import { app, isRouteCurrent } from '../router.js';
import { api } from '../api.js';
import { escapeHTML, formatTokenCount, formatCost } from '../utils.js';

export async function renderUsage(routeToken) {
  app.innerHTML = `
    <div class="page-header"><h2>Usage</h2></div>
    <div id="usage-content"><div class="usage-loading">Loading…</div></div>
  `;

  const [summary, toolsData, modelsData, tsData] = await Promise.all([
    api('/v1/stats/summary').catch(() => null),
    api('/v1/stats/top-tools?limit=20').catch(() => ({ tools: [] })),
    api('/v1/stats/top-models?limit=10').catch(() => ({ models: [] })),
    api('/v1/stats/timeseries?window=7d').catch(() => ({ series: [] })),
  ]);
  if (routeToken && !isRouteCurrent(routeToken)) return;

  const tools = toolsData.tools || [];
  const models = modelsData.models || [];
  const series = tsData.series || [];

  // Aggregate 7d totals from timeseries
  const totals7d = series.reduce((acc, b) => {
    acc.runs += b.runs || 0;
    acc.tools += b.tools || 0;
    acc.errors += b.errors || 0;
    acc.tokens += b.tokens || 0;
    acc.cost += b.cost || 0;
    return acc;
  }, { runs: 0, tools: 0, errors: 0, tokens: 0, cost: 0 });

  const s = summary || {};

  const content = document.getElementById('usage-content');
  if (!content) return;

  content.innerHTML = `
    <div class="usage-summary-tiles">
      <div class="meta-tile"><div class="meta-tile-label">Active Sessions</div><div class="meta-tile-value">${s.active_sessions || 0}</div></div>
      <div class="meta-tile"><div class="meta-tile-label">Runs Today</div><div class="meta-tile-value">${s.runs_today || 0}</div></div>
      <div class="meta-tile"><div class="meta-tile-label">Tool Calls Today</div><div class="meta-tile-value">${s.tool_calls_today || 0}</div></div>
      <div class="meta-tile"><div class="meta-tile-label">Errors Today</div><div class="meta-tile-value">${s.errors_today || 0}</div></div>
      <div class="meta-tile"><div class="meta-tile-label">Tokens Today</div><div class="meta-tile-value">${formatTokenCount(s.tokens_today || 0)}</div></div>
      <div class="meta-tile"><div class="meta-tile-label">Cost Today</div><div class="meta-tile-value">${formatCost(s.cost_today || 0)}</div></div>
    </div>

    <div class="usage-section-row">
      <div class="usage-panel">
        <div class="section-title">7-Day Totals</div>
        <div class="usage-7d-tiles">
          <div class="usage-7d-tile"><span class="usage-7d-label">Runs</span><strong>${totals7d.runs}</strong></div>
          <div class="usage-7d-tile"><span class="usage-7d-label">Tool Calls</span><strong>${totals7d.tools}</strong></div>
          <div class="usage-7d-tile"><span class="usage-7d-label">Errors</span><strong>${totals7d.errors}</strong></div>
          <div class="usage-7d-tile"><span class="usage-7d-label">Tokens</span><strong>${formatTokenCount(totals7d.tokens)}</strong></div>
          <div class="usage-7d-tile"><span class="usage-7d-label">Est. Cost</span><strong>${formatCost(totals7d.cost)}</strong></div>
        </div>
      </div>
    </div>

    <div class="usage-section-row">
      <div class="usage-panel">
        <div class="section-title">Top Models <span class="count">${models.length}</span></div>
        ${models.length === 0 ? '<p class="empty-state">No model data yet</p>' : `
        <ul class="stat-list" id="usage-models-list">
          ${(() => {
            const max = models[0]?.count || 1;
            return models.map(m => {
              const pct = (m.count / max * 100).toFixed(1);
              return `<li>
                <div class="stat-list-header">
                  <span class="stat-list-name">${escapeHTML(m.name)}</span>
                  <span class="stat-list-count">${m.count}</span>
                </div>
                <div class="stat-list-bar-track">
                  <div class="stat-list-bar-fill model" style="width:${pct}%"></div>
                </div>
              </li>`;
            }).join('');
          })()}
        </ul>`}
      </div>

      <div class="usage-panel">
        <div class="section-title">Top Tools <span class="count">${tools.length}</span></div>
        ${tools.length === 0 ? '<p class="empty-state">No tool data yet</p>' : `
        <ul class="stat-list" id="usage-tools-list">
          ${(() => {
            const max = tools[0]?.count || 1;
            return tools.map(t => {
              const pct = (t.count / max * 100).toFixed(1);
              return `<li>
                <div class="stat-list-header">
                  <span class="stat-list-name">${escapeHTML(t.name)}</span>
                  <span class="stat-list-count">${t.count}</span>
                </div>
                <div class="stat-list-bar-track">
                  <div class="stat-list-bar-fill tool" style="width:${pct}%"></div>
                </div>
              </li>`;
            }).join('');
          })()}
        </ul>`}
      </div>
    </div>
  `;
}