#!/bin/python2

# only using python2 because mutagen
from __future__ import print_function

import os
import os.path
import sys
import shutil
import tempfile
import mutagen

import mutaext
import convert

# BUG: doesn't work with my .m4a files?
goodexts = ('.mp3', '.m4a', '.flac', '.ogg')

matchtags = ['artist', 'album', 'title']
updatabletags = [\
    'albumartist', 'composer', 'comment' \
    'tracknumber', 'discnumber', \
    'genre', 'date', \
]
updatabletags.extend(mutaext.replaygain_tags)
updatabletags.extend(mutaext.extra_tags)
alltags = list(updatabletags)
alltags.extend(matchtags)

lament = lambda *args, **kwargs: print(*args, file=sys.stderr, **kwargs)
walkfiles = lambda w: (os.path.join(r, f) for r, _, fs in w for f in fs)
extof = lambda p: os.path.splitext(p)[1].lower()
filterext = lambda ps, es: (p for p in ps if extof(p) in es)

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

    return sync == 'yes' or type(rating) == int and rating >= 3 and sync != 'no' and sync != 'space'

def fixmetadata(md):
    md['artist'] = md.get('artist', u"Unknown Artist")
    md['album'] = md.get('album', u"Unknown Album")
    if 'title' not in md:
        fn = os.path.basename(md.path)
        fn = os.path.splitext(fn)[0]
        # TODO: attempt to infer trackNum/discNum from fn
        md['title'] = unicode(fn)

def findmatching(haystack, needle):
    matchme = [needle[t] for t in matchtags]
    ismatch = lambda hay: [hay[t] for t in matchtags] == matchme
    for match in (hay for hay in haystack if ismatch(hay)):
        if match.seen:
            # TODO: check other tags and filename and such?
            lament("Warning: duplicate match found:")
            lament(u"%(title)s by %(artist)s from %(album)s" % locals())
        match.seen = True
        return match

def updatemetadata(mdold, mdnew):
    modified = False
    for tag in updatabletags:
        # checking for length b/c sometimes (ID3 genre) exists but empty
        if tag in mdnew and len(mdnew[tag]):
            if not tag in mdold or mdnew[tag][0] != mdold[tag][0]:
                mdold[tag] = mdnew[tag]
                modified = True
        elif tag in mdold:
            del mdold[tag]
            modified = True
    return modified

def makefilename(md):
    title = md['title'][0]
    artist = md['artist'][0]
    album = md['album'][0]
    return u"%(artist)s - %(album)s - %(title)s.ogg" % locals()

def run(args):
    if not len(args) in (2, 3):
        lament("I need a path or two!")
        return 1
    inonly = len(args) == 2

    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:
                # TODO: don't use custom members on external metadata class
                md.path = p
                md.seen = False
                fixmetadata(md)
                tosync.append(md)

    if inonly:
        return 0

    lament("Matching...")

    outdir = args[2]
    for p in paths(outdir):
        md = mutagen.File(p, easy=True)
        match = findmatching(tosync, md)
        if not match:
            print("DEL", p)
            os.remove(p)
        elif updatemetadata(md, match):
            print("UPD", p)
            md.save()

    for md in tosync:
        if md.seen:
            continue
        print("ADD", md.path)

        fout = os.path.join(outdir, makefilename(md))
        _, ftemp = tempfile.mkstemp()
        try:
            convert.ogg(md.path, ftemp)
            mdnew = mutagen.File(ftemp, easy=True)
            for tag in alltags:
                if tag in md:
                    mdnew[tag] = md[tag]
            mdnew.save()
            shutil.copy2(ftemp, fout)
        finally:
            os.remove(ftemp)

    return 0

ret = 0
try:
    ret = run(sys.argv)
except KeyboardInterrupt:
    sys.exit(1)
sys.exit(ret)