from feedgen.feed import FeedGenerator
from nebula_rss import NebulaLoader


class NebulaFeed:
    def __init__(self, nebula_loader: NebulaLoader, feed_url: str):
        self.nebula_loader = nebula_loader
        self.feed_url = feed_url

    def generate(self, format: str = 'atom') -> str:
        videos = self.nebula_loader.load()
        fg = FeedGenerator()
        fg.id(self.feed_url)
        fg.title('Nebula subscriptions')
        fg.logo('https://nebula.app/apple-touch-icon.png')
        fg.subtitle('Your subscribed videos')
        fg.link(href=self.feed_url, rel='self')
        fg.language('en')

        for video in videos:
            fe = fg.add_entry()
            fe.id(video.url)
            fe.title(video.title)
            fe.link(href=video.url)
            fe.author({'name': video.creator, 'email': 'Unknown'})  # Email is required for RSS format, but is not known
            fe.enclosure(url=video.url)
            fe.summary(f'New video by {video.creator}: {video.title}')
            fe.published(video.release_at)
        feed = ''
        if format == 'atom':
            feed = fg.atom_str(pretty=True)
        elif format == 'rss':
            feed = fg.rss_str(pretty=True)
        else:
            raise Exception(f'Unknown format: "{format}". Use "atom" or "rss')
        return feed