import base64
from youtube import util, yt_data_extract, local_playlist, subscriptions
from youtube import yt_app

import urllib
import json
from string import Template
import youtube.proto as proto
import html
import math
import gevent
import re
import cachetools.func
import traceback

import flask
from flask import request

headers_desktop = (
    ('Accept', '*/*'),
    ('Accept-Language', 'en-US,en;q=0.5'),
    ('X-YouTube-Client-Name', '1'),
    ('X-YouTube-Client-Version', '2.20180830'),
) + util.desktop_ua
headers_mobile = (
    ('Accept', '*/*'),
    ('Accept-Language', 'en-US,en;q=0.5'),
    ('X-YouTube-Client-Name', '2'),
    ('X-YouTube-Client-Version', '2.20180830'),
) + util.mobile_ua
real_cookie = (('Cookie', 'VISITOR_INFO1_LIVE=8XihrAcN1l4'),)
generic_cookie = (('Cookie', 'VISITOR_INFO1_LIVE=ST1Ti53r4fU'),)

# added an extra nesting under the 2nd base64 compared to v4
# added tab support
# changed offset field to uint id 1
def channel_ctoken_v5(channel_id, page, sort, tab, view=1):
    new_sort = (2 if int(sort) == 1 else 1)
    offset = 30*(int(page) - 1)
    if tab == 'videos':
        tab = 15
    elif tab == 'shorts':
        tab = 10
    elif tab == 'streams':
        tab = 14
    pointless_nest = proto.string(80226972,
        proto.string(2, channel_id)
        + proto.string(3,
            proto.percent_b64encode(
                proto.string(110,
                    proto.string(3,
                        proto.string(tab,
                            proto.string(1,
                                proto.string(1,
                                    proto.unpadded_b64encode(
                                        proto.string(1,
                                        proto.string(1,
                                            proto.unpadded_b64encode(
                                                proto.string(2,
                                                    b"ST:"
                                                    + proto.unpadded_b64encode(
                                                        proto.uint(1, offset)
                                                    )
                                                )
                                            )
                                        )
                                        )
                                    )
                                )
                                 # targetId, just needs to be present but
                                 # doesn't need to be correct
                                + proto.string(2, "63faaff0-0000-23fe-80f0-582429d11c38")
                            )
                            # 1 - newest, 2 - popular
                            + proto.uint(3, new_sort)
                        )
                    )
                )
            )
        )
    )

    return base64.urlsafe_b64encode(pointless_nest).decode('ascii')

# https://github.com/user234683/youtube-local/issues/151
def channel_ctoken_v4(channel_id, page, sort, tab, view=1):
    new_sort = (2 if int(sort) == 1 else 1)
    offset = str(30*(int(page) - 1))
    pointless_nest = proto.string(80226972,
        proto.string(2, channel_id)
        + proto.string(3,
            proto.percent_b64encode(
                proto.string(110,
                    proto.string(3,
                        proto.string(15,
                            proto.string(1,
                                proto.string(1,
                                    proto.unpadded_b64encode(
                                        proto.string(1,
                                            proto.unpadded_b64encode(
                                                proto.string(2,
                                                    b"ST:"
                                                    + proto.unpadded_b64encode(
                                                        proto.string(2, offset)
                                                    )
                                                )
                                            )
                                        )
                                    )
                                )
                                 # targetId, just needs to be present but
                                 # doesn't need to be correct
                                + proto.string(2, "63faaff0-0000-23fe-80f0-582429d11c38")
                            )
                            # 1 - newest, 2 - popular
                            + proto.uint(3, new_sort)
                        )
                    )
                )
            )
        )
    )

    return base64.urlsafe_b64encode(pointless_nest).decode('ascii')

# SORT:
# videos:
#    Popular - 1
#    Oldest - 2
#    Newest - 3
# playlists:
#    Oldest - 2
#    Newest - 3
#    Last video added - 4

# view:
# grid: 0 or 1
# list: 2
def channel_ctoken_v3(channel_id, page, sort, tab, view=1):
    # page > 1 doesn't work when sorting by oldest
    offset = 30*(int(page) - 1)
    page_token = proto.string(61, proto.unpadded_b64encode(
        proto.string(1, proto.unpadded_b64encode(proto.uint(1,offset)))
    ))

    tab = proto.string(2, tab)
    sort = proto.uint(3, int(sort))

    shelf_view = proto.uint(4, 0)
    view = proto.uint(6, int(view))
    continuation_info = proto.string(3,
        proto.percent_b64encode(tab + sort + shelf_view + view + page_token)
    )

    channel_id = proto.string(2, channel_id)
    pointless_nest = proto.string(80226972, channel_id + continuation_info)

    return base64.urlsafe_b64encode(pointless_nest).decode('ascii')


def channel_ctoken_v2(channel_id, page, sort, tab, view=1):
    # see https://github.com/iv-org/invidious/issues/1319#issuecomment-671732646
    # page > 1 doesn't work when sorting by oldest
    offset = 30*(int(page) - 1)
    schema_number = {
        3: 6307666885028338688,
        2: 17254859483345278706,
        1: 16570086088270825023,
    }[int(sort)]
    page_token = proto.string(61, proto.unpadded_b64encode(proto.string(1,
            proto.uint(1, schema_number) + proto.string(2,
                proto.string(1, proto.unpadded_b64encode(proto.uint(1,offset)))
            )
    )))

    tab = proto.string(2, tab)
    sort = proto.uint(3, int(sort))
    #page = proto.string(15, str(page))

    shelf_view = proto.uint(4, 0)
    view = proto.uint(6, int(view))
    continuation_info = proto.string(
        3,
        proto.percent_b64encode(tab + sort + shelf_view + view + page_token)
    )

    channel_id = proto.string(2, channel_id)
    pointless_nest = proto.string(80226972, channel_id + continuation_info)

    return base64.urlsafe_b64encode(pointless_nest).decode('ascii')


def channel_ctoken_v1(channel_id, page, sort, tab, view=1):
    tab = proto.string(2, tab)
    sort = proto.uint(3, int(sort))
    page = proto.string(15, str(page))
    # example with shelves in videos tab: https://www.youtube.com/channel/UCNL1ZadSjHpjm4q9j2sVtOA/videos
    shelf_view = proto.uint(4, 0)
    view = proto.uint(6, int(view))
    continuation_info = proto.string(3, proto.percent_b64encode(tab + view + sort + shelf_view + page + proto.uint(23, 0)) )

    channel_id = proto.string(2, channel_id)
    pointless_nest = proto.string(80226972, channel_id + continuation_info)

    return base64.urlsafe_b64encode(pointless_nest).decode('ascii')


def get_channel_tab(channel_id, page="1", sort=3, tab='videos', view=1,
                    ctoken=None, print_status=True):
    message = 'Got channel tab' if print_status else None

    if not ctoken:
        if tab in ('videos', 'shorts', 'streams'):
            ctoken = channel_ctoken_v5(channel_id, page, sort, tab, view)
        else:
            ctoken = channel_ctoken_v3(channel_id, page, sort, tab, view)
        ctoken = ctoken.replace('=', '%3D')

    # Not sure what the purpose of the key is or whether it will change
    # For now it seems to be constant for the API endpoint, not dependent
    # on the browsing session or channel
    key = 'AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8'
    url = 'https://www.youtube.com/youtubei/v1/browse?key=' + key

    data = {
        'context': {
            'client': {
                'hl': 'en',
                'gl': 'US',
                'clientName': 'WEB',
                'clientVersion': '2.20180830',
            },
        },
        'continuation': ctoken,
    }

    content_type_header = (('Content-Type', 'application/json'),)
    content = util.fetch_url(
        url, headers_desktop + content_type_header,
        data=json.dumps(data), debug_name='channel_tab', report_text=message)

    return content


# cache entries expire after 30 minutes
@cachetools.func.ttl_cache(maxsize=128, ttl=30*60)
def get_number_of_videos_channel(channel_id):
    if channel_id is None:
        return 1000

    # Uploads playlist
    playlist_id = 'UU' + channel_id[2:]
    url = 'https://m.youtube.com/playlist?list=' + playlist_id + '&pbj=1'

    try:
        response = util.fetch_url(url, headers_mobile,
            debug_name='number_of_videos', report_text='Got number of videos')
    except urllib.error.HTTPError as e:
        traceback.print_exc()
        print("Couldn't retrieve number of videos")
        return 1000

    response = response.decode('utf-8')

    # match = re.search(r'"numVideosText":\s*{\s*"runs":\s*\[{"text":\s*"([\d,]*) videos"', response)
    match = re.search(r'"numVideosText".*?([,\d]+)', response)
    if match:
        return int(match.group(1).replace(',',''))
    else:
        return 0


channel_id_re = re.compile(r'videos\.xml\?channel_id=([a-zA-Z0-9_-]{24})"')


@cachetools.func.lru_cache(maxsize=128)
def get_channel_id(base_url):
    # method that gives the smallest possible response at ~4 kb
    # needs to be as fast as possible
    base_url = base_url.replace('https://www', 'https://m') # avoid redirect
    response = util.fetch_url(base_url + '/about?pbj=1', headers_mobile,
        debug_name='get_channel_id', report_text='Got channel id').decode('utf-8')
    match = channel_id_re.search(response)
    if match:
        return match.group(1)
    return None


metadata_cache = cachetools.LRUCache(128)
@cachetools.cached(metadata_cache)
def get_metadata(channel_id):
    base_url = 'https://www.youtube.com/channel/' + channel_id
    polymer_json = util.fetch_url(base_url + '/about?pbj=1',
                                  headers_desktop,
                                  debug_name='gen_channel_about',
                                  report_text='Retrieved channel metadata')
    info = yt_data_extract.extract_channel_info(json.loads(polymer_json),
                                                'about',
                                                continuation=False)
    return extract_metadata_for_caching(info)
def set_cached_metadata(channel_id, metadata):
    @cachetools.cached(metadata_cache)
    def dummy_func_using_same_cache(channel_id):
        return metadata
    dummy_func_using_same_cache(channel_id)
def extract_metadata_for_caching(channel_info):
    metadata = {}
    for key in ('approx_subscriber_count', 'short_description', 'channel_name',
                'avatar'):
        metadata[key] = channel_info[key]
    return metadata


def get_number_of_videos_general(base_url):
    return get_number_of_videos_channel(get_channel_id(base_url))


def get_channel_search_json(channel_id, query, page):
    offset = proto.unpadded_b64encode(proto.uint(3, (page-1)*30))
    params = proto.string(2, 'search') + proto.string(15, offset)
    params = proto.percent_b64encode(params)
    ctoken = proto.string(2, channel_id) + proto.string(3, params) + proto.string(11, query)
    ctoken = base64.urlsafe_b64encode(proto.nested(80226972, ctoken)).decode('ascii')

    key = 'AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8'
    url = 'https://www.youtube.com/youtubei/v1/browse?key=' + key

    data = {
        'context': {
            'client': {
                'hl': 'en',
                'gl': 'US',
                'clientName': 'WEB',
                'clientVersion': '2.20180830',
            },
        },
        'continuation': ctoken,
    }

    content_type_header = (('Content-Type', 'application/json'),)
    polymer_json = util.fetch_url(
        url, headers_desktop + content_type_header,
        data=json.dumps(data), debug_name='channel_search')

    return polymer_json


def post_process_channel_info(info):
    info['avatar'] = util.prefix_url(info['avatar'])
    info['channel_url'] = util.prefix_url(info['channel_url'])
    for item in info['items']:
        util.prefix_urls(item)
        util.add_extra_html_info(item)
    if info['current_tab'] == 'about':
        for i, (text, url) in enumerate(info['links']):
            if util.YOUTUBE_URL_RE.fullmatch(url):
                info['links'][i] = (text, util.prefix_url(url))


def get_channel_first_page(base_url=None, channel_id=None, tab='videos'):
    if channel_id:
        base_url = 'https://www.youtube.com/channel/' + channel_id
    return util.fetch_url(base_url + '/' + tab + '?pbj=1&view=0',
                          headers_desktop, debug_name='gen_channel_' + tab)


playlist_sort_codes = {'2': "da", '3': "dd", '4': "lad"}

# youtube.com/[channel_id]/[tab]
# youtube.com/user/[username]/[tab]
# youtube.com/c/[custom]/[tab]
# youtube.com/[custom]/[tab]


def get_channel_page_general_url(base_url, tab, request, channel_id=None):

    page_number = int(request.args.get('page', 1))
    sort = request.args.get('sort', '3')
    view = request.args.get('view', '1')
    query = request.args.get('query', '')
    ctoken = request.args.get('ctoken', '')
    default_params = (page_number == 1 and sort == '3' and view == '1')
    continuation = bool(ctoken) # whether or not we're using a continuation

    if (tab in ('videos', 'shorts', 'streams') and channel_id and
        not default_params):
        tasks = (
            gevent.spawn(get_number_of_videos_channel, channel_id),
            gevent.spawn(get_channel_tab, channel_id, page_number, sort,
                         tab, view, ctoken)
        )
        gevent.joinall(tasks)
        util.check_gevent_exceptions(*tasks)
        number_of_videos, polymer_json = tasks[0].value, tasks[1].value
        continuation = True
    elif tab in ('videos', 'shorts', 'streams'):
        if channel_id:
            num_videos_call = (get_number_of_videos_channel, channel_id)
        else:
            num_videos_call = (get_number_of_videos_general, base_url)
        tasks = (
            gevent.spawn(*num_videos_call),
            gevent.spawn(get_channel_first_page, base_url=base_url, tab=tab),
        )
        gevent.joinall(tasks)
        util.check_gevent_exceptions(*tasks)
        number_of_videos, polymer_json = tasks[0].value, tasks[1].value
    elif tab == 'about':
        polymer_json = util.fetch_url(base_url + '/about?pbj=1', headers_desktop, debug_name='gen_channel_about')
    elif tab == 'playlists' and page_number == 1:
        polymer_json = util.fetch_url(base_url+ '/playlists?pbj=1&view=1&sort=' + playlist_sort_codes[sort], headers_desktop, debug_name='gen_channel_playlists')
    elif tab == 'playlists':
        polymer_json = get_channel_tab(channel_id, page_number, sort,
                                       'playlists', view)
        continuation = True
    elif tab == 'search' and channel_id:
        polymer_json = get_channel_search_json(channel_id, query, page_number)
    elif tab == 'search':
        url = base_url + '/search?pbj=1&query=' + urllib.parse.quote(query, safe='')
        polymer_json = util.fetch_url(url, headers_desktop, debug_name='gen_channel_search')
    else:
        flask.abort(404, 'Unknown channel tab: ' + tab)


    info = yt_data_extract.extract_channel_info(json.loads(polymer_json), tab,
                                                continuation=continuation)
    if channel_id:
        info['channel_url'] = 'https://www.youtube.com/channel/' + channel_id
        info['channel_id'] = channel_id
    else:
        channel_id = info['channel_id']

    # Will have microformat present, cache metadata while we have it
    if channel_id and default_params:
        metadata = extract_metadata_for_caching(info)
        set_cached_metadata(channel_id, metadata)
    # Otherwise, populate with our (hopefully cached) metadata
    elif channel_id and info['channel_name'] is None:
        metadata = get_metadata(channel_id)
        for key, value in metadata.items():
            yt_data_extract.conservative_update(info, key, value)
        # need to add this metadata to the videos/playlists
        additional_info = {
            'author': info['channel_name'],
            'author_id': info['channel_id'],
            'author_url': info['channel_url'],
        }
        for item in info['items']:
            item.update(additional_info)

    if info['error'] is not None:
        return flask.render_template('error.html', error_message = info['error'])

    if tab in ('videos', 'shorts', 'streams'):
        info['number_of_videos'] = number_of_videos
        info['number_of_pages'] = math.ceil(number_of_videos/30)
        info['header_playlist_names'] = local_playlist.get_playlist_names()
    if tab in ('videos', 'shorts', 'streams', 'playlists'):
        info['current_sort'] = sort
    elif tab == 'search':
        info['search_box_value'] = query
        info['header_playlist_names'] = local_playlist.get_playlist_names()
    if tab in ('search', 'playlists'):
        info['page_number'] = page_number
    info['subscribed'] = subscriptions.is_subscribed(info['channel_id'])

    post_process_channel_info(info)

    return flask.render_template('channel.html',
        parameters_dictionary = request.args,
        **info
    )


@yt_app.route('/channel/<channel_id>/')
@yt_app.route('/channel/<channel_id>/<tab>')
def get_channel_page(channel_id, tab='videos'):
    return get_channel_page_general_url('https://www.youtube.com/channel/' + channel_id, tab, request, channel_id)


@yt_app.route('/user/<username>/')
@yt_app.route('/user/<username>/<tab>')
def get_user_page(username, tab='videos'):
    return get_channel_page_general_url('https://www.youtube.com/user/' + username, tab, request)


@yt_app.route('/c/<custom>/')
@yt_app.route('/c/<custom>/<tab>')
def get_custom_c_page(custom, tab='videos'):
    return get_channel_page_general_url('https://www.youtube.com/c/' + custom, tab, request)


@yt_app.route('/<custom>')
@yt_app.route('/<custom>/<tab>')
def get_toplevel_custom_page(custom, tab='videos'):
    return get_channel_page_general_url('https://www.youtube.com/' + custom, tab, request)