#! /usr/bin/env python
#
# mutagen aims to be an all purpose media tagging library
# Copyright (C) 2005  Michael Urman
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of version 2 of the GNU General Public License as
# published by the Free Software Foundation.
#
# $Id: __init__.py 4026 2007-04-27 02:13:05Z piman $
#

"""Mutagen aims to be an all purpose tagging library.

    import mutagen.[format]
    metadata = mutagen.[format].Open(filename)

metadata acts like a dictionary of tags in the file. Tags are generally a
list of string-like values, but may have additional methods available
depending on tag or format. They may also be entirely different objects
for certain keys, again depending on format.
"""

version = (1, 11)
version_string = ".".join(map(str, version))

import warnings

import mutagen._util

class Metadata(object):
    """An abstract dict-like object.

    Metadata is the base class for many of the tag objects in Mutagen.
    """

    def __init__(self, *args, **kwargs):
        if args or kwargs:
            self.load(*args, **kwargs)

    def load(self, *args, **kwargs):
        raise NotImplementedError

    def save(self, filename=None):
        raise NotImplementedError

    def delete(self, filename=None):
        raise NotImplementedError

class FileType(mutagen._util.DictMixin):
    """An abstract object wrapping tags and audio stream information.

    Attributes:
    info -- stream information (length, bitrate, sample rate)
    tags -- metadata tags, if any

    Each file format has different potential tags and stream
    information.

    FileTypes implement an interface very similar to Metadata; the
    dict interface, save, load, and delete calls on a FileType call
    the appropriate methods on its tag data.
    """

    info = None
    tags = None
    filename = None
    _mimes = ["application/octet-stream"]

    def __init__(self, filename=None, *args, **kwargs):
        if filename is None:
            warnings.warn("FileType constructor requires a filename",
                          DeprecationWarning)
        else:
            self.load(filename, *args, **kwargs)

    def load(self, filename, *args, **kwargs):
        raise NotImplementedError

    def __getitem__(self, key):
        """Look up a metadata tag key.

        If the file has no tags at all, a KeyError is raised.
        """
        if self.tags is None: raise KeyError, key
        else: return self.tags[key]

    def __setitem__(self, key, value):
        """Set a metadata tag.

        If the file has no tags, an appropriate format is added (but
        not written until save is called).
        """
        if self.tags is None:
            self.add_tags()
        self.tags[key] = value

    def __delitem__(self, key):
        """Delete a metadata tag key.

        If the file has no tags at all, a KeyError is raised.
        """
        if self.tags is None: raise KeyError, key
        else: del(self.tags[key])

    def keys(self):
        """Return a list of keys in the metadata tag.

        If the file has no tags at all, an empty list is returned.
        """
        if self.tags is None: return []
        else: return self.tags.keys()

    def delete(self, filename=None):
        """Remove tags from a file."""
        if self.tags is not None:
            if filename is None:
                filename = self.filename
            else:
                warnings.warn(
                    "delete(filename=...) is deprecated, reload the file",
                    DeprecationWarning)
            return self.tags.delete(filename)

    def save(self, filename=None, **kwargs):
        """Save metadata tags."""
        if filename is None:
            filename = self.filename
        else:
            warnings.warn(
                "save(filename=...) is deprecated, reload the file",
                DeprecationWarning)
        if self.tags is not None:
            return self.tags.save(filename, **kwargs)
        else: raise ValueError("no tags in file")

    def pprint(self):
        """Print stream information and comment key=value pairs."""
        stream = "%s (%s)" % (self.info.pprint(), self.mime[0])
        try: tags = self.tags.pprint()
        except AttributeError:
            return stream
        else: return stream + ((tags and "\n" + tags) or "")

    def add_tags(self):
        raise NotImplementedError

    def __get_mime(self):
        mimes = []
        for Kind in type(self).__mro__:
            for mime in getattr(Kind, '_mimes', []):
                if mime not in mimes:
                    mimes.append(mime)
        return mimes

    mime = property(__get_mime)

def File(filename, options=None):
    """Guess the type of the file and try to open it.

    The file type is decided by several things, such as the first 128
    bytes (which usually contains a file type identifier), the
    filename extension, and the presence of existing tags.

    If no appropriate type could be found, None is returned.
    """

    if options is None:
        from mutagen.asf import ASF
        from mutagen.apev2 import APEv2File
        from mutagen.flac import FLAC
        from mutagen.id3 import ID3FileType
        from mutagen.mp3 import MP3
        from mutagen.oggflac import OggFLAC
        from mutagen.oggspeex import OggSpeex
        from mutagen.oggtheora import OggTheora
        from mutagen.oggvorbis import OggVorbis
        from mutagen.trueaudio import TrueAudio
        from mutagen.wavpack import WavPack
        from mutagen.mp4 import MP4
        from mutagen.musepack import Musepack
        from mutagen.monkeysaudio import MonkeysAudio
        from mutagen.optimfrog import OptimFROG
        options = [MP3, TrueAudio, OggTheora, OggSpeex, OggVorbis, OggFLAC,
                   FLAC, APEv2File, MP4, ID3FileType, WavPack, Musepack,
                   MonkeysAudio, OptimFROG, ASF]

    if not options:
        return None

    fileobj = file(filename, "rb")
    try:
        header = fileobj.read(128)
        results = [Kind.score(filename, fileobj, header) for Kind in options]
    finally:
        fileobj.close()
    results = zip(results, options)
    results.sort()
    score, Kind = results[-1]
    if score > 0: return Kind(filename)
    else: return None
