"""FC-3e: /api/posts — cursor-paginated unified posts feed."""

from quart import Blueprint, jsonify, request

from ..extensions import get_session
from ..services.post_feed_service import PostFeedService
from ..services.source_service import KNOWN_PLATFORMS
from ._responses import error_response as _bad

posts_bp = Blueprint("posts", __name__, url_prefix="/api/posts")


@posts_bp.route("", methods=["GET"])
async def list_posts():
    args = request.args

    cursor = args.get("cursor") or None
    artist_id_raw = args.get("artist_id")
    platform = args.get("platform") or None
    limit_raw = args.get("limit", "24")

    try:
        limit = int(limit_raw)
    except ValueError:
        return _bad("invalid_limit", detail="limit must be an integer")
    if limit < 1 or limit > 100:
        return _bad("invalid_limit", detail="limit must be between 1 and 100")

    artist_id = None
    if artist_id_raw is not None:
        try:
            artist_id = int(artist_id_raw)
        except ValueError:
            return _bad("invalid_artist_id", detail="artist_id must be an integer")

    if platform is not None and platform not in KNOWN_PLATFORMS:
        return _bad(
            "unknown_platform",
            detail=f"platform must be one of {sorted(KNOWN_PLATFORMS)}",
        )

    async with get_session() as session:
        try:
            page = await PostFeedService(session).scroll(
                cursor=cursor, artist_id=artist_id,
                platform=platform, limit=limit,
            )
        except ValueError as exc:
            # Service raises ValueError for malformed cursors only;
            # limit bounds are validated above.
            return _bad("invalid_cursor", detail=str(exc))

    return jsonify(page)


@posts_bp.route("/<int:post_id>", methods=["GET"])
async def get_post(post_id: int):
    async with get_session() as session:
        item = await PostFeedService(session).get_post(post_id)
    if item is None:
        return _bad("not_found", status=404, detail=f"post id={post_id}")
    return jsonify(item)