ChingTech OS：移除多租戶架構

# Phase 1: 刪除非 chingtech 租戶的資料
tables_with_tenant_id = [
    'bot_files', 'bot_messages', 'bot_binding_codes',
    'bot_groups', 'bot_users', 'ai_chats', 'ai_prompts',
    'ai_agents', 'public_share_links', 'users',
]
for table in tables_with_tenant_id:
    connection.execute(sa.text(f"""
        DELETE FROM {table} WHERE tenant_id != :tid
    """), {'tid': CHINGTECH_TENANT_ID})

# Phase 2: 新增 bot_settings 表（取代租戶級設定）
# Phase 3: 更新角色（platform_admin/tenant_admin → admin）
# Phase 4: 移除外鍵約束
# Phase 5: 移除 tenant_id 索引
# Phase 6: 移除 tenant_id 欄位
# Phase 7: 重建索引（不含 tenant_id）
# Phase 8: 刪除 tenant_admins 表
# Phase 9: 刪除 tenants 表

def downgrade() -> None:
    raise NotImplementedError(
        "這是破壞性 migration，無法 downgrade。請從備份還原。"
    )

result = connection.execute(sa.text("""
    SELECT table_name FROM information_schema.columns
    WHERE column_name = 'tenant_id'
      AND table_schema = 'public'
    ORDER BY table_name
"""))
tables = [row[0] for row in result]

class SessionData(BaseModel):
    username: str
    password: str
    nas_host: str
    user_id: int | None = None
    tenant_id: str          # 移除
    created_at: datetime
    expires_at: datetime
    role: str = "user"      # 原本有 platform_admin/tenant_admin/user
    app_permissions: dict[str, bool] = {}

class SessionData(BaseModel):
    username: str
    password: str
    nas_host: str
    user_id: int | None = None
    created_at: datetime
    expires_at: datetime
    role: str = "user"      # 只剩 admin/user
    app_permissions: dict[str, bool] = {}

async def get_bot_credentials(platform: str) -> dict[str, str]:
    # 先從資料庫讀取
    async with get_connection() as conn:
        rows = await conn.fetch(
            "SELECT key, value FROM bot_settings WHERE platform = $1",
            platform,
        )
        db_values = {row["key"]: row["value"] for row in rows}

    for key in keys:
        db_val = db_values.get(key, "")
        if db_val:
            # 資料庫有值，解密後回傳
            result[key] = decrypt_credential(db_val)
        else:
            # fallback 到環境變數
            result[key] = _get_env_fallback(platform, key)
    return result

class TestSimplifiedAuth:
    def test_login_request_no_tenant_code(self): ...
    def test_session_data_no_tenant_id(self): ...

class TestSimplifiedRoles:
    def test_only_admin_and_user_roles(self): ...

class TestBotSettings:
    def test_bot_settings_module_exists(self): ...

class TestSimplifiedPaths:
    def test_knowledge_path_no_tenant(self): ...
    def test_linebot_path_no_tenant(self): ...

class TestUserServiceNoTenantId:
    async def test_upsert_user_no_tenant_id_param(self): ...
    async def test_get_user_no_tenant_filter(self): ...

class TestMcpToolsNoTenantId:
    def test_mcp_tools_signature(self): ...