# app/database.py
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, Session
from sqlalchemy.ext.declarative import declarative_base
from contextlib import contextmanager
from typing import Generator
import os

from .config import settings

# 创建数据库引擎
engine = create_engine(
    settings.DATABASE_URL,
    connect_args={"check_same_thread": False} if "sqlite" in settings.DATABASE_URL else {},
    echo=settings.DEBUG
)

# 创建会话工厂
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

# 声明基类
Base = declarative_base()

def get_db() -> Generator[Session, None, None]:
    """数据库会话依赖注入"""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

def init_db():
    """初始化数据库表"""
    from .models.user import User
    Base.metadata.create_all(bind=engine)
    print("✅ 数据库表创建完成")
    
    # 创建默认管理员用户
    db = SessionLocal()
    try:
        # 检查是否已存在管理员
        admin = db.query(User).filter(User.username == "admin").first()
        if not admin:
            from .core.security import password_hasher
            admin_user = User(
                username="admin",
                email="admin@caiyouhui.com",
                hashed_password=password_hasher.hash_password("Admin123!"),
                full_name="系统管理员",
                is_active=True,
                is_verified=True,
                is_superuser=True
            )
            db.add(admin_user)
            db.commit()
            print("✅ 默认管理员用户已创建")
    except Exception as e:
        print(f"⚠️  创建管理员用户时出错: {e}")
        db.rollback()
    finally:
        db.close()

# 导出
__all__ = ["Base", "engine", "SessionLocal", "get_db", "init_db"]