from pathlib import Path

from fastapi import FastAPI, HTTPException, Request
from fastapi.exceptions import RequestValidationError
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import HTMLResponse, JSONResponse
from fastapi.staticfiles import StaticFiles

from app.config import settings
from app.routers import api_router
from app.routers.activities import activity_share_landing


def create_app() -> FastAPI:
    app = FastAPI(title=settings.app_name, debug=settings.app_debug)

    app.add_middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )

    @app.get("/health", tags=["health"])
    async def health_check() -> dict[str, str]:
        return {"status": "ok"}

    @app.exception_handler(HTTPException)
    async def http_exception_handler(request: Request, exc: HTTPException) -> JSONResponse:
        _ = request
        code_map = {
            400: 1005,
            401: 1001,
            403: 1002,
            404: 1003,
        }
        return JSONResponse(
            status_code=exc.status_code,
            content={
                "code": code_map.get(exc.status_code, 1005),
                "message": exc.detail,
                "data": None,
            },
        )

    @app.exception_handler(RequestValidationError)
    async def validation_exception_handler(
        request: Request, exc: RequestValidationError
    ) -> JSONResponse:
        _ = request
        field_errors = []
        for error in exc.errors():
            location = error.get("loc", [])
            field_name = location[-1] if location else "unknown"
            field_errors.append(
                {
                    "field": field_name,
                    "message": error.get("msg", "参数校验失败"),
                    "type": error.get("type"),
                }
            )

        return JSONResponse(
            status_code=422,
            content={
                "code": 1004,
                "message": "参数校验失败",
                "data": {"field_errors": field_errors},
            },
        )

    @app.exception_handler(Exception)
    async def generic_exception_handler(request: Request, exc: Exception) -> JSONResponse:
        _ = request
        return JSONResponse(
            status_code=500,
            content={
                "code": 1005,
                "message": str(exc) if settings.app_debug else "服务器内部错误",
                "data": None,
            },
        )

    static_dir = Path(__file__).resolve().parent / "static"
    static_dir.mkdir(parents=True, exist_ok=True)
    app.mount("/static", StaticFiles(directory=static_dir), name="static")
    app.mount(f"{settings.api_v1_prefix}/static", StaticFiles(directory=static_dir), name="api-static")

    app.add_api_route(
        "/share/activity/{share_token}",
        activity_share_landing,
        methods=["GET"],
        response_class=HTMLResponse,
        include_in_schema=False,
    )
    app.include_router(api_router, prefix=settings.api_v1_prefix)
    return app


app = create_app()