Enhances header drawer with multi-row event layout

Improves header drawer rendering to support multi-row event stacking

Adds row-based layout algorithm for all-day events
Enables flexible height expansion based on event count
Provides more robust event placement across visible date range

src/v2/features/headerdrawer/HeaderDrawerRenderer.ts

@@ -10,6 +10,16 @@ import {
   IDragLeaveHeaderPayload
 } from '../../types/DragTypes';
 
+/**
+ * Layout information for a header item
+ */
+interface IHeaderItemLayout {
+  event: ICalendarEvent;
+  row: number;        // 1-indexed
+  colStart: number;   // 1-indexed
+  colEnd: number;     // exclusive
+}
+
 /**
  * HeaderDrawerRenderer - Handles rendering of items in the header drawer
  *
@@ -36,7 +46,7 @@ export class HeaderDrawerRenderer {
   }
 
   /**
-   * Render allDay events into the header drawer
+   * Render allDay events into the header drawer with row stacking
    */
   async render(container: HTMLElement, filter: Record<string, string[]>): Promise<void> {
     const drawer = container.querySelector('swp-header-drawer');
@@ -58,31 +68,27 @@ export class HeaderDrawerRenderer {
     // Clear existing items
     drawer.innerHTML = '';
 
-    // Render each allDay event
-    allDayEvents.forEach(event => {
-      const item = this.createHeaderItem(event, visibleDates);
-      if (item) drawer.appendChild(item);
+    if (allDayEvents.length === 0) return;
+
+    // Calculate layout with row stacking
+    const layouts = this.calculateLayout(allDayEvents, visibleDates);
+    const rowCount = Math.max(1, ...layouts.map(l => l.row));
+
+    // Render each item with layout
+    layouts.forEach(layout => {
+      const item = this.createHeaderItem(layout);
+      drawer.appendChild(item);
     });
 
-    // Expand drawer if there are items
-    if (allDayEvents.length > 0) {
-      this.headerDrawerManager.expand();
-    }
+    // Expand drawer to fit all rows
+    this.headerDrawerManager.expandToRows(rowCount);
   }
 
   /**
-   * Create a header item element for an allDay event
-   * Supports multi-day events with column span
+   * Create a header item element from layout
    */
-  private createHeaderItem(event: ICalendarEvent, visibleDates: string[]): HTMLElement | null {
-    const startDateKey = this.dateService.getDateKey(event.start);
-    const endDateKey = this.dateService.getDateKey(event.end);
-
-    const startColIndex = visibleDates.indexOf(startDateKey);
-    const endColIndex = visibleDates.indexOf(endDateKey);
-
-    // Event skal mindst starte eller slutte inden for synlige datoer
-    if (startColIndex === -1 && endColIndex === -1) return null;
+  private createHeaderItem(layout: IHeaderItemLayout): HTMLElement {
+    const { event, row, colStart, colEnd } = layout;
 
     const item = document.createElement('swp-header-item');
     item.dataset.eventId = event.id;
@@ -95,14 +101,68 @@ export class HeaderDrawerRenderer {
     const colorClass = this.getColorClass(event);
     if (colorClass) item.classList.add(colorClass);
 
-    // Grid position (1-indexed, clamp til synlige kolonner)
-    const col = Math.max(0, startColIndex) + 1;
-    const endCol = (endColIndex !== -1 ? endColIndex : visibleDates.length - 1) + 2;
-    item.style.gridArea = `1 / ${col} / 2 / ${endCol}`;
+    // Grid position from layout
+    item.style.gridArea = `${row} / ${colStart} / ${row + 1} / ${colEnd}`;
 
     return item;
   }
 
+  /**
+   * Calculate layout for all events with row stacking
+   * Uses track-based algorithm to find available rows for overlapping events
+   */
+  private calculateLayout(events: ICalendarEvent[], visibleDates: string[]): IHeaderItemLayout[] {
+    // tracks[row][col] = occupied
+    const tracks: boolean[][] = [new Array(visibleDates.length).fill(false)];
+    const layouts: IHeaderItemLayout[] = [];
+
+    for (const event of events) {
+      const startCol = this.getColIndex(event.start, visibleDates);
+      const endCol = this.getColIndex(event.end, visibleDates);
+      if (startCol === -1 && endCol === -1) continue;
+
+      // Clamp til synlige kolonner
+      const colStart = Math.max(0, startCol);
+      const colEnd = (endCol !== -1 ? endCol : visibleDates.length - 1) + 1;
+
+      // Find ledig række
+      const row = this.findAvailableRow(tracks, colStart, colEnd);
+
+      // Marker som optaget
+      for (let c = colStart; c < colEnd; c++) {
+        tracks[row][c] = true;
+      }
+
+      layouts.push({ event, row: row + 1, colStart: colStart + 1, colEnd: colEnd + 1 });
+    }
+
+    return layouts;
+  }
+
+  /**
+   * Find available row for event spanning columns [colStart, colEnd)
+   */
+  private findAvailableRow(tracks: boolean[][], colStart: number, colEnd: number): number {
+    for (let row = 0; row < tracks.length; row++) {
+      let available = true;
+      for (let c = colStart; c < colEnd; c++) {
+        if (tracks[row][c]) { available = false; break; }
+      }
+      if (available) return row;
+    }
+    // Ny række
+    tracks.push(new Array(tracks[0].length).fill(false));
+    return tracks.length - 1;
+  }
+
+  /**
+   * Get column index for a date (0-indexed, -1 if not found)
+   */
+  private getColIndex(date: Date, visibleDates: string[]): number {
+    const dateKey = this.dateService.getDateKey(date);
+    return visibleDates.indexOf(dateKey);
+  }
+
   /**
    * Get color class based on event metadata or type
    */