# -*- coding: utf-8 -*-
# pylint: disable=W0223
"""Video is ungraded Xmodule for support video content.
It's new improved video module, which support additional feature:

- Can play non-YouTube video sources via in-browser HTML5 video player.
- YouTube defaults to HTML5 mode from the start.
- Speed changes in both YouTube and non-YouTube videos happen via
in-browser HTML5 video method (when in HTML5 mode).
- Navigational subtitles can be disabled altogether via an attribute
in XML.

Examples of html5 videos for manual testing:
    https://s3.amazonaws.com/edx-course-videos/edx-intro/edX-FA12-cware-1_100.mp4
    https://s3.amazonaws.com/edx-course-videos/edx-intro/edX-FA12-cware-1_100.webm
    https://s3.amazonaws.com/edx-course-videos/edx-intro/edX-FA12-cware-1_100.ogv
"""
import json
import logging
from operator import itemgetter

from lxml import etree
from pkg_resources import resource_string
import copy

from collections import OrderedDict

from django.conf import settings

from xblock.fields import ScopeIds
from xblock.runtime import KvsFieldData

from xmodule.modulestore.inheritance import InheritanceKeyValueStore, own_metadata
from xmodule.x_module import XModule, module_attr
from xmodule.editing_module import TabsEditingDescriptor
from xmodule.raw_module import EmptyDataRawDescriptor
from xmodule.xml_module import is_pointer_tag, name_to_pathname, deserialize_field

from .video_utils import create_youtube_string, get_video_from_cdn
from .video_xfields import VideoFields
from .video_handlers import VideoStudentViewHandlers, VideoStudioViewHandlers

from xmodule.video_module import manage_video_subtitles_save

log = logging.getLogger(__name__)
_ = lambda text: text


class VideoModule(VideoFields, VideoStudentViewHandlers, XModule):
    """
    XML source example:

        <video show_captions="true"
            youtube="0.75:jNCf2gIqpeE,1.0:ZwkTiUPN0mg,1.25:rsq9auxASqI,1.50:kMyNdzVHHgg"
            url_name="lecture_21_3" display_name="S19V3: Vacancies"
        >
            <source src=".../mit-3091x/M-3091X-FA12-L21-3_100.mp4"/>
            <source src=".../mit-3091x/M-3091X-FA12-L21-3_100.webm"/>
            <source src=".../mit-3091x/M-3091X-FA12-L21-3_100.ogv"/>
        </video>
    """
    video_time = 0
    icon_class = 'video'

    # To make sure that js files are called in proper order we use numerical
    # index. We do that to avoid issues that occurs in tests.
    module = __name__.replace('.video_module', '', 2)
    js = {
        'js': [
            resource_string(module, 'js/src/video/00_video_storage.js'),
            resource_string(module, 'js/src/video/00_resizer.js'),
            resource_string(module, 'js/src/video/00_async_process.js'),
            resource_string(module, 'js/src/video/00_i18n.js'),
            resource_string(module, 'js/src/video/00_sjson.js'),
            resource_string(module, 'js/src/video/00_iterator.js'),
            resource_string(module, 'js/src/video/01_initialize.js'),
            resource_string(module, 'js/src/video/025_focus_grabber.js'),
            resource_string(module, 'js/src/video/02_html5_video.js'),
            resource_string(module, 'js/src/video/03_video_player.js'),
            resource_string(module, 'js/src/video/035_video_accessible_menu.js'),
            resource_string(module, 'js/src/video/04_video_control.js'),
            resource_string(module, 'js/src/video/05_video_quality_control.js'),
            resource_string(module, 'js/src/video/06_video_progress_slider.js'),
            resource_string(module, 'js/src/video/07_video_volume_control.js'),
            resource_string(module, 'js/src/video/08_video_speed_control.js'),
            resource_string(module, 'js/src/video/09_video_caption.js'),
            resource_string(module, 'js/src/video/10_main.js')
        ]
    }
    css = {'scss': [
        resource_string(module, 'css/video/display.scss'),
        resource_string(module, 'css/video/accessible_menu.scss'),
    ]}
    js_module_name = "Video"


    def get_html(self):
        track_url = None
        download_video_link = None
        transcript_download_format = self.transcript_download_format
        sources = filter(None, self.html5_sources)

        # If the user comes from China use China CDN for html5 videos.
        # 'CN' is China ISO 3166-1 country code.
        # Video caching is disabled for Studio. User_location is always None in Studio.
        # CountryMiddleware disabled for Studio.
        cdn_url = getattr(settings, 'VIDEO_CDN_URL', {}).get(self.system.user_location)

        if getattr(self, 'video_speed_optimizations', True) and cdn_url:
            for index, source_url in enumerate(sources):
                new_url = get_video_from_cdn(cdn_url, source_url)
                if new_url:
                    sources[index] = new_url

        if self.download_video:
            if self.source:
                download_video_link = self.source
            elif self.html5_sources:
                download_video_link = self.html5_sources[0]

        if self.download_track:
            if self.track:
                track_url = self.track
                transcript_download_format = None
            elif self.sub or self.transcripts:
                track_url = self.runtime.handler_url(self, 'transcript', 'download').rstrip('/?')

        if not self.transcripts:
            transcript_language = u'en'
            languages = {'en': 'English'}
        else:
            if self.transcript_language in self.transcripts:
                transcript_language = self.transcript_language
            elif self.sub:
                transcript_language = u'en'
            else:
                transcript_language = sorted(self.transcripts.keys())[0]

            native_languages = {lang: label for lang, label in settings.LANGUAGES if len(lang) == 2}
            languages = {
                lang: native_languages.get(lang, display)
                for lang, display in settings.ALL_LANGUAGES
                if lang in self.transcripts
            }

            if self.sub:
                languages['en'] = 'English'

        # OrderedDict for easy testing of rendered context in tests
        sorted_languages = sorted(languages.items(), key=itemgetter(1))
        if 'table' in self.transcripts:
            sorted_languages.insert(0, ('table', 'Table of Contents'))

        sorted_languages = OrderedDict(sorted_languages)

        return self.system.render_template('video.html', {
            'ajax_url': self.system.ajax_url + '/save_user_state',
            'autoplay': settings.FEATURES.get('AUTOPLAY_VIDEOS', False),
            # This won't work when we move to data that
            # isn't on the filesystem
            'data_dir': getattr(self, 'data_dir', None),
            'display_name': self.display_name_with_default,
            'end': self.end_time.total_seconds(),
            'handout': self.handout,
            'id': self.location.html_id(),
            'show_captions': json.dumps(self.show_captions),
            'download_video_link': download_video_link,
            'sources': json.dumps(sources),
            'speed': json.dumps(self.speed),
            'general_speed': self.global_speed,
            'saved_video_position': self.saved_video_position.total_seconds(),
            'start': self.start_time.total_seconds(),
            'sub': self.sub,
            'track': track_url,
            'youtube_streams': create_youtube_string(self),
            # TODO: Later on the value 1500 should be taken from some global
            # configuration setting field.
            'yt_test_timeout': 1500,
            'yt_api_url': settings.YOUTUBE['API'],
            'yt_test_url': settings.YOUTUBE['TEST_URL'],
            'transcript_download_format': transcript_download_format,
            'transcript_download_formats_list': self.descriptor.fields['transcript_download_format'].values,
            'transcript_language': transcript_language,
            'transcript_languages': json.dumps(sorted_languages),
            'transcript_translation_url': self.runtime.handler_url(self, 'transcript', 'translation').rstrip('/?'),
            'transcript_available_translations_url': self.runtime.handler_url(self, 'transcript', 'available_translations').rstrip('/?'),
        })


class VideoDescriptor(VideoFields, VideoStudioViewHandlers, TabsEditingDescriptor, EmptyDataRawDescriptor):
    """
    Descriptor for `VideoModule`.
    """
    module_class = VideoModule
    transcript = module_attr('transcript')

    tabs = [
        {
            'name': _("Basic"),
            'template': "video/transcripts.html",
            'current': True
        },
        {
            'name': _("Advanced"),
            'template': "tabs/metadata-edit-tab.html"
        }
    ]

    def __init__(self, *args, **kwargs):
        """
        Mostly handles backward compatibility issues.

        `source` is deprecated field.
        a) If `source` exists and `source` is not `html5_sources`: show `source`
            field on front-end as not-editable but clearable. Dropdown is a new
            field `download_video` and it has value True.
        b) If `source` is cleared it is not shown anymore.
        c) If `source` exists and `source` in `html5_sources`, do not show `source`
            field. `download_video` field has value True.
        """
        super(VideoDescriptor, self).__init__(*args, **kwargs)
        # For backwards compatibility -- if we've got XML data, parse it out and set the metadata fields
        if self.data:
            field_data = self._parse_video_xml(self.data)
            self._field_data.set_many(self, field_data)
            del self.data

        editable_fields = super(VideoDescriptor, self).editable_metadata_fields

        self.source_visible = False
        if self.source:
            # If `source` field value exist in the `html5_sources` field values,
            # then delete `source` field value and use value from `html5_sources` field.
            if self.source in self.html5_sources:
                self.source = ''  # Delete source field value.
                self.download_video = True
            else:  # Otherwise, `source` field value will be used.
                self.source_visible = True
                download_video = editable_fields['download_video']
                if not download_video['explicitly_set']:
                    self.download_video = True

        # for backward compatibility.
        # If course was existed and was not re-imported by the moment of adding `download_track` field,
        # we should enable `download_track` if following is true:
        download_track = editable_fields['download_track']
        if not download_track['explicitly_set'] and self.track:
            self.download_track = True

    def editor_saved(self, user, old_metadata, old_content):
        """
        Used to update video values during `self`:save method from CMS.

        old_metadata: dict, values of fields of `self` with scope=settings which were explicitly set by user.
        old_content, same as `old_metadata` but for scope=content.

        Due to nature of code flow in item.py::_save_item, before current function is called,
        fields of `self` instance have been already updated, but not yet saved.

        To obtain values, which were changed by user input,
        one should compare own_metadata(self) and old_medatada.

        Video player has two tabs, and due to nature of sync between tabs,
        metadata from Basic tab is always sent when video player is edited and saved first time, for example:
        {'youtube_id_1_0': u'OEoXaMPEzfM', 'display_name': u'Video', 'sub': u'OEoXaMPEzfM', 'html5_sources': []},
        that's why these fields will always present in old_metadata after first save. This should be fixed.

        At consequent save requests html5_sources are always sent too, disregard of their change by user.
        That means that html5_sources are always in list of fields that were changed (`metadata` param in save_item).
        This should be fixed too.
        """
        metadata_was_changed_by_user = old_metadata != own_metadata(self)
        if metadata_was_changed_by_user:
            manage_video_subtitles_save(
                self,
                user,
                old_metadata if old_metadata else None,
                generate_translation=True
            )

    def save_with_metadata(self, user):
        """
        Save module with updated metadata to database."
        """
        self.save()
        self.runtime.modulestore.update_item(self, user.id if user else None)

    @property
    def editable_metadata_fields(self):
        editable_fields = super(VideoDescriptor, self).editable_metadata_fields

        if self.source_visible:
            editable_fields['source']['non_editable'] = True
        else:
            editable_fields.pop('source')

        languages = [{'label': label, 'code': lang} for lang, label in settings.ALL_LANGUAGES if lang != u'en']
        languages.sort(key=lambda l: l['label'])
        languages.insert(0, {'label': 'Table of Contents', 'code': 'table'})
        editable_fields['transcripts']['languages'] = languages
        editable_fields['transcripts']['type'] = 'VideoTranslations'
        editable_fields['transcripts']['urlRoot'] = self.runtime.handler_url(self, 'studio_transcript', 'translation').rstrip('/?')
        editable_fields['handout']['type'] = 'FileUploader'

        return editable_fields

    @classmethod
    def from_xml(cls, xml_data, system, id_generator):
        """
        Creates an instance of this descriptor from the supplied xml_data.
        This may be overridden by subclasses

        xml_data: A string of xml that will be translated into data and children for
            this module
        system: A DescriptorSystem for interacting with external resources
        org and course are optional strings that will be used in the generated modules
            url identifiers
        """
        xml_object = etree.fromstring(xml_data)
        url_name = xml_object.get('url_name', xml_object.get('slug'))
        block_type = 'video'
        definition_id = id_generator.create_definition(block_type, url_name)
        usage_id = id_generator.create_usage(definition_id)
        if is_pointer_tag(xml_object):
            filepath = cls._format_filepath(xml_object.tag, name_to_pathname(url_name))
            xml_data = etree.tostring(cls.load_file(filepath, system.resources_fs, usage_id))
        field_data = cls._parse_video_xml(xml_data)
        kvs = InheritanceKeyValueStore(initial_values=field_data)
        field_data = KvsFieldData(kvs)
        video = system.construct_xblock_from_class(
            cls,
            # We're loading a descriptor, so student_id is meaningless
            # We also don't have separate notions of definition and usage ids yet,
            # so we use the location for both
            ScopeIds(None, block_type, definition_id, usage_id),
            field_data,
        )
        return video

    def definition_to_xml(self, resource_fs):
        """
        Returns an xml string representing this module.
        """
        xml = etree.Element('video')
        youtube_string = create_youtube_string(self)
        # Mild workaround to ensure that tests pass -- if a field
        # is set to its default value, we don't need to write it out.
        if youtube_string and youtube_string != '1.00:OEoXaMPEzfM':
            xml.set('youtube', unicode(youtube_string))
        xml.set('url_name', self.url_name)
        attrs = {
            'display_name': self.display_name,
            'show_captions': json.dumps(self.show_captions),
            'start_time': self.start_time,
            'end_time': self.end_time,
            'sub': self.sub,
            'download_track': json.dumps(self.download_track),
            'download_video': json.dumps(self.download_video),
        }
        for key, value in attrs.items():
            # Mild workaround to ensure that tests pass -- if a field
            # is set to its default value, we don't write it out.
            if value:
                if key in self.fields and self.fields[key].is_set_on(self):
                    xml.set(key, unicode(value))

        for source in self.html5_sources:
            ele = etree.Element('source')
            ele.set('src', source)
            xml.append(ele)

        if self.track:
            ele = etree.Element('track')
            ele.set('src', self.track)
            xml.append(ele)

        if self.handout:
            ele = etree.Element('handout')
            ele.set('src', self.handout)
            xml.append(ele)

        # sorting for easy testing of resulting xml
        for transcript_language in sorted(self.transcripts.keys()):
            ele = etree.Element('transcript')
            ele.set('language', transcript_language)
            ele.set('src', self.transcripts[transcript_language])
            xml.append(ele)

        return xml

    def get_context(self):
        """
        Extend context by data for transcript basic tab.
        """
        _context = super(VideoDescriptor, self).get_context()

        metadata_fields = copy.deepcopy(self.editable_metadata_fields)

        display_name = metadata_fields['display_name']
        video_url = metadata_fields['html5_sources']
        youtube_id_1_0 = metadata_fields['youtube_id_1_0']

        def get_youtube_link(video_id):
            if video_id:
                return 'http://youtu.be/{0}'.format(video_id)
            else:
                return ''

        _ = self.runtime.service(self, "i18n").ugettext
        video_url.update({
            'help': _('The URL for your video. This can be a YouTube URL or a link to an .mp4, .ogg, or .webm video file hosted elsewhere on the Internet.'),
            'display_name': _('Default Video URL'),
            'field_name': 'video_url',
            'type': 'VideoList',
            'default_value': [get_youtube_link(youtube_id_1_0['default_value'])]
        })

        youtube_id_1_0_value = get_youtube_link(youtube_id_1_0['value'])

        if youtube_id_1_0_value:
            video_url['value'].insert(0, youtube_id_1_0_value)

        metadata = {
            'display_name': display_name,
            'video_url': video_url
        }

        _context.update({'transcripts_basic_tab_metadata': metadata})
        return _context

    @classmethod
    def _parse_youtube(cls, data):
        """
        Parses a string of Youtube IDs such as "1.0:AXdE34_U,1.5:VO3SxfeD"
        into a dictionary. Necessary for backwards compatibility with
        XML-based courses.
        """
        ret = {'0.75': '', '1.00': '', '1.25': '', '1.50': ''}

        videos = data.split(',')
        for video in videos:
            pieces = video.split(':')
            try:
                speed = '%.2f' % float(pieces[0])  # normalize speed

                # Handle the fact that youtube IDs got double-quoted for a period of time.
                # Note: we pass in "VideoFields.youtube_id_1_0" so we deserialize as a String--
                # it doesn't matter what the actual speed is for the purposes of deserializing.
                youtube_id = deserialize_field(cls.youtube_id_1_0, pieces[1])
                ret[speed] = youtube_id
            except (ValueError, IndexError):
                log.warning('Invalid YouTube ID: %s', video)
        return ret

    @classmethod
    def _parse_video_xml(cls, xml_data):
        """
        Parse video fields out of xml_data. The fields are set if they are
        present in the XML.
        """
        xml = etree.fromstring(xml_data)
        field_data = {}

        # Convert between key types for certain attributes --
        # necessary for backwards compatibility.
        conversions = {
            # example: 'start_time': cls._example_convert_start_time
        }

        # Convert between key names for certain attributes --
        # necessary for backwards compatibility.
        compat_keys = {
            'from': 'start_time',
            'to': 'end_time'
        }
        sources = xml.findall('source')
        if sources:
            field_data['html5_sources'] = [ele.get('src') for ele in sources]

        track = xml.find('track')
        if track is not None:
            field_data['track'] = track.get('src')

        handout = xml.find('handout')
        if handout is not None:
            field_data['handout'] = handout.get('src')

        transcripts = xml.findall('transcript')
        if transcripts:
            field_data['transcripts'] = {tr.get('language'): tr.get('src') for tr in transcripts}

        for attr, value in xml.items():
            if attr in compat_keys:
                attr = compat_keys[attr]
            if attr in cls.metadata_to_strip + ('url_name', 'name'):
                continue
            if attr == 'youtube':
                speeds = cls._parse_youtube(value)
                for speed, youtube_id in speeds.items():
                    # should have made these youtube_id_1_00 for
                    # cleanliness, but hindsight doesn't need glasses
                    normalized_speed = speed[:-1] if speed.endswith('0') else speed
                    # If the user has specified html5 sources, make sure we don't use the default video
                    if youtube_id != '' or 'html5_sources' in field_data:
                        field_data['youtube_id_{0}'.format(normalized_speed.replace('.', '_'))] = youtube_id
            else:
                #  Convert XML attrs into Python values.
                if attr in conversions:
                    value = conversions[attr](value)
                else:
                # We export values with json.dumps (well, except for Strings, but
                # for about a month we did it for Strings also).
                    value = deserialize_field(cls.fields[attr], value)
                field_data[attr] = value

        # For backwards compatibility: Add `source` if XML doesn't have `download_video`
        # attribute.
        if 'download_video' not in field_data and sources:
            field_data['source'] = field_data['html5_sources'][0]

        # For backwards compatibility: if XML doesn't have `download_track` attribute,
        # it means that it is an old format. So, if `track` has some value,
        # `download_track` needs to have value `True`.
        if 'download_track' not in field_data and track is not None:
            field_data['download_track'] = True

        return field_data
