from fastapi import FastAPI
from starlette.middleware.sessions import SessionMiddleware

from app.core.settings import get_settings
from app.core.middleware.context import ContextResolveMiddleware
from app.core.middleware.domain_resolver import DomainResolverMiddleware
from app.core.middleware.security_headers import SecurityHeadersMiddleware
from app.core.startup import on_startup
from app.core.api import api_router
from app.ui.app import mount_ui


def create_app() -> FastAPI:
    s = get_settings()
    app = FastAPI(title=s.APP_NAME, debug=s.DEBUG)

    app.add_middleware(SecurityHeadersMiddleware)
    app.add_middleware(ContextResolveMiddleware)
    # Phase 7T.2: added after context so it resolves the request host before
    # context-aware middleware/routes need tenant/branch/domain state.
    app.add_middleware(DomainResolverMiddleware)
    # SessionMiddleware is added last so it is available to downstream
    # middleware/routes in Starlette's middleware execution order.
    app.add_middleware(
        SessionMiddleware,
        secret_key=s.SECRET_KEY,
        session_cookie=s.COOKIE_SESSION_NAME,
        same_site=s.COOKIE_SAMESITE,
        https_only=s.COOKIE_SECURE,
    )

    app.add_event_handler("startup", lambda: on_startup(app))

    app.include_router(api_router, prefix="/api")
    mount_ui(app)

    return app


app = create_app()