"""Scraper plugin discovery module.

Auto-detects *_scraper.py files and exposes their scrapers.
Each scraper module must define:
    PLATFORM_NAME: str
    Scraper: class inheriting BaseScraper
"""

from __future__ import annotations

import importlib
import pkgutil
from pathlib import Path

from .base_scraper import BaseScraper

_scrapers: dict[str, type] = {}


def discover_scrapers() -> dict[str, type]:
    """Auto-discover all *_scraper.py modules and return {platform_name: ScraperClass}."""
    if _scrapers:
        return _scrapers

    package_dir = Path(__file__).parent

    for finder, name, ispkg in pkgutil.iter_modules([str(package_dir)]):
        if not name.endswith("_scraper"):
            continue

        module = importlib.import_module(f".{name}", package=__package__)

        platform_name = getattr(module, "PLATFORM_NAME", None)
        scraper_class = getattr(module, "Scraper", None)

        if platform_name and scraper_class and issubclass(scraper_class, BaseScraper):
            _scrapers[platform_name] = scraper_class

    return _scrapers


def get_scraper(platform_name: str) -> BaseScraper | None:
    """Get an instantiated scraper for a platform."""
    scrapers = discover_scrapers()
    cls = scrapers.get(platform_name)
    return cls() if cls else None