// workflow-monitor.js — v0.35.0 Workflow Monitoring Dashboard
//
// Admin monitoring tab showing active instances, stage funnels,
// SLA status indicators, and stale instance detection.

export function mountMonitorTab(container, { basePath }) {
  container.innerHTML = `
    <div class="wf-monitor">
      <div class="wf-monitor-header" style="display:flex;justify-content:space-between;align-items:center;margin-bottom:16px">
        <h3 style="font-size:16px;font-weight:600">Workflow Monitor</h3>
        <button id="monRefresh" class="btn btn-sm btn-outline">Refresh</button>
      </div>
      <div id="monInstances" style="margin-bottom:24px">Loading…</div>
      <div id="monStale" style="margin-bottom:24px"></div>
    </div>
  `;

  let refreshTimer = null;

  async function loadInstances() {
    try {
      const resp = await fetch(`${basePath}/api/v1/admin/workflows/monitor/instances`);
      if (!resp.ok) throw new Error(resp.statusText);
      const { data } = await resp.json();
      renderInstances(data);
    } catch (e) {
      document.getElementById('monInstances').textContent = 'Failed to load: ' + e.message;
    }
  }

  async function loadStale() {
    try {
      const resp = await fetch(`${basePath}/api/v1/admin/workflows/monitor/stale`);
      if (!resp.ok) return;
      const { data } = await resp.json();
      renderStale(data);
    } catch (_) {}
  }

  function renderInstances(instances) {
    const el = document.getElementById('monInstances');
    if (!instances.length) {
      el.innerHTML = '<p style="color:var(--text-3)">No active workflow instances.</p>';
      return;
    }

    let html = '<table style="width:100%;border-collapse:collapse;font-size:13px">';
    html += '<thead><tr style="border-bottom:2px solid var(--border);text-align:left">';
    html += '<th style="padding:8px">Workflow</th><th style="padding:8px">Stage</th>';
    html += '<th style="padding:8px">Age</th><th style="padding:8px">SLA</th>';
    html += '</tr></thead><tbody>';

    for (const inst of instances) {
      const age = formatDuration(inst.age_seconds);
      const sla = renderSLA(inst);
      html += `<tr style="border-bottom:1px solid var(--border)">`;
      html += `<td style="padding:8px">${esc(inst.workflow_name)}<br><span style="font-size:11px;color:var(--text-3)">${esc(inst.channel_title)}</span></td>`;
      html += `<td style="padding:8px">${esc(inst.stage_name)} <span style="color:var(--text-3)">(${inst.current_stage})</span></td>`;
      html += `<td style="padding:8px">${age}</td>`;
      html += `<td style="padding:8px">${sla}</td>`;
      html += '</tr>';
    }
    html += '</tbody></table>';
    el.innerHTML = html;
  }

  function renderSLA(inst) {
    if (!inst.sla_seconds) return '<span style="color:var(--text-3)">—</span>';
    if (inst.sla_breached) {
      return '<span style="color:var(--danger,#e74c3c);font-weight:600">BREACHED</span>';
    }
    if (inst.sla_remaining_seconds != null) {
      const remaining = inst.sla_remaining_seconds;
      const pct = Math.max(0, remaining / inst.sla_seconds);
      const color = pct > 0.5 ? 'var(--success,#2ecc71)' : pct > 0.2 ? 'var(--warning,#f39c12)' : 'var(--danger,#e74c3c)';
      return `<span style="color:${color}">${formatDuration(remaining)}</span>`;
    }
    return '—';
  }

  function renderStale(instances) {
    const el = document.getElementById('monStale');
    if (!instances.length) {
      el.innerHTML = '';
      return;
    }
    let html = '<h4 style="font-size:14px;color:var(--danger,#e74c3c);margin-bottom:8px">Stale Instances (' + instances.length + ')</h4>';
    html += '<ul style="list-style:none;padding:0">';
    for (const inst of instances) {
      html += `<li style="padding:4px 0;font-size:13px">${esc(inst.workflow_name)} — ${esc(inst.stage_name)} (${formatDuration(inst.age_seconds)} old)</li>`;
    }
    html += '</ul>';
    el.innerHTML = html;
  }

  function formatDuration(seconds) {
    if (seconds < 60) return seconds + 's';
    if (seconds < 3600) return Math.floor(seconds / 60) + 'm';
    if (seconds < 86400) return Math.floor(seconds / 3600) + 'h ' + Math.floor((seconds % 3600) / 60) + 'm';
    return Math.floor(seconds / 86400) + 'd ' + Math.floor((seconds % 86400) / 3600) + 'h';
  }

  function esc(s) {
    const d = document.createElement('div');
    d.textContent = s || '';
    return d.innerHTML;
  }

  // Initial load
  loadInstances();
  loadStale();

  // Auto-refresh every 30s
  refreshTimer = setInterval(() => {
    loadInstances();
    loadStale();
  }, 30000);

  document.getElementById('monRefresh')?.addEventListener('click', () => {
    loadInstances();
    loadStale();
  });

  // Return cleanup function
  return () => {
    if (refreshTimer) clearInterval(refreshTimer);
  };
}