-- IM group-message monthly sharding, baseline month: 2026-09 (UTC).
-- Run in each tenant database. The application pre-creates subsequent months.

CREATE TABLE IF NOT EXISTS im_group_message_shards (
  shard_month CHAR(6) NOT NULL,
  table_name VARCHAR(64) NOT NULL,
  shard_start DATETIME(3) NOT NULL,
  shard_end DATETIME(3) NOT NULL,
  status VARCHAR(16) NOT NULL DEFAULT 'prepared',
  row_count BIGINT NOT NULL DEFAULT 0,
  min_created_at DATETIME(3) NULL,
  max_created_at DATETIME(3) NULL,
  created_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
  updated_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3) ON UPDATE CURRENT_TIMESTAMP(3),
  PRIMARY KEY (shard_month),
  UNIQUE KEY uk_im_group_message_shards_table (table_name),
  KEY idx_im_group_message_shards_status (status, shard_month)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

DROP TABLE IF EXISTS im_group_message_topic_shards;

DROP TABLE IF EXISTS im_group_message_dedup;

CREATE TABLE IF NOT EXISTS im_group_messages_202609 (
  message_id BIGINT NOT NULL,
  topic VARCHAR(64) NOT NULL,
  group_id BIGINT NOT NULL,
  seqid BIGINT NOT NULL,
  from_user BIGINT NOT NULL,
  client_msg_id VARCHAR(64) NULL,
  msg_type VARCHAR(32) NOT NULL DEFAULT 'text',
  status VARCHAR(32) NOT NULL DEFAULT 'normal',
  content JSON NULL,
  head JSON NULL,
  mentioned_user_ids JSON NULL,
  mention_all TINYINT(1) NOT NULL DEFAULT 0,
  reply_seqid BIGINT NULL,
  root_seqid BIGINT NULL,
  file_count INT NOT NULL DEFAULT 0,
  content_size INT NOT NULL DEFAULT 0,
  has_risk TINYINT(1) NOT NULL DEFAULT 0,
  audit_status VARCHAR(32) NOT NULL DEFAULT 'pass',
  version INT NOT NULL DEFAULT 1,
  recalled_at DATETIME(3) NULL,
  recalled_by BIGINT NULL,
  deleted_at DATETIME(3) NULL,
  expires_at DATETIME(3) NULL,
  created_at DATETIME(3) NOT NULL,
  updated_at DATETIME(3) NOT NULL,
  PRIMARY KEY (message_id),
  UNIQUE KEY uk_202609_group_seq (group_id, seqid),
  UNIQUE KEY uk_202609_topic_seq (topic, seqid),
  UNIQUE KEY uk_202609_sender_client (topic, from_user, client_msg_id),
  KEY idx_202609_group_status_seq (group_id, status, seqid),
  KEY idx_202609_topic_created (topic, created_at),
  KEY idx_202609_topic_from_seq (topic, from_user, seqid),
  KEY idx_202609_audit_created (audit_status, created_at),
  KEY idx_202609_expires (expires_at)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

CREATE TABLE IF NOT EXISTS im_group_messages_202608 LIKE im_group_messages_202609;
CREATE TABLE IF NOT EXISTS im_group_messages_202610 LIKE im_group_messages_202609;
CREATE TABLE IF NOT EXISTS im_group_messages_202611 LIKE im_group_messages_202609;

INSERT INTO im_group_message_shards
  (shard_month,table_name,shard_start,shard_end,status)
VALUES
  ('202608','im_group_messages_202608','2026-08-01 00:00:00.000','2026-09-01 00:00:00.000','sealing'),
  ('202609','im_group_messages_202609','2026-09-01 00:00:00.000','2026-10-01 00:00:00.000','writable'),
  ('202610','im_group_messages_202610','2026-10-01 00:00:00.000','2026-11-01 00:00:00.000','prepared'),
  ('202611','im_group_messages_202611','2026-11-01 00:00:00.000','2026-12-01 00:00:00.000','prepared')
ON DUPLICATE KEY UPDATE
  table_name=VALUES(table_name),
  shard_start=VALUES(shard_start),
  shard_end=VALUES(shard_end),
  status=IF(status IN ('sealed','archived'),status,VALUES(status));

-- Historical migration is deliberately separate from schema deployment.
-- Backfill im_group_messages into the matching month table in bounded batches,
-- then warm Redis topic routes before removing legacy reads.