// Terminal page: shells on one or more machines, in tabs. With one tab the
// page is a plain terminal and a faint "+" in the corner; a second tab brings
// the tab strip in. On a computer a tab can be dragged onto the current one
// to share it - up to four terminals, split side by side or one above the
// other - and a terminal dragged out of it back to the strip. Splits resize
// by their gutters; a tab is renamed by a double click on its title.
(function () {
  'use strict';
  const PAGE = window.TERM_PAGE;
  const touch = matchMedia('(pointer: coarse)').matches;
  const desk = !touch; // drag and drop, splits: computers only
  if (touch) document.body.classList.add('touch');
  const $ = id => document.getElementById(id);
  const statusEl = $('status'), area = $('area'), tablist = $('tablist'), addBtn = $('tabadd'),
    floatAdd = $('floatadd'), addMenu = $('addmenu'), hint = $('hint'), mark = $('tabmark');
  const base = '/api/panel/term/';
  const GAP = 6;
  const X = '<svg width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.6" stroke-linecap="round"><path d="M18 6 6 18M6 6l12 12"/></svg>';

  function bytesToB64(bytes) {
    let bin = '';
    for (let i = 0; i < bytes.length; i++) bin += String.fromCharCode(bytes[i]);
    return btoa(bin);
  }
  function b64ToBytes(b64) {
    const bin = atob(b64), u = new Uint8Array(bin.length);
    for (let i = 0; i < bin.length; i++) u[i] = bin.charCodeAt(i);
    return u;
  }

  // ---------- one shell ----------
  class Session {
    constructor(agent) {
      this.agent = agent;
      this.sid = null; this.closed = false; this.connected = false;
      this.state = 'wait'; this.text = 'подключение…';
      this.inSeq = 0; this.inBusy = false; this.inQueue = [];
      this.el = document.createElement('div');
      this.el.className = 'pane';
      this.el.innerHTML = '<div class="pane-head"><span class="dot wait"></span><span class="pane-title"></span>' +
        '<button type="button" class="pane-x" title="Закрыть терминал" aria-label="Закрыть терминал">' + X + '</button></div>' +
        '<div class="pane-body"></div>';
      this.el.querySelector('.pane-title').textContent = agent.user + '@' + agent.host;
      this.el.querySelector('.pane-title').title = agent.name;
      this.term = new Terminal({
        cursorBlink: true, fontSize: touch ? 13 : 14,
        fontFamily: 'ui-monospace, SFMono-Regular, Menlo, monospace', theme: { background: '#0c0f13' }
      });
      this.fitter = new FitAddon.FitAddon();
      this.term.loadAddon(this.fitter);
      this.term.open(this.el.querySelector('.pane-body'));
      this.term.onData(d => this.send(TermKeys.withMods(d)));
      this.term.onResize(() => this.queueIn({ t: 'r', cols: this.term.cols, rows: this.term.rows }));
      this.term.onSelectionChange(() => TermKeys.selectionChanged(this));
      this.el.addEventListener('pointerdown', () => setActivePane(this), true);
      this.term.textarea.addEventListener('focus', () => setActivePane(this));
      this.el.querySelector('.pane-x').onclick = ev => { ev.stopPropagation(); closePane(this); };
      if (desk) this.el.querySelector('.pane-head').addEventListener('pointerdown', ev => startDrag(ev, 'pane', this));
      this.open();
    }
    setState(state, text) {
      this.state = state; this.text = text;
      this.el.querySelector('.dot').className = 'dot ' + state;
      const t = tabOf(this);
      if (t) renderTab(t);
      showStatus();
    }
    async open() {
      try {
        const r = await fetch(base + encodeURIComponent(this.agent.id) + '/open', { method: 'POST' });
        if (!r.ok) {
          this.setState('err', 'ошибка открытия (' + r.status + ')');
          this.term.write('\r\n\x1b[31m[не удалось открыть сессию: HTTP ' + r.status + ']\x1b[0m\r\n');
          return;
        }
        this.sid = (await r.json()).session_id;
        this.setState('wait', 'ожидание агента…');
        this.fit();
        this.queueIn({ t: 'r', cols: this.term.cols, rows: this.term.rows });
        this.poll();
      } catch (e) {
        this.setState('err', 'ошибка сети');
        this.term.write('\r\n\x1b[31m[ошибка сети: ' + (e && e.message ? e.message : e) + ']\x1b[0m\r\n');
      }
    }
    async poll() {
      while (!this.closed && this.sid) {
        let r;
        try { r = await fetch(base + this.sid + '/out', { cache: 'no-store' }); }
        catch (e) { await new Promise(res => setTimeout(res, 1000)); continue; }
        if (this.closed) return;
        if (!r.ok) { this.finish('[соединение закрыто]'); return; }
        const j = await r.json();
        if (j.closed) { this.finish('[сессия завершена]'); return; }
        for (const f of j.frames || []) {
          if (f.exit) { this.finish('[сессия завершена]'); return; }
          if (f.data) {
            if (!this.connected) { this.connected = true; this.setState('ok', 'подключено'); }
            this.term.write(b64ToBytes(f.data));
          }
        }
      }
    }
    finish(msg) {
      if (this.ended) return;
      this.ended = true;
      this.setState('off', 'соединение закрыто');
      this.term.write('\r\n\x1b[33m' + msg + '\x1b[0m\r\n');
    }
    // Input goes out one request at a time, so on a slow link a keystroke can
    // never overtake the one before it; a request that fails goes again under
    // the same number, and the server drops one it already has.
    queueIn(m) {
      if (this.closed || !this.sid) return;
      const q = this.inQueue, last = q[q.length - 1];
      if (last && last.t === 'i' && m.t === 'i') last.text += m.text;
      else if (last && last.t === 'r' && m.t === 'r') q[q.length - 1] = m;
      else q.push(m);
      this.pumpIn();
    }
    async pumpIn() {
      if (this.inBusy || !this.inQueue.length) return;
      this.inBusy = true;
      while (this.inQueue.length && !this.closed) {
        const m = this.inQueue.shift();
        const body = m.t === 'i'
          ? { t: 'i', d: bytesToB64(new TextEncoder().encode(m.text)), seq: ++this.inSeq }
          : { t: 'r', cols: m.cols, rows: m.rows, seq: ++this.inSeq };
        for (let wait = 300; !this.closed; wait = Math.min(wait * 2, 5000)) {
          let r = null;
          try {
            r = await fetch(base + this.sid + '/in', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(body) });
          } catch (e) { /* no answer: send it again */ }
          if (r && r.status < 500) break;
          await new Promise(res => setTimeout(res, wait));
        }
      }
      this.inBusy = false;
    }
    send(data) { this.queueIn({ t: 'i', text: data }); }
    fit() {
      const b = this.el.querySelector('.pane-body');
      if (b.clientWidth > 20 && b.clientHeight > 20) { try { this.fitter.fit(); } catch (e) { /* not shown yet */ } }
    }
    close() {
      if (this.closed) return;
      this.closed = true;
      if (this.sid) fetch(base + this.sid + '/close', { method: 'POST', keepalive: true }).catch(() => {});
      this.term.dispose();
      this.el.remove();
    }
  }

  // ---------- tabs ----------
  const tabs = [];
  let active = null, activePane = null;
  const tabOf = s => tabs.find(t => t.panes.includes(s));

  function makeTab(panes, index) {
    const t = { title: null, panes: panes, layout: panes.length === 1 ? '1' : 'h', c: 0.5, r: 0.5, gutters: [] };
    t.view = document.createElement('div');
    t.view.className = 'tabview';
    area.insertBefore(t.view, hint);
    panes.forEach(s => t.view.appendChild(s.el));
    t.el = document.createElement('div');
    t.el.className = 'tab enter';
    t.el.innerHTML = '<span class="dot wait"></span><span class="tab-title"></span>' +
      '<button type="button" class="tab-x" title="Закрыть вкладку" aria-label="Закрыть вкладку">' + X + '</button>';
    t.el.addEventListener('click', ev => { if (!ev.target.closest('.tab-x, input') && !dragJustEnded) activate(t); });
    t.el.querySelector('.tab-x').onclick = ev => { ev.stopPropagation(); closeTab(t); };
    t.el.querySelector('.tab-title').addEventListener('dblclick', ev => { ev.stopPropagation(); rename(t); });
    if (desk) t.el.addEventListener('pointerdown', ev => { if (!ev.target.closest('.tab-x, input')) startDrag(ev, 'tab', t); });
    const at = index == null ? tabs.length : index;
    tablist.insertBefore(t.el, tabs[at] ? tabs[at].el : mark);
    tabs.splice(at, 0, t);
    requestAnimationFrame(() => requestAnimationFrame(() => t.el.classList.remove('enter')));
    renderTab(t);
    return t;
  }
  function tabTitle(t) {
    if (t.title) return t.title;
    const a = t.panes[0].agent;
    return t.panes.length > 1 ? a.name + ' +' + (t.panes.length - 1) : a.name;
  }
  function renderTab(t) {
    t.el.querySelector('.tab-title').textContent = tabTitle(t);
    t.el.title = t.panes.map(s => s.agent.user + '@' + s.agent.host).join(', ');
    // The tab's dot: red if any shell failed, amber while one connects.
    const st = t.panes.map(s => s.state);
    t.el.querySelector('.dot').className = 'dot ' + (st.includes('err') ? 'err' : st.includes('wait') ? 'wait' : st.includes('ok') ? 'ok' : 'off');
    t.el.classList.toggle('on', t === active);
    t.view.classList.toggle('split', t.panes.length > 1);
  }
  function activate(t) {
    if (!t) return;
    active = t;
    tabs.forEach(x => { x.view.classList.toggle('on', x === t); renderTab(x); });
    if (!t.panes.includes(activePane)) setActivePane(t.panes[0]);
    layout(t, false);
    t.el.scrollIntoView({ block: 'nearest', inline: 'nearest', behavior: 'smooth' });
    if (desk && activePane) activePane.term.focus();
    updateMode();
  }
  function setActivePane(s) {
    activePane = s;
    document.querySelectorAll('.pane.active').forEach(p => p.classList.toggle('active', p === s.el));
    s.el.classList.add('active');
    showStatus();
  }
  function showStatus() {
    if (!activePane) { statusEl.textContent = ''; return; }
    statusEl.textContent = activePane.text;
    statusEl.className = activePane.state === 'ok' ? 'st-ok' : activePane.state === 'err' ? 'st-err' : 'muted';
  }
  // One tab: a plain terminal, the strip folded into the corner "+".
  function updateMode() {
    const multi = tabs.length > 1;
    if (document.body.classList.contains('multi') === multi) return;
    document.body.classList.toggle('multi', multi);
    setTimeout(() => active && layout(active, false), 280);
  }
  function openTerminal(agent) {
    $('empty').hidden = true;
    const t = makeTab([new Session(agent)]);
    activate(t);
  }
  function closeTab(t) {
    const i = tabs.indexOf(t);
    if (i < 0) return;
    if (t.panes.length > 1 && !confirm('Закрыть вкладку с ' + t.panes.length + ' терминалами?')) return;
    tabs.splice(i, 1);
    t.panes.forEach(s => s.close());
    t.el.classList.add('leave');
    t.view.classList.remove('on');
    setTimeout(() => { t.el.remove(); t.view.remove(); }, 220);
    if (active === t) {
      active = null;
      activate(tabs[Math.min(i, tabs.length - 1)]);
    }
    if (!tabs.length) { activePane = null; showStatus(); $('empty').hidden = false; }
    updateMode();
  }
  function rename(t) {
    const span = t.el.querySelector('.tab-title');
    const inp = document.createElement('input');
    inp.className = 'tab-edit';
    inp.value = tabTitle(t);
    inp.size = Math.max(6, inp.value.length);
    span.replaceWith(inp);
    inp.focus(); inp.select();
    let done = false;
    const end = save => {
      if (done) return;
      done = true;
      if (save) t.title = inp.value.trim() || null;
      inp.replaceWith(span);
      renderTab(t);
    };
    inp.onkeydown = ev => { if (ev.key === 'Enter') end(true); else if (ev.key === 'Escape') end(false); ev.stopPropagation(); };
    inp.onblur = () => end(true);
    inp.onpointerdown = ev => ev.stopPropagation();
  }

  // ---------- splits ----------
  // Where each terminal of a tab goes, and its gutters, for a layout:
  // 1, h (side by side), v (one above the other), top2 (two over one),
  // bottom2 (one over two), grid (two over two). c and r are where the
  // column and the row divide.
  function rects(layout, c, r, W, H) {
    const g = GAP, cw = Math.round((W - g) * c), rh = Math.round((H - g) * r);
    const top = (y, h) => [{ x: 0, y, w: cw, h }, { x: cw + g, y, w: W - cw - g, h }];
    const colG = (y, h) => ({ k: 'c', x: cw, y, w: g, h });
    const rowG = { k: 'r', x: 0, y: rh, w: W, h: g };
    const bottomY = rh + g, bottomH = H - rh - g;
    switch (layout) {
      case 'h': return { panes: top(0, H), gutters: [colG(0, H)] };
      case 'v': return { panes: [{ x: 0, y: 0, w: W, h: rh }, { x: 0, y: bottomY, w: W, h: bottomH }], gutters: [rowG] };
      case 'top2': return { panes: top(0, rh).concat([{ x: 0, y: bottomY, w: W, h: bottomH }]), gutters: [colG(0, rh), rowG] };
      case 'bottom2': return { panes: [{ x: 0, y: 0, w: W, h: rh }].concat(top(bottomY, bottomH)), gutters: [colG(bottomY, bottomH), rowG] };
      case 'grid': return { panes: top(0, rh).concat(top(bottomY, bottomH)), gutters: [colG(0, H), rowG] };
      default: return { panes: [{ x: 0, y: 0, w: W, h: H }], gutters: [] };
    }
  }
  function layout(t, animate) {
    const W = t.view.clientWidth, H = t.view.clientHeight;
    if (!W || !H) return;
    const L = rects(t.layout, t.c, t.r, W, H);
    t.view.classList.toggle('instant', !animate);
    t.panes.forEach((s, i) => {
      const p = L.panes[i];
      s.el.style.left = p.x + 'px'; s.el.style.top = p.y + 'px';
      s.el.style.width = p.w + 'px'; s.el.style.height = p.h + 'px';
    });
    while (t.gutters.length < L.gutters.length) {
      const g = document.createElement('div');
      g.className = 'gutter';
      g.addEventListener('pointerdown', ev => startResize(ev, t, g));
      t.view.appendChild(g);
      t.gutters.push(g);
    }
    t.gutters.forEach((g, i) => {
      const d = L.gutters[i];
      g.hidden = !d;
      if (!d) return;
      g.className = 'gutter ' + d.k;
      g.style.left = d.x + 'px'; g.style.top = d.y + 'px'; g.style.width = d.w + 'px'; g.style.height = d.h + 'px';
    });
    clearTimeout(t.fitTimer);
    t.fitTimer = setTimeout(() => t.panes.forEach(s => s.fit()), animate ? 270 : 0);
  }
  function startResize(ev, t, g) {
    ev.preventDefault();
    g.setPointerCapture(ev.pointerId);
    const box = t.view.getBoundingClientRect(), k = g.classList.contains('c') ? 'c' : 'r';
    g.classList.add('drag');
    let raf = 0;
    const move = e => {
      const v = k === 'c' ? (e.clientX - box.left) / box.width : (e.clientY - box.top) / box.height;
      t[k] = Math.min(0.85, Math.max(0.15, v));
      if (!raf) raf = requestAnimationFrame(() => { raf = 0; layout(t, false); });
    };
    const up = () => {
      g.classList.remove('drag');
      g.removeEventListener('pointermove', move);
      g.removeEventListener('pointerup', up);
      layout(t, false);
    };
    g.addEventListener('pointermove', move);
    g.addEventListener('pointerup', up);
  }
  // A layout with one terminal fewer, the others keeping their places.
  function withoutPane(layout, i) {
    if (layout === 'h' || layout === 'v') return '1';
    if (layout === 'top2') return i === 2 ? 'h' : 'v';
    if (layout === 'bottom2') return i === 0 ? 'h' : 'v';
    if (layout === 'grid') return i < 2 ? 'bottom2' : 'top2';
    return '1';
  }
  function takePane(t, s) {
    const i = t.panes.indexOf(s);
    t.layout = withoutPane(t.layout, i);
    t.panes.splice(i, 1);
  }
  function closePane(s) {
    const t = tabOf(s);
    if (!t) return;
    if (t.panes.length === 1) { closeTab(t); return; }
    takePane(t, s);
    s.close();
    if (activePane === s) setActivePane(t.panes[0]);
    renderTab(t);
    layout(t, true);
  }
  // Where a terminal dropped on tab t at (x, y) would go: the new layout,
  // the order of its terminals ('P' the new one), and its place.
  const SIDE = { left: 'слева', right: 'справа', top: 'сверху', bottom: 'снизу' };
  function mergePlan(t, x, y) {
    const n = t.panes.length, W = t.view.clientWidth, H = t.view.clientHeight;
    const fx = x / W, fy = y / H;
    let lay, order, label;
    if (n === 1) {
      const d = { left: fx, right: 1 - fx, top: fy, bottom: 1 - fy };
      const k = Object.keys(d).reduce((a, b) => d[a] <= d[b] ? a : b);
      lay = k === 'left' || k === 'right' ? 'h' : 'v';
      order = k === 'left' || k === 'top' ? ['P', 0] : [0, 'P'];
      label = SIDE[k];
    } else if (n === 2 && t.layout === 'h') {
      if (fy < 0.5) { lay = 'bottom2'; order = ['P', 0, 1]; label = 'сверху'; }
      else { lay = 'top2'; order = [0, 1, 'P']; label = 'снизу'; }
    } else if (n === 2) {
      if (fy < 0.5) { lay = 'top2'; order = fx < 0.5 ? ['P', 0, 1] : [0, 'P', 1]; }
      else { lay = 'bottom2'; order = fx < 0.5 ? [0, 'P', 1] : [0, 1, 'P']; }
      label = (fy < 0.5 ? 'сверху ' : 'снизу ') + (fx < 0.5 ? 'слева' : 'справа');
    } else if (n === 3) {
      lay = 'grid';
      if (t.layout === 'top2') { order = fx < 0.5 ? [0, 1, 'P', 2] : [0, 1, 2, 'P']; label = 'снизу ' + (fx < 0.5 ? 'слева' : 'справа'); }
      else { order = fx < 0.5 ? ['P', 0, 1, 2] : [0, 'P', 1, 2]; label = 'сверху ' + (fx < 0.5 ? 'слева' : 'справа'); }
    } else return null;
    return { layout: lay, order, label, rect: rects(lay, t.c, t.r, W, H).panes[order.indexOf('P')] };
  }

  // ---------- drag and drop ----------
  // A tab: along the strip to reorder it, or onto the current tab to join
  // it. A terminal from a split, by its title bar: to the strip to make it a
  // tab of its own, or onto another terminal of its tab to swap places.
  let drag = null, dragJustEnded = false;
  function startDrag(ev, kind, obj) {
    if (ev.button !== 0) return;
    drag = { kind, obj, x0: ev.clientX, y0: ev.clientY, on: false, id: ev.pointerId };
  }
  function beginDrag() {
    drag.on = true;
    const src = drag.kind === 'tab' ? drag.obj.el : drag.obj.el.querySelector('.pane-head');
    const g = document.createElement('div');
    g.className = 'drag-ghost ' + drag.kind;
    g.textContent = drag.kind === 'tab' ? tabTitle(drag.obj) : drag.obj.agent.user + '@' + drag.obj.agent.host;
    document.body.appendChild(g);
    drag.ghost = g;
    drag.src = src;
    src.classList.add('dragging');
    document.body.classList.add('dnd');
    // Pulling a terminal out: the strip shows, one tab or not, to drop it on.
    if (drag.kind === 'pane') document.body.classList.add('multi-hint');
  }
  function stripIndex(x) {
    const others = tabs.filter(t => !(drag.kind === 'tab' && t === drag.obj));
    let i = others.findIndex(t => { const r = t.el.getBoundingClientRect(); return x < r.left + r.width / 2; });
    if (i < 0) i = others.length;
    const ref = others[i] ? others[i].el.getBoundingClientRect() : (others.length ? others[others.length - 1].el.getBoundingClientRect() : null);
    const lr = tablist.getBoundingClientRect();
    const mx = others[i] ? ref.left - 3 : ref ? ref.right + 1 : lr.left;
    return { i, others, mx: mx - lr.left + tablist.scrollLeft };
  }
  function showHint(r, label, bad) {
    hint.hidden = false;
    hint.classList.toggle('bad', !!bad);
    const v = active.view;
    hint.style.left = (v.offsetLeft + r.x) + 'px'; hint.style.top = (v.offsetTop + r.y) + 'px';
    hint.style.width = r.w + 'px'; hint.style.height = r.h + 'px';
    hint.textContent = label;
  }
  function onDragMove(ev) {
    if (!drag || ev.pointerId !== drag.id) return;
    if (!drag.on) {
      if (Math.hypot(ev.clientX - drag.x0, ev.clientY - drag.y0) < 6) return;
      beginDrag();
    }
    drag.ghost.style.transform = 'translate(' + (ev.clientX + 10) + 'px,' + (ev.clientY + 8) + 'px)';
    drag.target = null;
    hint.hidden = true; mark.hidden = true;
    const strip = $('tabs').getBoundingClientRect();
    const stripShown = document.body.classList.contains('multi') || document.body.classList.contains('multi-hint');
    const inStrip = stripShown && ev.clientY >= strip.top - 6 && ev.clientY <= strip.bottom + 10;
    const inArea = active && (() => { const r = active.view.getBoundingClientRect(); return ev.clientX >= r.left && ev.clientX <= r.right && ev.clientY >= r.top && ev.clientY <= r.bottom; })();
    if (inStrip) {
      const s = stripIndex(ev.clientX);
      mark.hidden = false; mark.style.left = s.mx + 'px';
      drag.target = { kind: 'strip', index: s.i, others: s.others };
      drag.ghost.dataset.hint = drag.kind === 'tab' ? 'переставить' : 'отдельной вкладкой';
    } else if (inArea && drag.kind === 'tab' && drag.obj !== active) {
      const r = active.view.getBoundingClientRect();
      if (drag.obj.panes.length > 1) {
        showHint({ x: 0, y: 0, w: r.width, h: r.height }, 'вкладку с несколькими терминалами не объединить', true);
      } else if (active.panes.length >= 4) {
        showHint({ x: 0, y: 0, w: r.width, h: r.height }, 'в одной вкладке не больше 4 терминалов', true);
      } else {
        const plan = mergePlan(active, ev.clientX - r.left, ev.clientY - r.top);
        showHint(plan.rect, plan.label);
        drag.target = { kind: 'merge', plan };
      }
      drag.ghost.dataset.hint = '';
    } else if (inArea && drag.kind === 'pane' && tabOf(drag.obj) === active) {
      const r = active.view.getBoundingClientRect();
      const over = active.panes.find(s => { const p = s.el.getBoundingClientRect(); return s !== drag.obj && ev.clientX >= p.left && ev.clientX <= p.right && ev.clientY >= p.top && ev.clientY <= p.bottom; });
      if (over) {
        const p = over.el.getBoundingClientRect();
        showHint({ x: p.left - r.left, y: p.top - r.top, w: p.width, h: p.height }, 'поменять местами');
        drag.target = { kind: 'swap', with: over };
      }
      drag.ghost.dataset.hint = over ? '' : 'к вкладкам - отдельной вкладкой';
    } else {
      drag.ghost.dataset.hint = '';
    }
  }
  function onDragEnd(ev) {
    if (!drag || ev.pointerId !== drag.id) return;
    const d = drag;
    drag = null;
    if (!d.on) return;
    d.ghost.remove();
    d.src.classList.remove('dragging');
    document.body.classList.remove('dnd', 'multi-hint');
    hint.hidden = true; mark.hidden = true;
    dragJustEnded = true;
    setTimeout(() => { dragJustEnded = false; }, 0);
    const tg = d.target;
    if (!tg) return;
    if (d.kind === 'tab' && tg.kind === 'strip') {
      const t = d.obj, ref = tg.others[tg.index];
      tabs.splice(tabs.indexOf(t), 1);
      tabs.splice(ref ? tabs.indexOf(ref) : tabs.length, 0, t);
      tablist.insertBefore(t.el, ref ? ref.el : mark);
    } else if (d.kind === 'tab' && tg.kind === 'merge') {
      const src = d.obj, s = src.panes[0], t = active, plan = tg.plan;
      // The joining terminal starts where the hint showed it.
      s.el.classList.add('instant');
      s.el.style.left = plan.rect.x + 'px'; s.el.style.top = plan.rect.y + 'px';
      s.el.style.width = plan.rect.w + 'px'; s.el.style.height = plan.rect.h + 'px';
      t.view.appendChild(s.el);
      requestAnimationFrame(() => s.el.classList.remove('instant'));
      t.panes = plan.order.map(o => o === 'P' ? s : t.panes[o]);
      t.layout = plan.layout;
      tabs.splice(tabs.indexOf(src), 1);
      src.el.classList.add('leave');
      setTimeout(() => { src.el.remove(); src.view.remove(); }, 220);
      setActivePane(s);
      renderTab(t);
      layout(t, true);
      updateMode();
      s.term.focus();
    } else if (d.kind === 'pane' && tg.kind === 'strip') {
      const s = d.obj, from = tabOf(s), ref = tg.others[tg.index];
      takePane(from, s);
      renderTab(from);
      const t = makeTab([s], ref ? tabs.indexOf(ref) : tabs.length);
      layout(from, true);
      activate(t);
    } else if (d.kind === 'pane' && tg.kind === 'swap') {
      const t = active, a = t.panes.indexOf(d.obj), b = t.panes.indexOf(tg.with);
      [t.panes[a], t.panes[b]] = [t.panes[b], t.panes[a]];
      layout(t, true);
    }
  }
  window.addEventListener('pointermove', onDragMove);
  window.addEventListener('pointerup', onDragEnd);
  window.addEventListener('pointercancel', onDragEnd);

  // ---------- the "+" menu ----------
  let agentsCache = null;
  function openMenu(anchor) {
    const here = (activePane && activePane.agent) || PAGE.agent;
    addMenu.innerHTML = '';
    const item = (html, fn, cls) => {
      const b = document.createElement('button');
      b.type = 'button'; b.className = 'item ' + (cls || ''); b.innerHTML = html;
      b.onclick = fn;
      addMenu.appendChild(b);
      return b;
    };
    const esc = s => String(s).replace(/[&<>"]/g, c => ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;' }[c]));
    item('<span class="ico">+</span><span><b>Новый терминал здесь</b><small>' + esc(here.name) + ' · ' + esc(here.user + '@' + here.host) + '</small></span>',
      () => { closeMenu(); openTerminal(here); });
    const other = item('<span class="ico">⇄</span><span><b>На другой машине</b><small>выбрать из списка</small></span><span class="chev">›</span>', () => {
      other.remove();
      const list = document.createElement('div');
      list.className = 'mlist';
      list.innerHTML = '<div class="muted" style="padding:8px 10px;font-size:13px">загрузка…</div>';
      addMenu.appendChild(list);
      (agentsCache ? Promise.resolve(agentsCache) : fetch('/api/panel/agents/presence', { cache: 'no-store' }).then(r => r.json()))
        .then(all => {
          agentsCache = all;
          list.innerHTML = '';
          all.forEach(a => {
            const b = document.createElement('button');
            b.type = 'button'; b.className = 'item machine'; b.disabled = !a.online;
            b.innerHTML = '<span class="dot ' + (a.online ? 'ok' : 'off') + '"></span><span><b>' + esc(a.name) + '</b><small>' +
              esc(a.user + '@' + a.hostname) + (a.online ? '' : ' · ' + esc(a.seen)) + '</small></span>';
            b.onclick = () => { closeMenu(); openTerminal({ id: a.id, name: a.name, host: a.hostname, user: a.user }); };
            list.appendChild(b);
          });
          if (!all.length) list.innerHTML = '<div class="muted" style="padding:8px 10px">машин нет</div>';
          placeMenu(anchor);
        })
        .catch(() => { list.innerHTML = '<div class="muted" style="padding:8px 10px">не загрузилось</div>'; });
    });
    addMenu.hidden = false;
    placeMenu(anchor);
    setTimeout(() => document.addEventListener('pointerdown', outside, true), 0);
  }
  function placeMenu(anchor) {
    const r = anchor.getBoundingClientRect(), m = addMenu.getBoundingClientRect();
    addMenu.style.left = Math.max(8, Math.min(innerWidth - m.width - 8, r.right - m.width)) + 'px';
    addMenu.style.top = Math.min(innerHeight - m.height - 8, r.bottom + 6) + 'px';
  }
  function outside(ev) { if (!addMenu.contains(ev.target)) closeMenu(); }
  function closeMenu() {
    addMenu.hidden = true;
    agentsCache = null;
    document.removeEventListener('pointerdown', outside, true);
  }
  addBtn.onclick = () => openMenu(addBtn);
  floatAdd.onclick = () => openMenu(floatAdd);
  $('emptyadd').onclick = ev => openMenu(ev.currentTarget);
  document.addEventListener('keydown', ev => { if (ev.key === 'Escape' && !addMenu.hidden) closeMenu(); });

  // ---------- page ----------
  function refit() {
    if (touch && window.visualViewport) {
      // Follow the visible area, so the extra keys sit right above the
      // on-screen keyboard.
      const vv = window.visualViewport;
      document.body.style.top = vv.offsetTop + 'px';
      document.body.style.height = vv.height + 'px';
    }
    if (active) layout(active, false);
  }
  window.addEventListener('resize', refit);
  if (touch && window.visualViewport) {
    window.visualViewport.addEventListener('resize', refit);
    window.visualViewport.addEventListener('scroll', refit);
  }
  window.addEventListener('pagehide', () => {
    tabs.forEach(t => t.panes.forEach(s => { if (s.sid) navigator.sendBeacon(base + s.sid + '/close'); }));
  });

  // For the touch helpers in the page: the terminal being typed in.
  window.TermPane = { active: () => activePane };
  openTerminal(PAGE.agent);
  refit();
})();