-- Backfill mappings for historical ZhiYun data.
-- Safe to run repeatedly. This script only backfills resources where the old
-- sync logic stored the ZhiYun id directly as the local id.

CREATE TABLE IF NOT EXISTS external_resource_mapping (
  id VARCHAR(64) NOT NULL PRIMARY KEY,
  source_system VARCHAR(32) NOT NULL COMMENT '外部来源系统',
  resource_type VARCHAR(32) NOT NULL COMMENT '资源类型',
  local_id VARCHAR(64) NOT NULL COMMENT '本系统ID',
  external_id VARCHAR(128) NOT NULL COMMENT '外部系统ID',
  external_code VARCHAR(128) NULL COMMENT '外部编码',
  external_name VARCHAR(255) NULL COMMENT '外部名称快照',
  create_time DATETIME NULL COMMENT '创建时间',
  update_time DATETIME NULL COMMENT '更新时间',
  UNIQUE KEY uk_external_resource (source_system, resource_type, external_id),
  KEY idx_external_resource_local (resource_type, local_id)
) COMMENT='外部系统资源映射';

-- Historical ZhiYun sync stored school_id directly from ZhiYun schoolId.
INSERT INTO external_resource_mapping (
  id, source_system, resource_type, local_id, external_id, external_code, external_name, create_time, update_time
)
SELECT
  REPLACE(UUID(), '-', ''),
  'ZHIYUN',
  'SCHOOL',
  s.school_id,
  s.school_id,
  s.school_id,
  s.school_name,
  NOW(),
  NOW()
FROM school s
WHERE EXISTS (
  SELECT 1
  FROM userinfo u
  WHERE u.school_id = s.school_id
    AND u.code_from = '智云同步'
)
AND NOT EXISTS (
  SELECT 1
  FROM external_resource_mapping m
  WHERE m.source_system = 'ZHIYUN'
    AND m.resource_type = 'SCHOOL'
    AND m.external_id = s.school_id
);

-- Historical ZhiYun student sync stored school_class_id directly from ZhiYun classId.
INSERT INTO external_resource_mapping (
  id, source_system, resource_type, local_id, external_id, external_code, external_name, create_time, update_time
)
SELECT
  REPLACE(UUID(), '-', ''),
  'ZHIYUN',
  'CLASS',
  c.school_class_id,
  c.school_class_id,
  c.school_class_id,
  c.class_name,
  NOW(),
  NOW()
FROM school_class c
WHERE EXISTS (
  SELECT 1
  FROM userinfo u
  WHERE u.school_class_id = c.school_class_id
    AND u.code_from = '智云同步'
)
AND NOT EXISTS (
  SELECT 1
  FROM external_resource_mapping m
  WHERE m.source_system = 'ZHIYUN'
    AND m.resource_type = 'CLASS'
    AND m.external_id = c.school_class_id
);

-- Mark classes that came from historical ZhiYun student sync as administrative
-- ZhiYun classes. Local teaching classes are not touched by this condition.
UPDATE school_class c
SET c.class_type = 'ADMIN',
    c.data_source = 'ZHIYUN'
WHERE EXISTS (
  SELECT 1
  FROM userinfo u
  WHERE u.school_class_id = c.school_class_id
    AND u.code_from = '智云同步'
);

-- Important:
-- Historical rows do not retain ZhiYun userId / collegeId / majorId anywhere
-- reliable. Do not fabricate USER / FACULTY / MAJOR mappings from username or
-- names. The updated sync code will add those mappings on the next full ZhiYun
-- sync because it receives the real external ids in ZYUserInfo.