-- +goose Up
-- Platform staff roles for least-privilege admin/support desk access.
-- NULL staff_role + is_platform_admin=true keeps legacy full-admin behavior.

ALTER TABLE users
  ADD COLUMN IF NOT EXISTS staff_role TEXT
    CHECK (staff_role IS NULL OR staff_role IN ('admin', 'developer', 'support_staff'));

CREATE INDEX IF NOT EXISTS users_staff_role_idx
  ON users (staff_role)
  WHERE staff_role IS NOT NULL;

COMMENT ON COLUMN users.staff_role IS
  'Platform staff role: admin|developer|support_staff. NULL with is_platform_admin=true = legacy full admin.';

-- Backfill existing platform admins to explicit admin role (idempotent).
UPDATE users
SET staff_role = 'admin', updated_at = now()
WHERE is_platform_admin = true AND staff_role IS NULL;

-- +goose Down
DROP INDEX IF EXISTS users_staff_role_idx;
ALTER TABLE users DROP COLUMN IF EXISTS staff_role;