ALTER TABLE assignments
  ADD COLUMN IF NOT EXISTS title TEXT,
  ADD COLUMN IF NOT EXISTS sequence JSONB NOT NULL DEFAULT '[]'::jsonb;

CREATE TABLE IF NOT EXISTS assignment_step_progress (
  assignment_id BIGINT NOT NULL REFERENCES assignments(id) ON DELETE CASCADE,
  pupil_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
  step_id TEXT NOT NULL,
  completed_at TIMESTAMPTZ NOT NULL DEFAULT now(),
  PRIMARY KEY (assignment_id, pupil_id, step_id)
);

CREATE INDEX IF NOT EXISTS idx_assignment_step_progress_pupil
  ON assignment_step_progress (pupil_id, assignment_id);

ALTER TABLE users
  ADD COLUMN IF NOT EXISTS reward_points INTEGER NOT NULL DEFAULT 0;

CREATE TABLE IF NOT EXISTS user_avatar_rewards (
  user_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
  reward_key TEXT NOT NULL,
  unlocked_at TIMESTAMPTZ NOT NULL DEFAULT now(),
  PRIMARY KEY (user_id, reward_key)
);