Add combined model selector and refactor working indicator

packages/app/src/utils/working-indicator.test.ts

@@ -0,0 +1,33 @@
+import { describe, expect, it } from "vitest";
+import {
+  getWorkingIndicatorDotStrength,
+  WORKING_INDICATOR_OFFSETS,
+} from "./working-indicator";
+
+describe("getWorkingIndicatorDotStrength", () => {
+  it("returns a stable triangular pulse over one cycle", () => {
+    expect(getWorkingIndicatorDotStrength(0, 0)).toBe(0);
+    expect(getWorkingIndicatorDotStrength(0.125, 0)).toBe(0.25);
+    expect(getWorkingIndicatorDotStrength(0.25, 0)).toBe(0.5);
+    expect(getWorkingIndicatorDotStrength(0.5, 0)).toBe(1);
+    expect(getWorkingIndicatorDotStrength(0.75, 0)).toBe(0.5);
+    expect(getWorkingIndicatorDotStrength(1, 0)).toBe(0);
+  });
+
+  it("keeps the dots phase-shifted instead of identical", () => {
+    const strengths = WORKING_INDICATOR_OFFSETS.map((offset) =>
+      getWorkingIndicatorDotStrength(0, offset)
+    );
+
+    expect(strengths).toEqual([0, 0.26666666666666666, 0.5333333333333333]);
+  });
+
+  it("wraps progress cleanly across loop boundaries", () => {
+    expect(getWorkingIndicatorDotStrength(1.1, 0)).toBeCloseTo(
+      getWorkingIndicatorDotStrength(0.1, 0)
+    );
+    expect(getWorkingIndicatorDotStrength(-0.1, 0)).toBeCloseTo(
+      getWorkingIndicatorDotStrength(0.9, 0)
+    );
+  });
+});

packages/app/src/utils/working-indicator.ts

@@ -0,0 +1,22 @@
+export const WORKING_INDICATOR_CYCLE_MS = 1200;
+export const WORKING_INDICATOR_OFFSETS = [
+  0,
+  160 / WORKING_INDICATOR_CYCLE_MS,
+  320 / WORKING_INDICATOR_CYCLE_MS,
+] as const;
+
+function normalizePhase(value: number): number {
+  const wrapped = value % 1;
+  return wrapped < 0 ? wrapped + 1 : wrapped;
+}
+
+export function getWorkingIndicatorDotStrength(
+  progress: number,
+  offset: number
+): number {
+  const phase = normalizePhase(progress + offset);
+  if (phase <= 0.5) {
+    return phase * 2;
+  }
+  return (1 - phase) * 2;
+}