"""Teach feedparser the Podcasting 2.0 tags we read.

feedparser 6 doesn't know the podcast namespace. Unknown tags still come
through, but only under whatever prefix the feed happened to declare, and an
unknown tag with attributes is stored as a single dict, so a second
<podcast:transcript> overwrites the first. Registering the namespace fixes the
prefix ("podcast_…" for every feed); the handler below keeps every
transcript in a list, entry["podcast_transcripts"].

podcast:chapters is left to feedparser's default handling, which gives
entry["podcast_chapters"] = {"url": …, "type": …} (one per item, as the spec
says).
"""

from feedparser.mixin import _FeedParserMixin as FeedParserMixin
from feedparser.util import FeedParserDict

PODCAST_NAMESPACES = (
    'https://podcastindex.org/namespace/1.0',
    # The URL the namespace was announced under; some early feeds still use it.
    'https://github.com/podcastindex-org/podcast-namespace/blob/main/docs/1.0.md',
)


def _start_podcast_transcript(self, attrs_d):
    context = self._get_context()
    context.setdefault('podcast_transcripts', []).append(FeedParserDict(attrs_d))


def _end_podcast_transcript(self):
    pass


def install():
    """Idempotent; called when podcasts.views is imported."""
    for uri in PODCAST_NAMESPACES:
        FeedParserMixin.namespaces.setdefault(uri, 'podcast')
        # Filled lazily from `namespaces` by the first parser; once it has
        # been, later additions have to go in here directly.
        if FeedParserMixin._matchnamespaces:
            FeedParserMixin._matchnamespaces.setdefault(uri.lower(), 'podcast')
    FeedParserMixin._start_podcast_transcript = _start_podcast_transcript
    FeedParserMixin._end_podcast_transcript = _end_podcast_transcript