/* =====================================================================
   PULSE — Workers page (WP-C)
   Owns DOM id prefix `wk-` and action namespace `wk:*`.
   ===================================================================== */
'use strict';

(function () {
  const esc = Pulse.esc;
  const fmt = Pulse.fmt;

  function parseMeta(worker) {
    if (!worker || !worker.metadata) return null;
    if (typeof worker.metadata === 'string') {
      try { return JSON.parse(worker.metadata); } catch (e) { return null; }
    }
    return worker.metadata;
  }

  function memPct(meta) {
    if (!meta || !meta.totalMem) return 0;
    return ((meta.totalMem - meta.freeMem) / meta.totalMem * 100);
  }

  function loadAvgText(meta) {
    if (!meta || !meta.loadavg) return 'N/A';
    return meta.loadavg.map(l => Number(l).toFixed(2)).join(', ');
  }

  /* -------------------------------------------------------------------
     Card construction
     ------------------------------------------------------------------- */
  function footerHtml(worker) {
    if (!Pulse.isAdmin) return '';
    return (
      '<div class="lt-card-footer">' +
        '<button type="button" class="lt-btn lt-btn-danger lt-btn-sm" data-action="wk:delete" ' +
          'data-worker-id="' + esc(worker.id) + '" data-worker-name="' + esc(worker.name) + '">Delete</button>' +
      '</div>'
    );
  }

  function cardHtml(worker) {
    const meta = parseMeta(worker);
    const online = worker.status === 'online';
    const pct = memPct(meta).toFixed(1);
    return (
      '<div class="wk-card-header">' +
        '<span class="lt-dot ' + (online ? 'lt-dot-up' : 'lt-dot-down') + '" data-wk-dot></span>' +
        '<span class="wk-name" data-wk-name>' + esc(worker.name) + '</span>' +
        '<span class="' + fmt.status(worker.status) + '" data-wk-status>' + esc(String(worker.status || '').toUpperCase()) + '</span>' +
      '</div>' +
      '<div class="wk-lastseen" data-wk-lastseen data-last-heartbeat="' + esc(worker.last_heartbeat || '') + '">' +
        'Last seen: ' + esc(fmt.ago(worker.last_heartbeat)) +
      '</div>' +
      '<div class="lt-kv-grid">' +
        '<div class="lt-kv-key">System</div>' +
        '<div class="lt-kv-val" data-wk-system>' + (meta ? esc((meta.platform || 'N/A') + ' ' + (meta.arch || '') + ' | ' + (meta.cpus || '?') + ' CPU cores') : 'N/A') + '</div>' +
        '<div class="lt-kv-key">Memory</div>' +
        '<div class="lt-kv-val" data-wk-memory>' +
          (meta ? esc(fmt.bytes(meta.totalMem - meta.freeMem) + ' / ' + fmt.bytes(meta.totalMem) + ' (' + pct + '% used)') : 'N/A') +
          '<div class="lt-progress"><div class="lt-progress-bar" data-wk-membar style="width:' + (meta ? pct : 0) + '%"></div></div>' +
        '</div>' +
        '<div class="lt-kv-key">Load Avg</div>' +
        '<div class="lt-kv-val" data-wk-load>' + esc(loadAvgText(meta)) + '</div>' +
        '<div class="lt-kv-key">Uptime</div>' +
        '<div class="lt-kv-val" data-wk-uptime>' + esc(fmt.uptime(meta && meta.uptime)) + '</div>' +
        '<div class="lt-kv-key">Active Tasks</div>' +
        '<div class="lt-kv-val" data-wk-tasks>' + esc((meta && meta.activeTasks || 0) + ' / ' + (meta && meta.maxConcurrentTasks || 0)) + '</div>' +
      '</div>' +
      footerHtml(worker)
    );
  }

  function createCard(worker) {
    const div = document.createElement('div');
    div.className = 'lt-card wk-card';
    div.setAttribute('data-worker-id', worker.id);
    div.classList.add(worker.status === 'online' ? 'wk-card-online' : 'wk-card-offline');
    div.innerHTML = cardHtml(worker);
    return div;
  }

  /* Update an existing card's fields in place — never replaces the card
     node itself, so identity is preserved across refreshes. */
  function patchCard(card, worker) {
    const meta = parseMeta(worker);
    const online = worker.status === 'online';

    card.classList.toggle('wk-card-online', online);
    card.classList.toggle('wk-card-offline', !online);

    const dot = card.querySelector('[data-wk-dot]');
    if (dot) dot.className = 'lt-dot ' + (online ? 'lt-dot-up' : 'lt-dot-down');

    const name = card.querySelector('[data-wk-name]');
    if (name) name.textContent = worker.name;

    const status = card.querySelector('[data-wk-status]');
    if (status) {
      status.className = fmt.status(worker.status);
      status.textContent = String(worker.status || '').toUpperCase();
    }

    const lastSeen = card.querySelector('[data-wk-lastseen]');
    if (lastSeen) {
      lastSeen.setAttribute('data-last-heartbeat', worker.last_heartbeat || '');
      lastSeen.textContent = 'Last seen: ' + fmt.ago(worker.last_heartbeat);
    }

    const system = card.querySelector('[data-wk-system]');
    if (system) system.textContent = meta ? ((meta.platform || 'N/A') + ' ' + (meta.arch || '') + ' | ' + (meta.cpus || '?') + ' CPU cores') : 'N/A';

    const pct = memPct(meta).toFixed(1);
    const memory = card.querySelector('[data-wk-memory]');
    if (memory) {
      const bar = memory.querySelector('[data-wk-membar]');
      const text = meta ? (fmt.bytes(meta.totalMem - meta.freeMem) + ' / ' + fmt.bytes(meta.totalMem) + ' (' + pct + '% used)') : 'N/A';
      if (memory.firstChild && memory.firstChild.nodeType === Node.TEXT_NODE) {
        memory.firstChild.textContent = text;
      } else {
        memory.insertBefore(document.createTextNode(text), memory.firstChild);
      }
      if (bar) bar.style.width = (meta ? pct : 0) + '%';
    }

    const load = card.querySelector('[data-wk-load]');
    if (load) load.textContent = loadAvgText(meta);

    const uptime = card.querySelector('[data-wk-uptime]');
    if (uptime) uptime.textContent = fmt.uptime(meta && meta.uptime);

    const tasks = card.querySelector('[data-wk-tasks]');
    if (tasks) tasks.textContent = (meta && meta.activeTasks || 0) + ' / ' + (meta && meta.maxConcurrentTasks || 0);

    // Admin footer can appear/disappear if isAdmin changes mid-session (rare,
    // but keep it correct rather than assuming it's static).
    const hasFooter = !!card.querySelector('.lt-card-footer');
    if (Pulse.isAdmin && !hasFooter) {
      card.insertAdjacentHTML('beforeend', footerHtml(worker));
    } else if (!Pulse.isAdmin && hasFooter) {
      const f = card.querySelector('.lt-card-footer');
      if (f) f.remove();
    } else if (hasFooter) {
      const btn = card.querySelector('[data-action="wk:delete"]');
      if (btn) btn.setAttribute('data-worker-name', worker.name);
    }
  }

  /* -------------------------------------------------------------------
     Grid rendering — patches existing cards, adds/removes as needed.
     ------------------------------------------------------------------- */
  function renderGrid(workers) {
    const grid = document.getElementById('wk-grid');
    if (!grid) return;

    if (workers.length === 0) {
      grid.innerHTML =
        '<div class="lt-empty-state">' +
          '<div class="lt-empty-state-icon">&#x2699;</div>' +
          '<div class="lt-empty-state-title">No workers connected</div>' +
          '<div class="lt-empty-state-body">Workers appear here once they connect and send a heartbeat.</div>' +
        '</div>';
      return;
    }

    const loading = document.getElementById('wk-loading');
    if (loading) loading.remove();

    const seen = new Set();
    const order = [];
    workers.forEach(worker => {
      seen.add(String(worker.id));
      let card = grid.querySelector('.wk-card[data-worker-id="' + cssEscape(worker.id) + '"]');
      if (!card) {
        card = createCard(worker);
      } else {
        patchCard(card, worker);
      }
      order.push(card);
    });

    // Remove cards for workers no longer present.
    Array.prototype.slice.call(grid.querySelectorAll('.wk-card')).forEach(card => {
      if (!seen.has(String(card.getAttribute('data-worker-id')))) card.remove();
    });

    // Ensure DOM order matches API order without detaching untouched nodes
    // unnecessarily (appendChild on an already-positioned node is a no-op
    // move, not a re-create, so identity is preserved either way).
    order.forEach(card => grid.appendChild(card));
  }

  function cssEscape(v) {
    if (window.CSS && CSS.escape) return CSS.escape(String(v));
    return String(v).replace(/["\\]/g, '\\$&');
  }

  function renderError() {
    const grid = document.getElementById('wk-grid');
    if (!grid) return;
    grid.innerHTML = '<div class="lt-alert lt-alert--error"><div class="lt-alert-body"><div class="lt-alert-msg">Failed to load workers</div></div></div>';
  }

  /* -------------------------------------------------------------------
     Data loading + actions
     ------------------------------------------------------------------- */
  async function loadWorkers() {
    try {
      const workers = await Pulse.api.get('/api/workers') || [];
      renderGrid(workers);
    } catch (e) {
      console.error('[Pulse:workers] failed to load workers', e);
      renderError();
    }
  }

  async function deleteWorker(el) {
    const id = el.getAttribute('data-worker-id');
    const name = el.getAttribute('data-worker-name') || 'this worker';
    const ok = await Pulse.confirm({
      title: 'Delete worker',
      message: 'Delete worker ' + name + '?',
      type: 'error',
    });
    if (!ok) return;
    try {
      await Pulse.api.delete('/api/workers/' + encodeURIComponent(id));
      Pulse.toast.success('Worker deleted');
      await loadWorkers();
    } catch (e) {
      Pulse.toast.error((e && e.message) || 'Failed to delete worker');
    }
  }

  function onTick() {
    document.querySelectorAll('#wk-grid [data-wk-lastseen][data-last-heartbeat]').forEach(el => {
      const v = el.getAttribute('data-last-heartbeat');
      if (v) el.textContent = 'Last seen: ' + fmt.ago(v);
    });
  }

  function init() {
    Pulse.actions.register('wk:delete', deleteWorker);
    Pulse.events.on('tick', onTick);
    return loadWorkers();
  }

  function onEvent(type) {
    if (type === 'worker_update') {
      loadWorkers();
      return true;
    }
    return false;
  }

  Pulse.registerPage({ name: 'workers', init, refresh: loadWorkers, onEvent });
})();