text: # -*- coding: utf-8 -*-
  # This file is part of beets.
  # Copyright 2016, Adrian Sampson.
  #
  # Permission is hereby granted, free of charge, to any person obtaining
  # a copy of this software and associated documentation files (the
  # "Software"), to deal in the Software without restriction, including
  # without limitation the rights to use, copy, modify, merge, publish,
  # distribute, sublicense, and/or sell copies of the Software, and to
  # permit persons to whom the Software is furnished to do so, subject to
  # the following conditions:
  #
  # The above copyright notice and this permission notice shall be
  # included in all copies or substantial portions of the Software.
  
  """Glue between metadata sources and the matching logic."""
  from __future__ import division, absolute_import, print_function
  
  from collections import namedtuple
  from functools import total_ordering
  import re
  
  from beets import logging
  from beets import plugins
  from beets import config
  from beets.util import as_string
  from beets.autotag import mb
  from jellyfish import levenshtein_distance
  from unidecode import unidecode
  import six
  
  log = logging.getLogger('beets')
  
  # The name of the type for patterns in re changed in Python 3.7.
  try:
      Pattern = re._pattern_type
  except AttributeError:
      Pattern = re.Pattern
  
  
  # Classes used to represent candidate options.
  class AttrDict(dict):
      """A dictionary that supports attribute ("dot") access, so `d.field`
      is equivalent to `d['field']`.
      """
  
      def __getattr__(self, attr):
          if attr in self:
              return self.get(attr)
          else:
              raise AttributeError
  
      def __setattr__(self, key, value):
          self.__setitem__(key, value)
  
      def __hash__(self):
          return id(self)
  
  
  class AlbumInfo(AttrDict):
      """Describes a canonical release that may be used to match a release
      in the library. Consists of these data members:
  
      - ``album``: the release title
      - ``album_id``: MusicBrainz ID; UUID fragment only
      - ``artist``: name of the release's primary artist
      - ``artist_id``
      - ``tracks``: list of TrackInfo objects making up the release
  
      ``mediums`` along with the fields up through ``tracks`` are required.
      The others are optional and may be None.
      """
      def __init__(self, tracks, album=None, album_id=None, artist=None,
                   artist_id=None, asin=None, albumtype=None, va=False,
                   year=None, month=None, day=None, label=None, mediums=None,
                   artist_sort=None, releasegroup_id=None, catalognum=None,
                   script=None, language=None, country=None, style=None,
                   genre=None, albumstatus=None, media=None, albumdisambig=None,
                   releasegroupdisambig=None, artist_credit=None,
                   original_year=None, original_month=None,
                   original_day=None, data_source=None, data_url=None,
                   discogs_albumid=None, discogs_labelid=None,
                   discogs_artistid=None, **kwargs):
          self.album = album
          self.album_id = album_id
          self.artist = artist
          self.artist_id = artist_id
          self.tracks = tracks
          self.asin = asin
          self.albumtype = albumtype
          self.va = va
          self.year = year
          self.month = month
          self.day = day
          self.label = label
          self.mediums = mediums
          self.artist_sort = artist_sort
          self.releasegroup_id = releasegroup_id
          self.catalognum = catalognum
          self.script = script
          self.language = language
          self.country = country
          self.style = style
          self.genre = genre
          self.albumstatus = albumstatus
          self.media = media
          self.albumdisambig = albumdisambig
          self.releasegroupdisambig = releasegroupdisambig
          self.artist_credit = artist_credit
          self.original_year = original_year
          self.original_month = original_month
          self.original_day = original_day
          self.data_source = data_source
          self.data_url = data_url
          self.discogs_albumid = discogs_albumid
          self.discogs_labelid = discogs_labelid
          self.discogs_artistid = discogs_artistid
          self.update(kwargs)
  
      # Work around a bug in python-musicbrainz-ngs that causes some
      # strings to be bytes rather than Unicode.
      # https://github.com/alastair/python-musicbrainz-ngs/issues/85
      def decode(self, codec='utf-8'):
          """Ensure that all string attributes on this object, and the
          constituent `TrackInfo` objects, are decoded to Unicode.
          """
          for fld in ['album', 'artist', 'albumtype', 'label', 'artist_sort',
                      'catalognum', 'script', 'language', 'country', 'style',
                      'genre', 'albumstatus', 'albumdisambig',
                      'releasegroupdisambig', 'artist_credit',
                      'media', 'discogs_albumid', 'discogs_labelid',
                      'discogs_artistid']:
              value = getattr(self, fld)
              if isinstance(value, bytes):
                  setattr(self, fld, value.decode(codec, 'ignore'))
  
          for track in self.tracks:
              track.decode(codec)
  
      def copy(self):
          dupe = AlbumInfo([])
          dupe.update(self)
          dupe.tracks = [track.copy() for track in self.tracks]
          return dupe
  
  
  class TrackInfo(AttrDict):
      """Describes a canonical track present on a release. Appears as part
      of an AlbumInfo's ``tracks`` list. Consists of these data members:
  
      - ``title``: name of the track
      - ``track_id``: MusicBrainz ID; UUID fragment only
  
      Only ``title`` and ``track_id`` are required. The rest of the fields
      may be None. The indices ``index``, ``medium``, and ``medium_index``
      are all 1-based.
      """
      def __init__(self, title=None, track_id=None, release_track_id=None,
                   artist=None, artist_id=None, length=None, index=None,
                   medium=None, medium_index=None, medium_total=None,
                   artist_sort=None, disctitle=None, artist_credit=None,
                   data_source=None, data_url=None, media=None, lyricist=None,
                   composer=None, composer_sort=None, arranger=None,
                   track_alt=None, work=None, mb_workid=None,
                   work_disambig=None, bpm=None, initial_key=None, genre=None,
                   **kwargs):
          self.title = title
          self.track_id = track_id
          self.release_track_id = release_track_id
          self.artist = artist
          self.artist_id = artist_id
          self.length = length
          self.index = index
          self.media = media
          self.medium = medium
          self.medium_index = medium_index
          self.medium_total = medium_total
          self.artist_sort = artist_sort
          self.disctitle = disctitle
          self.artist_credit = artist_credit
          self.data_source = data_source
          self.data_url = data_url
          self.lyricist = lyricist
          self.composer = composer
          self.composer_sort = composer_sort
          self.arranger = arranger
          self.track_alt = track_alt
          self.work = work
          self.mb_workid = mb_workid
          self.work_disambig = work_disambig
          self.bpm = bpm
          self.initial_key = initial_key
          self.genre = genre
          self.update(kwargs)
  
      # As above, work around a bug in python-musicbrainz-ngs.
      def decode(self, codec='utf-8'):
          """Ensure that all string attributes on this object are decoded
          to Unicode.
          """
          for fld in ['title', 'artist', 'medium', 'artist_sort', 'disctitle',
                      'artist_credit', 'media']:
              value = getattr(self, fld)
              if isinstance(value, bytes):
                  setattr(self, fld, value.decode(codec, 'ignore'))
  
      def copy(self):
          dupe = TrackInfo()
          dupe.update(self)
          return dupe
  
  
  # Candidate distance scoring.
  
  # Parameters for string distance function.
  # Words that can be moved to the end of a string using a comma.
  SD_END_WORDS = ['the', 'a', 'an']
  # Reduced weights for certain portions of the string.
  SD_PATTERNS = [
      (r'^the ', 0.1),
      (r'[\[\(]?(ep|single)[\]\)]?', 0.0),
      (r'[\[\(]?(featuring|feat|ft)[\. :].+', 0.1),
      (r'\(.*?\)', 0.3),
      (r'\[.*?\]', 0.3),
      (r'(, )?(pt\.|part) .+', 0.2),
  ]
  # Replacements to use before testing distance.
  SD_REPLACE = [
      (r'&', 'and'),
  ]
  
  
  def _string_dist_basic(str1, str2):
      """Basic edit distance between two strings, ignoring
      non-alphanumeric characters and case. Comparisons are based on a
      transliteration/lowering to ASCII characters. Normalized by string
      length.
      """
      assert isinstance(str1, six.text_type)
      assert isinstance(str2, six.text_type)
      str1 = as_string(unidecode(str1))
      str2 = as_string(unidecode(str2))
      str1 = re.sub(r'[^a-z0-9]', '', str1.lower())
      str2 = re.sub(r'[^a-z0-9]', '', str2.lower())
      if not str1 and not str2:
          return 0.0
      return levenshtein_distance(str1, str2) / float(max(len(str1), len(str2)))
  
  
  def string_dist(str1, str2):
      """Gives an "intuitive" edit distance between two strings. This is
      an edit distance, normalized by the string length, with a number of
      tweaks that reflect intuition about text.
      """
      if str1 is None and str2 is None:
          return 0.0
      if str1 is None or str2 is None:
          return 1.0
  
      str1 = str1.lower()
      str2 = str2.lower()
  
      # Don't penalize strings that move certain words to the end. For
      # example, "the something" should be considered equal to
      # "something, the".
      for word in SD_END_WORDS:
          if str1.endswith(', %s' % word):
              str1 = '%s %s' % (word, str1[:-len(word) - 2])
          if str2.endswith(', %s' % word):
              str2 = '%s %s' % (word, str2[:-len(word) - 2])
  
      # Perform a couple of basic normalizing substitutions.
      for pat, repl in SD_REPLACE:
          str1 = re.sub(pat, repl, str1)
          str2 = re.sub(pat, repl, str2)
  
      # Change the weight for certain string portions matched by a set
      # of regular expressions. We gradually change the strings and build
      # up penalties associated with parts of the string that were
      # deleted.
      base_dist = _string_dist_basic(str1, str2)
      penalty = 0.0
      for pat, weight in SD_PATTERNS:
          # Get strings that drop the pattern.
          case_str1 = re.sub(pat, '', str1)
          case_str2 = re.sub(pat, '', str2)
  
          if case_str1 != str1 or case_str2 != str2:
              # If the pattern was present (i.e., it is deleted in the
              # the current case), recalculate the distances for the
              # modified strings.
              case_dist = _string_dist_basic(case_str1, case_str2)
              case_delta = max(0.0, base_dist - case_dist)
              if case_delta == 0.0:
                  continue
  
              # Shift our baseline strings down (to avoid rematching the
              # same part of the string) and add a scaled distance
              # amount to the penalties.
              str1 = case_str1
              str2 = case_str2
              base_dist = case_dist
              penalty += weight * case_delta
  
      return base_dist + penalty
  
  
  class LazyClassProperty(object):
      """A decorator implementing a read-only property that is *lazy* in
      the sense that the getter is only invoked once. Subsequent accesses
      through *any* instance use the cached result.
      """
      def __init__(self, getter):
          self.getter = getter
          self.computed = False
  
      def __get__(self, obj, owner):
          if not self.computed:
              self.value = self.getter(owner)
              self.computed = True
          return self.value
  
  
  @total_ordering
  @six.python_2_unicode_compatible
  class Distance(object):
      """Keeps track of multiple distance penalties. Provides a single
      weighted distance for all penalties as well as a weighted distance
      for each individual penalty.
      """
      def __init__(self):
          self._penalties = {}
  
      @LazyClassProperty
      def _weights(cls):  # noqa: N805
          """A dictionary from keys to floating-point weights.
          """
          weights_view = config['match']['distance_weights']
          weights = {}
          for key in weights_view.keys():
              weights[key] = weights_view[key].as_number()
          return weights
  
      # Access the components and their aggregates.
  
      @property
      def distance(self):
          """Return a weighted and normalized distance across all
          penalties.
          """
          dist_max = self.max_distance
          if dist_max:
              return self.raw_distance / self.max_distance
          return 0.0
  
      @property
      def max_distance(self):
          """Return the maximum distance penalty (normalization factor).
          """
          dist_max = 0.0
          for key, penalty in self._penalties.items():
              dist_max += len(penalty) * self._weights[key]
          return dist_max
  
      @property
      def raw_distance(self):
          """Return the raw (denormalized) distance.
          """
          dist_raw = 0.0
          for key, penalty in self._penalties.items():
              dist_raw += sum(penalty) * self._weights[key]
          return dist_raw
  
      def items(self):
          """Return a list of (key, dist) pairs, with `dist` being the
          weighted distance, sorted from highest to lowest. Does not
          include penalties with a zero value.
          """
          list_ = []
          for key in self._penalties:
              dist = self[key]
              if dist:
                  list_.append((key, dist))
          # Convert distance into a negative float we can sort items in
          # ascending order (for keys, when the penalty is equal) and
          # still get the items with the biggest distance first.
          return sorted(
              list_,
              key=lambda key_and_dist: (-key_and_dist[1], key_and_dist[0])
          )
  
      def __hash__(self):
          return id(self)
  
      def __eq__(self, other):
          return self.distance == other
  
      # Behave like a float.
  
      def __lt__(self, other):
          return self.distance < other
  
      def __float__(self):
          return self.distance
  
      def __sub__(self, other):
          return self.distance - other
  
      def __rsub__(self, other):
          return other - self.distance
  
      def __str__(self):
          return "{0:.2f}".format(self.distance)
  
      # Behave like a dict.
  
      def __getitem__(self, key):
          """Returns the weighted distance for a named penalty.
          """
          dist = sum(self._penalties[key]) * self._weights[key]
          dist_max = self.max_distance
          if dist_max:
              return dist / dist_max
          return 0.0
  
      def __iter__(self):
          return iter(self.items())
  
      def __len__(self):
          return len(self.items())
  
      def keys(self):
          return [key for key, _ in self.items()]
  
      def update(self, dist):
          """Adds all the distance penalties from `dist`.
          """
          if not isinstance(dist, Distance):
              raise ValueError(
                  u'`dist` must be a Distance object, not {0}'.format(type(dist))
              )
          for key, penalties in dist._penalties.items():
              self._penalties.setdefault(key, []).extend(penalties)
  
      # Adding components.
  
      def _eq(self, value1, value2):
          """Returns True if `value1` is equal to `value2`. `value1` may
          be a compiled regular expression, in which case it will be
          matched against `value2`.
          """
          if isinstance(value1, Pattern):
              return bool(value1.match(value2))
          return value1 == value2
  
      def add(self, key, dist):
          """Adds a distance penalty. `key` must correspond with a
          configured weight setting. `dist` must be a float between 0.0
          and 1.0, and will be added to any existing distance penalties
          for the same key.
          """
          if not 0.0 <= dist <= 1.0:
              raise ValueError(
                  u'`dist` must be between 0.0 and 1.0, not {0}'.format(dist)
              )
          self._penalties.setdefault(key, []).append(dist)
  
      def add_equality(self, key, value, options):
          """Adds a distance penalty of 1.0 if `value` doesn't match any
          of the values in `options`. If an option is a compiled regular
          expression, it will be considered equal if it matches against
          `value`.
          """
          if not isinstance(options, (list, tuple)):
              options = [options]
          for opt in options:
              if self._eq(opt, value):
                  dist = 0.0
                  break
          else:
              dist = 1.0
          self.add(key, dist)
  
      def add_expr(self, key, expr):
          """Adds a distance penalty of 1.0 if `expr` evaluates to True,
          or 0.0.
          """
          if expr:
              self.add(key, 1.0)
          else:
              self.add(key, 0.0)
  
      def add_number(self, key, number1, number2):
          """Adds a distance penalty of 1.0 for each number of difference
          between `number1` and `number2`, or 0.0 when there is no
          difference. Use this when there is no upper limit on the
          difference between the two numbers.
          """
          diff = abs(number1 - number2)
          if diff:
              for i in range(diff):
                  self.add(key, 1.0)
          else:
              self.add(key, 0.0)
  
      def add_priority(self, key, value, options):
          """Adds a distance penalty that corresponds to the position at
          which `value` appears in `options`. A distance penalty of 0.0
          for the first option, or 1.0 if there is no matching option. If
          an option is a compiled regular expression, it will be
          considered equal if it matches against `value`.
          """
          if not isinstance(options, (list, tuple)):
              options = [options]
          unit = 1.0 / (len(options) or 1)
          for i, opt in enumerate(options):
              if self._eq(opt, value):
                  dist = i * unit
                  break
          else:
              dist = 1.0
          self.add(key, dist)
  
      def add_ratio(self, key, number1, number2):
          """Adds a distance penalty for `number1` as a ratio of `number2`.
          `number1` is bound at 0 and `number2`.
          """
          number = float(max(min(number1, number2), 0))
          if number2:
              dist = number / number2
          else:
              dist = 0.0
          self.add(key, dist)
  
      def add_string(self, key, str1, str2):
          """Adds a distance penalty based on the edit distance between
          `str1` and `str2`.
          """
          dist = string_dist(str1, str2)
          self.add(key, dist)
  
  
  # Structures that compose all the information for a candidate match.
  
  AlbumMatch = namedtuple('AlbumMatch', ['distance', 'info', 'mapping',
                                         'extra_items', 'extra_tracks'])
  
  TrackMatch = namedtuple('TrackMatch', ['distance', 'info'])
  
  
  # Aggregation of sources.
  
  def album_for_mbid(release_id):
      """Get an AlbumInfo object for a MusicBrainz release ID. Return None
      if the ID is not found.
      """
      try:
          album = mb.album_for_id(release_id)
          if album:
              plugins.send(u'albuminfo_received', info=album)
          return album
      except mb.MusicBrainzAPIError as exc:
          exc.log(log)
  
  
  def track_for_mbid(recording_id):
      """Get a TrackInfo object for a MusicBrainz recording ID. Return None
      if the ID is not found.
      """
      try:
          track = mb.track_for_id(recording_id)
          if track:
              plugins.send(u'trackinfo_received', info=track)
          return track
      except mb.MusicBrainzAPIError as exc:
          exc.log(log)
  
  
  def albums_for_id(album_id):
      """Get a list of albums for an ID."""
      a = album_for_mbid(album_id)
      if a:
          yield a
      for a in plugins.album_for_id(album_id):
          if a:
              plugins.send(u'albuminfo_received', info=a)
              yield a
  
  
  def tracks_for_id(track_id):
      """Get a list of tracks for an ID."""
      t = track_for_mbid(track_id)
      if t:
          yield t
      for t in plugins.track_for_id(track_id):
          if t:
              plugins.send(u'trackinfo_received', info=t)
              yield t
  
  
  @plugins.notify_info_yielded(u'albuminfo_received')
  def album_candidates(items, artist, album, va_likely, extra_tags):
      """Search for album matches. ``items`` is a list of Item objects
      that make up the album. ``artist`` and ``album`` are the respective
      names (strings), which may be derived from the item list or may be
      entered by the user. ``va_likely`` is a boolean indicating whether
      the album is likely to be a "various artists" release. ``extra_tags``
      is an optional dictionary of additional tags used to further
      constrain the search.
      """  
      # Candidates from plugins.
      for candidate in plugins.candidates(items, artist, album, va_likely,
                                          extra_tags):
          yield candidate
  
  
  @plugins.notify_info_yielded(u'trackinfo_received')
  def item_candidates(item, artist, title):
      """Search for item matches. ``item`` is the Item to be matched.
      ``artist`` and ``title`` are strings and either reflect the item or
      are specified by the user.
      """
      # Plugin candidates.
      for candidate in plugins.item_candidates(item, artist, title):
          yield candidate
  