// Ops Alerts panel: firing/pending Grafana alert rules (`devdesk attach --alerts`),
// each with an "Ask Claude" button that types an investigation prompt into the
// current session (without pressing Enter).

import { el } from './dom.js';

const SEVERITY = {
  critical: 'lt-chip-critical',
  warning: 'lt-chip-warn',
};

function age(iso) {
  const t = Date.parse(iso || '');
  if (Number.isNaN(t)) return '';
  const s = Math.max(0, (Date.now() - t) / 1000);
  if (s < 3600) return `${Math.max(1, Math.floor(s / 60))}m`;
  if (s < 86400) return `${Math.floor(s / 3600)}h`;
  return `${Math.floor(s / 86400)}d`;
}

export function investigatePrompt(alert) {
  const where = alert.instances?.length ? ` on ${alert.instances.join('; ')}` : '';
  return `Investigate the ${alert.state} Grafana alert "${alert.name}"`
    + ` (${alert.severity || 'no severity'}, ${alert.folder} / ${alert.group}${where}, since ${alert.since}).`
    + ` Summary: ${alert.summary || 'n/a'}. Use the grafana MCP server to look at the rule and the related`
    + ' metrics, find the cause, and tell me what you would change before changing anything.';
}

export function renderAlerts(root, data) {
  const list = root.querySelector('.dd-alert-list');
  const note = root.querySelector('.dd-alerts-note');
  const count = root.querySelector('.dd-alert-count');
  const alerts = data?.alerts ?? [];
  count.textContent = alerts.length ? String(alerts.length) : '';
  count.className = `lt-badge lt-badge-sm dd-alert-count${alerts.some((a) => a.severity === 'critical') ? ' lt-badge-p1' : alerts.length ? ' lt-badge-p2' : ''}`;

  if (!data) {
    root.dataset.state = 'empty';
    list.replaceChildren(el('li', { class: 'dd-empty' }, 'Loading…'));
    note.textContent = '';
    return;
  }
  if (!data.configured) {
    root.dataset.state = 'empty';
    list.replaceChildren(el('li', { class: 'dd-empty' }, 'Grafana is not configured.'));
    note.textContent = 'Set DEVDESK_GRAFANA_URL and a token file in /etc/devdesk/env.local.';
    return;
  }
  root.dataset.state = 'live';
  note.textContent = data.error ? `Grafana unreachable: ${data.error}` : '';
  if (!alerts.length) {
    list.replaceChildren(el('li', { class: 'dd-all-clear' },
      el('span', { class: 'lt-dot lt-dot-up' }), data.error ? 'No data' : 'All clear: nothing firing'));
    return;
  }
  list.replaceChildren(...alerts.map((a) => el('li', { class: `dd-alert is-${a.state}` },
    el('div', { class: 'dd-alert-head' },
      el('span', { class: `lt-chip ${SEVERITY[a.severity] || 'lt-chip-info'}` }, a.state === 'pending' ? 'pending' : (a.severity || 'alert')),
      el('a', { class: 'dd-alert-name', href: a.url, target: '_blank', rel: 'noopener', title: `${a.folder} / ${a.group}` }, a.name),
      el('span', { class: 'dd-muted dd-alert-age' }, age(a.since))),
    a.instances?.length ? el('div', { class: 'dd-muted dd-alert-instances' }, a.instances.join(' · ')) : null,
    a.summary ? el('div', { class: 'dd-alert-summary' }, a.summary) : null,
    el('div', { class: 'dd-ask-row' },
      el('button', { type: 'button', class: 'lt-btn lt-btn-sm dd-ask', 'data-ask-claude': investigatePrompt(a), title: 'Type the prompt into the current session (not sent)' }, 'Ask Claude'),
      el('button', {
        type: 'button', class: 'lt-btn lt-btn-ghost lt-btn-sm dd-ask', 'data-ask-claude': investigatePrompt(a),
        'data-ask-session': `alert-${a.name}`, title: 'Open a separate ops session for this alert and type the prompt there (not sent)',
      }, 'In a new session')))));
}