"""漫画源注册表（插件化）

源适配器为插件，需用户自行实现并放置于 sources/ 目录下。
插件模块应继承 BaseSource 并在模块顶层调用 register_source() 注册。
启动时自动扫描 sources/ 下所有 .py 文件（排除 base.py）并尝试加载。
"""

import importlib
import logging
from pathlib import Path

from kobo_manga.sources.base import BaseSource

logger = logging.getLogger(__name__)

_registry: dict[str, type[BaseSource]] = {}


def register_source(cls: type[BaseSource]) -> type[BaseSource]:
    """注册源适配器类。"""
    _registry[cls.name] = cls
    return cls


def get_source(name: str) -> BaseSource:
    """按名字实例化源。"""
    _ensure_registered()
    if name not in _registry:
        available = ", ".join(_registry.keys()) or "(无已安装的源插件)"
        raise ValueError(f"未知源 '{name}'，可用: {available}")
    return _registry[name]()


def list_sources() -> list[str]:
    """返回所有已注册的源名称。"""
    _ensure_registered()
    return list(_registry.keys())


def infer_source_from_url(url: str) -> str | None:
    """从 URL 推断源名称。"""
    _ensure_registered()
    for name, cls in _registry.items():
        if hasattr(cls, "URL_PATTERNS"):
            for pattern in cls.URL_PATTERNS:
                if pattern in url:
                    return name
    return None


_registered = False


def _ensure_registered():
    """自动扫描 sources/ 目录下的插件模块并注册。"""
    global _registered
    if _registered:
        return
    _registered = True

    sources_dir = Path(__file__).parent
    skip = {"__init__.py", "base.py"}

    for py_file in sorted(sources_dir.glob("*.py")):
        if py_file.name in skip:
            continue
        module_name = f"kobo_manga.sources.{py_file.stem}"
        try:
            importlib.import_module(module_name)
        except Exception as e:
            logger.debug(f"跳过源插件 {py_file.name}: {e}")