-- Junction / mapping tables get a table-local AUTO_INCREMENT row id.
-- Business uniqueness stays UNIQUE (same columns as the old composite PK).
-- Snowflake PKs (t_users / t_messages / t_conversations / moments posts) are unchanged.

ALTER TABLE t_user_emails
    DROP PRIMARY KEY,
    ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT COMMENT '行 id，表内自增，仅内部用；业务唯一键是 email' FIRST,
    ADD PRIMARY KEY (id),
    ADD UNIQUE KEY uk_email (email);

ALTER TABLE t_p2p_conversations
    DROP PRIMARY KEY,
    ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT COMMENT '行 id，表内自增，仅内部用；业务唯一键是 (user_small, user_big)' FIRST,
    ADD PRIMARY KEY (id),
    ADD UNIQUE KEY uk_p2p_users (user_small, user_big);

ALTER TABLE t_conversation_members
    DROP PRIMARY KEY,
    ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT COMMENT '行 id，表内自增，仅内部用；业务唯一键是 (conversation_id, user_id)' FIRST,
    ADD PRIMARY KEY (id),
    ADD UNIQUE KEY uk_conversation_members (conversation_id, user_id);

ALTER TABLE t_device_sync_cursors
    DROP PRIMARY KEY,
    ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT COMMENT '行 id，表内自增，仅内部用；业务唯一键是 (user_id, device_id)' FIRST,
    ADD PRIMARY KEY (id),
    ADD UNIQUE KEY uk_user_device (user_id, device_id);

ALTER TABLE t_group_members
    DROP PRIMARY KEY,
    ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT COMMENT '行 id，表内自增，仅内部用；业务唯一键是 (group_id, user_id)' FIRST,
    ADD PRIMARY KEY (id),
    ADD UNIQUE KEY uk_group_members (group_id, user_id);

ALTER TABLE t_message_deletes
    DROP PRIMARY KEY,
    ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT COMMENT '行 id，表内自增，仅内部用；业务唯一键是 (user_id, msg_id)' FIRST,
    ADD PRIMARY KEY (id),
    ADD UNIQUE KEY uk_user_msg (user_id, msg_id);

ALTER TABLE t_moment_audience
    DROP PRIMARY KEY,
    ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT COMMENT '行 id，表内自增，仅内部用；业务唯一键是 (post_id, peer_id)' FIRST,
    ADD PRIMARY KEY (id),
    ADD UNIQUE KEY uk_post_peer (post_id, peer_id);

ALTER TABLE t_moment_likes
    DROP PRIMARY KEY,
    ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT COMMENT '行 id，表内自增，仅内部用；业务唯一键是 (post_id, user_id)' FIRST,
    ADD PRIMARY KEY (id),
    ADD UNIQUE KEY uk_post_user (post_id, user_id);

ALTER TABLE t_moment_settings
    DROP PRIMARY KEY,
    ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT COMMENT '行 id，表内自增，仅内部用；业务唯一键是 user_id' FIRST,
    ADD PRIMARY KEY (id),
    ADD UNIQUE KEY uk_user_id (user_id);

ALTER TABLE t_moment_hides
    DROP PRIMARY KEY,
    ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT COMMENT '行 id，表内自增，仅内部用；业务唯一键是 (user_id, peer_id)' FIRST,
    ADD PRIMARY KEY (id),
    ADD UNIQUE KEY uk_user_peer (user_id, peer_id);