Positioning, sizing and sorting of the gadgets improved.

frontend/src/components/today/today-dashboard-layout.ts

@@ -0,0 +1,135 @@
+import type { ReactNode } from 'react';
+
+/** Dashboard grid is always 4 columns (at lg+). Widgets use fixed width/height units. */
+export type TodayDashboardWidth = 1 | 2;
+export type TodayDashboardHeight = 1 | 2 | 3;
+
+export interface TodayDashboardLayout {
+  width: TodayDashboardWidth;
+  height: TodayDashboardHeight;
+}
+
+/** Shared layout presets — assign when registering a dashboard widget. */
+export const TODAY_DASHBOARD_LAYOUT = {
+  kpi: { width: 1, height: 1 },
+  subscription: { width: 1, height: 2 },
+  upcoming: { width: 2, height: 3 },
+  /** Tall charts: area, stacked bar, pie with side legend */
+  chart: { width: 2, height: 3 },
+  /** Medium charts: horizontal bar, vertical bar, radial gauge */
+  chartMedium: { width: 2, height: 2 },
+} as const satisfies Record<string, TodayDashboardLayout>;
+
+export interface TodayDashboardCell {
+  id: string;
+  layout: TodayDashboardLayout;
+  content: ReactNode;
+}
+
+export interface PackedDashboardCell extends TodayDashboardCell {
+  gridColumn: string;
+  gridRow: string;
+}
+
+export function compareDashboardLayout(
+  a: TodayDashboardLayout,
+  b: TodayDashboardLayout,
+): number {
+  if (a.width !== b.width) return a.width - b.width;
+  return a.height - b.height;
+}
+
+export function sortDashboardCells<T extends { layout: TodayDashboardLayout; id: string }>(
+  cells: T[],
+): T[] {
+  return [...cells].sort((a, b) => {
+    const byLayout = compareDashboardLayout(a.layout, b.layout);
+    if (byLayout !== 0) return byLayout;
+    return a.id.localeCompare(b.id);
+  });
+}
+
+/** Wide widgets (width > 1) anchor to column pairs — never straddle the grid center. */
+export function allowedStartColumns(
+  width: number,
+  columns: number,
+): number[] {
+  if (width <= 1) {
+    return Array.from({ length: columns }, (_, index) => index);
+  }
+
+  if (width === 2 && columns === 4) {
+    return [0, 2];
+  }
+
+  return Array.from({ length: columns - width + 1 }, (_, index) => index);
+}
+
+/**
+ * First-fit placement in ascending layout order (top-left scan).
+ * Multi-column widgets may only start at aligned column pairs (1–2 or 3–4 on a 4-col grid).
+ */
+export function packDashboardCells(
+  cells: TodayDashboardCell[],
+  columns = 4,
+): PackedDashboardCell[] {
+  const sorted = sortDashboardCells(cells);
+  const occupied = new Set<string>();
+
+  function canPlace(row: number, col: number, width: number, height: number): boolean {
+    if (col + width > columns) return false;
+    for (let r = row; r < row + height; r += 1) {
+      for (let c = col; c < col + width; c += 1) {
+        if (occupied.has(`${r}-${c}`)) return false;
+      }
+    }
+    return true;
+  }
+
+  function mark(row: number, col: number, width: number, height: number) {
+    for (let r = row; r < row + height; r += 1) {
+      for (let c = col; c < col + width; c += 1) {
+        occupied.add(`${r}-${c}`);
+      }
+    }
+  }
+
+  const placed: PackedDashboardCell[] = [];
+
+  for (const cell of sorted) {
+    const { width, height } = cell.layout;
+    let found = false;
+    const startColumns = allowedStartColumns(width, columns);
+
+    for (let row = 0; !found; row += 1) {
+      for (const col of startColumns) {
+        if (!canPlace(row, col, width, height)) continue;
+        mark(row, col, width, height);
+        placed.push({
+          ...cell,
+          gridColumn: `${col + 1} / span ${width}`,
+          gridRow: `${row + 1} / span ${height}`,
+        });
+        found = true;
+        break;
+      }
+    }
+  }
+
+  return placed;
+}
+
+export function packedCellClassName(layout: TodayDashboardLayout): string {
+  const rowSpan =
+    layout.height === 3 ? 'row-span-3' : layout.height === 2 ? 'row-span-2' : 'row-span-1';
+
+  const colSpan =
+    layout.width === 2
+      ? 'col-span-2 max-sm:col-span-1'
+      : 'col-span-1';
+
+  return `${colSpan} ${rowSpan} min-h-0 min-w-0 overflow-hidden flex flex-col max-lg:${colSpan}`;
+}
+
+export const TODAY_DASHBOARD_GRID_CLASS =
+  'today-dashboard-grid grid grid-cols-4 max-lg:grid-cols-2 max-sm:grid-cols-1 gap-4';