/**
 * report.js — human-readable summary generator + severity logic
 */

/**
 * Compute severity for a parsed provider result.
 * @param {Object} provider
 * @returns {'critical'|'warning'|'ok'|'unknown'}
 */
export function getSeverity(provider) {
  if (provider.type === 'teams-direct') {
    if (provider.status === 'rejected') return 'critical';
    if (provider.status === 'policy_rejected') return 'critical';
    if (provider.utilization_7d > 0.85) return 'warning';
    if (provider.utilization_5h > 0.7) return 'warning';
    return 'ok';
  }
  if (provider.type === 'shelley-proxy') {
    const tokenPct = 1 - (provider.tokens_remaining / provider.tokens_limit);
    if (tokenPct > 0.85) return 'warning';
    return 'ok';
  }
  if (provider.type === 'gemini-api') {
    if (provider.status === 'exhausted') return 'critical';
    if (provider.status === 'ok') return 'ok';
    return 'unknown';
  }
  if (provider.type === 'xai-api') {
    if (provider.status === 'rate_limited') return 'critical';
    if (provider.status === 'ok') {
      const reqPct = provider.requests_remaining / provider.requests_limit;
      const tokPct = provider.tokens_remaining / provider.tokens_limit;
      if ((reqPct < 0.1) || (tokPct < 0.1)) return 'warning';
      return 'ok';
    }
    return 'unknown';
  }
  return 'unknown';
}

/**
 * Format seconds as "Xh Ym" or "Xm" or "Xs".
 */
function formatDuration(seconds) {
  if (seconds == null || isNaN(seconds) || seconds < 0) return '?';
  const h = Math.floor(seconds / 3600);
  const m = Math.floor((seconds % 3600) / 60);
  const s = seconds % 60;
  if (h > 0) return `${h}h ${m}m`;
  if (m > 0) return `${m}m`;
  return `${s}s`;
}

/**
 * Format a float as a percentage string.
 */
function pct(v) {
  if (v == null) return '?';
  return `${Math.round(v * 100)}%`;
}

/**
 * Severity badge string.
 */
function badge(severity) {
  switch (severity) {
    case 'critical': return '[CRITICAL]';
    case 'warning':  return '[WARNING] ';
    case 'ok':       return '[OK]      ';
    default:         return '[UNKNOWN] ';
  }
}

/**
 * Generate a human-readable summary from a full monitor result.
 * @param {Object} result — { timestamp, providers: { name: {...} } }
 * @returns {string}
 */
export function generateReport(result) {
  const ts = result.timestamp
    ? result.timestamp.replace('T', ' ').replace(/\.\d+Z$/, ' UTC').replace('Z', ' UTC')
    : new Date().toUTCString();

  const lines = [];
  const width = 60;

  lines.push(`Token Monitor — ${ts}`);
  lines.push('═'.repeat(width));
  lines.push('');

  const counts = { critical: 0, warning: 0, ok: 0, unknown: 0 };

  for (const [name, p] of Object.entries(result.providers)) {
    const sev = p.severity || getSeverity(p);
    counts[sev] = (counts[sev] || 0) + 1;

    const b = badge(sev);
    let detail = '';

    if (p.type === 'teams-direct') {
      if (p.status === 'invalid_key') {
        detail = 'Invalid API key (401)';
      } else if (p.status === 'policy_rejected') {
        detail = `POLICY BLOCKED — 7d: ${pct(p.utilization_7d)} | extra-usage billing required`;
      } else if (p.status === 'rejected') {
        const resetIn = formatDuration(p.reset_in_seconds);
        detail = `MAXED — 7d: ${pct(p.utilization_7d)} | resets in ${resetIn}`;
      } else {
        detail = `5h: ${pct(p.utilization_5h)} | 7d: ${pct(p.utilization_7d)}`;
        if (p.reset_in_seconds != null) {
          detail += ` | resets in ${formatDuration(p.reset_in_seconds)}`;
        }
      }
    } else if (p.type === 'shelley-proxy') {
      if (p.status === 'error') {
        detail = `Error: ${p.message || 'unknown'}`;
      } else {
        detail = `tokens: ${p.tokens_remaining?.toLocaleString()}/${p.tokens_limit?.toLocaleString()}`;
        if (p.cost_per_call_usd != null) {
          detail += ` | cost: $${p.cost_per_call_usd}/call`;
        }
      }
    } else if (p.type === 'api-direct') {
      detail = p.message || 'No billing data available';
    } else if (p.type === 'gemini-api') {
      if (p.status === 'invalid_key') {
        detail = 'Invalid API key (401)';
      } else if (p.status === 'no_key') {
        detail = 'No API key configured';
      } else if (p.status === 'exhausted') {
        const retryIn = p.retry_delay_seconds ? formatDuration(p.retry_delay_seconds) : '?';
        const violated = p.quota_violations?.length || 0;
        detail = `EXHAUSTED — retry in ${retryIn} | ${violated} quota(s) violated`;
      } else if (p.status === 'ok') {
        detail = 'Reachable — no quota depth visible';
      } else if (p.status === 'error') {
        detail = `Error: ${p.message || 'unknown'}`;
      }
    } else if (p.type === 'xai-api') {
      if (p.status === 'no_key') {
        detail = 'No API key configured';
      } else if (p.status === 'invalid_key') {
        detail = 'Invalid API key (401)';
      } else if (p.status === 'rate_limited') {
        detail = 'Rate limited (429)';
      } else if (p.status === 'ok') {
        const reqPct = p.requests_limit ? `${p.requests_remaining}/${p.requests_limit} req` : '';
        const tokPct = p.tokens_limit ? ` | ${p.tokens_remaining?.toLocaleString()}/${p.tokens_limit?.toLocaleString()} tok` : '';
        detail = reqPct + tokPct || 'OK';
      } else if (p.status === 'error') {
        detail = `Error: ${p.message || 'unknown'}`;
      }
    } else {
      detail = p.message || '';
    }

    // Pad provider name to 14 chars
    const paddedName = name.padEnd(14);
    lines.push(`${paddedName}  ${b}  ${detail}`);
  }

  lines.push('');
  lines.push('─'.repeat(width));

  const parts = [];
  if (counts.critical) parts.push(`${counts.critical} CRITICAL`);
  if (counts.warning)  parts.push(`${counts.warning} WARNING`);
  if (counts.ok)       parts.push(`${counts.ok} OK`);
  if (counts.unknown)  parts.push(`${counts.unknown} UNKNOWN`);
  lines.push(`Overall: ${parts.join(', ') || 'no providers'}`);
  lines.push('');

  return lines.join('\n');
}