from __future__ import annotations

import asyncio
import logging
import sys
from contextlib import asynccontextmanager
from pathlib import Path

from fastapi import (
    FastAPI,
    Request,
)
from fastapi.middleware.cors import (
    CORSMiddleware,
)


PROJECT_ROOT = Path(__file__).resolve().parents[1]

if str(PROJECT_ROOT) not in sys.path:
    sys.path.insert(
        0,
        str(PROJECT_ROOT),
    )


from app.routes import router
from app.security import (
    validate_security_configuration,
)
from scripts.embedding_utils import embed_query


logger = logging.getLogger(__name__)


OPENWEBUI_ORIGIN = (
    "https://ui.tukekemt.xyz"
)


@asynccontextmanager
async def lifespan(
    _: FastAPI,
):
    validate_security_configuration()

    try:
        await asyncio.to_thread(
            embed_query,
            "warmup",
        )

    except Exception:
        logger.exception(
            "Predhriatie embedding modelu "
            "zlyhalo. API pokračuje bez "
            "úspešného warm-upu."
        )

    yield


app = FastAPI(
    title="ZP Agent API",
    description=(
        "RAG API pre vyhľadávanie "
        "a získavanie informácií "
        "z repozitára záverečných prác "
        "ZP Wiki."
    ),
    version="0.9.0",
    lifespan=lifespan,

    # Interaktívne Swagger/ReDoc rozhrania
    # nepotrebujeme vystavovať.
    # /openapi.json zostáva dostupné,
    # pretože ho používa OpenWebUI.
    docs_url=None,
    redoc_url=None,
)


app.add_middleware(
    CORSMiddleware,
    allow_origins=[
        OPENWEBUI_ORIGIN,
    ],
    allow_credentials=True,
    allow_methods=[
        "GET",
        "POST",
        "OPTIONS",
    ],
    allow_headers=[
        "Authorization",
        "Content-Type",
        "X-API-Key",
    ],
    allow_private_network=True,
)


@app.middleware(
    "http"
)
async def add_security_headers(
    request: Request,
    call_next,
):
    response = await call_next(
        request
    )

    # API odpovede obsahujú retrieval kontext,
    # preto ich nechceme ukladať do cache.
    response.headers[
        "Cache-Control"
    ] = "no-store"

    response.headers[
        "X-Content-Type-Options"
    ] = "nosniff"

    response.headers[
        "Referrer-Policy"
    ] = "no-referrer"

    response.headers[
        "X-Frame-Options"
    ] = "DENY"

    return response


app.include_router(
    router
)