"""
main.py — FastAPI application entry point for the RAG API.
"""

from __future__ import annotations

import logging
import sys

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

from core.database import create_pool, close_pool
from core.settings import Settings
from routers import search, chat, documents, index, meta

# Global settings instance (imported by routers via dependency)
app_settings = Settings()


def setup_logging(level: str) -> None:
    logging.basicConfig(
        level=getattr(logging, level.upper(), logging.INFO),
        format='%(asctime)s [%(levelname)s] %(name)s: %(message)s',
        datefmt='%Y-%m-%dT%H:%M:%S',
        stream=sys.stdout,
    )


@asynccontextmanager
async def lifespan(app: FastAPI):
    setup_logging(app_settings.log_level)
    logging.getLogger('rag-api').info('Starting RAG API v%s', app_settings.app_version)
    await create_pool(app_settings)
    yield
    await close_pool()


app = FastAPI(
    title=app_settings.app_title,
    version=app_settings.app_version,
    lifespan=lifespan,
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=app_settings.cors_origins_list,
    allow_credentials=True,
    allow_methods=['*'],
    allow_headers=['*'],
)

# Register routers
app.include_router(search.router, prefix='/api/v1')
app.include_router(chat.router, prefix='/api/v1')
app.include_router(documents.router, prefix='/api/v1')
app.include_router(index.router, prefix='/api/v1')
app.include_router(meta.router, prefix='/api/v1')