BEGIN;

-- Step A: rename project 4 away from the canonical name first (still active).
UPDATE projects
SET name = '全自动冲击波治疗仪 (retired-4)',
    updated_at = now()
WHERE id = 4;

-- Step B: retire project 4.
UPDATE projects
SET status = 'demo_retired',
    updated_at = now()
WHERE id = 4;

-- Step C: restore project 5 canonical name.
UPDATE projects
SET name = '全自动冲击波治疗仪',
    updated_at = now()
WHERE id = 5;

-- Step D: fix session owners.
UPDATE chat_sessions SET user_id = 32, updated_at = now()
WHERE session_id = 'sess-p5-u32' AND project_id = 5 AND user_id = 4;

UPDATE chat_sessions SET user_id = 33, updated_at = now()
WHERE session_id = 'sess-p5-u33' AND project_id = 5 AND user_id = 4;

INSERT INTO chat_sessions (session_id, user_id, project_id, title, created_at, updated_at)
VALUES ('sess-p5-u35', 35, 5, '全自动冲击波治疗仪', now(), now())
ON CONFLICT (session_id) DO UPDATE SET
    user_id = EXCLUDED.user_id,
    project_id = EXCLUDED.project_id,
    title = COALESCE(NULLIF(EXCLUDED.title, ''), chat_sessions.title),
    updated_at = now();

COMMIT;

SELECT id, name, creator_user_id, status FROM projects WHERE id IN (4,5) ORDER BY id;
SELECT session_id, user_id, project_id FROM chat_sessions WHERE project_id=5 ORDER BY session_id;