from contextlib import asynccontextmanager
from pathlib import Path

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles

from app.config import get_settings
from app.routers import docs, ingest, query
from app.state import AppState


@asynccontextmanager
async def lifespan(app: FastAPI):
    settings = get_settings()
    state = AppState.from_settings(settings)
    state.vector_store.load_existing()
    app.state.rag = state
    yield


app = FastAPI(
    title="RAG Document Q&A API",
    description="A low-level RAG pipeline for document ingestion and grounded Q&A.",
    version="0.1.0",
    lifespan=lifespan,
)

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

app.include_router(ingest.router)
app.include_router(query.router)
app.include_router(docs.router)

frontend_dir = Path(__file__).resolve().parent.parent / "frontend"
if frontend_dir.exists():
    app.mount("/static", StaticFiles(directory=frontend_dir), name="static")


@app.get("/", include_in_schema=False)
def frontend() -> FileResponse:
    return FileResponse(frontend_dir / "index.html")


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