From 6614ff9a2f912c67726633971880e1d0d7d033a5 Mon Sep 17 00:00:00 2001
From: Alex Kontos <MrAlex94@users.noreply.github.com>
Date: Mon, 4 Aug 2025 12:34:24 +0100
Subject: [PATCH] feat(sidebar): part 2 - tree vertical tabs v1.1

---
 browser/base/content/browser-box.inc.xhtml    |   4 +
 .../components/places/content/controller.js   |   4 +
 browser/components/sidebar/browser-sidebar.js | 177 ++++++++++++++++++
 .../components/sidebar/sidebar-customize.html |   1 +
 .../components/sidebar/sidebar-customize.mjs  |  14 ++
 browser/components/sidebar/sidebar-main.mjs   |   3 +
 .../tabbrowser/content/tab-hover-preview.mjs  |  27 ++-
 toolkit/components/places/PlacesUtils.sys.mjs |  14 ++
 8 files changed, 243 insertions(+), 1 deletion(-)

diff --git a/browser/base/content/browser-box.inc.xhtml b/browser/base/content/browser-box.inc.xhtml
index afa7f8e7dd74..7f27e13a4463 100644
--- a/browser/base/content/browser-box.inc.xhtml
+++ b/browser/base/content/browser-box.inc.xhtml
@@ -6,6 +6,10 @@
   <box context="sidebar-context-menu" id="sidebar-main" hidden="true">
     <html:sidebar-main flex="1">
       <box id="vertical-tabs" slot="tabstrip" customizable="true" contextmenu="toolbar-context-menu"></box>
+      <box id="tree-vertical-tabs-box"
+       slot="tabstrip"
+       orient="vertical"
+       hidden="true"/>
     </html:sidebar-main>
   </box>
   <splitter id="sidebar-launcher-splitter" class="chromeclass-extrachrome sidebar-splitter" resizebefore="sibling" resizeafter="none" hidden="true"/>
diff --git a/browser/components/places/content/controller.js b/browser/components/places/content/controller.js
index a5095e61b838..d5964680186f 100644
--- a/browser/components/places/content/controller.js
+++ b/browser/components/places/content/controller.js
@@ -1510,6 +1510,8 @@ var PlacesControllerDragHelper = {
    * @returns {string} The most relevant flavor, or undefined.
    */
   getMostRelevantFlavor(flavors) {
+    if (flavors.contains(PlacesUtils.TYPE_X_WS_TREE))
+      return PlacesUtils.TYPE_X_WS_TREE;
     // The DnD API returns a DOMStringList, but tests may pass an Array.
     flavors = Array.from(flavors);
     return PlacesUIUtils.SUPPORTED_FLAVORS.find(f => flavors.includes(f));
@@ -1526,6 +1528,8 @@ var PlacesControllerDragHelper = {
    * @returns {boolean}
    */
   canDrop: function PCDH_canDrop(ip, dt) {
+    if (dt.mozTypesAt(0).contains(PlacesUtils.TYPE_X_WS_TREE))
+      return true;
     let dropCount = dt.mozItemCount;
 
     // Check every dragged item.
diff --git a/browser/components/sidebar/browser-sidebar.js b/browser/components/sidebar/browser-sidebar.js
index 597da4246167..00f3141a7924 100644
--- a/browser/components/sidebar/browser-sidebar.js
+++ b/browser/components/sidebar/browser-sidebar.js
@@ -580,6 +580,165 @@ var SidebarController = {
     );
   },
 
+  _toggleTreeInProgress: false,
+
+  /**
+   * Toggle the vertical tabs preference.
+   */
+  async toggleTreeVerticalTabs(shouldShow) {
+    // Using a lock to prevent re-entrancy from the preference observer
+    // while the function is already being executed from the UI event.
+    if (this._toggleTreeInProgress) {
+      return;
+    }
+    this._toggleTreeInProgress = true;
+
+    try {
+      const treeVerticalTabsBox = document.querySelector(
+        "#tree-vertical-tabs-box"
+      );
+      const verticalTabs = document.querySelector("#vertical-tabs");
+      shouldShow ??= !this.treeVerticalTabsBrowser;
+      const addon = await AddonManager.getAddonByID("sidebar@waterfox.net");
+      if (shouldShow != this.treeVerticalTabsEnabled) {
+        Services.prefs.setBoolPref("browser.sidebar.enabled", shouldShow);
+      }
+      if (shouldShow) {
+        if (this.treeVerticalTabsBrowser) {
+          return;
+        }
+        if (!addon.isActive) {
+          await addon.enable({ allowSystemAddons: true });
+        }
+        await addon.startupPromise;
+        if (!Services.prefs.getBoolPref("sidebar.revamp")) {
+          await this.toggleRevampSidebar();
+        }
+        if (!Services.prefs.getBoolPref("sidebar.verticalTabs")) {
+          Services.prefs.setBoolPref("sidebar.verticalTabs", true);
+          // The sidebar-main maybe not initialized yet at the first time.
+          while (!this.sidebarMain.requestUpdate) {
+            await new Promise(resolve => setTimeout(resolve, 100));
+          }
+          this.toggleTabstrip();
+        }
+
+        treeVerticalTabsBox.removeAttribute("hidden");
+        treeVerticalTabsBox.setAttribute("shown", true);
+
+        verticalTabs.setAttribute("hidden", true);
+        verticalTabs.removeAttribute("visible");
+
+        const policy = WebExtensionPolicy.getByID("sidebar@waterfox.net");
+
+        const treeVerticalTabs = document.createXULElement("browser");
+        treeVerticalTabs.setAttribute("id", "tree-vertical-tabs");
+        treeVerticalTabs.setAttribute("type", "content");
+        treeVerticalTabs.setAttribute("flex", "1");
+        treeVerticalTabs.setAttribute("disableglobalhistory", "true");
+        treeVerticalTabs.setAttribute(
+          "messagemanagergroup",
+          "webext-browsers"
+        );
+        treeVerticalTabs.setAttribute("webextension-view-type", "sidebar");
+        treeVerticalTabs.setAttribute("context", "contentAreaContextMenu");
+        treeVerticalTabs.setAttribute("tooltip", "aHTMLTooltip");
+        treeVerticalTabs.setAttribute("autocompletepopup", "PopupAutoComplete");
+        treeVerticalTabs.setAttribute("transparent", "true");
+        treeVerticalTabs.setAttribute("remote", "true");
+        treeVerticalTabs.setAttribute("remoteType", "extension");
+        treeVerticalTabs.setAttribute("maychangeremoteness", "true");
+        treeVerticalTabs.setAttribute("remoteType", "extension");
+        treeVerticalTabs.setAttribute("transparent", "true");
+        treeVerticalTabs.setAttribute(
+          "initialBrowsingContextGroupId",
+          policy.browsingContextGroupId
+        );
+
+        const { ExtensionUtils } = ChromeUtils.importESModule(
+          "resource://gre/modules/ExtensionUtils.sys.mjs"
+        );
+        const { promiseEvent } = ExtensionUtils;
+        const initBrowser = () => {
+          const { ExtensionParent } = ChromeUtils.importESModule(
+            "resource://gre/modules/ExtensionParent.sys.mjs"
+          );
+          ExtensionParent.apiManager.emit(
+            "extension-browser-inserted",
+            treeVerticalTabs,
+            {}
+          );
+          treeVerticalTabs.messageManager.loadFrameScript(
+            "chrome://extensions/content/ext-browser-content.js",
+            false,
+            true
+          );
+          treeVerticalTabs.messageManager.sendAsyncMessage(
+            "Extension:InitBrowser",
+            {}
+          );
+
+          const sidebarPanelUrl = policy.getURL("sidebar/sidebar.html");
+          const uri = Services.io.newURI(sidebarPanelUrl);
+          const triggeringPrincipal =
+            Services.scriptSecurityManager.createContentPrincipal(uri, {});
+          treeVerticalTabs.fixupAndLoadURIString(sidebarPanelUrl, {
+            triggeringPrincipal,
+          });
+        };
+        promiseEvent(treeVerticalTabs, "XULFrameLoaderCreated").then(
+          initBrowser
+        );
+        treeVerticalTabs.addEventListener(
+          "DidChangeBrowserRemoteness",
+          initBrowser
+        );
+
+        treeVerticalTabsBox.appendChild(treeVerticalTabs);
+
+        const event = new CustomEvent("TreeVerticalTabsShown", {
+          bubbles: true,
+        });
+        treeVerticalTabsBox.dispatchEvent(event);
+      } else {
+        const treeVerticalTabs = this.treeVerticalTabsBrowser;
+        if (!treeVerticalTabs) {
+          return;
+        }
+        const uri = Services.io.newURI("about:blank");
+        const triggeringPrincipal =
+          Services.scriptSecurityManager.createContentPrincipal(uri, {});
+        treeVerticalTabs.fixupAndLoadURIString("about:blank", {
+          triggeringPrincipal,
+        });
+        treeVerticalTabsBox.removeChild(treeVerticalTabs);
+
+        treeVerticalTabsBox.setAttribute("hidden", true);
+        treeVerticalTabsBox.removeAttribute("shown");
+
+        verticalTabs.removeAttribute("hidden");
+        if (Services.prefs.getBoolPref("sidebar.verticalTabs")) {
+          verticalTabs.setAttribute("visible", "");
+        }
+
+        const event = new CustomEvent("TreeVerticalTabsHidden", {
+          bubbles: true,
+        });
+        treeVerticalTabsBox.dispatchEvent(event);
+
+        if (!shouldShow && addon.isActive) {
+          await addon.disable({ allowSystemAddons: true });
+        }
+      }
+    } finally {
+      this._toggleTreeInProgress = false;
+    }
+  },
+
+  get treeVerticalTabsBrowser() {
+    return document.querySelector("#tree-vertical-tabs");
+  },
+
   /**
    * The handler for Services.obs.addObserver.
    */
@@ -760,6 +919,7 @@ var SidebarController = {
     if (content && content.updatePosition) {
       content.updatePosition();
     }
+    this.treeVerticalTabsBrowser?.reload();
   },
 
   /**
@@ -857,6 +1017,10 @@ var SidebarController = {
       return;
     }
 
+    if (this.treeVerticalTabsEnabled) {
+      this.toggleTreeVerticalTabs();
+    }
+
     let sourceWindow = window.opener;
     // No source window means this is the initial window.  If we're being
     // opened from another window, check that it is one we might open a sidebar
@@ -1979,6 +2143,9 @@ var SidebarController = {
       arrowScrollbox.setAttribute("orient", "horizontal");
       tabStrip.removeAttribute("expanded");
       tabStrip.setAttribute("orient", "horizontal");
+      if (this.treeVerticalTabsEnabled) {
+         this.toggleTreeVerticalTabs(false);
+       }
     }
 
     let verticalToolbar = document.getElementById(
@@ -2307,3 +2474,13 @@ XPCOMUtils.defineLazyPreferenceGetter(
     }
   }
 );
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  SidebarController,
+  "treeVerticalTabsEnabled",
+  "browser.sidebar.enabled",
+  false,
+  (_aPreference, _previousValue, newValue) => {
+    SidebarController.toggleTreeVerticalTabs(newValue);
+  }
+);
diff --git a/browser/components/sidebar/sidebar-customize.html b/browser/components/sidebar/sidebar-customize.html
index 3996bae0ea6e..70014e75775f 100644
--- a/browser/components/sidebar/sidebar-customize.html
+++ b/browser/components/sidebar/sidebar-customize.html
@@ -14,6 +14,7 @@
     <title data-l10n-id="sidebar-customize-title"></title>
     <link rel="localization" href="branding/brand.ftl" />
     <link rel="localization" href="browser/sidebar.ftl" />
+    <link rel="localization" href="browser/waterfox.ftl" />
     <link
       rel="stylesheet"
       href="chrome://browser/content/sidebar/sidebar.css"
diff --git a/browser/components/sidebar/sidebar-customize.mjs b/browser/components/sidebar/sidebar-customize.mjs
index b9036bd22d84..c9c130143e1a 100644
--- a/browser/components/sidebar/sidebar-customize.mjs
+++ b/browser/components/sidebar/sidebar-customize.mjs
@@ -296,6 +296,15 @@ export class SidebarCustomize extends SidebarPage {
                 ?disabled=${this.getWindow().SidebarController._state
                   .revampVisibility === "expand-on-hover"}
               ></moz-checkbox>
+              <moz-checkbox
+                slot="nested"
+                type="checkbox"
+                id="tree-vertical-tabs"
+                name="treeVerticalTabs"
+                data-l10n-id="sidebar-tree-vertical-tabs"
+                @change=${this.#handleTreeVerticalTabsChange}
+                ?checked=${this.getWindow().SidebarController.treeVerticalTabsEnabled}
+              ></moz-checkbox>
             `
           )}
           </moz-checkbox>
@@ -356,6 +365,11 @@ export class SidebarCustomize extends SidebarPage {
     });
   }
 
+  #handleTreeVerticalTabsChange(e) {
+    e.stopPropagation();
+    this.getWindow().SidebarController.toggleTreeVerticalTabs(e.target.checked);
+  }
+
   #toggleExpandOnHover(e) {
     e.stopPropagation();
     if (e.target.checked) {
diff --git a/browser/components/sidebar/sidebar-main.mjs b/browser/components/sidebar/sidebar-main.mjs
index 0b6d809f0a10..42a5bca380a9 100644
--- a/browser/components/sidebar/sidebar-main.mjs
+++ b/browser/components/sidebar/sidebar-main.mjs
@@ -132,6 +132,9 @@ export default class SidebarMain extends MozLitElement {
   }
 
   onSidebarPopupShowing(event) {
+    if (event.target == SidebarController.treeVerticalTabsBrowser) {
+      return;
+    }
     // Store the context menu target which holds the id required for managing sidebar items
     let targetHost = event.explicitOriginalTarget.getRootNode().host;
     let toolbarContextMenuTarget =
diff --git a/browser/components/tabbrowser/content/tab-hover-preview.mjs b/browser/components/tabbrowser/content/tab-hover-preview.mjs
index 3280a391bd80..05259df4702c 100644
--- a/browser/components/tabbrowser/content/tab-hover-preview.mjs
+++ b/browser/components/tabbrowser/content/tab-hover-preview.mjs
@@ -62,7 +62,14 @@ export default class TabHoverPreviewPanel {
     this._panelOpener = new TabPreviewPanelTimedFunction(
       () => {
         if (!this._isDisabled()) {
-          this._panel.openPopup(this._tab, this.#popupOptions);
+          if (this._win.SidebarController.treeVerticalTabsEnabled &&
+              typeof this.__ws__top == 'number') {
+            const [x, y] = this.calculateCoordinatesForVertical();
+            this._panel.openPopupAtScreen(x, y, false);
+          }
+          else {
+            this._panel.openPopup(this._tab, this.#popupOptions);
+          }
         }
       },
       this._prefPreviewDelay,
@@ -165,6 +172,18 @@ export default class TabHoverPreviewPanel {
       });
   }
 
+  calculateCoordinatesForVertical() {
+    const treeVerticalTabs = this._win.document.querySelector('#tree-vertical-tabs');
+    const treeVerticalTabsRect = treeVerticalTabs.getBoundingClientRect();
+    const align = Services.prefs.getBoolPref('sidebar.position_start') ? 'left' : 'right';
+    const previewRect = this._panel.getBoundingClientRect();
+    const x = align == 'left' ?
+      treeVerticalTabs.screenX + treeVerticalTabsRect.width - 2 :
+      treeVerticalTabs.screenX - previewRect.width + 2;
+    const y = Math.min(treeVerticalTabs.screenY + this.__ws__top, treeVerticalTabs.screenY + treeVerticalTabsRect.height - previewRect.height);
+    return [x, y];
+  }
+
   activate(tab) {
     if (this._isDisabled()) {
       return;
@@ -270,6 +289,12 @@ export default class TabHoverPreviewPanel {
 
   _movePanel() {
     if (this._tab) {
+      if (this._win.SidebarController.treeVerticalTabsEnabled &&
+          typeof this.__ws__top == 'number') {
+        const [x, y] = this.calculateCoordinatesForVertical();
+        this._panel.moveTo(x, y);
+        return;
+      }
       this._panel.moveToAnchor(
         this._tab,
         this.#popupOptions.position,
diff --git a/toolkit/components/places/PlacesUtils.sys.mjs b/toolkit/components/places/PlacesUtils.sys.mjs
index d11573403881..5f779b00eadf 100644
--- a/toolkit/components/places/PlacesUtils.sys.mjs
+++ b/toolkit/components/places/PlacesUtils.sys.mjs
@@ -430,6 +430,9 @@ export var PlacesUtils = {
   // Used to track the action that populated the clipboard.
   TYPE_X_MOZ_PLACE_ACTION: "text/x-moz-place-action",
 
+  // Used to track actouns from the Tree Vertical Tabs sidebar.
+  TYPE_X_WS_TREE: "application/x-ws-tree",
+
   // Deprecated: Remaining only for supporting migration of old livemarks.
   LMANNO_FEEDURI: "livemark/feedURI",
   LMANNO_SITEURI: "livemark/siteURI",
@@ -1305,6 +1308,17 @@ export var PlacesUtils = {
         }
         break;
       }
+      case this.TYPE_X_WS_TREE: {
+        const data = JSON.parse(blob);
+        for (const tab of data.tabs) {
+          validNodes.push({
+            uri:   tab.url,
+            title: tab.title,
+            type:  "text/x-moz-url",
+          });
+        }
+        break;
+      }
       default:
         throw Components.Exception("", Cr.NS_ERROR_INVALID_ARG);
     }