# app/main.py
from fastapi import FastAPI, Header, Depends

from .config import get_settings
from .db import check_health

app = FastAPI(
    title="LLZQ Backend",
    version="0.1.0",
)


def resolve_db_name(x_llzq_env: str | None = Header(default=None, alias="X-LLZQ-Env")) -> str:
    """
    从请求头 X-LLZQ-Env 中解析要用的 DB 名。
    """
    settings = get_settings()
    return settings.resolve_db_name(x_llzq_env)


@app.get("/api/ping")
def ping(db_name: str = Depends(resolve_db_name)):
    """
    最简单调通接口：
    - 返回当前后端环境
    - 返回实际连接的 DB 名
    - 简单做一个 DB 健康检查
    """
    settings = get_settings()
    ok = False
    error_msg = None

    try:
        ok = check_health(db_name)
    except Exception as e:
        error_msg = str(e)

    return {
        "ok": ok,
        "app_env": settings.app_env,
        "db": db_name,
        "error": error_msg,
    }


@app.get("/api/healthz")
def healthz():
    """
    给 Nginx / 监控用的探活接口，不查 DB。
    """
    return {"status": "ok"}