"""Async PRAW wrapper — yields `RawPost` from a subreddit's top listing.

We use asyncpraw because the rest of the pipeline is asyncio-native and
we want to fan out across 12 subs concurrently via `asyncio.gather`.
"""
from __future__ import annotations

import logging
from collections.abc import AsyncIterator
from datetime import date
from typing import Any, Literal

from fire_planner.examples.models import RawPost

log = logging.getLogger(__name__)

TopWhen = Literal["all", "year", "month", "week", "day"]
REDDIT_BASE = "https://www.reddit.com"


async def fetch_top(
    reddit: Any,                 # asyncpraw.Reddit
    subreddit: str,
    when: TopWhen,
    limit: int = 1000,
) -> AsyncIterator[RawPost]:
    """Yield `RawPost`s from `r/{subreddit}/top/?t={when}` (PRAW 1000 cap)."""
    sub = await reddit.subreddit(subreddit)
    async for submission in sub.top(time_filter=when, limit=limit):
        yield _to_raw_post(submission, subreddit)


def _to_raw_post(submission: Any, source_sub: str) -> RawPost:
    return RawPost(
        reddit_id=submission.id,
        source_sub=source_sub,
        url=f"{REDDIT_BASE}{submission.permalink}",
        title=submission.title or "",
        body=submission.selftext or "",
        created_at=date.fromtimestamp(submission.created_utc),
    )