import os
from dataclasses import dataclass
from pathlib import Path
from typing import Optional


@dataclass(frozen=True)
class AppConfig:
    secret_key: str
    database_path: Path
    mysql_host: str
    mysql_port: int
    mysql_user: str
    mysql_password: str
    mysql_database: str
    gogs_base_url: str
    gogs_token: Optional[str]
    require_login_to_view_repo: bool
    enable_mock_pay: bool
    max_preview_bytes: int
    # 支付宝中间层 REST API 配置
    pay_api_base_url: str
    pay_return_url: str
    pay_callback_url: str


def load_config() -> AppConfig:
    project_root = Path(__file__).resolve().parent.parent
    data_dir = project_root / "data"
    data_dir.mkdir(parents=True, exist_ok=True)

    # 自动加载 .env 文件（仅当环境变量未设置时生效）
    env_file = project_root / ".env"
    if env_file.exists():
        with open(env_file, encoding="utf-8") as f:
            for line in f:
                line = line.strip()
                if not line or line.startswith("#") or "=" not in line:
                    continue
                key, _, val = line.partition("=")
                key = key.strip()
                val = val.strip()
                if key and key not in os.environ:
                    os.environ[key] = val

    return AppConfig(
        secret_key=os.environ.get("SECRET_KEY", "dev-secret-key"),
        database_path=Path(os.environ.get("DATABASE_PATH", str(data_dir / "app.db"))),
        mysql_host=(os.environ.get("MYSQL_HOST") or "").strip(),
        mysql_port=int(os.environ.get("MYSQL_PORT", "3306")),
        mysql_user=(os.environ.get("MYSQL_USER") or "").strip(),
        mysql_password=(os.environ.get("MYSQL_PASSWORD") or "").strip(),
        mysql_database=(os.environ.get("MYSQL_DATABASE") or "sourceshare").strip(),
        gogs_base_url=os.environ.get("GOGS_BASE_URL", "http://localhost:6066").rstrip("/"),
        gogs_token=os.environ.get("GOGS_TOKEN"),
        require_login_to_view_repo=os.environ.get("REQUIRE_LOGIN_TO_VIEW_REPO", "1") not in {"0", "false", "False"},
        enable_mock_pay=os.environ.get("ENABLE_MOCK_PAY", "1") in {"1", "true", "True"},
        max_preview_bytes=int(os.environ.get("MAX_PREVIEW_BYTES", "200000")),
        pay_api_base_url=(os.environ.get("PAY_API_BASE_URL") or "https://aigc-api.aitoolcore.com").rstrip("/"),
        pay_return_url=(os.environ.get("PAY_RETURN_URL") or "").strip(),
        pay_callback_url=(os.environ.get("PAY_CALLBACK_URL") or "").strip(),
    )