BEGIN;

WITH active_todos AS (
  SELECT t.id, t.user_id, t.product_id, t.title, t.description, t.created_at
  FROM todos t
  WHERE t.done = false
    AND t.archived = false
    AND NOT EXISTS (
      SELECT 1 FROM ideas i
      WHERE i.user_id = t.user_id
        AND lower(trim(i.title)) = lower(trim(t.title))
    )
),
user_base AS (
  SELECT ut.user_id, u.idea_code_counter AS base_counter
  FROM (SELECT DISTINCT user_id FROM active_todos) ut
  JOIN users u ON u.id = ut.user_id
),
ranked AS (
  SELECT
    at.user_id, at.product_id, at.title, at.description, at.created_at,
    ub.base_counter,
    ROW_NUMBER() OVER (PARTITION BY at.user_id ORDER BY at.created_at, at.id) AS rn
  FROM active_todos at
  JOIN user_base ub ON ub.user_id = at.user_id
),
inserted AS (
  INSERT INTO ideas (
    id, user_id, product_id, code, title, description,
    status, archived, created_at, updated_at
  )
  SELECT
    gen_random_uuid()::text,
    user_id,
    product_id,
    'IDEA-' || lpad((base_counter + rn)::text, 3, '0'),
    title,
    description,
    'DRAFT',
    false,
    created_at,
    now()
  FROM ranked
  RETURNING user_id,
    (regexp_replace(code, '^IDEA-0*', ''))::int AS used_counter
)
UPDATE users u
SET idea_code_counter = sub.max_counter
FROM (
  SELECT user_id, MAX(used_counter) AS max_counter
  FROM inserted
  GROUP BY user_id
) sub
WHERE u.id = sub.user_id
  AND sub.max_counter > u.idea_code_counter;

DROP TABLE todos;

COMMIT;