# -*- coding: utf-8 -*-
# Copyright (C) 2010 Mathias Brodala
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
#
# The developers of the Exaile media player hereby grant permission
# for non-GPL compatible GStreamer and Exaile plugins to be used and
# distributed together with GStreamer and Exaile. This permission is
# above and beyond the permissions granted by the GPL license by which
# Exaile is covered. If you modify this code, you may extend this
# exception to your version of the code, but you are not obligated to
# do so. If you do not wish to do so, delete this exception statement
# from your version.

"""
Provides an extensible framework for processing and
preparation of data for display in various contexts.
"""

from datetime import date
import gio
import glib
import gobject
import re
from string import Template, _TemplateMetaclass

from xl import (
    common,
    event,
    main,
    providers,
    settings,
    trax
)
from xl.common import TimeSpan
from xl.nls import gettext as _, ngettext

class _ParameterTemplateMetaclass(_TemplateMetaclass):
    # Allows for $tag, ${tag}, ${tag:parameter} and ${tag:parameter=argument}
    pattern = r"""
    %(delim)s(?:
      (?P<escaped>%(delim)s) |     # Escape sequence of two delimiters
      (?P<named>%(id)s)      |     # Delimiter and a Python identifier
      {
        (?P<braced>%(id)s)         # Delimiter and a braced identifier
        (!?:
          (?P<parameters>
            %(id)s                 # First optional parameter indicated with ':'
            (!?=(!?%(arg)s)+?)?    # Optional argument indicated with '='
            (!?,\s*%(id)s          # Further optional parameters separated with ','
              (!?=(!?%(arg)s)+?)?  # Optional argument indicated with '='
            )*      
          )
        )?
      }                      |
      (?P<invalid>)                # Other ill-formed delimiter expressions
    )
    """
    def __init__(cls, name, bases, dct):
        super(_ParameterTemplateMetaclass, cls).__init__(name, bases, dct)
        if 'pattern' in dct:
            pattern = cls.pattern
        else:
            pattern = _ParameterTemplateMetaclass.pattern % {
                'delim': re.escape(cls.delimiter),
                'id': cls.idpattern,
                'arg': cls.argpattern,
            }
        cls.pattern = re.compile(pattern, re.IGNORECASE | re.VERBOSE)

class ParameterTemplate(Template):
    """
        An extended template class which additionally
        accepts parameters assigned to identifiers.

        This introduces another pattern group named
        "parameters" in addition to the groups
        created by :class:`string.Template`

        Examples:

        * ``${foo:parameter1}``
        * ``${bar:parameter1, parameter2}``
        * ``${qux:parameter1=argument1, parameter2}``
    """
    __metaclass__ = _ParameterTemplateMetaclass
    argpattern = r'[^,}=]|\,|\}|\='

    def __init__(self, template):
        """
            :param template: the template string
        """
        Template.__init__(self, template)

    def safe_substitute(self, *args, **kwargs):
        """
            Overridden to allow for parametrized identifiers
        """
        if len(args) > 1:
            raise TypeError('Too many positional arguments')

        if not args:
            mapping = kwargs
        elif kwargs:
            mapping = _multimap(kwargs, args[0])
        else:
            mapping = args[0]

        # Helper function for .sub()
        def convert(mo):
            named = mo.group('named')

            if named is not None:
                try:
                    # We use this idiom instead of str() because the latter
                    # will fail if val is a Unicode containing non-ASCII
                    return '%s' % (mapping[named],)
                except KeyError:
                    return self.delimiter + named

            braced = mo.group('braced')

            if braced is not None:
                parts = [braced]
                parameters = mo.group('parameters')

                if parameters is not None:
                    parts += [parameters]

                try:
                    return '%s' % (mapping[':'.join(parts)],)
                except KeyError:
                    return self.delimiter + '{' + ':'.join(parts) + '}'

            if mo.group('escaped') is not None:
                return self.delimiter

            if mo.group('invalid') is not None:
                return self.delimiter

            raise ValueError('Unrecognized named group in pattern',
                             self.pattern)

        return self.pattern.sub(convert, self.template)

class Formatter(gobject.GObject):
    """
        A generic text formatter based on a format string

        By default the following parameters are provided
        to each identifier:

        * ``prefix``, ``suffix``: a string to put before or after the formatted string if that string is not empty
            * Whitespace will be not be touched and transferred as is
            * The characters ``,``, ``}`` and ``=`` need to be escaped like ``\,``, ``\}`` and ``\=`` respectively
        * ``pad``: desired length the formatted string should have, will be achieved using the ``padstring``
        * ``padstring``: a string to use for padding, will be repeated as often as possible to achieve the desired length specified by ``pad``
            * Example: ``${identifier:pad=4, padstring=XY}`` for *identifier* having the value *a* will become *XYXa*
    """
    __gproperties__ = {
        'format': (
            gobject.TYPE_STRING,
            'format string',
            'String the formatting is based on',
            '',
            gobject.PARAM_READWRITE
        )
    }
    def __init__(self, format):
        """
            :param format: the initial format, see the documentation
                of :class:`string.Template` for details
            :type format: string
        """
        gobject.GObject.__init__(self)

        self._template = ParameterTemplate(format)
        self._substitutions = {}

    def do_get_property(self, property):
        """
            Gets GObject properties
        """
        if property.name == 'format':
            return self._template.template
        else:
            raise AttributeError('unkown property %s' % property.name)

    def do_set_property(self, property, value):
        """
            Sets GObject properties
        """
        if property.name == 'format':
            if value != self._template.template:
                self._template.template = value
        else:
            raise AttributeError('unkown property %s' % property.name)

    def extract(self):
        """
            Retrieves the identifiers and their optional parameters

            Example of the returned dictionary::

                extractions = {
                    'identifier1': (
                        'identifier1', {}),
                    'identifier2:parameter': (
                        'identifier2', {'parameter': True}),
                    'identifier3:parameter=argument': (
                        'identifier3', {'parameter': 'argument'})
                }

            :returns: the extractions
            :rtype: dict
        """
        matches = self._template.pattern.finditer(self._template.template)
        extractions = {}

        # Extract list of identifiers and parameters from the format string
        for match in matches:
            groups = match.groupdict()

            # We only care about braced and named, not escaped and invalid
            identifier = groups['braced'] or groups['named']

            if identifier is None:
                continue

            identifier_parts = [identifier]
            parameters = {}

            if groups['parameters'] is not None:
                # Split parameters on unescaped comma
                parameters = [p.lstrip() \
                    for p in re.split(r'(?<!\\),', groups['parameters'])]
                # Split arguments on unescaped equals sign
                parameters = [(re.split(r'(?<!\\)=', p, 1) + [True])[:2] \
                    for p in parameters]
                # Turn list of lists into a proper dictionary
                parameters = dict(parameters)

                # Remove now obsolete escapes
                for p in parameters:
                    argument = parameters[p]

                    if type(argument) is not bool:
                        argument = argument.replace(r'\,', ',')
                        argument = argument.replace(r'\}', '}')
                        argument = argument.replace(r'\=', '=')
                        parameters[p] = argument

                identifier_parts += [groups['parameters']]

            # Required to make multiple occurences of the same
            # identifier with different parameters work
            extractions[':'.join(identifier_parts)] = (identifier, parameters)

        return extractions

    def format(self, *args):
        """
            Returns a string by formatting the passed data

            :param args: data to base the formatting on
            :returns: the formatted text
            :rtype: string
        """
        extractions = self.extract()
        substitutions = {}

        for needle, (identifier, parameters) in extractions.iteritems():
            substitute = None

            if needle in self._substitutions:
                substitute = self._substitutions[needle]
            elif identifier in self._substitutions:
                substitute = self._substitutions[identifier]

            if substitute is not None:
                prefix = parameters.pop('prefix', '')
                suffix = parameters.pop('suffix', '')
                pad = int(parameters.pop('pad', 0))
                padstring = parameters.pop('padstring', '')

                if callable(substitute):
                    substitute = substitute(*args, **parameters)

                if pad > 0 and padstring:
                    # Decrease pad length by value length
                    pad = max(0, pad - len(substitute))
                    # Retrieve the maximum multiplier for the pad string
                    padcount = pad / len(padstring) + 1
                    # Generate pad string
                    padstring = padcount * padstring
                    # Clamp pad string
                    padstring = padstring[0:pad]
                    substitute = '%s%s' % (padstring, substitute)

                if substitute:
                    substitute = '%s%s%s' % (prefix, substitute, suffix)

                substitutions[needle] = substitute

        return self._template.safe_substitute(substitutions)

class ProgressTextFormatter(Formatter):
    """
        A text formatter for progress indicators
    """
    def __init__(self, format, player):
        Formatter.__init__(self, format)
        self._player = player

    def format(self, current_time=None, total_time=None):
        """
            Returns a string suitable for progress indicators

            :param current_time: the current progress, taken from the current playback if not set
            :type current_time: float
            :param total_time: the total length of a track, taken from the current playback if not set
            :type total_time: float
            :returns: The formatted text
            :rtype: string
        """
        total_remaining_time = 0
        
        if current_time is None:
            current_time = self._player.get_time()

        if total_time is None:
            track = self._player.current

            if track is not None:
                total_time = track.get_tag_raw('__length')

        if total_time is None:
            total_time = remaining_time = 0
        else:
            remaining_time = total_time - current_time

        playlist = self._player.queue.current_playlist

        if playlist and playlist.current_position >= 0:        
            tracks = playlist[playlist.current_position:]
            total_remaining_time = sum([t.get_tag_raw('__length') \
                for t in tracks if t.get_tag_raw('__length')])
            total_remaining_time -= current_time

        self._substitutions['current_time'] = \
            LengthTagFormatter.format_value(current_time)
        self._substitutions['remaining_time'] = \
            LengthTagFormatter.format_value(remaining_time)
        self._substitutions['total_time'] = \
            LengthTagFormatter.format_value(total_time)
        self._substitutions['total_remaining_time'] = \
            LengthTagFormatter.format_value(total_remaining_time)

        return Formatter.format(self)

class TrackFormatter(Formatter):
    """
        A formatter for track data
    """
    def format(self, track, markup_escape=False):
        """
            Returns a string for places where
            track data is presented to the user

            :param track: a single track to take data from
            :type track: :class:`xl.trax.Track`
            :param markup_escape: whether to escape markup-like
                characters in tag values
            :type markup_escape: bool
            :returns: the formatted text
            :rtype: string
        """
        if not isinstance(track, trax.Track):
            raise TypeError('First argument to format() needs '
                            'to be of type xl.trax.Track')

        extractions = self.extract()
        self._substitutions = {}

        for identifier, (tag, parameters) in extractions.iteritems():
            provider = providers.get_provider('tag-formatting', tag)

            if provider is None:
                substitute = track.get_tag_display(tag)
            else:
                substitute = provider.format(track, parameters)

            if markup_escape:
                substitute = glib.markup_escape_text(substitute)

            self._substitutions[identifier] = substitute

        return Formatter.format(self)

class TagFormatter():
    """
        A formatter provider for a tag of a track
    """
    def __init__(self, name):
        """
            :param name: the name of the tag
            :type name: string
        """
        self.name = name

    def format(self, track, parameters):
        """
            Formats a raw tag value. Accepts optional
            parameters to manipulate the formatting
            process.

            :param track: the track to get the tag from
            :type track: :class:`xl.trax.Track`
            :param parameters: optionally passed parameters
            :type parameters: dictionary
            :returns: the formatted value
            :rtype: string
        """
        pass

class TrackNumberTagFormatter(TagFormatter):
    """
        A formatter for the tracknumber of a track
    """
    def __init__(self):
        TagFormatter.__init__(self, 'tracknumber')

    def format(self, track, parameters):
        """
            Formats a raw tag value

            :param track: the track to get the tag from
            :type track: :class:`xl.trax.Track`
            :param parameters: optionally passed parameters
            :type parameters: dictionary
            :returns: the formatted value
            :rtype: string
        """
        value = track.get_tag_raw(self.name, join=True)

        if not value:
            return ''

        try: # n/n
            value, count = value.split('/')
        except ValueError: # n
            pass

        if not value:
            return ''

        try:
            value = int(value)
        except ValueError:
            return ''

        return '%d' % value
providers.register('tag-formatting', TrackNumberTagFormatter())

class DiscNumberTagFormatter(TagFormatter):
    """
        A formatter for the tracknumber of a track
    """
    def __init__(self):
        TagFormatter.__init__(self, 'discnumber')

    def format(self, track, parameters):
        """
            Formats a raw tag value

            :param track: the track to get the tag from
            :type track: :class:`xl.trax.Track`
            :param parameters: optionally passed parameters
            :type parameters: dictionary
            :returns: the formatted value
            :rtype: string
        """
        value = track.get_tag_raw(self.name, join=True)

        if not value:
            return ''

        try: # n/n
            value, count = value.split('/')
        except ValueError: # n
            pass

        if not value:
            return ''

        try:
            value = int(value)
        except ValueError:
            return ''

        return '%d' % value
providers.register('tag-formatting', DiscNumberTagFormatter())

class ArtistTagFormatter(TagFormatter):
    """
        A formatter for the artist of a track
    """
    def __init__(self):
        TagFormatter.__init__(self, 'artist')

    def format(self, track, parameters):
        """
            Formats a raw tag value

            :param track: the track to get the tag from
            :type track: :class:`xl.trax.Track`
            :param parameters: optionally passed parameters
                Possible values are:

                * compilate:
                  Allows for proper handling of compilations,
                  either via albumartist tag, a fallback value,
                  or simply all artists
            :returns: the formatted value
            :rtype: string
        """
        compilate = parameters.get('compilate', False)
        value = track.get_tag_display(self.name,
            artist_compilations=compilate)

        return value
providers.register('tag-formatting', ArtistTagFormatter())

class LengthTagFormatter(TagFormatter):
    """
        A formatter for the length of a track
    """
    def __init__(self):
        TagFormatter.__init__(self, '__length')

    def format(self, track, parameters):
        """
            Formats a raw tag value

            :param track: the track to get the tag from
            :type track: :class:`xl.trax.Track`
            :param parameters: Verbosity of the output,
                possible values for "format" are:

                * short: "1:02:42"
                * long: "1h, 2m, 42s"
                * verbose: "1 hour, 2 minutes, 42 seconds"
            :type parameters: dictionary
            :returns: the formatted value
            :rtype: string
        """
        value = track.get_tag_raw(self.name)
        format = parameters.get('format', 'short')

        return self.format_value(value, format)

    @staticmethod
    def format_value(value, format='short'):
        """
            Formats a length value

            :param value: the length in seconds
            :type value: float
            :param format: verbosity of the output,
                possible values are:

                * short: "1:02:42"
                * long: "1h, 2m, 42s"
                * verbose: "1 hour, 2 minutes, 42 seconds"
            :type format: string
            :returns: the formatted value
            :rtype: string
        """
        span = TimeSpan(value)
        text = ''

        if format == 'verbose':
            if span.days > 0:
                text += ngettext('%d day, ', '%d days, ', span.days) % span.days
            if span.hours > 0:
                text += ngettext('%d hour, ', '%d hours, ', span.hours) % span.hours
            text += ngettext('%d minute, ', '%d minutes, ', span.minutes) % span.minutes
            text += ngettext('%d second', '%d seconds', span.seconds) % span.seconds

        elif format == 'long':
            if span.days > 0:
                # TRANSLATORS: Short form of an amount of days
                text += _('%dd, ') % span.days
            if span.hours > 0:
                # TRANSLATORS: Short form of an amount of hours
                text += _('%dh, ') % span.hours
            # TRANSLATORS: Short form of an amount of minutes
            text += _('%dm, ') % span.minutes
            # TRANSLATORS: Short form of an amount of seconds
            text += _('%ds') % span.seconds

        elif format == 'short':
            if span.days > 0:
                # TRANSLATORS: Short form of an amount of days
                text += _('%dd ') % span.days
            if span.hours > 0 or text: # always show hours when > 1 day
                # TRANSLATORS: Time duration (hours:minutes:seconds)
                text += _('%d:%02d:%02d') % (
                        span.hours, span.minutes, span.seconds)
            else:
                # TRANSLATORS: Time duration (minutes:seconds)
                text += _('%d:%02d') % (span.minutes, span.seconds)

        else:
            raise ValueError('Invalid argument "%s" passed to parameter '
                '"format" for tag "__length", possible arguments are '
                '"short", "long" and "verbose"' % format)

        return text
providers.register('tag-formatting', LengthTagFormatter())

class RatingTagFormatter(TagFormatter):
    """
        A formatter for the rating of a track
        
        Will return glyphs representing the rating like ★★★☆☆
    """
    def __init__(self):
        TagFormatter.__init__(self, '__rating')

    def format(self, track, parameters):
        """
            Formats a raw tag value

            :param track: the track to get the tag from
            :type track: :class:`xl.trax.Track`
            :param parameters: optionally passed parameters
            :type parameters: dictionary
            :returns: the formatted value
            :rtype: string
        """
        rating = track.get_rating()
        maximum = settings.get_option('rating/maximum', 5)

        filled = '★' * int(rating)
        empty = '☆' * int(maximum - rating)

        return ('%s%s' % (filled, empty)).decode('utf-8')
providers.register('tag-formatting', RatingTagFormatter())

class DateTagFormatter(TagFormatter):
    """
        A generic formatter for timestamp formatting

        Will return the localized string for *Today*, *Yesterday*
        or the respective localized date for earlier dates
    """
    def __init__(self, name):
        """
            :param name: the name of the tag
            :type name: string
        """
        TagFormatter.__init__(self, name)

    def format(self, track, parameters):
        """
            Formats a raw tag value

            :param track: the track to get the tag from
            :type track: :class:`xl.trax.Track`
            :param parameters: optionally passed parameters
            :type parameters: dictionary
            :returns: the formatted value
            :rtype: string
        """
        value = track.get_tag_raw(self.name)
        # TRANSLATORS: Indicates that a track has never been played before
        text = _('Never')

        try:
            last_played = date.fromtimestamp(value)
        except TypeError, ValueError:
            text = _('Never')
        else:
            today = date.today()
            delta = today - last_played

            if delta.days == 0:
                text = _('Today')
            elif delta.days == 1:
                text = _('Yesterday')
            else:
                text = last_played.strftime('%x')

        return text

class LastPlayedTagFormatter(DateTagFormatter):
    """
        A formatter for the last time a track was played
    """
    def __init__(self):
        DateTagFormatter.__init__(self, '__last_played')
providers.register('tag-formatting', LastPlayedTagFormatter())

class DateAddedTagFormatter(DateTagFormatter):
    """
        A formatter for the date a track
        was added to the collection
    """
    def __init__(self):
        DateTagFormatter.__init__(self, '__date_added')
providers.register('tag-formatting', DateAddedTagFormatter())

class LocationTagFormatter(TagFormatter):
    """
        A formatter for the location of a track,
        properly sanitized if necessary
    """
    def __init__(self):
        TagFormatter.__init__(self, '__loc')

    def format(self, track, parameters):
        """
            Formats a raw tag value

            :param track: the track to get the tag from
            :type track: :class:`xl.trax.Track`
            :param parameters: optionally passed parameters
            :type parameters: dictionary
            :returns: the formatted value
            :rtype: string
        """
        return common.sanitize_url(track.get_tag_raw('__loc'))
providers.register('tag-formatting', LocationTagFormatter())

class CommentTagFormatter(TagFormatter):
    """
        A formatter for comments embedded in tracks
    """
    def __init__(self):
        TagFormatter.__init__(self, 'comment')

    def format(self, track, parameters):
        """
            Formats a raw tag value

            :param track: the track to get the tag from
            :type track: :class:`xl.trax.Track`
            :param parameters: whether to keep newlines,
                possible values for "newlines" are:

                * keep: do not strip newlines (default)
                * strip: strip newlines
            :type parameters: dictionary
            :returns: the formatted value
            :rtype: string
        """
        value = track.get_tag_disk(self.name)

        if not value:
            return ''

        value = '\n\n'.join(value)
        newlines = parameters.get('newlines', 'keep')

        return self.format_value(value, newlines)

    @staticmethod
    def format_value(value, newlines='keep'):
        """
            Formats a comment value

            :param value: the comment text
            :type value: string
            :param newlines: whether to keep newlines,
                possible values are:

                * keep: do not strip newlines (default)
                * strip: strip newlines

            :type newlines: string
            :returns: the formatted value
            :rtype: string
        """
        if newlines == 'strip':
            value = ' '.join(value.splitlines())

        return value
providers.register('tag-formatting', CommentTagFormatter())

# vim: et sts=4 sw=4
