from pathlib import Path
from typing import NoReturn

from fastapi import FastAPI, Request
from loguru import logger as l

from routers import router
from service.redis import RedisManager
from sqlmodels.database_connection import DatabaseManager
from sqlmodels.migration import migration
from utils import JWT
from utils.conf import appmeta
from utils.http.http_exceptions import raise_internal_error
from utils.lifespan import lifespan

# 尝试加载企业版功能
try:
    from ee import init_ee
    from ee.license import LicenseError

    async def _init_ee_and_routes() -> None:
        try:
            await init_ee()
        except LicenseError as exc:
            l.critical(f"许可证验证失败: {exc}")
            raise SystemExit(1) from exc

        from ee.routers import ee_router
        from routers.api.v1 import router as v1_router
        v1_router.include_router(ee_router)

    lifespan.add_startup(_init_ee_and_routes)
except ImportError:
    l.info("以 Community 版本运行")

STATICS_DIR: Path = (Path(__file__).parent / "statics").resolve()
"""前端静态文件目录（由 Docker 构建时复制）"""

async def _init_db() -> None:
    """初始化数据库连接引擎"""
    await DatabaseManager.init(appmeta.database_url, debug=appmeta.debug)

# 添加初始化数据库启动项
lifespan.add_startup(_init_db)
lifespan.add_startup(migration)
lifespan.add_startup(JWT.load_secret_key)
lifespan.add_startup(RedisManager.connect)

# 添加关闭项
lifespan.add_shutdown(DatabaseManager.close)
lifespan.add_shutdown(RedisManager.disconnect)

# 创建应用实例并设置元数据
app = FastAPI(
    title=appmeta.APP_NAME,
    summary=appmeta.summary,
    description=appmeta.description,
    version=appmeta.BackendVersion,
    license_info=appmeta.license_info,
    lifespan=lifespan.lifespan,
    debug=appmeta.debug,
    openapi_url="/openapi.json" if appmeta.debug else None,
)
# 添加跨域 CORS 中间件,仅在调试模式下启用,以允许所有来源访问 API
if appmeta.debug:
    from fastapi.middleware.cors import CORSMiddleware
    app.add_middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )

@app.exception_handler(Exception)
async def handle_unexpected_exceptions(
    request: Request, 
    exc: Exception
) -> NoReturn:
    """
    捕获所有未经处理的 FastAPI 异常,防止敏感信息泄露。
    """
    l.exception(exc)
    l.error(f"An unhandled exception occurred for request: {request.method} {request.url.path}")

    raise_internal_error()

# 挂载路由
app.include_router(router)

# 挂载前端静态文件（仅当 statics/ 目录存在时，即 Docker 部署环境）
if STATICS_DIR.is_dir():
    from starlette.staticfiles import StaticFiles
    from fastapi.responses import FileResponse

    _assets_dir: Path = STATICS_DIR / "assets"
    if _assets_dir.is_dir():
        app.mount("/assets", StaticFiles(directory=_assets_dir), name="assets")

    @app.get("/{path:path}")
    async def spa_fallback(path: str) -> FileResponse:
        """
        SPA fallback 路由

        优先级：API 路由 > /assets 静态挂载 > 此 catch-all 路由。
        若请求路径对应 statics/ 下的真实文件则直接返回，否则返回 index.html。
        """
        file_path: Path = (STATICS_DIR / path).resolve()
        # 防止路径穿越
        if file_path.is_relative_to(STATICS_DIR) and path and file_path.is_file():
            return FileResponse(file_path)
        return FileResponse(STATICS_DIR / "index.html")

    l.info(f"前端静态文件已挂载: {STATICS_DIR}")

# 防止直接运行 main.py
if __name__ == "__main__":
    l.error("请用 fastapi ['dev', 'run'] 命令启动服务")
    exit(1)