// Claude Context panel: the current session's model, context-window use, cost
// and edits, from the snapshot devdesk-statusline writes on every Claude update.

import { ago } from './sessions.js';

function compact(tokens) {
  if (tokens == null) return '—';
  if (tokens >= 1e6) return `${+(tokens / 1e6).toFixed(tokens % 1e6 ? 1 : 0)}M`;
  if (tokens >= 1e3) return `${Math.round(tokens / 1e3)}k`;
  return String(tokens);
}

export function renderContext(root, session, context) {
  const set = (field, text) => {
    const node = root.querySelector(`[data-field="${field}"]`);
    if (node) node.textContent = text;
  };
  const bar = root.querySelector('.lt-progress');
  const fill = root.querySelector('.lt-progress-bar');
  const note = root.querySelector('.dd-context-note');

  if (!context) {
    root.dataset.state = 'empty';
    fill.style.width = '0%';
    bar.setAttribute('aria-valuenow', '0');
    for (const f of ['used', 'model', 'cost', 'lines', 'updated']) set(f, '—');
    note.textContent = session
      ? 'No data yet: it appears once Claude has redrawn its status line in this session.'
      : 'Open a session to see its context.';
    return;
  }

  const pct = context.used_pct;
  root.dataset.state = 'live';
  fill.style.width = `${Math.min(100, pct ?? 0)}%`;
  bar.setAttribute('aria-valuenow', String(Math.round(pct ?? 0)));
  bar.classList.remove('lt-progress--cyan', 'lt-progress--red');
  if (pct == null || pct < 70) bar.classList.add('lt-progress--cyan');
  else if (pct >= 90) bar.classList.add('lt-progress--red');

  set('used', pct == null
    ? `— / ${compact(context.window)}`
    : `${compact(context.used_tokens)} / ${compact(context.window)} (${pct.toFixed(pct < 10 ? 1 : 0)}%)`);
  set('model', [context.model, context.effort].filter(Boolean).join(' · ') || '—');
  set('cost', context.cost_usd == null ? '—' : `$${context.cost_usd.toFixed(2)}`);
  set('lines', `+${context.lines_added ?? 0} −${context.lines_removed ?? 0}`);
  set('updated', context.updated ? `${ago(context.updated)} ago`.replace('now ago', 'just now') : '—');
  note.textContent = pct != null && pct >= 80
    ? 'Context is filling up; consider /compact or a new conversation.'
    : '';
}