import logging
import uuid
from contextlib import asynccontextmanager

from fastapi import FastAPI, HTTPException, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from sqlalchemy import text
from starlette.middleware.sessions import SessionMiddleware

from app.api.routers import (
    audit,
    auth,
    bookings,
    customers,
    dashboard,
    data_quality,
    demo,
    integration_status,
    integrations,
    knowledge,
    mcp_integrations,
    observability,
    privacy,
    search,
    users,
    vehicles,
    workflows,
)
from app.api.routers.auth import bootstrap_initial_admin
from app.core.config import PRODUCT_NAME, get_settings
from app.core.db import SessionLocal
from app.core.errors import AppError, error_body
from app.core.observability import (
    DATABASE_READY,
    configure_logging,
    correlation_id_context,
    correlation_id_for,
    request_finished,
    request_started,
)
from app.services.dispatcher import start_background_dispatcher, stop_background_dispatcher

settings = get_settings()
configure_logging(settings.log_level)
request_logger = logging.getLogger("mobilityops.request")


@asynccontextmanager
async def lifespan(_app: FastAPI):
    with SessionLocal() as db:
        bootstrap_initial_admin(db)
    start_background_dispatcher()
    yield
    stop_background_dispatcher()


production = settings.mobilityops_env.lower() == "production"
app = FastAPI(
    title=f"{PRODUCT_NAME} API",
    version="0.1.0",
    lifespan=lifespan,
    docs_url=None if production else "/docs",
    redoc_url=None if production else "/redoc",
    openapi_url=None if production else "/openapi.json",
)

app.add_middleware(
    SessionMiddleware,
    secret_key=settings.app_secret,
    session_cookie="mobilityops_oidc_state",
    max_age=600,
    same_site="lax",
    https_only=settings.session_cookie_secure,
)


@app.middleware("http")
async def request_observability(request: Request, call_next):
    correlation_id = correlation_id_for(request)
    request.state.correlation_id = correlation_id
    token = correlation_id_context.set(correlation_id)
    started_at = request_started()
    status_code = 500
    try:
        response = await call_next(request)
        status_code = response.status_code
        response.headers["X-Correlation-Id"] = correlation_id
        return response
    finally:
        duration = request_finished(request, status_code, started_at)
        request_logger.info(
            "request_completed",
            extra={
                "method": request.method,
                "path": request.url.path,
                "status_code": status_code,
                "duration_ms": round(duration * 1000, 2),
                "client_ip": request.client.host if request.client else None,
            },
        )
        correlation_id_context.reset(token)


app.add_middleware(
    CORSMiddleware,
    allow_origins=[o.strip() for o in settings.cors_allow_origins.split(",")],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


@app.exception_handler(AppError)
def handle_app_error(request: Request, exc: AppError) -> JSONResponse:
    return JSONResponse(
        status_code=exc.status_code,
        content=error_body(
            exc.code,
            exc.message,
            request.state.correlation_id,
            exc.details,
        ),
    )


@app.exception_handler(HTTPException)
def handle_http_exception(request: Request, exc: HTTPException) -> JSONResponse:
    return JSONResponse(
        status_code=exc.status_code,
        content=error_body(
            code=str(exc.status_code),
            message=str(exc.detail),
            correlation_id=getattr(request.state, "correlation_id", str(uuid.uuid4())),
            details={},
        ),
        headers=exc.headers,
    )


@app.get("/health")
def health() -> dict[str, str]:
    return {"status": "ok", "service": "mobilityops-api"}


@app.get("/health/live")
def liveness() -> dict[str, str]:
    """Process liveness only; external dependencies deliberately do not affect it."""
    return {"status": "ok", "service": "mobilityops-api"}


@app.get("/health/ready")
def readiness() -> JSONResponse:
    """Traffic readiness: the API is useful only while its canonical database responds."""
    try:
        with SessionLocal() as db:
            db.execute(text("SELECT 1"))
    except Exception:  # noqa: BLE001 -- readiness must convert infrastructure errors to 503
        DATABASE_READY.set(0)
        return JSONResponse(
            status_code=503,
            content={"status": "not_ready", "service": "mobilityops-api", "database": "down"},
        )
    DATABASE_READY.set(1)
    return JSONResponse(content={"status": "ready", "service": "mobilityops-api", "database": "up"})


@app.get("/api/v1/system/status")
def system_status() -> dict[str, object]:
    return {
        "service": "mobilityops-api",
        "environment": settings.mobilityops_env,
        "demo_mode": settings.mobilityops_demo_mode,
        "knowledge_provider": settings.knowledge_provider,
        "oidc_enabled": auth.oidc_status().enabled,
        "oidc_provider_name": auth.oidc_status().provider_name,
    }


app.include_router(demo.router)
app.include_router(auth.router)
app.include_router(dashboard.router)
app.include_router(vehicles.router)
app.include_router(bookings.router)
app.include_router(customers.router)
app.include_router(audit.router)
app.include_router(data_quality.router)
app.include_router(workflows.router)
app.include_router(integrations.router)
app.include_router(knowledge.router)
app.include_router(mcp_integrations.router)
app.include_router(search.router)
app.include_router(integration_status.router)
app.include_router(users.router)
app.include_router(observability.router)
app.include_router(privacy.router)