import os
import requests
import dateutil.parser
from datetime import datetime, timezone
from xml.etree import ElementTree
from urllib.parse import parse_qs
from configparser import ConfigParser

cf = ConfigParser()
config_filename = os.environ.get('YT_CONFIG', '/etc/yt/config.ini')
cf.read(config_filename)

def fetch_xml(feed_type, feed_id):
    r = requests.get(f"https://www.youtube.com/feeds/videos.xml?{feed_type}={feed_id}")
    if not r.ok:
        return None

    return r.text

def parse_xml(xmldata):
    ns = {
        'atom':"http://www.w3.org/2005/Atom",
        'yt': "http://www.youtube.com/xml/schemas/2015",
        'media':"http://search.yahoo.com/mrss/"
    }

    feed = ElementTree.fromstring(xmldata)
    author = feed.find('atom:author',ns).find('atom:name',ns).text if feed.find('atom:author',ns) else None
    if feed.find('yt:channelId',ns):
        channel_id = feed.find('yt:channelId',ns).text
    else: # TODO: clean this up (websub has no yt:channelId, this should be adapted for playlists)
        self = feed.find('atom:link[@rel="self"]',ns).get('href')
        channel_id = parse_qs(self.split('?')[1]).get('channel_id')[0]
    title = feed.find('atom:title',ns).text
    videos = []
    for entry in feed.findall('atom:entry',ns):
        videos.append({
            'video_id': entry.find('yt:videoId',ns).text,
            'title': entry.find('atom:title',ns).text,
            'published': entry.find('atom:published',ns).text,
            'channel_id': entry.find('yt:channelId',ns).text,
            'author': entry.find('atom:author',ns).find('atom:name',ns).text,
            # extra fields for pull_subs/webhook:
            'updated': entry.find('atom:updated',ns).text,
            #'description': entry.find('media:group',ns).find('media:description',ns).text ##xxx:missing for websub
        })

    return title, author, channel_id, videos

def update_channel(db, xmldata):
    """
    returns True on success, False on failure. rigorous error checking is required, otherwise data will be lost!
    the caller MUST (as per RFC 2119) write (append) the xmlfeed into a file on error.
    """
    if not xmldata: return False

    # Note: wbesub does not return global author
    title, author, channel_id, videos = parse_xml(xmldata) #xxx: perl-code had this eval'd for a die

    c = db.cursor()
    for video in videos:
        now = datetime.now(timezone.utc)
        updated = dateutil.parser.parse(video['updated'])
        published = dateutil.parser.parse(video['updated'])
        # if update and published time are near-identical, it's new. use crawl time if it was published within a week.
        # else, it's just an update to an older video (before we subscribed, so use original upload time).
        if (updated - published).seconds < 60 and (now - published).days < 7:
            timestamp = now
        else:
            timestamp = published

        c.execute("""
	INSERT OR IGNORE INTO videos (id, channel_id, title, published, crawled)
	               VALUES (?, ?, ?, datetime(?), datetime(?))
        """, (video['video_id'], video['channel_id'], video['title'], video['published'], timestamp)) #XXX:errorcheck

    # update channel name (we don't fetch it on subscribing)
        author = video['author'] # XXX: doing this once per channel is enough (for pull-subs.pl)
        c.execute("""
            INSERT OR REPLACE INTO channels (id, name)
                            VALUES (?, ?)
        """, (channel_id, author)) #XXX:errorcheck

    return True