"""
GraphoLab Backend — FastAPI application entry point.

Run locally:
    uvicorn backend.main:app --reload --port 8000

Interactive API docs:
    http://localhost:8000/docs   (Swagger UI)
    http://localhost:8000/redoc  (ReDoc)
"""

from __future__ import annotations

import threading
from contextlib import asynccontextmanager

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

from backend.config import settings
from backend.database import init_db
from backend.routers import auth, users, projects, analysis, rag, audit, compliance, agent


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Startup / shutdown lifecycle."""
    await init_db()
    # Load RAG index in background so startup is non-blocking
    from core.rag import rag_load_docs
    threading.Thread(
        target=lambda: rag_load_docs(settings.rag_cache_dir),
        daemon=True,
        name="rag-loader",
    ).start()
    yield


app = FastAPI(
    title=settings.app_name,
    version=settings.app_version,
    docs_url="/docs",
    redoc_url="/redoc",
    lifespan=lifespan,
)

# ── CORS (allow React dev server) ─────────────────────────────────────────────
app.add_middleware(
    CORSMiddleware,
    allow_origins=settings.cors_origins,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# ── Routers ───────────────────────────────────────────────────────────────────
app.include_router(auth.router)
app.include_router(users.router)
app.include_router(projects.router)
app.include_router(analysis.router)
app.include_router(rag.router)
app.include_router(compliance.router)
app.include_router(agent.router)
app.include_router(audit.router)


# ── Health check ──────────────────────────────────────────────────────────────
@app.get("/health", tags=["system"])
async def health() -> dict:
    return {"status": "ok", "version": settings.app_version}