import re
import requests
from datetime import datetime, timezone

from ..common.common import fetch_xml, parse_xml

def fetch_searchresults(q=None, sp=None):
  for _ in range(2):
    today = datetime.now(timezone.utc).strftime("%Y%m%d")
    r = requests.get(f"https://www.youtube.com/results", {
        'search_query': q,
        'pbj': 1, # makes youtube return a json-response
        'hl': 'en', #'en_US',
        'sp': sp,
    }, headers={
        'x-youtube-client-name': '1',
        'x-youtube-client-version': f'2.{today}.01.01', # the version is parsed as a date, and if it's invalid (e.g. month>12 or even feb>=30), youtube throws an encrypted stacktrace :D (but any random date >= 20160323 as of 20200802 works (even year 3000)
    })
    if not r.ok:
        return None

    # Sometimes, youtube throws an exception after the response already begun.
    # This can manifest in two ways:
    # 1) So the status code is 200, begins with JSON and switches to HTML half
    #    way through. WTF?! (This should be "fixed" by retrying, though)
    # 2) The response just stopping mid-way through like this: response.text ==
    #    '[\r\n{"page": "search","rootVe": "4724"},\r\n{"page": "search",'
    # hence, just try-catching the decoding step is the easiest way out.
    try:
        return r.json()
    except:
        continue # will return None once we break out of the loop

def fetch_ajax(params):
    """
    fetch data using a continuation protobuf
    """
    # TODO: handle auto_generated!
    today = datetime.now(timezone.utc).strftime("%Y%m%d")

    r = requests.get(f"https://www.youtube.com/browse_ajax", {
        'continuation': params,
        'gl': 'US',
        'hl': 'en',
    }, headers={
        'x-youtube-client-name': '1',
        'x-youtube-client-version': f'2.{today}.01.01', # see fetch_searchresults()
    })

    if not r.ok:
        return None

    return r.json()

def canonicalize_channel(name):
    if re.fullmatch(r"(UC[A-Za-z0-9_-]{22})", name):
        return name

    # try /user/ (legacy URLs):
    xmlfeed = fetch_xml("user", name)
    if xmlfeed:
        _, _, _, channel_id, _ = parse_xml(xmlfeed)
        return channel_id

    # get UCID of /c/ (vanity URLs):
    today = datetime.now(timezone.utc).strftime("%Y%m%d")
    r = requests.get(f'https://www.youtube.com/c/{name}/about?pbj=1&hl=en_US', headers={
        'x-youtube-client-name': '1',
        'x-youtube-client-version': f'2.{today}.01.01', # see fetch_searchresults()
    })
    try:
        return r.json()[1]['response']['metadata']['channelMetadataRenderer']['rssUrl'].split("=")[1]
    except:
        pass

    # unable to extract:
    return None