// Attempt lifecycle — the Phase 3B core. One scenario_attempts row per continuous working
// session on a scenario (not per validation click, see migrations/012). Every mutation here
// updates that one row in place; nothing is ever inserted twice for the same open attempt.
//
// Phase 4.1 (docs/PHASE4_1_PREPRODUCTION_HARDENING.md §13) added real abandonment handling —
// see abandonAttempt/abandonOpenAttemptsFor* below and their call sites (environment
// destroy/reset in server.js and admin-routes.js, logout in server.js, the session sweeper in
// sessions.js, and the "different scenario" transition inline in getOrCreateOpenAttempt just
// below). Still deliberately NOT a new standalone background job — every trigger either rides
// an existing request handler or the session sweeper that already runs periodically.

// An attempt is never silently deleted or marked as a failure by abandonment — result stays
// NULL, the row stays queryable, instructors see "abandoned (reason)" as a real, honest status
// rather than a punitive one. No-op (and does not overwrite an existing abandoned_reason) if
// the attempt is already terminal.
async function abandonAttempt(pool, attemptId, reason) {
  const { rows } = await pool.query(
    `UPDATE scenario_attempts SET status = 'abandoned', abandoned_at = now(), abandoned_reason = $2
     WHERE attempt_id = $1 AND status = 'in_progress' RETURNING *`,
    [attemptId, reason]
  );
  return rows[0] || null;
}

// Trigger: environment destroyed (idle reaper, student reset, admin reset/destroy — see
// server.js's student reset route and admin-routes.js's reset/destroy routes, all of which
// call this right after telling the Provisioner to tear the environment down). A reset creates
// a fresh environment_id in some flows and reuses the same one in others (see
// provisioner lifecycle.js's reset — same environment_id, fresh container) — either way, any
// attempt still open against the OLD container state is honestly "not going to be resumed as
// the same working session," so it's abandoned rather than left open indefinitely.
async function abandonOpenAttemptsForEnvironment(pool, environmentId) {
  const { rows } = await pool.query(
    `UPDATE scenario_attempts SET status = 'abandoned', abandoned_at = now(), abandoned_reason = 'environment_destroyed'
     WHERE environment_id = $1 AND status = 'in_progress' RETURNING attempt_id`,
    [environmentId]
  );
  return rows.length;
}

// Trigger: logout (server.js POST /api/logout) and the session sweeper's periodic pass for
// students whose sessions have all expired (sessions.js). Deliberately student-scoped, not
// environment-scoped — a student can log out while their Lab keeps running (it isn't
// destroyed until reaped or explicitly ended), but the WORKING SESSION on whatever scenario
// they had open is over the moment they're no longer authenticated to record more progress on it.
async function abandonOpenAttemptsForStudent(pool, studentId) {
  const { rows } = await pool.query(
    `UPDATE scenario_attempts SET status = 'abandoned', abandoned_at = now(), abandoned_reason = 'session_ended'
     WHERE student_id = $1 AND status = 'in_progress' RETURNING attempt_id`,
    [studentId]
  );
  return rows.length;
}

async function getOrCreateOpenAttempt(pool, { studentId, scenarioId, environmentId, cohortId, curriculumStage, assessmentSessionId }) {
  const { rows: existing } = await pool.query(
    `SELECT * FROM scenario_attempts
     WHERE student_id = $1 AND scenario_id = $2 AND environment_id = $3 AND status = 'in_progress'
     ORDER BY started_at DESC LIMIT 1`,
    [studentId, scenarioId, environmentId]
  );
  if (existing[0]) return existing[0];

  // Trigger: student starts a different scenario while a previous one is still open (started
  // via /start or implicitly via /validate, never finished). Only one scenario is "the one
  // currently being worked on" per student+environment at a time from the app's own UX, so an
  // open attempt on ANY OTHER scenario in this same environment is abandoned before the new
  // one is created — never silently left as a phantom "still in progress" row.
  await pool.query(
    `UPDATE scenario_attempts SET status = 'abandoned', abandoned_at = now(), abandoned_reason = 'scenario_switched'
     WHERE student_id = $1 AND environment_id = $2 AND scenario_id != $3 AND status = 'in_progress'`,
    [studentId, environmentId, scenarioId]
  );

  const { rows } = await pool.query(
    `INSERT INTO scenario_attempts
       (student_id, scenario_id, environment_id, cohort_id, curriculum_stage, started_at, status, assessment_session_id)
     VALUES ($1, $2, $3, $4, $5, now(), 'in_progress', $6)
     RETURNING *`,
    [studentId, scenarioId, environmentId, cohortId || null, curriculumStage || null, assessmentSessionId || null]
  );
  return rows[0];
}

// Records one validation outcome against the currently open attempt (creating one first if
// none exists — a student can hit Validate without an explicit "start" call ever having fired,
// e.g. if the frontend missed it; this stays correct either way). Closes the attempt on a pass.
async function recordValidation(pool, ctx, passed) {
  const attempt = await getOrCreateOpenAttempt(pool, ctx);
  const now = new Date();
  if (passed) {
    const durationSeconds = attempt.started_at ? Math.max(0, Math.round((now - new Date(attempt.started_at)) / 1000)) : null;
    const { rows } = await pool.query(
      `UPDATE scenario_attempts SET
         validation_attempt_count = validation_attempt_count + 1,
         validation_pass_count = validation_pass_count + 1,
         status = 'completed', result = 'passed', completed_at = now(), duration_seconds = $2
       WHERE attempt_id = $1 RETURNING *`,
      [attempt.attempt_id, durationSeconds]
    );
    return rows[0];
  }
  const { rows } = await pool.query(
    `UPDATE scenario_attempts SET
       validation_attempt_count = validation_attempt_count + 1,
       validation_fail_count = validation_fail_count + 1
     WHERE attempt_id = $1 RETURNING *`,
    [attempt.attempt_id]
  );
  return rows[0];
}

// Reveals the next hint, sequentially — level N can only be revealed once level N-1 has been.
// Returns null if the requested reveal is out of order (caller treats that as a 409/400) or if
// there are no more hints left.
async function recordHintReveal(pool, ctx, totalHints) {
  const attempt = await getOrCreateOpenAttempt(pool, ctx);
  const nextLevel = attempt.highest_hint_level + 1;
  if (nextLevel > totalHints) return { ok: false, reason: 'no_more_hints', attempt };
  const { rows } = await pool.query(
    `UPDATE scenario_attempts SET hint_count = hint_count + 1, highest_hint_level = $2
     WHERE attempt_id = $1 RETURNING *`,
    [attempt.attempt_id, nextLevel]
  );
  return { ok: true, level: nextLevel, attempt: rows[0] };
}

async function getAttemptSummary(pool, { studentId, scenarioId, environmentId }) {
  const { rows } = await pool.query(
    `SELECT * FROM scenario_attempts
     WHERE student_id = $1 AND scenario_id = $2 AND ($3::uuid IS NULL OR environment_id = $3)
     ORDER BY started_at DESC LIMIT 1`,
    [studentId, scenarioId, environmentId || null]
  );
  return rows[0] || null;
}

module.exports = {
  getOrCreateOpenAttempt, recordValidation, recordHintReveal, getAttemptSummary,
  abandonAttempt, abandonOpenAttemptsForEnvironment, abandonOpenAttemptsForStudent,
};