-- MySQL 5.7
-- 客户业务员工号 -> 系统用户ID 存量迁移。
-- 上线前先执行 20261028_customer_sales_user_classification.sql 并核对 ID_USERNAME_COLLISION。
-- 自动转换仅处理唯一 user_name 匹配；未匹配、重复匹配和 ID/工号冲突会备份原值、清空 sales_user_id，留给管理员在客户编辑页处理。
-- 本脚本不连接数据库执行；可重复运行。完成标记写入后，重复运行不会再次处理存量或改写备份。

-- 新增内部源工号列（兼容 MySQL 5.7，不依赖 ADD COLUMN IF NOT EXISTS）。
SET @add_source_sales_code_sql = (
    SELECT IF(COUNT(*) = 0,
        'ALTER TABLE ctr_customer ADD COLUMN source_sales_code varchar(255) DEFAULT NULL COMMENT ''客户同步源业务员工号（内部字段）'' AFTER sales_user_id',
        'SELECT 1')
    FROM information_schema.columns
    WHERE table_schema = DATABASE()
      AND table_name = 'ctr_customer'
      AND column_name = 'source_sales_code'
);
PREPARE add_source_sales_code_stmt FROM @add_source_sales_code_sql;
EXECUTE add_source_sales_code_stmt;
DEALLOCATE PREPARE add_source_sales_code_stmt;

-- 未匹配时使用 NULL，避免空字符串伪装成用户ID。
ALTER TABLE ctr_customer
    MODIFY COLUMN sales_user_id varchar(64) DEFAULT NULL COMMENT '业务员系统用户ID（sys_user.user_id）';

-- 备份表同时保留分类结果和候选ID；PRIMARY KEY + INSERT IGNORE 保证原始值不会被后续重跑覆盖。
CREATE TABLE IF NOT EXISTS ctr_customer_sales_user_migration_backup (
    customer_id bigint(20) NOT NULL COMMENT '客户ID',
    customer_code varchar(50) NOT NULL COMMENT '客户编码',
    original_sales_user_id varchar(64) DEFAULT NULL COMMENT '迁移前 sales_user_id 原值',
    classification varchar(40) NOT NULL COMMENT '迁移前分类',
    user_id_match_count int NOT NULL DEFAULT 0 COMMENT '精确 user_id 匹配数',
    user_name_match_count int NOT NULL DEFAULT 0 COMMENT '精确 user_name 匹配数',
    user_id_candidates text COMMENT 'user_id 匹配候选',
    user_name_candidates text COMMENT 'user_name 匹配候选',
    backup_time datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '备份时间',
    PRIMARY KEY (customer_id),
    KEY idx_customer_sales_user_backup_classification (classification)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='客户业务员ID迁移原值及分类备份';

-- 防止成功执行后重跑时把后来新建/人工维护的客户重新当作存量数据处理。
CREATE TABLE IF NOT EXISTS ctr_customer_sales_user_migration_control (
    migration_key varchar(64) NOT NULL,
    status varchar(16) NOT NULL DEFAULT 'PENDING',
    completed_at datetime DEFAULT NULL,
    PRIMARY KEY (migration_key)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='客户业务员ID迁移执行状态';

INSERT IGNORE INTO ctr_customer_sales_user_migration_control (migration_key, status)
VALUES ('20261028_customer_sales_user', 'PENDING');

START TRANSACTION;

-- 首次运行时先保留旧值和候选；后续事务失败可安全重跑，成功后由 control 表阻止再次处理。
INSERT IGNORE INTO ctr_customer_sales_user_migration_backup (
    customer_id, customer_code, original_sales_user_id, classification,
    user_id_match_count, user_name_match_count, user_id_candidates, user_name_candidates
)
SELECT c.customer_id,
       c.customer_code,
       c.sales_user_id,
       CASE
           WHEN c.sales_user_id IS NULL OR TRIM(c.sales_user_id) = '' THEN 'EMPTY'
           WHEN id_match.match_count > 0 AND name_match.match_count > 0 THEN 'ID_USERNAME_COLLISION'
           WHEN id_match.match_count > 0 THEN 'VALID_USER_ID'
           WHEN name_match.match_count = 1 THEN 'UNIQUE_USERNAME'
           WHEN name_match.match_count > 1 THEN 'AMBIGUOUS_USERNAME'
           ELSE 'NO_MATCH'
       END,
       COALESCE(id_match.match_count, 0),
       COALESCE(name_match.match_count, 0),
       id_match.candidate_user_ids,
       name_match.candidate_user_ids
FROM ctr_customer c
JOIN ctr_customer_sales_user_migration_control migration
  ON migration.migration_key = '20261028_customer_sales_user'
 AND migration.status = 'PENDING'
LEFT JOIN (
    SELECT CAST(user_id AS CHAR) AS lookup_value,
           COUNT(*) AS match_count,
           GROUP_CONCAT(CAST(user_id AS CHAR) ORDER BY user_id SEPARATOR ',') AS candidate_user_ids
    FROM sys_user
    WHERE del_flag = '0'
    GROUP BY CAST(user_id AS CHAR)
) id_match ON BINARY id_match.lookup_value = BINARY TRIM(c.sales_user_id)
LEFT JOIN (
    SELECT BINARY TRIM(user_name) AS lookup_value,
           COUNT(*) AS match_count,
           GROUP_CONCAT(CAST(user_id AS CHAR) ORDER BY user_id SEPARATOR ',') AS candidate_user_ids
    FROM sys_user
    WHERE del_flag = '0'
      AND user_name IS NOT NULL
      AND user_name != ''
    GROUP BY BINARY TRIM(user_name)
) name_match ON name_match.lookup_value = BINARY TRIM(c.sales_user_id)
WHERE c.del_flag = '0'
  AND c.source_sales_code IS NULL;

-- 唯一工号映射到系统用户ID；不唯一、不匹配或存在ID/工号冲突的项不猜测，清空关联并保留源值。
UPDATE ctr_customer c
JOIN ctr_customer_sales_user_migration_backup b
  ON b.customer_id = c.customer_id
JOIN ctr_customer_sales_user_migration_control migration
  ON migration.migration_key = '20261028_customer_sales_user'
 AND migration.status = 'PENDING'
SET c.source_sales_code = b.original_sales_user_id,
    c.sales_user_id = CASE
        WHEN b.classification = 'UNIQUE_USERNAME'
            THEN b.user_name_candidates
        ELSE NULL
    END
WHERE c.del_flag = '0'
  AND c.source_sales_code IS NULL
  AND b.classification IN (
      'UNIQUE_USERNAME',
      'AMBIGUOUS_USERNAME',
      'NO_MATCH',
      'ID_USERNAME_COLLISION'
  );

-- 将旧空字符串归一为 NULL，已确认是系统用户ID的行保持不变。
UPDATE ctr_customer c
JOIN ctr_customer_sales_user_migration_control migration
  ON migration.migration_key = '20261028_customer_sales_user'
 AND migration.status = 'PENDING'
SET c.sales_user_id = NULL
WHERE c.del_flag = '0'
  AND c.sales_user_id IS NOT NULL
  AND TRIM(c.sales_user_id) = '';

UPDATE ctr_customer_sales_user_migration_control
SET status = 'DONE', completed_at = NOW()
WHERE migration_key = '20261028_customer_sales_user'
  AND status = 'PENDING';

COMMIT;

-- 执行后核对人工处理清单；原值和候选均保存在备份表中。
SELECT customer_id, customer_code, original_sales_user_id, classification,
       user_id_candidates, user_name_candidates
FROM ctr_customer_sales_user_migration_backup
WHERE classification IN ('ID_USERNAME_COLLISION', 'AMBIGUOUS_USERNAME', 'NO_MATCH')
ORDER BY classification, customer_id;