# database.py
import os
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession
from sqlalchemy.orm import sessionmaker, declarative_base

# 优先从环境变量读取（Docker 部署推荐）
SQLALCHEMY_DATABASE_URL = os.getenv("DATABASE_URL", "postgresql+asyncpg://user:password@db:5432/fastapi_db")

engine = create_async_engine(SQLALCHEMY_DATABASE_URL, echo=True)
AsyncSessionLocal = sessionmaker(bind=engine, class_=AsyncSession, expire_on_commit=False)

Base = declarative_base()

async def get_db():
    async with AsyncSessionLocal() as session:
        yield session
        # 注意：通常不在 get_db 里统一 commit，建议在 endpoint 里手动 commit

async def init_db():
    async with engine.begin() as conn:
        # 导入模型以确保 metadata 注册了表
        from . import models 
        # 自动创建表
        await conn.run_sync(Base.metadata.create_all)
    
    # 创建默认管理员用户
    async with AsyncSessionLocal() as session:
        from . import auth
        from sqlalchemy.future import select
        
        # 检查是否已存在 admin 用户
        result = await session.execute(
            select(models.User).where(models.User.username == "admin")
        )
        existing_admin = result.scalars().first()
        
        if not existing_admin:
            # 创建管理员用户
            private_key, public_key = auth.generate_key_pair()
            admin_user = models.User(
                username="admin",
                hashed_password=auth.hash_password("admin123"),
                private_key=private_key,
                public_key=public_key,
                is_admin=True,
                guale=False
            )
            session.add(admin_user)
            await session.commit()
            print("✅ Default admin user created (username: admin, password: admin123)")

        # 检查是否已存在 Gemini 配置
        result = await session.execute(
            select(models.AIConfig).where(models.AIConfig.provider_name == "gemini")
        )
        existing_gemini = result.scalars().first()

        if not existing_gemini:
            gemini_config = models.AIConfig(
                provider_name="gemini",
                api_key=os.getenv("GEMINI_API_KEY", "your-gemini-api-key"),
                api_url="https://generativelanguage.googleapis.com/v1beta/openai/chat/completions",
                default_model="gemini-3-flash-preview",
                is_active=True
            )
            session.add(gemini_config)
            await session.commit()
            print("✅ Default Gemini AI configuration created")