from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import DeclarativeBase
from backend.config import get_settings

settings = get_settings()

engine = create_async_engine(settings.database_url, echo=False)
async_session = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)


class Base(DeclarativeBase):
    pass


async def get_db():
    async with async_session() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise


# ────────────── CRUD 工具函数 ──────────────

async def db_add(db: AsyncSession, obj, *, refresh: bool = False):
    """创建记录并提交。refresh=True 会在提交后刷新对象（获取生成的 id 等）。"""
    db.add(obj)
    await db.flush()
    if refresh:
        await db.refresh(obj)
    await db.commit()


async def db_update(db: AsyncSession, obj, data: dict):
    """批量更新字段并提交。data 一般来自 model_dump(exclude_unset=True)。"""
    for key, value in data.items():
        setattr(obj, key, value)
    await db.commit()


async def db_delete(db: AsyncSession, obj):
    """删除记录并提交。"""
    await db.delete(obj)
    await db.commit()


async def db_flush(db: AsyncSession):
    """将待写操作刷到数据库（不提交事务），用于需要获取生成 ID 等中间状态的场景。"""
    await db.flush()


async def init_db():
    async with engine.begin() as conn:
        # 迁移旧表：acme_config → acme_configs
        try:
            result = await conn.execute(
                __import__("sqlalchemy").text("SELECT name FROM sqlite_master WHERE type='table' AND name='acme_config'")
            )
            if result.fetchone():
                await conn.execute(__import__("sqlalchemy").text("ALTER TABLE acme_config RENAME TO acme_configs"))
        except Exception:
            pass

        await conn.run_sync(Base.metadata.create_all)

        # 给 acme_configs 表补全新列（旧表迁移后可能缺少这些列）
        for col_def in [
            "ALTER TABLE acme_configs ADD COLUMN name VARCHAR(100) NOT NULL DEFAULT '默认配置'",
            "ALTER TABLE acme_configs ADD COLUMN created_at DATETIME",
            "ALTER TABLE acme_configs ADD COLUMN updated_at DATETIME",
        ]:
            try:
                await conn.execute(__import__("sqlalchemy").text(col_def))
            except Exception:
                pass  # 列已存在

        # 迁移：给 domains 表加 acme_config_id 列
        try:
            await conn.execute(
                __import__("sqlalchemy").text("ALTER TABLE domains ADD COLUMN acme_config_id INTEGER REFERENCES acme_configs(id)")
            )
        except Exception:
            pass  # 列已存在

        # 迁移：给 deploy_logs 表加 hostname 列
        try:
            await conn.execute(__import__("sqlalchemy").text("ALTER TABLE deploy_logs ADD COLUMN hostname VARCHAR(200)"))
        except Exception:
            pass

        # 迁移：给 acme_logs 表加证书信息列
        for col_def in [
            "ALTER TABLE acme_logs ADD COLUMN cert_not_after DATETIME",
            "ALTER TABLE acme_logs ADD COLUMN cert_serial VARCHAR(100)",
            "ALTER TABLE acme_logs ADD COLUMN cert_san VARCHAR(500)",
        ]:
            try:
                await conn.execute(__import__("sqlalchemy").text(col_def))
            except Exception:
                pass  # 列已存在

        # 确保至少有一条默认配置
        result = await conn.execute(
            __import__("sqlalchemy").text("SELECT COUNT(*) FROM acme_configs")
        )
        count = result.scalar()
        if count == 0:
            await conn.execute(
                __import__("sqlalchemy").text(
                    "INSERT INTO acme_configs (name, acme_server, email, dns_provider, dns_credentials, renew_days) "
                    "VALUES ('默认配置', 'https://acme-v02.api.letsencrypt.org/directory', '', 'aliyun', '{}', 30)"
                )
            )