-- 仅用于本地环境：将高数据量表迁移为“共库、按商户分表”。
-- 目标命名：
--   im_001_friendships
--   im_001_messages
--   im_001_group_messages_YYYYMM
-- 测试环境不得执行本文件。

-- 1. 商户编号改为事务序列分配，下一编号按当前最大 ID 顺序递增。
USE `hotgo`;

CREATE TABLE IF NOT EXISTS `im_tenant_id_sequence` (
    `sequence_name` VARCHAR(32) NOT NULL,
    `next_id` BIGINT NOT NULL,
    `updated_at` DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3) ON UPDATE CURRENT_TIMESTAMP(3),
    PRIMARY KEY (`sequence_name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

INSERT INTO `im_tenant_id_sequence` (`sequence_name`, `next_id`)
SELECT 'tenant', COALESCE(MAX(`id`), 0) + 1 FROM `im_tenant`
ON DUPLICATE KEY UPDATE `next_id` = GREATEST(`next_id`, VALUES(`next_id`));

-- 禁止绕过序列表使用 AUTO_INCREMENT 生成跳号或历史大整数编号。
ALTER TABLE `hg_admin_member` DROP FOREIGN KEY `fk_hg_admin_member_im_tenant`;
ALTER TABLE `im_tenant_config` DROP FOREIGN KEY `fk_im_tenant_config_tenant`;
ALTER TABLE `im_tenant` MODIFY `id` BIGINT NOT NULL;
ALTER TABLE `hg_admin_member` ADD CONSTRAINT `fk_hg_admin_member_im_tenant`
    FOREIGN KEY (`tenant_id`) REFERENCES `im_tenant` (`id`);
ALTER TABLE `im_tenant_config` ADD CONSTRAINT `fk_im_tenant_config_tenant`
    FOREIGN KEY (`tenant_id`) REFERENCES `im_tenant` (`id`);

UPDATE `im_tenant` AS target
JOIN `im_tenant` AS shared ON shared.`code`='default'
SET target.`db_name`=shared.`db_name`, target.`db_dsn`=shared.`db_dsn`
WHERE target.`id`<>shared.`id`;

-- 2. 月表路由元数据改为以 tenant_id 为第一维度。
USE `tinode`;

ALTER TABLE `im_group_message_shards`
    DROP PRIMARY KEY,
    DROP INDEX `uk_im_group_message_shards_table`,
    DROP INDEX `idx_im_group_message_shards_status`,
    ADD PRIMARY KEY (`tenant_id`, `shard_month`),
    ADD UNIQUE INDEX `uk_im_group_message_shards_table` (`tenant_id`, `table_name`),
    ADD INDEX `idx_im_group_message_shards_status` (`tenant_id`, `status`, `shard_month`);

ALTER TABLE `im_group_message_topic_shards`
    DROP PRIMARY KEY,
    DROP INDEX `idx_im_group_message_topic_shards_seq`,
    DROP INDEX `idx_im_group_message_topic_shards_month`,
    ADD PRIMARY KEY (`tenant_id`, `topic`, `shard_month`),
    ADD INDEX `idx_im_group_message_topic_shards_seq` (`tenant_id`, `topic`, `max_seq`),
    ADD INDEX `idx_im_group_message_topic_shards_month` (`tenant_id`, `shard_month`, `topic`);

ALTER TABLE `im_group_message_dedup`
    DROP PRIMARY KEY,
    DROP INDEX `idx_im_group_message_dedup_topic_seq`,
    ADD PRIMARY KEY (`tenant_id`, `topic`, `from_user`, `client_msg_id`),
    ADD INDEX `idx_im_group_message_dedup_topic_seq` (`tenant_id`, `topic`, `seqid`);

-- 3. 创建好友与单聊消息分表并迁移现有数据。
CREATE TABLE IF NOT EXISTS `im_001_friendships` LIKE `im_friendships`;
ALTER TABLE `im_001_friendships` MODIFY `tenant_id` BIGINT NOT NULL DEFAULT 1 COMMENT '商户ID';
INSERT IGNORE INTO `im_001_friendships` SELECT * FROM `im_friendships` WHERE `tenant_id` = 1;

CREATE TABLE IF NOT EXISTS `im_001_messages` LIKE `im_messages`;
ALTER TABLE `im_001_messages` MODIFY `tenant_id` BIGINT NOT NULL DEFAULT 1 COMMENT '商户ID';
INSERT IGNORE INTO `im_001_messages` SELECT * FROM `im_messages` WHERE `tenant_id` = 1;

CREATE TABLE IF NOT EXISTS `im_002_friendships` LIKE `im_friendships`;
ALTER TABLE `im_002_friendships` MODIFY `tenant_id` BIGINT NOT NULL DEFAULT 2 COMMENT '商户ID';
INSERT IGNORE INTO `im_002_friendships` SELECT * FROM `meeting_im`.`im_friendships`;

CREATE TABLE IF NOT EXISTS `im_002_messages` LIKE `im_messages`;
ALTER TABLE `im_002_messages` MODIFY `tenant_id` BIGINT NOT NULL DEFAULT 2 COMMENT '商户ID';
INSERT IGNORE INTO `im_002_messages` SELECT * FROM `meeting_im`.`im_messages`;

-- 4. 迁移所有已存在的标准月表。过程只识别 im_group_messages_YYYYMM。
DELIMITER $$

DROP PROCEDURE IF EXISTS migrate_group_month_tables$$
CREATE PROCEDURE migrate_group_month_tables(IN source_schema VARCHAR(64), IN source_tenant BIGINT, IN tenant_code CHAR(3))
BEGIN
    DECLARE done INT DEFAULT 0;
    DECLARE source_table VARCHAR(64);
    DECLARE month_code CHAR(6);
    DECLARE target_table VARCHAR(64);
    DECLARE month_cursor CURSOR FOR
        SELECT table_name
        FROM information_schema.tables
        WHERE table_schema = source_schema
          AND table_name REGEXP '^im_group_messages_[0-9]{6}$';
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;

    OPEN month_cursor;
    month_loop: LOOP
        FETCH month_cursor INTO source_table;
        IF done = 1 THEN
            LEAVE month_loop;
        END IF;
        SET month_code = RIGHT(source_table, 6);
        SET target_table = CONCAT('im_', tenant_code, '_group_messages_', month_code);
        SET @create_sql = CONCAT('CREATE TABLE IF NOT EXISTS `tinode`.`', target_table,
                                 '` LIKE `', source_schema, '`.`', source_table, '`');
        PREPARE stmt FROM @create_sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;
        SET @alter_sql = CONCAT('ALTER TABLE `tinode`.`', target_table,
                                '` MODIFY `tenant_id` BIGINT NOT NULL DEFAULT ', source_tenant, ' COMMENT ''商户ID''');
        PREPARE stmt FROM @alter_sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;
        SET @copy_sql = CONCAT('INSERT IGNORE INTO `tinode`.`', target_table,
                               '` SELECT * FROM `', source_schema, '`.`', source_table,
                               '` WHERE `tenant_id`=', source_tenant);
        PREPARE stmt FROM @copy_sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;
    END LOOP;
    CLOSE month_cursor;
END$$

DELIMITER ;

CALL migrate_group_month_tables('tinode', 1, '001');
CALL migrate_group_month_tables('meeting_im', 2, '002');
DROP PROCEDURE IF EXISTS migrate_group_month_tables;

-- 旧的非月表数据按创建月份归入 1 号商户月表（本地现有数据为 202608）。
INSERT IGNORE INTO `im_001_group_messages_202608`
(`tenant_id`,`message_id`,`topic`,`group_id`,`seqid`,`from_user`,`client_msg_id`,`msg_type`,`status`,
 `content`,`content_nonce`,`key_version`,`head`,`mentioned_user_ids`,`mention_all`,`reply_seqid`,`root_seqid`,
 `file_count`,`content_size`,`has_risk`,`audit_status`,`version`,`recalled_at`,`recalled_by`,`deleted_at`,
 `expires_at`,`created_at`,`updated_at`)
SELECT 1,`id`,`topic`,`group_id`,`seqid`,`from_user`,`client_msg_id`,`msg_type`,`status`,
       `content`,`content_nonce`,`key_version`,`head`,`mentioned_user_ids`,`mention_all`,`reply_seqid`,`root_seqid`,
       `file_count`,`content_size`,`has_risk`,`audit_status`,`version`,`recalled_at`,`recalled_by`,`deleted_at`,
       `expires_at`,`created_at`,`updated_at`
FROM `im_group_messages`
WHERE `tenant_id` = 1 AND DATE_FORMAT(`created_at`, '%Y%m') = '202608';

-- 5. 修正 1 号商户路由，并合入 2 号商户路由元数据。
UPDATE `im_group_message_shards`
SET `table_name` = CONCAT('im_001_group_messages_', `shard_month`)
WHERE `tenant_id` = 1;

INSERT INTO `im_group_message_shards`
(`tenant_id`,`shard_month`,`table_name`,`shard_start`,`shard_end`,`status`,`row_count`,
 `min_created_at`,`max_created_at`,`created_at`,`updated_at`)
SELECT 2,`shard_month`,CONCAT('im_002_group_messages_', `shard_month`),`shard_start`,`shard_end`,`status`,
       `row_count`,`min_created_at`,`max_created_at`,`created_at`,`updated_at`
FROM `meeting_im`.`im_group_message_shards`
ON DUPLICATE KEY UPDATE `table_name`=VALUES(`table_name`),`status`=VALUES(`status`);

INSERT IGNORE INTO `im_group_message_topic_shards` SELECT * FROM `meeting_im`.`im_group_message_topic_shards`;
INSERT IGNORE INTO `im_group_message_dedup` SELECT * FROM `meeting_im`.`im_group_message_dedup`;

-- 旧非月表迁移后补齐 Topic 路由，并按物理表实际数据校准分片统计。
INSERT INTO `im_group_message_topic_shards`
(`tenant_id`,`topic`,`shard_month`,`min_seq`,`max_seq`,`message_count`,`min_created_at`,`max_created_at`)
SELECT 1,`topic`,'202608',MIN(`seqid`),MAX(`seqid`),COUNT(*),MIN(`created_at`),MAX(`created_at`)
FROM `im_001_group_messages_202608`
GROUP BY `topic`
ON DUPLICATE KEY UPDATE `min_seq`=VALUES(`min_seq`),`max_seq`=VALUES(`max_seq`),
`message_count`=VALUES(`message_count`),`min_created_at`=VALUES(`min_created_at`),`max_created_at`=VALUES(`max_created_at`);

UPDATE `im_group_message_shards` AS s
SET s.`row_count`=(SELECT COUNT(*) FROM `im_001_group_messages_202608`),
    s.`min_created_at`=(SELECT MIN(`created_at`) FROM `im_001_group_messages_202608`),
    s.`max_created_at`=(SELECT MAX(`created_at`) FROM `im_001_group_messages_202608`)
WHERE s.`tenant_id`=1 AND s.`shard_month`='202608';

-- 验证结果。
SELECT `sequence_name`,`next_id` FROM `hotgo`.`im_tenant_id_sequence`;
SELECT `table_name`,`table_rows`
FROM information_schema.tables
WHERE table_schema = 'tinode'
  AND table_name REGEXP '^im_[0-9]{3}_(friendships|messages|group_messages_[0-9]{6})$'
ORDER BY table_name;