from __future__ import annotations

from fastapi import FastAPI, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from sqlalchemy.exc import OperationalError

from .settings import settings
from .routes import ai, debug, metrics, trend
from .services.db_sample import print_db_sample_to_logs


app = FastAPI(title="Crawl BI Backend", version="0.1.0")

@app.exception_handler(OperationalError)
async def db_operational_error_handler(_: Request, exc: OperationalError):
    return JSONResponse(
        status_code=503,
        content={
            "detail": "数据库连接失败（请检查 MYSQL_HOST/USER/PASSWORD 以及 MySQL 授权 host/IP 白名单）。",
            "error": str(exc.orig) if getattr(exc, "orig", None) else str(exc),
        },
    )

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

app.include_router(metrics.router, prefix="/api/metrics", tags=["metrics"])
app.include_router(trend.router, prefix="/api/trend", tags=["trend"])
app.include_router(ai.router, prefix="/api/ai", tags=["ai"])
app.include_router(debug.router, prefix="/api/debug", tags=["debug"])


@app.on_event("startup")
def _startup_print_sample() -> None:
    if settings.debug_print_db_sample:
        print_db_sample_to_logs()