from __future__ import annotations

from fastapi import FastAPI, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from sqlalchemy.orm import Session

from app.core.config import get_settings
from app.core.security import constant_time_equal, hash_token
from app.db.base import SessionLocal, init_db
from app.models import AppSession
from app.routers import auth, chat, groups, home, remote


settings = get_settings()
app = FastAPI(title=settings.app_name, version="0.1.0")

app.add_middleware(
    CORSMiddleware,
    allow_origins=settings.allowed_origins,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


@app.on_event("startup")
def on_startup() -> None:
    init_db()


@app.middleware("http")
async def csrf_protection(request: Request, call_next):
    if not settings.dev_mode and request.method not in {"GET", "HEAD", "OPTIONS"}:
        session_id = request.cookies.get(settings.session_cookie_name)
        if session_id:
            header_token = request.headers.get("x-csrf-token") or request.cookies.get("grouphome_csrf")
            if not header_token:
                return JSONResponse(
                    status_code=403,
                    content={"error": {"code": "csrf_required", "message": "Security check failed.", "details": {}}},
                )
            db: Session = SessionLocal()
            try:
                session = db.get(AppSession, session_id)
                if not session or not constant_time_equal(session.csrf_token_hash, hash_token(header_token)):
                    return JSONResponse(
                        status_code=403,
                        content={"error": {"code": "csrf_invalid", "message": "Security check failed.", "details": {}}},
                    )
            finally:
                db.close()
    return await call_next(request)


@app.exception_handler(Exception)
async def unhandled_exception_handler(request: Request, exc: Exception):
    if settings.dev_mode:
        raise exc
    return JSONResponse(
        status_code=500,
        content={"error": {"code": "server_error", "message": "Something went wrong.", "details": {}}},
    )


app.include_router(auth.router)
app.include_router(home.router)
app.include_router(chat.router)
app.include_router(groups.router)
app.include_router(remote.api_router)
app.include_router(remote.well_known_router)