"""
LangChain Learning Kit - FastAPI 应用程序入口
"""
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from contextlib import asynccontextmanager

from app.config import get_settings
from app.db.session import init_db_manager
from app.api import models, kb, conv, agent
from app.utils.logger import get_logger

logger = get_logger(__name__)


@asynccontextmanager
async def lifespan(app: FastAPI):
    """
    应用程序生命周期管理器。

    处理启动和关闭事件。
    """
    # 启动
    logger.info("application_starting")

    try:
        settings = get_settings()

        # 初始化数据库管理器
        db_manager = init_db_manager(settings)
        logger.info("database_manager_initialized")

        # 如果表不存在则创建
        db_manager.create_all_tables()
        logger.info("database_tables_verified")

        logger.info(
            "application_started",
            environment=settings.environment,
            debug=settings.debug,
        )

    except Exception as e:
        logger.error("application_startup_failed", error=str(e))
        raise

    yield

    # 关闭
    logger.info("application_shutting_down")


# 创建 FastAPI 应用程序
app = FastAPI(
    title="LangChain Learning Kit",
    description="Enterprise-grade LangChain learning platform with RAG, multi-turn conversations, and agent orchestration",
    version="1.0.0",
    lifespan=lifespan,
)

# CORS 中间件
settings = get_settings()
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # 在生产环境中，请指定实际的源
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


# 包含路由
app.include_router(models.router, prefix="/api/v1")
app.include_router(kb.router, prefix="/api/v1")
app.include_router(conv.router, prefix="/api/v1")
app.include_router(agent.router, prefix="/api/v1")


@app.get("/")
def root():
    """根端点。"""
    return {
        "message": "Welcome to LangChain Learning Kit API",
        "version": "1.0.0",
        "docs": "/docs",
        "health": "/health",
    }


@app.get("/health")
def health_check():
    """健康检查端点。"""
    return {
        "status": "healthy",
        "environment": settings.environment,
    }


if __name__ == "__main__":
    import uvicorn

    logger.info("starting_uvicorn_server")

    uvicorn.run(
        "app.main:app",
        host=settings.host,
        port=settings.port,
        reload=settings.debug,
        log_level="info",
    )