"""健康检查。

/healthz    → 存活探针（liveness）：不触碰依赖，快速返回。
/api/health → 就绪探针（readiness）：探测 SQLite + 文件存储。
"""

import time

from fastapi import APIRouter, Response, status
from pydantic import BaseModel
from sqlalchemy import text

from app.core.config import get_settings
from app.core.db import get_session_factory

router = APIRouter()


class HealthComponent(BaseModel):
    status: str
    latency_ms: int | None = None
    error: str | None = None


class HealthReport(BaseModel):
    status: str
    environment: str
    components: dict[str, HealthComponent]


@router.get("/healthz")
async def liveness() -> dict[str, str]:
    return {"status": "ok"}


@router.get("/health", response_model=HealthReport)
async def readiness(response: Response) -> HealthReport:
    report = HealthReport(
        status="ok",
        environment=get_settings().environment,
        components={
            "database": _check_db(),
            "storage": _check_storage(),
        },
    )
    if any(c.status != "ok" for c in report.components.values()):
        report.status = "degraded"
        response.status_code = status.HTTP_503_SERVICE_UNAVAILABLE
    return report


def _check_db() -> HealthComponent:
    start = time.perf_counter()
    try:
        factory = get_session_factory()
        with factory() as session:
            session.execute(text("SELECT 1"))
    except Exception as exc:  # noqa: BLE001
        return HealthComponent(status="down", error=_brief(exc))
    return HealthComponent(status="ok", latency_ms=_ms(start))


def _check_storage() -> HealthComponent:
    start = time.perf_counter()
    try:
        from app.storage.local_storage import get_storage

        storage = get_storage()
        root = storage._root
        if not root.exists():
            root.mkdir(parents=True, exist_ok=True)
    except Exception as exc:  # noqa: BLE001
        return HealthComponent(status="down", error=_brief(exc))
    return HealthComponent(status="ok", latency_ms=_ms(start))


def _ms(start: float) -> int:
    return int((time.perf_counter() - start) * 1000)


def _brief(exc: Exception) -> str:
    text = f"{type(exc).__name__}: {exc}"
    return text.split("\n")[0][:200]