"""FastAPI application factory.

Nothing in the inner layers imports FastAPI; this module wires them together.
"""

from __future__ import annotations

import logging
from contextlib import asynccontextmanager

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware

from app.core.config import settings
from app.core.database import Base, engine
from app.interfaces.http.errors import register_exception_handlers
from app.interfaces.http.request_context import RequestContextMiddleware
from app.interfaces.http.routers import (
    admin,
    agy,
    auth,
    billing,
    health,
    knowledge,
    organizations,
    projects,
    sandbox,
    workforce,
)

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s %(levelname)-7s %(name)s: %(message)s",
)
logger = logging.getLogger("agy.api")


@asynccontextmanager
async def lifespan(_: FastAPI):
    try:
        # In development we create any missing tables so `pnpm dev` works on a
        # fresh clone. Production schema changes go through Alembic
        # (`pnpm db:migrate`).
        if not settings.is_production:
            import app.infrastructure.db.models  # noqa: F401 - register metadata

            async with engine.begin() as conn:
                await conn.run_sync(Base.metadata.create_all)
            logger.info("Development schema ensured.")
        logger.info(
            "Adapters -> ai=%s git=%s domain=%s sandbox=%s payment=%s",
            settings.ai_default_provider,
            settings.git_provider,
            settings.domain_router,
            settings.sandbox_provider,
            settings.payment_provider,
        )
    except Exception as exc:
        # Startup failures are the hardest to diagnose after the fact: the
        # process is gone and all that remains is whatever reached stderr, which
        # a container runtime routinely discards. Record it, then still fail
        # loudly — a half-started API must not accept traffic.
        await _record_startup_failure(exc)
        raise
    yield


async def _record_startup_failure(exc: BaseException) -> None:
    """Persist a boot failure. Never raises; the caller re-raises regardless."""
    try:
        from app.domain.audit.models import ErrorSeverity, ErrorSource
        from app.infrastructure.error_log import record_error

        await record_error(
            kind="startup_failed",
            message=str(exc) or type(exc).__name__,
            exc=exc,
            source=ErrorSource.STARTUP,
            severity=ErrorSeverity.CRITICAL,
            metadata={"app_env": settings.app_env},
        )
    except Exception:  # pragma: no cover - boot is already failing
        logger.exception("Could not record the startup failure.")


def create_app() -> FastAPI:
    application = FastAPI(
        title=settings.app_name,
        version="0.1.0",
        description="AI Workforce Platform — standalone multi-tenant SaaS.",
        lifespan=lifespan,
        docs_url="/docs",
        openapi_url="/openapi.json",
    )

    # Starlette applies middleware outermost-first in reverse registration
    # order, so the last one added wraps everything else. The request-context
    # middleware goes last on purpose: that way even a CORS rejection gets an
    # ``X-Request-ID`` — and a CORS rejection is exactly the kind of opaque
    # failure where a correlatable id is worth having.
    application.add_middleware(
        CORSMiddleware,
        allow_origins=settings.cors_origin_list,
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
        # Without this the browser cannot read the header off a cross-origin
        # response, and the id would be useless to the web client.
        expose_headers=["X-Request-ID"],
    )

    application.add_middleware(RequestContextMiddleware)

    register_exception_handlers(application)

    application.include_router(health.router)
    application.include_router(auth.router, prefix="/api")
    application.include_router(organizations.router, prefix="/api")
    application.include_router(projects.router, prefix="/api")
    application.include_router(workforce.router, prefix="/api")
    application.include_router(billing.router, prefix="/api")
    application.include_router(knowledge.router, prefix="/api")
    application.include_router(sandbox.router, prefix="/api")
    application.include_router(admin.router, prefix="/api")
    application.include_router(agy.router, prefix="/api")

    @application.get("/", tags=["meta"])
    async def root() -> dict:
        return {
            "name": settings.app_name,
            "version": "0.1.0",
            "docs": "/docs",
            "health": "/health",
        }

    return application


app = create_app()