import gzip

from youtube import yt_data_extract

try:
    import brotli
    have_brotli = True
except ImportError:
    have_brotli = False
import urllib.parse
import re
import time
import os
import json
import gevent
import gevent.queue
import gevent.lock

# The trouble with the requests library: It ships its own certificate bundle via certifi
#  instead of using the system certificate store, meaning self-signed certificates
#  configured by the user will not work. Some draconian networks block TLS unless a corporate
#  certificate is installed on the system. Additionally, some users install a self signed cert
#  in order to use programs to modify or monitor requests made by programs on the system.

# Finally, certificates expire and need to be updated, or are sometimes revoked. Sometimes
#  certificate authorites go rogue and need to be untrusted. Since we are going through Tor exit nodes,
#  this becomes all the more important. A rogue CA could issue a fake certificate for accounts.google.com, and a
#  malicious exit node could use this to decrypt traffic when logging in and retrieve passwords. Examples:
#   https://www.engadget.com/2015/10/29/google-warns-symantec-over-certificates/
#   https://nakedsecurity.sophos.com/2013/12/09/serious-security-google-finds-fake-but-trusted-ssl-certificates-for-its-domains-made-in-france/

# In the requests documentation it says:
#    "Before version 2.16, Requests bundled a set of root CAs that it trusted, sourced from the Mozilla trust store.
#     The certificates were only updated once for each Requests version. When certifi was not installed,
#     this led to extremely out-of-date certificate bundles when using significantly older versions of Requests.
#     For the sake of security we recommend upgrading certifi frequently!"
#   (http://docs.python-requests.org/en/master/user/advanced/#ca-certificates)

# Expecting users to remember to manually update certifi on Linux isn't reasonable in my view.
#  On windows, this is even worse since I am distributing all dependencies. This program is not
#  updated frequently, and using requests would lead to outdated certificates. Certificates
#  should be updated with OS updates, instead of thousands of developers of different programs
#  being expected to do this correctly 100% of the time.

# There is hope that this might be fixed eventually:
#   https://github.com/kennethreitz/requests/issues/2966

# Until then, I will use a mix of urllib3 and urllib.
import urllib3
import urllib3.contrib.socks

URL_ORIGIN = "/https://www.youtube.com"

connection_pool = urllib3.PoolManager(cert_reqs = 'CERT_REQUIRED')

def get_pool(use_tor):
    return connection_pool

class HTTPAsymmetricCookieProcessor(urllib.request.BaseHandler):
    '''Separate cookiejars for receiving and sending'''
    def __init__(self, cookiejar_send=None, cookiejar_receive=None):
        self.cookiejar_send = cookiejar_send
        self.cookiejar_receive = cookiejar_receive

    def http_request(self, request):
        if self.cookiejar_send is not None:
            self.cookiejar_send.add_cookie_header(request)
        return request

    def http_response(self, request, response):
        if self.cookiejar_receive is not None:
            self.cookiejar_receive.extract_cookies(response, request)
        return response

    https_request = http_request
    https_response = http_response

class FetchError(Exception):
    def __init__(self, code, reason='', ip=None):
        Exception.__init__(self, 'HTTP error during request: ' + code + ' ' + reason)
        self.code = code
        self.reason = reason
        self.ip = ip

def decode_content(content, encoding_header):
    encodings = encoding_header.replace(' ', '').split(',')
    for encoding in reversed(encodings):
        if encoding == 'identity':
            continue
        if encoding == 'br':
            content = brotli.decompress(content)
        elif encoding == 'gzip':
            content = gzip.decompress(content)
    return content

def fetch_url_response(url, headers=(), timeout=15, data=None,
                       cookiejar_send=None, cookiejar_receive=None,
                       use_tor=True, max_redirects=None):
    '''
    returns response, cleanup_function
    When cookiejar_send is set to a CookieJar object,
     those cookies will be sent in the request (but cookies in response will not be merged into it)
    When cookiejar_receive is set to a CookieJar object,
     cookies received in the response will be merged into the object (nothing will be sent from it)
    When both are set to the same object, cookies will be sent from the object,
     and response cookies will be merged into it.
    '''
    headers = dict(headers)     # Note: Calling dict() on a dict will make a copy
    if have_brotli:
        headers['Accept-Encoding'] = 'gzip, br'
    else:
        headers['Accept-Encoding'] = 'gzip'

    # prevent python version being leaked by urllib if User-Agent isn't provided
    #  (urllib will use ex. Python-urllib/3.6 otherwise)
    if 'User-Agent' not in headers and 'user-agent' not in headers and 'User-agent' not in headers:
        headers['User-Agent'] = 'Python-urllib'

    method = "GET"
    if data is not None:
        method = "POST"
        if isinstance(data, str):
            data = data.encode('ascii')
        elif not isinstance(data, bytes):
            data = urllib.parse.urlencode(data).encode('ascii')

    if cookiejar_send is not None or cookiejar_receive is not None:     # Use urllib
        req = urllib.request.Request(url, data=data, headers=headers)

        cookie_processor = HTTPAsymmetricCookieProcessor(cookiejar_send=cookiejar_send, cookiejar_receive=cookiejar_receive)
        opener = urllib.request.build_opener(cookie_processor)

        response = opener.open(req, timeout=timeout)
        cleanup_func = (lambda r: None)

    else:           # Use a urllib3 pool. Cookies can't be used since urllib3 doesn't have easy support for them.
        # default: Retry.DEFAULT = Retry(3)
        # (in connectionpool.py in urllib3)
        # According to the documentation for urlopen, a redirect counts as a
        # retry. So there are 3 redirects max by default.
        if max_redirects:
            retries = urllib3.Retry(3+max_redirects, redirect=max_redirects)
        else:
            retries = urllib3.Retry(3)
        pool = get_pool(use_tor)
        response = pool.request(method, url, headers=headers,
                                timeout=timeout, preload_content=False,
                                decode_content=False, retries=retries)
        cleanup_func = (lambda r: r.release_conn())

    return response, cleanup_func

def fetch_url(url, headers=(), timeout=15, report_text=None, data=None,
              cookiejar_send=None, cookiejar_receive=None, use_tor=True,
              debug_name=None):
    start_time = time.time()

    response, cleanup_func = fetch_url_response(
        url, headers, timeout=timeout,
        cookiejar_send=cookiejar_send, cookiejar_receive=cookiejar_receive,
        use_tor=use_tor)
    response_time = time.time()

    content = response.read()
    read_finish = time.time()

    cleanup_func(response)  # release_connection for urllib3

    if (response.status == 429
            and content.startswith(b'<!DOCTYPE')
            and b'Our systems have detected unusual traffic' in content):
        ip = re.search(br'IP address: ((?:[\da-f]*:)+[\da-f]+|(?:\d+\.)+\d+)',
            content)
        ip = ip.group(1).decode('ascii') if ip else None
        raise FetchError('429', reason=response.reason, ip=ip)

    elif response.status >= 400:
        raise FetchError(str(response.status), reason=response.reason, ip=None)

    if report_text:
        print(report_text, '    Latency:', round(response_time - start_time,3), '    Read time:', round(read_finish - response_time,3))
    content = decode_content(content, response.getheader('Content-Encoding', default='identity'))
    return content

def head(url, use_tor=False, report_text=None, max_redirects=10):
    pool = get_pool(use_tor)
    start_time = time.time()

    # default: Retry.DEFAULT = Retry(3)
    # (in connectionpool.py in urllib3)
    # According to the documentation for urlopen, a redirect counts as a retry
    # So there are 3 redirects max by default. Let's change that
    # to 10 since googlevideo redirects a lot.
    retries = urllib3.Retry(3+max_redirects, redirect=max_redirects,
        raise_on_redirect=False)
    headers = {'User-Agent': 'Python-urllib'}
    response = pool.request('HEAD', url, headers=headers, retries=retries)
    if report_text:
        print(report_text, '    Latency:', round(time.time() - start_time,3))
    return response

mobile_user_agent = 'Mozilla/5.0 (Linux; Android 7.0; Redmi Note 4 Build/NRD90M) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Mobile Safari/537.36'
mobile_ua = (('User-Agent', mobile_user_agent),)
desktop_user_agent = 'Mozilla/5.0 (Windows NT 6.1; rv:52.0) Gecko/20100101 Firefox/52.0'
desktop_ua = (('User-Agent', desktop_user_agent),)






class RateLimitedQueue(gevent.queue.Queue):
    ''' Does initial_burst (def. 30) at first, then alternates between waiting waiting_period (def. 5) seconds and doing subsequent_bursts (def. 10) queries. After 5 seconds with nothing left in the queue, resets rate limiting. '''

    def __init__(self, initial_burst=30, waiting_period=5, subsequent_bursts=10):
        self.initial_burst = initial_burst
        self.waiting_period = waiting_period
        self.subsequent_bursts = subsequent_bursts

        self.count_since_last_wait = 0
        self.surpassed_initial = False

        self.lock = gevent.lock.BoundedSemaphore(1)
        self.currently_empty = False
        self.empty_start = 0
        gevent.queue.Queue.__init__(self)


    def get(self):
        self.lock.acquire()     # blocks if another greenlet currently has the lock
        if self.count_since_last_wait >= self.subsequent_bursts and self.surpassed_initial:
            gevent.sleep(self.waiting_period)
            self.count_since_last_wait = 0

        elif self.count_since_last_wait >= self.initial_burst and not self.surpassed_initial:
            self.surpassed_initial = True
            gevent.sleep(self.waiting_period)
            self.count_since_last_wait = 0

        self.count_since_last_wait += 1

        if not self.currently_empty and self.empty():
            self.currently_empty = True
            self.empty_start = time.monotonic()

        item = gevent.queue.Queue.get(self)     # blocks when nothing left

        if self.currently_empty:
            if time.monotonic() - self.empty_start >= self.waiting_period:
                self.count_since_last_wait = 0
                self.surpassed_initial = False

            self.currently_empty = False

        self.lock.release()

        return item



def download_thumbnail(save_directory, video_id):
    url = "https://i.ytimg.com/vi/" + video_id + "/mqdefault.jpg"
    save_location = os.path.join(save_directory, video_id + ".jpg")
    try:
        thumbnail = fetch_url(url, report_text="Saved thumbnail: " + video_id)
    except urllib.error.HTTPError as e:
        print("Failed to download thumbnail for " + video_id + ": " + str(e))
        return False
    try:
        f = open(save_location, 'wb')
    except FileNotFoundError:
        os.makedirs(save_directory, exist_ok = True)
        f = open(save_location, 'wb')
    f.write(thumbnail)
    f.close()
    return True

def download_thumbnails(save_directory, ids):
    if not isinstance(ids, (list, tuple)):
        ids = list(ids)
    # only do 5 at a time
    # do the n where n is divisible by 5
    i = -1
    for i in range(0, int(len(ids)/5) - 1 ):
        gevent.joinall([gevent.spawn(download_thumbnail, save_directory, ids[j]) for j in range(i*5, i*5 + 5)])
    # do the remainders (< 5)
    gevent.joinall([gevent.spawn(download_thumbnail, save_directory, ids[j]) for j in range(i*5 + 5, len(ids))])






def dict_add(*dicts):
    for dictionary in dicts[1:]:
        dicts[0].update(dictionary)
    return dicts[0]

def video_id(url):
    url_parts = urllib.parse.urlparse(url)
    return urllib.parse.parse_qs(url_parts.query)['v'][0]


# default, sddefault, mqdefault, hqdefault, hq720
def get_thumbnail_url(video_id):
    return "/i.ytimg.com/vi/" + video_id + "/mqdefault.jpg"

def seconds_to_timestamp(seconds):
    seconds = int(seconds)
    hours, seconds = divmod(seconds,3600)
    minutes, seconds = divmod(seconds,60)
    if hours != 0:
        timestamp = str(hours) + ":"
        timestamp += str(minutes).zfill(2)  # zfill pads with zeros
    else:
        timestamp = str(minutes)

    timestamp += ":" + str(seconds).zfill(2)
    return timestamp



def update_query_string(query_string, items):
    parameters = urllib.parse.parse_qs(query_string)
    parameters.update(items)
    return urllib.parse.urlencode(parameters, doseq=True)



def uppercase_escape(s):
     return re.sub(
         r'\\U([0-9a-fA-F]{8})',
         lambda m: chr(int(m.group(1), base=16)), s)

def prefix_url(url):
    if url is None:
        return None
    url = url.lstrip('/')     # some urls have // before them, which has a special meaning
    return '/' + url

def left_remove(string, substring):
    '''removes substring from the start of string, if present'''
    if string.startswith(substring):
        return string[len(substring):]
    return string

def concat_or_none(*strings):
    '''Concatenates strings. Returns None if any of the arguments are None'''
    result = ''
    for string in strings:
        if string is None:
            return None
        result += string
    return result


def prefix_urls(item):
    try:
        item['thumbnail'] = prefix_url(item['thumbnail'])
    except KeyError:
        pass

    try:
        item['author_url'] = prefix_url(item['author_url'])
    except KeyError:
        pass

def add_extra_html_info(item):
    if item['type'] == 'video':
        item['url'] = (URL_ORIGIN + '/watch?v=' + item['id']) if item.get('id') else None

        video_info = {}
        for key in ('id', 'title', 'author', 'duration'):
            try:
                video_info[key] = item[key]
            except KeyError:
                video_info[key] = ''

        item['video_info'] = json.dumps(video_info)

    elif item['type'] == 'playlist':
        item['url'] = (URL_ORIGIN + '/playlist?list=' + item['id']) if item.get('id') else None
    elif item['type'] == 'channel':
        item['url'] = (URL_ORIGIN + "/channel/" + item['id']) if item.get('id') else None

def parse_info_prepare_for_html(renderer, additional_info={}):
    item = yt_data_extract.extract_item_info(renderer, additional_info)
    prefix_urls(item)
    add_extra_html_info(item)

    return item

def check_gevent_exceptions(*tasks):
    for task in tasks:
        if task.exception:
            raise task.exception