feat: functional gridfinity calculator app

src/calculator.ts

@@ -0,0 +1,66 @@
+export interface GridfinitySpec {
+  gridSize: number; // e.g., 42mm
+  heightUnit: number; // e.g., 7mm
+  baseThickness: number; // Height of baseplate above drawer surface
+}
+
+export const DEFAULT_SPEC: GridfinitySpec = {
+  gridSize: 42,
+  heightUnit: 7,
+  baseThickness: 4.8, // Standard baseplate height is 5mm, but usually 4.8mm-5mm
+};
+
+export interface CalculatorInputs {
+  width: number;
+  length: number;
+  height: number;
+  unit: 'mm' | 'in';
+  spec: GridfinitySpec;
+}
+
+export interface CalculatorResults {
+  widthGrids: number;
+  lengthGrids: number;
+  fullGridsX: number;
+  fullGridsY: number;
+  maxBinUnits: number;
+  remainingWidth: number;
+  remainingLength: number;
+  remainingHeight: number;
+}
+
+const INCH_TO_MM = 25.4;
+
+export function calculateGridfinity(inputs: CalculatorInputs): CalculatorResults {
+  const { width, length, height, unit, spec } = inputs;
+  
+  // Convert all to mm for internal calculation
+  const w = unit === 'in' ? width * INCH_TO_MM : width;
+  const l = unit === 'in' ? length * INCH_TO_MM : length;
+  const h = unit === 'in' ? height * INCH_TO_MM : height;
+
+  const widthGrids = w / spec.gridSize;
+  const lengthGrids = l / spec.gridSize;
+  
+  const fullGridsX = Math.floor(widthGrids);
+  const fullGridsY = Math.floor(lengthGrids);
+  
+  // Height calculation: (Available Height - Baseplate Thickness) / 7mm
+  // We floor this because bins come in whole unit increments
+  const maxBinUnits = Math.max(0, Math.floor((h - spec.baseThickness) / spec.heightUnit));
+  
+  const remainingWidth = w % spec.gridSize;
+  const remainingLength = l % spec.gridSize;
+  const remainingHeight = (h - spec.baseThickness) % spec.heightUnit;
+
+  return {
+    widthGrids,
+    lengthGrids,
+    fullGridsX,
+    fullGridsY,
+    maxBinUnits,
+    remainingWidth,
+    remainingLength,
+    remainingHeight
+  };
+}