.path.join(targetdir, basename)


def convert_contents(filename):

    def is_relative_songline(line):
        line = line.strip()
        if line == "": return False
        if line[0] == '#': return False
        if line[0] == '/': return False
        if line[1] == ':': return False
        return True

    directory = os.path.dirname(filename)
    newcontents = []
    for line in open(filename):
        if is_relative_songline(line):
            newcontents.append(os.path.join(directory, line))
        else:
            newcontents.append(line)
    return newcontents


def convert_playlist(filename, targetdir):
    return (convert_name(filename, targetdir),
            convert_contents(filename))


def squeezify_playlists(sourcedir, targetdir):

    for filename in collect_playlists(sourcedir):
#        print "found", os.path.join(filename)
        (newname, newcontents) = convert_playlist(filename, targetdir)
        store_playlist(newname, newcontents)


if __name__ == "__main__":

    try:
        sourcedir = sys.argv[1]
    except IndexError:
        sourcedir = "/backup/cygnus/music/music"

    targetdir = "/hex/slimserver-playlists"
    squeezify_playlists(sourcedir, targetdir)