export function readEnvValue(envRaw, key) {
  for (const line of String(envRaw ?? '').split('\n')) {
    const trimmed = line.trim();
    if (!trimmed || trimmed.startsWith('#')) continue;
    const idx = trimmed.indexOf('=');
    if (idx < 0) continue;
    const envKey = trimmed.slice(0, idx).trim();
    if (envKey !== key) continue;
    let value = trimmed.slice(idx + 1).trim();
    if ((value.startsWith('"') && value.endsWith('"')) || (value.startsWith("'") && value.endsWith("'"))) {
      value = value.slice(1, -1);
    }
    return value;
  }
  return null;
}

export function isGuardPaused(envRaw) {
  const value = readEnvValue(envRaw, 'MEMIND_AGENT_CODE_RUNS_ENABLED');
  return value != null && String(value).trim() === '0';
}

export function evaluateHealth(queue) {
  const positiveInt = (value, fallback) => {
    const parsed = Number(value);
    return Number.isFinite(parsed) && parsed > 0 ? Math.floor(parsed) : fallback;
  };
  const thresholds = {
    maxRecentFailures: positiveInt(process.env.MEMIND_AGENT_RUN_GUARD_MAX_RECENT_FAILURES, 3),
    maxPendingAgeMs: positiveInt(process.env.MEMIND_AGENT_RUN_GUARD_MAX_PENDING_AGE_MS, 5 * 60 * 1000),
    maxPendingCount: positiveInt(process.env.MEMIND_AGENT_RUN_GUARD_MAX_PENDING_COUNT, 10),
    maxRunningAgeMs: positiveInt(process.env.MEMIND_AGENT_RUN_GUARD_MAX_RUNNING_AGE_MS, 15 * 60 * 1000),
  };
  const reasons = [];
  if (queue.failedRecentCount >= thresholds.maxRecentFailures) {
    reasons.push(`recent_failed_count ${queue.failedRecentCount} >= ${thresholds.maxRecentFailures}`);
  }
  if (queue.oldestPendingAgeMs >= thresholds.maxPendingAgeMs) {
    reasons.push(`oldest_pending_age_ms ${queue.oldestPendingAgeMs} >= ${thresholds.maxPendingAgeMs}`);
  }
  if (queue.queuedOrRetryable >= thresholds.maxPendingCount) {
    reasons.push(`pending_count ${queue.queuedOrRetryable} >= ${thresholds.maxPendingCount}`);
  }
  if (queue.oldestRunningHeartbeatAgeMs >= thresholds.maxRunningAgeMs) {
    reasons.push(`oldest_running_heartbeat_age_ms ${queue.oldestRunningHeartbeatAgeMs} >= ${thresholds.maxRunningAgeMs}`);
  }
  return { thresholds, reasons, shouldPause: reasons.length > 0 };
}

export function buildPausePlan({ shouldPause, envRaw, dryRun }) {
  if (!shouldPause) {
    return {
      action: 'none',
      alreadyPaused: isGuardPaused(envRaw),
      applied: false,
      actions: ['skip_pause: queue healthy'],
    };
  }
  if (isGuardPaused(envRaw)) {
    return {
      action: 'skip',
      alreadyPaused: true,
      applied: false,
      actions: dryRun
        ? ['would skip pause: MEMIND_AGENT_CODE_RUNS_ENABLED already 0']
        : ['skip_pause: MEMIND_AGENT_CODE_RUNS_ENABLED already 0'],
    };
  }
  return {
    action: 'apply',
    alreadyPaused: false,
    applied: false,
    actions: dryRun
      ? ['would apply first-time pause']
      : ['apply_pause: first trigger'],
  };
}