desktop-os-theme/shell/shell.js at main · rampstackco/desktop-os-theme · GitHub

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/* ==========================================================================
   desktop-os-theme / shell.js
   --------------------------------------------------------------------------
   The whole shell in one file. Vanilla JS, zero dependencies, and the page
   must remain fully readable without it: everything here is enhancement.
   The contract with shell.css is the `os-live` class on <html>; every
   behavior and every piece of ARIA this script adds is added here, at
   enhance time, so the no-JS document never claims semantics it cannot
   honor.

   What the script does, in order:
     1. flips the document into live mode
     2. registers every [data-os-window] and gives it dialog semantics
     3. injects the minimize and close controls (a control that does
        nothing must not exist, so they cannot be static markup)
     4. turns icon and in-content anchors into window openers
     5. manages the pile: open, close, minimize, raise on click
     6. fills the taskbar's open-window list (and only that list; the
        shortcut strip beside it is never touched)
     7. injects the mobile launcher button
     8. binds Escape to close the topmost openable
     9. runs the taskbar clock

   Focus is managed at the three moments it can be lost: opening a window
   moves focus into it, closing one returns focus to the element that
   opened it, minimizing one moves focus to the window's taskbar entry.
   There is no focus trap anywhere: Tab always walks the whole document,
   and closed windows leave the tab order via display:none.
   ========================================================================== */

(function () {
  "use strict";

  var doc = document;
  var root = doc.documentElement;

  /* 1. Live mode. Everything shell.css does differently, it does under
     this class. If the script fails to run, this line never happens and
     the page stays a page. */
  root.classList.add("os-live");

  /* ------------------------------------------------------------------
     Window registry.
     openOrder holds open (including minimized) windows, bottom to top.
     ------------------------------------------------------------------ */
  var windows = [];
  var byId = {};
  var openOrder = [];
  var openCount = 0; // total opens ever, drives the cascade offsets

  var Z_BASE = 10; // matches --os-z-window; stays below --os-z-chrome (30)

  var ICON_MIN =
    '<svg viewBox="0 0 14 14" aria-hidden="true" fill="none" ' +
    'stroke="currentColor" stroke-width="2" stroke-linecap="round">' +
    '<path d="M2 11h10"/></svg>';
  var ICON_CLOSE =
    '<svg viewBox="0 0 14 14" aria-hidden="true" fill="none" ' +
    'stroke="currentColor" stroke-width="2" stroke-linecap="round">' +
    '<path d="M3 3l8 8M11 3l-8 8"/></svg>';
  var ICON_GRID =
    '<svg viewBox="0 0 20 20" aria-hidden="true" fill="none" ' +
    'stroke="currentColor" stroke-width="2" stroke-linejoin="round">' +
    '<rect x="2.5" y="2.5" width="6" height="6" rx="1"/>' +
    '<rect x="11.5" y="2.5" width="6" height="6" rx="1"/>' +
    '<rect x="2.5" y="11.5" width="6" height="6" rx="1"/>' +
    '<rect x="11.5" y="11.5" width="6" height="6" rx="1"/></svg>';

  /* ------------------------------------------------------------------
     2 + 3. Register windows, add dialog semantics, inject controls.
     Non-modal dialogs: role="dialog" names the pattern, aria-modal is
     deliberately absent because nothing is modal and nothing traps.
     ------------------------------------------------------------------ */
  var winEls = doc.querySelectorAll("[data-os-window]");
  Array.prototype.forEach.call(winEls, function (el) {
    var title = el.querySelector(".os-title");
    if (title && !title.id) title.id = el.id + "-title";

    el.setAttribute("role", "dialog");
    if (title) el.setAttribute("aria-labelledby", title.id);
    el.tabIndex = -1;

    var body = el.querySelector(".os-window-body");
    if (body) {
      /* The scroll region has to be keyboard-scrollable, which means
         focusable. It borrows the window's name so a screen reader says
         what it is scrolling. */
      body.tabIndex = 0;
      if (title) body.setAttribute("aria-labelledby", title.id);
      body.setAttribute("role", "region");
    }

    var slot = el.querySelector("[data-os-controls]");
    var minBtn = null;
    var closeBtn = null;
    if (slot) {
      var name = title ? title.textContent.trim() : el.id;
      minBtn = makeControl("Minimize " + name, ICON_MIN);
      closeBtn = makeControl("Close " + name, ICON_CLOSE);
      slot.appendChild(minBtn);
      slot.appendChild(closeBtn);
    }

    var win = {
      el: el,
      id: el.id,
      minimized: false,
      opener: null, // where focus returns on close
      taskBtn: null,
    };
    windows.push(win);
    byId[el.id] = win;

    if (minBtn)
      minBtn.addEventListener("click", function () {
        minimize(win);
      });
    if (closeBtn)
      closeBtn.addEventListener("click", function () {
        close(win);
      });

    /* Clicking anywhere in a window raises it: z-order on click. */
    el.addEventListener("pointerdown", function () {
      if (top() !== win) raise(win);
    });
  });

  function makeControl(label, svg) {
    var b = doc.createElement("button");
    b.type = "button";
    b.className = "os-control";
    b.setAttribute("aria-label", label);
    b.innerHTML = svg;
    return b;
  }

  /* ------------------------------------------------------------------
     4. Anchors become openers. Any link to #<window-id>, wherever it is
     (icon rail, launcher panel, window content), opens that window. The
     same listener closes the launcher panel behind a successful open.
     ------------------------------------------------------------------ */
  doc.addEventListener("click", function (e) {
    var a = e.target.closest ? e.target.closest('a[href^="#"]') : null;
    if (!a) return;
    var win = byId[a.getAttribute("href").slice(1)];
    if (!win) return;
    e.preventDefault();
    setLauncher(false);
    open(win, a);
  });

  /* ------------------------------------------------------------------
     5. The pile.
     ------------------------------------------------------------------ */
  function top() {
    return openOrder.length ? openOrder[openOrder.length - 1] : null;
  }

  /* The topmost window a user can actually see. A minimized window can sit
     high in the order, and Escape and focus-return must both look past it. */
  function topVisible() {
    for (var i = openOrder.length - 1; i >= 0; i--) {
      if (!openOrder[i].minimized) return openOrder[i];
    }
    return null;
  }

  function open(win, opener) {
    if (opener) win.opener = opener;
    if (openOrder.indexOf(win) === -1) {
      openOrder.push(win);
      /* The cascade: each opening lands a step down-right from the last,
         cycling so the pile never walks off screen. */
      var step = openCount % 5;
      win.el.style.setProperty("--os-dx", step * cascade() + "px");
      win.el.style.setProperty("--os-dy", step * cascade() + "px");
      openCount += 1;
    }
    win.minimized = false;
    win.el.classList.add("os-open");
    raise(win);
    win.el.focus({ preventScroll: true });
  }

  function close(win) {
    var i = openOrder.indexOf(win);
    if (i !== -1) openOrder.splice(i, 1);
    win.minimized = false;
    win.el.classList.remove("os-open", "os-top");
    restack();
    /* Never a dead end: focus returns to whatever opened the window, and
       the desktop with its icons is what remains. */
    if (win.opener && isVisible(win.opener)) {
      win.opener.focus();
    } else {
      var t = topVisible();
      if (t) t.el.focus({ preventScroll: true });
    }
  }

  function minimize(win) {
    win.minimized = true;
    win.el.classList.remove("os-open", "os-top");
    restack();
    /* The window went to the taskbar, so focus honestly follows it. */
    if (win.taskBtn) win.taskBtn.focus();
  }

  function raise(win) {
    var i = openOrder.indexOf(win);
    if (i !== -1) {
      openOrder.splice(i, 1);
      openOrder.push(win);
    }
    restack();
  }

  /* Reassign z-indexes bottom-to-top on every change, so the range stays
     bounded and never creeps toward the chrome layer. */
  function restack() {
    var tv = topVisible();
    openOrder.forEach(function (w, i) {
      w.el.style.zIndex = String(Z_BASE + i);
      w.el.classList.toggle("os-top", w === tv);
    });
    syncTaskbar();
  }

  function isVisible(el) {
    return !!(el.offsetWidth || el.offsetHeight || el.getClientRects().length);
  }

  function cascade() {
    var v = getComputedStyle(root).getPropertyValue("--os-cascade");
    return parseInt(v, 10) || 28;
  }

  /* ------------------------------------------------------------------
     6. Taskbar. This fills the open-window list and only that list. The
     shortcut strip next to it is a fixed text index of every window and
     no selector in this file reaches it, which is deliberate: it is the
     navigation guarantee that has to read the same with the script and
     without it (class decision 44). Rebuilding the taskbar used to
     destroy it.

     Click behavior follows the desktop convention: raise it if it is
     behind, restore it if it is minimized, minimize it if it is already
     on top.
     ------------------------------------------------------------------ */
  var tasklist = doc.querySelector("[data-os-tasklist]");

  function syncTaskbar() {
    if (!tasklist) return;
    tasklist.textContent = "";
    openOrder.forEach(function (win) {
      var li = doc.createElement("li");
      var b = doc.createElement("button");
      b.type = "button";
      b.className = "os-task" + (win.minimized ? " os-task-min" : "");
      var title = win.el.querySelector(".os-title");
      b.textContent = title ? title.textContent : win.id;
      var isTop = topVisible() === win;
      b.setAttribute("aria-pressed", isTop ? "true" : "false");
      b.addEventListener("click", function () {
        if (win.minimized) {
          open(win);
        } else if (topVisible() === win) {
          minimize(win);
        } else {
          raise(win);
          win.el.focus({ preventScroll: true });
        }
      });
      li.appendChild(b);
      tasklist.appendChild(li);
      win.taskBtn = b;
    });
  }

  /* ------------------------------------------------------------------
     7. Launcher. Injected because it only means something live. It
     controls the icon nav, which shell.css re-hangs as a panel on narrow
     screens.
     ------------------------------------------------------------------ */
  var icons = doc.querySelector(".os-icons");
  var launcher = null;
  if (icons) {
    if (!icons.id) icons.id = "os-icons";
    launcher = doc.createElement("button");
    launcher.type = "button";
    launcher.className = "os-launcher";
    launcher.setAttribute("aria-label", "Programs");
    launcher.setAttribute("aria-expanded", "false");
    launcher.setAttribute("aria-controls", icons.id);
    launcher.innerHTML = ICON_GRID;
    launcher.addEventListener("click", function () {
      setLauncher(launcher.getAttribute("aria-expanded") !== "true");
    });
    doc.body.appendChild(launcher);
  }

  function setLauncher(openIt) {
    if (!launcher) return;
    var was = launcher.getAttribute("aria-expanded") === "true";
    launcher.setAttribute("aria-expanded", openIt ? "true" : "false");
    icons.classList.toggle("os-open", openIt);
    if (!openIt && was) launcher.focus();
  }

  /* ------------------------------------------------------------------
     8. Escape closes the topmost openable: the launcher panel if it is
     open, otherwise the top window. One key, one rule, no exceptions.
     ------------------------------------------------------------------ */
  doc.addEventListener("keydown", function (e) {
    if (e.key !== "Escape") return;
    if (launcher && launcher.getAttribute("aria-expanded") === "true") {
      setLauncher(false);
      return;
    }
    var t = topVisible();
    if (t) close(t);
  });

  /* ------------------------------------------------------------------
     8b. Wallpaper. The ground is a wallpaper slot; this script's whole
     involvement is one attribute on the body and one tray button. All
     the styling lives in shell.css under body[data-wallpaper]. The
     enhanced desktop defaults to the scene; the no-JS document gets the
     quiet field from plain CSS because this line never runs. Per-session
     only, no storage: a demo desktop should greet everyone the same way.
     ------------------------------------------------------------------ */
  var WALLPAPERS = ["scene", "quiet"];
  var ICON_WALL =
    '<svg viewBox="0 0 20 20" aria-hidden="true" fill="none" ' +
    'stroke="currentColor" stroke-width="1.8" stroke-linejoin="round" ' +
    'stroke-linecap="round">' +
    '<rect x="2.5" y="3.5" width="15" height="13" rx="2"/>' +
    '<circle cx="7.2" cy="8.2" r="1.4"/>' +
    '<path d="M4.5 14.5l4-4.5 3 3 2.5-2.5 3.5 4"/></svg>';

  doc.body.setAttribute("data-wallpaper", WALLPAPERS[0]);

  var clockEl = doc.querySelector("[data-os-clock]");
  if (clockEl && clockEl.parentNode) {
    var wallBtn = doc.createElement("button");
    wallBtn.type = "button";
    wallBtn.className = "os-tray-btn";
    wallBtn.innerHTML = ICON_WALL;
    var labelWall = function () {
      wallBtn.setAttribute(
        "aria-label",
        "Switch wallpaper, now " + doc.body.getAttribute("data-wallpaper")
      );
    };
    labelWall();
    wallBtn.addEventListener("click", function () {
      var cur = doc.body.getAttribute("data-wallpaper");
      var next = WALLPAPERS[(WALLPAPERS.indexOf(cur) + 1) % WALLPAPERS.length];
      doc.body.setAttribute("data-wallpaper", next);
      labelWall();
    });
    clockEl.parentNode.insertBefore(wallBtn, clockEl);
  }

  /* ------------------------------------------------------------------
     9. The clock. A desktop without a clock is a screenshot.
     ------------------------------------------------------------------ */
  var clock = doc.querySelector("[data-os-clock]");
  if (clock) {
    var tick = function () {
      var d = new Date();
      var h = String(d.getHours());
      var m = String(d.getMinutes());
      clock.textContent =
        (h.length < 2 ? "0" + h : h) + ":" + (m.length < 2 ? "0" + m : m);
    };
    tick();
    setInterval(tick, 30000);
  }

  /* ------------------------------------------------------------------
     Boot: open whatever the page marked data-os-open, in document order,
     so the desktop greets rather than sitting empty. The last one marked
     ends up on top. Focus is left alone at boot; stealing focus on page
     load is rude to screen readers and to everyone else.
     ------------------------------------------------------------------ */
  windows.forEach(function (win) {
    if (win.el.hasAttribute("data-os-open")) {
      var icon = doc.querySelector('.os-icons a[href="#' + win.id + '"]');
      if (icon) win.opener = icon;
      if (openOrder.indexOf(win) === -1) {
        openOrder.push(win);
        var step = openCount % 5;
        win.el.style.setProperty("--os-dx", step * cascade() + "px");
        win.el.style.setProperty("--os-dy", step * cascade() + "px");
        openCount += 1;
      }
      win.el.classList.add("os-open");
    }
  });
  restack();
})();