#!/bin/python2

# only using python2 because mutagen
from __future__ import print_function

import os
import os.path
import sys
import mutagen
import mutagen.id3
import mutagen.easyid3

def popm_any(id3):
    for k, v in id3.iteritems():
        if k.startswith('POPM'):
            return v

def byte2rating(b):
    if b >= 224: return 5
    if b >= 160: return 4
    if b >= 96: return 3
    if b >= 32: return 2
    if b >= 1: return 1
    return 0

def rating_get(id3, key):
    try:
        return list(id3['TXXX:RATING'])
    except KeyError:
        try:
            return list(unicode(byte2rating(popm_any(id3).rating)))
        except AttributeError:
            return
def rating_set(id3, key, val):
    # TODO: test
    try:
        frame = id3["TXXX:RATING"]
    except KeyError:
        id3.add(mutagen.id3.TXXX(encoding=3, desc=u'RATING', text=val))
    else:
        frame.encoding = 3
        frame.text = val
def rating_delete(id3, key):
    # TODO: delete POPM too?
    del(id3["TXXX:RATING"])

mutagen.easyid3.EasyID3.RegisterTXXXKey('sync', 'SYNC')
mutagen.easyid3.EasyID3.RegisterKey('rating', rating_get, rating_set, rating_delete)

def safetydance(d, k):
    if k in d: return d[k]

def walkfiles(walker):
    for root, _, files in walker:
        for f in files:
            yield os.path.join(root, f)

def filterext(paths, exts):
    for p in paths:
        ext = os.path.splitext(p)[1].lower()
        if ext in exts:
            yield p

def shouldsync(md):
    rating = -1
    sync = u''
    if safetydance(md, 'rating'):
        try:
            rating = int(md['rating'][0])
        except ValueError:
            pass
    if safetydance(md, 'sync'):
        sync = md['sync'][0].lower()

    if sync == u'no' or sync == u'space':
        return False
    if sync == u'yes' or sync == u'share':
        return True
    if rating >= 3:
        return True
    return False

def findmatching(haystack, needle):
    artist = safetydance(needle, 'artist')
    album = safetydance(needle, 'album')
    title = safetydance(needle, 'title')
    for match in haystack:
        if artist == safetydance(match, 'artist') \
          and album == safetydance(match, 'album') \
          and title == safetydance(match, 'title'):
            return match

def run(args):
    if not len(args) in (2, 3):
        print("I need a path or two!", file=sys.stderr)
        sys.exit(1)

    inonly = len(args) == 2

    # BUG: doesn't work with my .m4a files?
    goodexts = ('.mp3', '.m4a', '.flac', '.ogg')
    tosync = []
    indir = args[1]
    paths = lambda dir: filterext(walkfiles(os.walk(dir)), goodexts)

    for p in paths(indir):
        md = mutagen.File(p, easy=True)
        if shouldsync(md):
            if inonly: print(p)
            else: tosync.append(md)

    if inonly: return
    print("Beginning matching...", file=sys.stderr)

    outdir = args[2]
    for p in paths(outdir):
        md = mutagen.File(p, easy=True)
        match = findmatching(tosync, md)
        # TODO: don't print anything
        # TODO: don't match mismatched lengths (Xing?)
        # TODO: update important tags on mostly matching files
        # TODO: don't sync files that wouldn't match!
        # TODO: convert files in loop that works on altered tosync
        if match:
            print("MATCHING", p)
        else:
            # TODO: just delete missing ones here
            print("MISSING", p)

try:
    run(sys.argv)
except KeyboardInterrupt:
    sys.exit(1)