// Ops Alerts panel: firing/pending Grafana alert rules (`devdesk attach --alerts`),
// the Proxmox guest or node each is about (CT id, the node it runs on now), and
// an "Ask Claude" button that starts an investigation in a session of its own
// (devdesk#39).

import { el } from './dom.js';
import { slugify } from './protocol.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`;
}

// "CT 110 draupnir · monitor-02 · stopped", "node compute-storage-01".
function targetLabel(t) {
  if (t.kind === 'unknown') return null;
  const what = t.kind === 'node' ? `node ${t.name}` : `${t.kind.toUpperCase()} ${t.id} ${t.name}`;
  const parts = [what, t.kind === 'node' ? null : t.node, t.status === 'running' || t.status === 'online' ? null : t.status];
  return parts.filter(Boolean).join(' · ') + (t.by === 'name' ? ' (by name)' : '');
}

function targetTitle(t) {
  const how = t.kind === 'ct' ? `ssh ${t.node} pct exec ${t.id} -- …`
    : t.kind === 'vm' ? `ssh ${t.node} qm guest exec ${t.id} -- …` : `ssh ${t.name}`;
  const note = t.by === 'name' ? '\nMatched by name, not by IP (the guest has not been seen running with this IP).'
    : t.ip_seen ? '\nIts IP when it was last seen running.' : '';
  return `${how}${t.ha ? `\nHA state: ${t.ha}` : ''}${note}`;
}

export const alertSession = (alert) => slugify(`alert-${alert.name}`).toLowerCase().slice(0, 48) || 'alert';

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} / ${a.group}` }, a.name),
      el('span', { class: 'dd-muted dd-alert-age' }, age(a.since))),
    a.instances?.length ? el('div', { class: 'dd-muted dd-alert-instances' }, a.instances.join(' · ')) : null,
    ...(a.targets ?? []).map((t) => {
      const label = targetLabel(t);
      return label ? el('div', { class: `dd-alert-where${t.by === 'name' ? ' is-guess' : ''}`, title: targetTitle(t) }, label) : 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-investigate': a.uid, 'data-session': alertSession(a),
        title: `Start Claude in a new session (${alertSession(a)}) on this alert, with the rule, the query and where it runs (CT id, node)`,
      }, 'Ask Claude')))));
}