-- Abandoned/interrupted attempt handling — Phase 4.1, docs/PHASE4_1_PREPRODUCTION_HARDENING.md
-- §13. 'abandoned' was already a valid scenario_attempts.status value (migration 012's CHECK
-- constraint) but nothing ever set it — an attempt left open when a Lab was reaped, an
-- environment destroyed, a session ended, or a student moved on to a different scenario just
-- stayed 'in_progress' forever, an honest but incomplete signal. This is NOT an academic
-- failure marker — an abandoned attempt has no `result`, doesn't count against the student,
-- and the row is never deleted (see src/attempts.js abandonAttempt for the enforcement of
-- that). It exists so instructor views and needs-attention logic can tell "still working" from
-- "stopped, for a reason we know."

ALTER TABLE scenario_attempts ADD COLUMN IF NOT EXISTS abandoned_at TIMESTAMPTZ;
ALTER TABLE scenario_attempts ADD COLUMN IF NOT EXISTS abandoned_reason TEXT;

DO $$ BEGIN
  ALTER TABLE scenario_attempts ADD CONSTRAINT scenario_attempts_abandoned_reason_check
    CHECK (abandoned_reason IS NULL OR abandoned_reason IN
      ('environment_destroyed', 'session_ended', 'scenario_switched'));
EXCEPTION
  WHEN duplicate_object THEN NULL;
END $$;