/**
 * pc-live  |  Window Manager
 * Handles: create, focus, drag, resize, maximize, minimize, close, taskbar
 */
const WindowManager = (() => {
  const layer       = document.getElementById('window-layer');
  const taskbarApps = document.getElementById('taskbar-apps');
  let   zCounter    = 10;
  const windows     = new Map(); // id -> { el, tbBtn, minimized, maximized, preMax, title, icon }

  /* ── Helpers ──────────────────────────────────────────── */
  function nextZ() { return ++zCounter; }

  function clampPos(el) {
    const lw = layer.clientWidth;
    const lh = layer.clientHeight;
    let   l  = parseInt(el.style.left) || 0;
    let   t  = parseInt(el.style.top)  || 0;
    const w  = el.offsetWidth;
    const h  = el.offsetHeight;
    el.style.left = Math.min(Math.max(0, l), lw - w) + 'px';
    el.style.top  = Math.min(Math.max(0, t), lh - Math.max(40, h - 300)) + 'px';
  }

  /* ── Drag ─────────────────────────────────────────────── */
  function makeDraggable(el, handle) {
    let startX, startY, startL, startT;
    handle.addEventListener('mousedown', (e) => {
      if (e.target.classList.contains('wc-btn')) return;
      if (e.target.classList.contains('wc-resize')) return;
      const win = windows.get(el.dataset.wid);
      if (win && win.maximized) return;
      startX = e.clientX; startY = e.clientY;
      startL = parseInt(el.style.left) || 0;
      startT = parseInt(el.style.top)  || 0;
      focus(el.dataset.wid);
      const mm = (e2) => {
        el.style.left = (startL + e2.clientX - startX) + 'px';
        el.style.top  = (startT + e2.clientY - startY) + 'px';
      };
      const mu = () => {
        clampPos(el);
        document.removeEventListener('mousemove', mm);
        document.removeEventListener('mouseup', mu);
      };
      document.addEventListener('mousemove', mm);
      document.addEventListener('mouseup', mu);
    });
    // Double-click titlebar → toggle maximize
    handle.addEventListener('dblclick', (e) => {
      if (e.target.classList.contains('wc-btn')) return;
      toggleMaximize(el.dataset.wid);
    });
  }

  /* ── Resize ───────────────────────────────────────────── */
  function makeResizable(el, id) {
    const dirs = ['n', 's', 'e', 'w', 'nw', 'ne', 'sw', 'se'];
    dirs.forEach(dir => {
      const h = document.createElement('div');
      h.className = 'wc-resize wc-resize-' + dir;
      el.appendChild(h);

      let startX, startY, startL, startT, startW, startH;
      const MIN_W = 320, MIN_H = 200;

      h.addEventListener('mousedown', (e) => {
        const win = windows.get(id);
        if (!win || win.maximized) return;
        e.stopPropagation();
        focus(id);
        startX = e.clientX; startY = e.clientY;
        startL = parseInt(el.style.left)   || 0;
        startT = parseInt(el.style.top)    || 0;
        startW = el.offsetWidth;
        startH = el.offsetHeight;

        const mm = (e2) => {
          const dx = e2.clientX - startX;
          const dy = e2.clientY - startY;
          let newL = startL, newT = startT, newW = startW, newH = startH;

          if (dir.includes('e')) newW = Math.max(MIN_W, startW + dx);
          if (dir.includes('w')) { newW = Math.max(MIN_W, startW - dx); newL = startL + startW - newW; }
          if (dir.includes('s')) newH = Math.max(MIN_H, startH + dy);
          if (dir.includes('n')) { newH = Math.max(MIN_H, startH - dy); newT = startT + startH - newH; }

          el.style.left   = newL + 'px';
          el.style.top    = newT + 'px';
          el.style.width  = newW + 'px';
          el.style.height = newH + 'px';
        };
        const mu = () => {
          document.removeEventListener('mousemove', mm);
          document.removeEventListener('mouseup', mu);
        };
        document.addEventListener('mousemove', mm);
        document.addEventListener('mouseup', mu);
      });
    });
  }

  /* ── Focus ────────────────────────────────────────────── */
  function focus(id) {
    const win = windows.get(id);
    if (!win) return;
    windows.forEach((w, wid) => {
      w.el.classList.toggle('focused', wid === id);
      w.tbBtn && w.tbBtn.classList.toggle('active', wid === id);
    });
    win.el.style.zIndex = nextZ();
  }

  /* ── Maximize / Restore ───────────────────────────────── */
  function maximize(id) {
    const win = windows.get(id);
    if (!win || win.maximized) return;
    win.preMax = {
      left:   win.el.style.left,
      top:    win.el.style.top,
      width:  win.el.style.width,
      height: win.el.style.height,
    };
    win.maximized = true;
    win.el.classList.add('maximized');
    win.el.style.left   = '0';
    win.el.style.top    = '0';
    win.el.style.width  = layer.clientWidth  + 'px';
    win.el.style.height = layer.clientHeight + 'px';
    const btn = win.el.querySelector('.wc-maximize');
    if (btn) btn.title = 'Restore';
    focus(id);
  }

  function unmaximize(id) {
    const win = windows.get(id);
    if (!win || !win.maximized || !win.preMax) return;
    win.maximized = false;
    win.el.classList.remove('maximized');
    win.el.style.left   = win.preMax.left;
    win.el.style.top    = win.preMax.top;
    win.el.style.width  = win.preMax.width;
    win.el.style.height = win.preMax.height;
    win.preMax = null;
    const btn = win.el.querySelector('.wc-maximize');
    if (btn) btn.title = 'Maximize';
    focus(id);
  }

  function toggleMaximize(id) {
    const win = windows.get(id);
    if (!win) return;
    if (win.maximized) unmaximize(id); else maximize(id);
  }

  /* ── Create ───────────────────────────────────────────── */
  function create({ id, title, icon = '🖥', width = 700, height = 480, content }) {
    if (windows.has(id)) {
      restore(id);
      return windows.get(id).el;
    }

    const lw = layer.clientWidth;
    const lh = layer.clientHeight;
    const left = Math.max(20, Math.floor(lw / 2 - width / 2));
    const top  = Math.max(20, Math.floor(lh / 2 - height / 2));

    const el = document.createElement('div');
    el.className   = 'window fade-in';
    el.dataset.wid = id;
    el.style.cssText = `left:${left}px;top:${top}px;width:${width}px;height:${height}px;z-index:${nextZ()}`;

    el.innerHTML = `
      <div class="window-titlebar">
        <span class="window-title-icon">${icon}</span>
        <span class="window-title-text">${title}</span>
        <div class="window-controls">
          <button class="wc-btn wc-minimize" title="Minimize">─</button>
          <button class="wc-btn wc-maximize" title="Maximize">□</button>
          <button class="wc-btn wc-close"    title="Close">✕</button>
        </div>
      </div>
      <div class="window-body">${content || ''}</div>
    `;

    el.querySelector('.wc-minimize').addEventListener('click', () => minimize(id));
    el.querySelector('.wc-maximize').addEventListener('click', () => toggleMaximize(id));
    el.querySelector('.wc-close').addEventListener('click',    () => close(id));
    el.addEventListener('mousedown', () => focus(id));

    makeDraggable(el, el.querySelector('.window-titlebar'));
    makeResizable(el, id);

    layer.appendChild(el);

    const tbBtn = document.createElement('div');
    tbBtn.className = 'taskbar-btn';
    tbBtn.innerHTML = `<span>${icon}</span><span>${title}</span>`;
    tbBtn.addEventListener('click', () => toggle(id));
    taskbarApps.appendChild(tbBtn);

    windows.set(id, { el, tbBtn, minimized: false, maximized: false, preMax: null, title, icon });
    focus(id);
    return el;
  }

  /* ── Minimize / restore / toggle ────────────────────────── */
  function minimize(id) {
    const win = windows.get(id);
    if (!win) return;
    win.minimized = true;
    win.el.classList.add('minimized');
    win.tbBtn && win.tbBtn.classList.remove('active');
    win.tbBtn && win.tbBtn.classList.add('minimized');
  }

  function restore(id) {
    const win = windows.get(id);
    if (!win) return;
    win.minimized = false;
    win.el.classList.remove('minimized');
    win.tbBtn && win.tbBtn.classList.remove('minimized');
    focus(id);
  }

  function toggle(id) {
    const win = windows.get(id);
    if (!win) return;
    if (win.minimized) restore(id); else minimize(id);
  }

  /* ── Close ───────────────────────────────────────────────── */
  function close(id) {
    const win = windows.get(id);
    if (!win) return;
    win.el.remove();
    win.tbBtn && win.tbBtn.remove();
    windows.delete(id);
  }

  function closeAll() {
    windows.forEach((_, id) => close(id));
  }

  /* ── Get body element ────────────────────────────────────── */
  function getBody(id) {
    const win = windows.get(id);
    return win ? win.el.querySelector('.window-body') : null;
  }

  return { create, close, closeAll, focus, minimize, restore, toggle, maximize, unmaximize, toggleMaximize, getBody };
})();