-- =============================================================================
-- FDW 映射配置（测试环境）— 在 test_zqyy_app 数据库中执行
-- 用途：通过 postgres_fdw 将 test_etl_feiqiu.app schema 只读映射到 test_zqyy_app，
--       使业务后端在测试环境下无需直接连接 ETL 测试库即可读取汇总/维度数据。
-- 前提：test_etl_feiqiu 数据库已部署 app schema 及 app_reader 角色
-- 基于 setup_fdw.sql，仅将目标库替换为测试库
-- =============================================================================

-- -----------------------------------------------------------------------------
-- 1. 安装 postgres_fdw 扩展
-- -----------------------------------------------------------------------------
CREATE EXTENSION IF NOT EXISTS postgres_fdw;

-- -----------------------------------------------------------------------------
-- 2. 创建外部服务器（指向 test_etl_feiqiu 测试库）
--    部署时按实际环境替换 host / port
-- -----------------------------------------------------------------------------
CREATE SERVER IF NOT EXISTS test_etl_feiqiu_server
    FOREIGN DATA WRAPPER postgres_fdw
    OPTIONS (host 'localhost', dbname 'test_etl_feiqiu', port '5432');

-- -----------------------------------------------------------------------------
-- 3. 创建用户映射（只读角色）
--    app_user  = test_zqyy_app 侧的应用连接角色
--    app_reader = test_etl_feiqiu 侧的只读角色
--    密码占位符 '***'，部署时替换为真实凭据
-- -----------------------------------------------------------------------------
CREATE USER MAPPING IF NOT EXISTS FOR app_user
    SERVER test_etl_feiqiu_server
    OPTIONS (user 'app_reader', password '***');

-- -----------------------------------------------------------------------------
-- 4. 创建目标 schema（存放外部表）
-- -----------------------------------------------------------------------------
CREATE SCHEMA IF NOT EXISTS fdw_etl;

-- -----------------------------------------------------------------------------
-- 5. 导入 test_etl_feiqiu.app schema 的所有外部表到 fdw_etl
-- -----------------------------------------------------------------------------
IMPORT FOREIGN SCHEMA app
    FROM SERVER test_etl_feiqiu_server
    INTO fdw_etl;

-- -----------------------------------------------------------------------------
-- 6. 授权：允许 app_user 访问 fdw_etl schema 及其外部表
-- -----------------------------------------------------------------------------
GRANT USAGE ON SCHEMA fdw_etl TO app_user;
GRANT SELECT ON ALL TABLES IN SCHEMA fdw_etl TO app_user;

-- 未来新导入的外部表自动授权
ALTER DEFAULT PRIVILEGES IN SCHEMA fdw_etl GRANT SELECT ON TABLES TO app_user;


-- =============================================================================
-- 回滚脚本（按逆序执行）
-- =============================================================================
-- ALTER DEFAULT PRIVILEGES IN SCHEMA fdw_etl REVOKE SELECT ON TABLES FROM app_user;
-- REVOKE SELECT ON ALL TABLES IN SCHEMA fdw_etl FROM app_user;
-- REVOKE USAGE ON SCHEMA fdw_etl FROM app_user;
-- DROP SCHEMA IF EXISTS fdw_etl CASCADE;
-- DROP USER MAPPING IF EXISTS FOR app_user SERVER test_etl_feiqiu_server;
-- DROP SERVER IF EXISTS test_etl_feiqiu_server CASCADE;
-- DROP EXTENSION IF EXISTS postgres_fdw;