feat(workspace): add resizable markdown editor/preview split with draggable handle and markdown outlet styling/demo

ts_web/elements/00group-workspace/dees-workspace-markdown/dees-workspace-markdown.ts

@@ -6,7 +6,8 @@ import {
   type TemplateResult,
   css,
   cssManager,
-  domtools
+  domtools,
+  state,
 } from '@design.estate/dees-element';
 import { themeDefaultStyles } from '../../00theme.js';
 import { DeesWorkspaceMonaco } from '../dees-workspace-monaco/dees-workspace-monaco.js';
@@ -27,31 +28,113 @@ export class DeesWorkspaceMarkdown extends DeesElement {
     themeDefaultStyles,
     cssManager.defaultStyles,
     css`
-      /* TODO: Migrate hardcoded values to --dees-* CSS variables */
-      .gridcontainer {
+      :host {
+        display: block;
+        position: relative;
+        width: 100%;
+        height: 100%;
+      }
+
+      .splitContainer {
         position: absolute;
         height: 100%;
         width: 100%;
-        display: grid;
-        grid-template-columns: 60% 40%;
+        display: flex;
+        flex-direction: row;
       }
+
       .editorContainer {
         position: relative;
+        height: 100%;
+        min-width: 100px;
+        overflow: hidden;
       }
+
+      .resizeHandle {
+        width: 6px;
+        height: 100%;
+        background: ${cssManager.bdTheme('#e5e7eb', '#30363d')};
+        cursor: col-resize;
+        flex-shrink: 0;
+        transition: background 0.15s ease;
+        position: relative;
+      }
+
+      .resizeHandle:hover,
+      .resizeHandle.dragging {
+        background: ${cssManager.bdTheme('#3b82f6', '#58a6ff')};
+      }
+
+      .resizeHandle::after {
+        content: '';
+        position: absolute;
+        top: 50%;
+        left: 50%;
+        transform: translate(-50%, -50%);
+        width: 2px;
+        height: 32px;
+        background: ${cssManager.bdTheme('#9ca3af', '#6e7681')};
+        border-radius: 1px;
+        opacity: 0.6;
+      }
+
+      .resizeHandle:hover::after,
+      .resizeHandle.dragging::after {
+        background: ${cssManager.bdTheme('#ffffff', '#ffffff')};
+        opacity: 1;
+      }
+
       .outletContainer {
-        background: #111;
-        color: #fff;
-        font-family: 'Roboto Slab';
+        position: relative;
+        height: 100%;
+        min-width: 100px;
+        background: ${cssManager.bdTheme('#ffffff', '#0d1117')};
+        color: ${cssManager.bdTheme('#24292f', '#e6edf3')};
+        font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans', Helvetica, Arial, sans-serif;
         padding: 20px;
-        overflow-y: scroll;
+        overflow-y: auto;
+        box-sizing: border-box;
+      }
+
+      /* Prevent text selection while dragging */
+      .splitContainer.dragging {
+        user-select: none;
+      }
+
+      .splitContainer.dragging .editorContainer,
+      .splitContainer.dragging .outletContainer {
+        pointer-events: none;
       }
     `,
   ];
 
+  /**
+   * Initial split ratio for the editor (left) panel.
+   * Value from 0 to 100 representing percentage width.
+   * Default is 50 (50/50 split).
+   */
+  @property({ type: Number })
+  accessor splitRatio: number = 50;
+
+  /**
+   * Minimum width percentage for either panel.
+   */
+  @property({ type: Number })
+  accessor minPanelSize: number = 10;
+
+  @state()
+  accessor currentSplitRatio: number = 50;
+
+  @state()
+  accessor isDragging: boolean = false;
+
+  private resizeHandleElement: HTMLElement;
+  private containerElement: HTMLElement;
+
   public render() {
     return html`
-      <div class="gridcontainer">
-        <div class="editorContainer">
+      <div class="splitContainer ${this.isDragging ? 'dragging' : ''}">
+        <div class="editorContainer" style="width: ${this.currentSplitRatio}%">
           <dees-workspace-monaco
             .language=${'markdown'}
             .content=${`# a test content
@@ -78,7 +161,11 @@ const hello = 'yes'
             wordWrap="bounded"
           ></dees-workspace-monaco>
         </div>
-        <div class="outletContainer">
+        <div
+          class="resizeHandle ${this.isDragging ? 'dragging' : ''}"
+          @mousedown=${this.handleMouseDown}
+        ></div>
+        <div class="outletContainer" style="width: ${100 - this.currentSplitRatio}%">
           <dees-workspace-markdownoutlet></dees-workspace-markdownoutlet>
         </div>
       </div>
@@ -87,9 +174,17 @@ const hello = 'yes'
 
   public async firstUpdated(_changedPropertiesArg) {
     await super.firstUpdated(_changedPropertiesArg);
+
+    // Initialize current ratio from property
+    this.currentSplitRatio = this.splitRatio;
+
+    // Cache elements
+    this.containerElement = this.shadowRoot.querySelector('.splitContainer');
+    this.resizeHandleElement = this.shadowRoot.querySelector('.resizeHandle');
+
     const editor = this.shadowRoot.querySelector('dees-workspace-monaco') as DeesWorkspaceMonaco;
 
-    // lets care about wiring the markdown stuff.
+    // Wire up markdown rendering
     const markdownOutlet = this.shadowRoot.querySelector('dees-workspace-markdownoutlet');
     const smartmarkdownInstance = new domtools.plugins.smartmarkdown.SmartMarkdown();
     const mdParsedResult = await smartmarkdownInstance.getMdParsedResultFromMarkdown('loading...')
@@ -97,6 +192,64 @@ const hello = 'yes'
       await mdParsedResult.updateFromMarkdownString(contentArg)
       const html = mdParsedResult.html;
       markdownOutlet.updateHtmlText(html);
-    })
+    });
+  }
+
+  private handleMouseDown = (e: MouseEvent) => {
+    e.preventDefault();
+    this.isDragging = true;
+
+    document.addEventListener('mousemove', this.handleMouseMove);
+    document.addEventListener('mouseup', this.handleMouseUp);
+  };
+
+  private handleMouseMove = (e: MouseEvent) => {
+    if (!this.isDragging || !this.containerElement) return;
+
+    const containerRect = this.containerElement.getBoundingClientRect();
+    const containerWidth = containerRect.width;
+    const mouseX = e.clientX - containerRect.left;
+
+    // Calculate percentage, accounting for the resize handle width (6px)
+    let newRatio = (mouseX / containerWidth) * 100;
+
+    // Clamp to min/max
+    newRatio = Math.max(this.minPanelSize, Math.min(100 - this.minPanelSize, newRatio));
+
+    this.currentSplitRatio = newRatio;
+  };
+
+  private handleMouseUp = () => {
+    this.isDragging = false;
+    document.removeEventListener('mousemove', this.handleMouseMove);
+    document.removeEventListener('mouseup', this.handleMouseUp);
+
+    // Trigger resize on monaco editor
+    const editor = this.shadowRoot.querySelector('dees-workspace-monaco') as DeesWorkspaceMonaco;
+    if (editor) {
+      // Monaco needs to be notified of size changes
+      window.dispatchEvent(new Event('resize'));
+    }
+  };
+
+  async disconnectedCallback() {
+    await super.disconnectedCallback();
+    // Clean up event listeners
+    document.removeEventListener('mousemove', this.handleMouseMove);
+    document.removeEventListener('mouseup', this.handleMouseUp);
+  }
+
+  /**
+   * Programmatically set the split ratio
+   */
+  public setSplitRatio(ratio: number) {
+    this.currentSplitRatio = Math.max(this.minPanelSize, Math.min(100 - this.minPanelSize, ratio));
+  }
+
+  /**
+   * Reset to initial split ratio
+   */
+  public resetSplitRatio() {
+    this.currentSplitRatio = this.splitRatio;
   }
 }