"""FastAPI 入口（B7 集成）：路由挂载、trace 中间件、lifespan、统一错误体。

lifespan（B7 挂账⑤⑥）：
- 启动期校验：非 development 环境且鉴权工厂仍为 debug 头实现 → 拒绝启动
  （T-01 接入 JWT 后置 deps.AUTH_FACTORY_IS_DEBUG=False 放行）；
- Redis 网关单例注册（惰性连接，publish/DEL 失败降级不阻塞业务）；
- shutdown 统一 dispose 数据库引擎（utils/db 工厂，B6 复审 P3 泄漏收口）。
trace：X-Trace-Id 透传/生成 + 响应头回写（trace.py 约束：call_next 前 set，
同步路由线程池由 anyio 传播，一致性 B8 断言兜底）。
"""

from __future__ import annotations

import re
from contextlib import asynccontextmanager

from fastapi import FastAPI, Request

from app.api import deps
from app.api.risk import router as risk_router
from app.api.simulate import router as simulate_router
from app.config.settings import settings
from app.service.risk import redis_gateway
from app.utils.db import dispose_engines
from app.utils.response import register_error_handlers
from app.utils.trace import new_trace, reset_trace, set_trace

# 透传外部 X-Trace-Id 的格式白名单（防响应头注入；不合规一律新生成）
_TRACE_ID_PATTERN = re.compile(r"^[A-Za-z0-9._-]{1,64}$")


@asynccontextmanager
async def lifespan(_: FastAPI):
    if settings.app_env != "development" and deps.AUTH_FACTORY_IS_DEBUG:
        raise RuntimeError(
            "debug auth factory is wired but app_env is not 'development'; "
            "deploy T-01 JWT auth first or set app_env=development"
        )
    redis_gateway.set_gateway(redis_gateway.RedisGateway())
    try:
        yield
    finally:
        redis_gateway.set_gateway(None)
        dispose_engines()


app = FastAPI(title="JinRong Agent Platform", version="0.2.0", lifespan=lifespan)
register_error_handlers(app)
app.include_router(risk_router)
app.include_router(simulate_router)


@app.middleware("http")
async def trace_middleware(request: Request, call_next):
    """trace_id 贯通：透传合法 X-Trace-Id，否则生成；响应头回写。"""
    incoming = request.headers.get("X-Trace-Id", "")
    trace_id = incoming if _TRACE_ID_PATTERN.fullmatch(incoming) else new_trace()
    token = set_trace(trace_id)
    try:
        response = await call_next(request)
    finally:
        reset_trace(token)
    response.headers["X-Trace-Id"] = trace_id
    return response


@app.get("/health")
def health():
    return {"status": "ok", "env": settings.app_env}