-- scenario_attempts — new capability, did not exist before Phase 2B. The old model only ever
-- kept aggregate progress (status + a bare attempts counter); this is a per-attempt log,
-- giving instructors real "validation outcomes where recorded" visibility instead of just a
-- final status.
--
-- hint_count is deliberately nullable and unpopulated: the existing Lab engine's hints are
-- static UI content only (frontend/src/components/ScenarioPanel.jsx renders them from the
-- scenario JSON) — nothing server-side ever records a hint being viewed. Do not invent a
-- number here. If hint-view tracking is added to the Lab engine later, this column is ready
-- for it without a schema change.

CREATE TABLE IF NOT EXISTS scenario_attempts (
  attempt_id        BIGSERIAL PRIMARY KEY,
  student_id        TEXT NOT NULL REFERENCES students(student_id),
  scenario_id       TEXT NOT NULL,
  environment_id    UUID REFERENCES environments(environment_id),
  started_at        TIMESTAMPTZ,
  completed_at      TIMESTAMPTZ,
  result            TEXT NOT NULL,          -- 'passed' | 'failed'
  validation_count  INTEGER,                -- number of validation checks run this attempt
  hint_count        INTEGER,                -- NULL — not measurable today, see note above
  metadata          JSONB,
  created_at        TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE INDEX IF NOT EXISTS idx_attempts_student ON scenario_attempts(student_id);
CREATE INDEX IF NOT EXISTS idx_attempts_scenario ON scenario_attempts(scenario_id);
CREATE INDEX IF NOT EXISTS idx_attempts_environment ON scenario_attempts(environment_id);
CREATE INDEX IF NOT EXISTS idx_attempts_created ON scenario_attempts(created_at);