-- 资料处理媒体重试：记录从既有知识附件重新解析的来源，支持直接从 OSS 原件重新入队。
-- 可重复执行；依赖 aihr_knowledge_upload_item。

SET @has_source_attach_id := (
  SELECT COUNT(*) FROM information_schema.columns
  WHERE table_schema = DATABASE()
    AND table_name = 'aihr_knowledge_upload_item'
    AND column_name = 'source_attach_id'
);
SET @media_reprocess_ddl := IF(
  @has_source_attach_id = 0,
  'ALTER TABLE aihr_knowledge_upload_item ADD COLUMN source_attach_id bigint DEFAULT NULL COMMENT ''从既有附件重新解析时的附件ID'' AFTER staging_path',
  'SELECT 1'
);
PREPARE media_reprocess_stmt FROM @media_reprocess_ddl;
EXECUTE media_reprocess_stmt;
DEALLOCATE PREPARE media_reprocess_stmt;

SET @has_media_source_index := (
  SELECT COUNT(*) FROM information_schema.statistics
  WHERE table_schema = DATABASE()
    AND table_name = 'aihr_knowledge_upload_item'
    AND index_name = 'idx_aihr_upload_item_source'
);
SET @media_reprocess_ddl := IF(
  @has_media_source_index = 0,
  'ALTER TABLE aihr_knowledge_upload_item ADD KEY idx_aihr_upload_item_source (tenant_id, source_attach_id, id)',
  'SELECT 1'
);
PREPARE media_reprocess_stmt FROM @media_reprocess_ddl;
EXECUTE media_reprocess_stmt;
DEALLOCATE PREPARE media_reprocess_stmt;

SET @has_source_attach_id := NULL;
SET @has_media_source_index := NULL;
SET @media_reprocess_ddl := NULL;