import asyncio
import logging
import os
from contextlib import asynccontextmanager

from alembic import command
from alembic.config import Config as AlembicConfig
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from fastapi.staticfiles import StaticFiles

from config import settings
from services.embeddings import EmbeddingService
from services.llm_client import LLMClient
from services.vectorstore import VectorStoreService

logger = logging.getLogger(__name__)

embedding_service: EmbeddingService | None = None
vectorstore_service: VectorStoreService | None = None
llm_client: LLMClient | None = None


def _run_migrations() -> None:
    """Автоматически подтягиваем схему до последней ревизии при старте."""
    os.makedirs(os.path.dirname(settings.sqlite_path), exist_ok=True)
    cfg = AlembicConfig("alembic.ini")
    command.upgrade(cfg, "head")


@asynccontextmanager
async def lifespan(app: FastAPI):
    global embedding_service, vectorstore_service, llm_client
    logging.basicConfig(level=getattr(logging, settings.log_level.upper(), logging.INFO))
    logger.info("Running DB migrations…")
    await asyncio.to_thread(_run_migrations)
    logger.info("Loading embedding model: %s", settings.embedding_model)
    embedding_service = EmbeddingService(settings.embedding_model)
    logger.info("Embedding model loaded")
    vectorstore_service = VectorStoreService(
        persist_dir=settings.chroma_persist_dir,
        embedding_service=embedding_service,
    )
    logger.info("ChromaDB initialized at %s", settings.chroma_persist_dir)
    llm_client = LLMClient()
    logger.info("LLM client ready (model=%s)", llm_client.model)
    yield
    logger.info("Shutting down")


app = FastAPI(
    title="Chat Agent for Patients — Tuning Tool",
    description="RAG-ядро и инструмент настройки пациентского чат-агента",
    version="0.1.0",
    lifespan=lifespan,
)

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

from routers import chat, documents, health, query, threads  # noqa: E402

app.include_router(health.router)
app.include_router(documents.router)
app.include_router(query.router)
app.include_router(chat.router)
app.include_router(threads.router)

app.mount("/", StaticFiles(directory="static", html=True), name="static")