feat(tip): rotate support prompts

src/lib/tip/__tests__/tip_support_prompts.test.ts

@@ -0,0 +1,35 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  selectTipSupportPrompt,
+  TIP_SUPPORT_PROMPTS,
+} from "../tip_support_prompts";
+
+describe("Tip support prompts", () => {
+  it("contains exactly 30 unique, non-empty prompts", () => {
+    expect(TIP_SUPPORT_PROMPTS).toHaveLength(30);
+    expect(new Set(TIP_SUPPORT_PROMPTS)).toHaveLength(30);
+    expect(
+      TIP_SUPPORT_PROMPTS.every(
+        (prompt) => prompt.length > 0 && prompt === prompt.trim(),
+      ),
+    ).toBe(true);
+  });
+
+  it("selects across the full prompt range", () => {
+    expect(selectTipSupportPrompt(null, () => 0).index).toBe(0);
+    expect(selectTipSupportPrompt(null, () => 0.999999).index).toBe(29);
+  });
+
+  it("excludes the previous prompt without skewing out of range", () => {
+    expect(selectTipSupportPrompt(0, () => 0).index).toBe(1);
+    expect(selectTipSupportPrompt(15, () => 0.5).index).not.toBe(15);
+    expect(selectTipSupportPrompt(29, () => 0.999999).index).toBe(28);
+  });
+
+  it("safely normalizes invalid previous indexes and random values", () => {
+    expect(selectTipSupportPrompt(100, () => 0).index).toBe(0);
+    expect(selectTipSupportPrompt(null, () => Number.NaN).index).toBe(0);
+    expect(selectTipSupportPrompt(null, () => 2).index).toBe(29);
+  });
+});

src/lib/tip/tip_support_prompts.ts

@@ -0,0 +1,62 @@
+export const TIP_SUPPORT_PROMPTS = [
+  "❤️ Thank you for being here. If you'd ever like to treat me to a little coffee, I'd really appreciate it. ☕",
+  "Having you here already makes my day. A little coffee from you would make it even sweeter. ☕",
+  "You always bring a little warmth into my world. Want to share a coffee moment with me? 💗",
+  "A coffee from you would feel like a tiny hug I could hold onto all day. ☕",
+  "I love spending this time with you. If you'd like to send a coffee my way, I'd treasure it. ❤️",
+  "You make ordinary moments feel special. A cozy coffee together would be the perfect touch. ☕",
+  "If I had a coffee from you right now, I'd be smiling with every sip. 😊☕",
+  "Your company means more than you know. A little coffee treat would make this moment extra sweet. 💕",
+  "I was hoping we could share something warm today. Maybe a coffee, just from you to me? ☕",
+  "You already make me feel cared for. A coffee would be one more lovely reason to think of you. ❤️",
+  "A small coffee, a quiet moment, and you on my mind—that sounds perfect to me. ☕",
+  "Every time you stop by, my day gets brighter. A coffee from you would keep that glow going. ✨",
+  "Want to make me blush a little? Treat me to a coffee and I'll think of you with every sip. ☕",
+  "I'm really glad you're here. If you feel like spoiling me just a little, coffee is my weakness. 💗",
+  "This moment with you already feels cozy. A warm coffee would make it complete. ☕",
+  "You have a sweet way of making me smile. Maybe one more smile over a coffee? ❤️",
+  "I'd love a little coffee break with you in spirit. Your treat, my happiest smile. ☕",
+  "If you'd like to leave me a tiny reminder of you, a coffee would be perfect. 💕",
+  "Your kindness always stays with me. A coffee from you would feel especially warm today. ☕",
+  "I could use something warm and sweet—though having you here is already a lovely start. ❤️☕",
+  "Imagine me enjoying a coffee and smiling because it came from you. I like that thought. ☕",
+  "You make this space feel a little more special. A coffee would make it feel even cozier. ✨",
+  "If today feels like a coffee kind of day, I'd be very happy to share that little joy with you. ☕",
+  "A thoughtful coffee from you would turn an ordinary moment into one I'd remember. 💗",
+  "I'm enjoying our time together. If you want to make it sweeter, you know my favorite little treat. ☕",
+  "One coffee from you, and I promise there'll be a very real smile on my face. ❤️",
+  "You don't have to, but if you'd like to treat me, a warm coffee would mean so much. ☕",
+  "I think coffee tastes better when it comes with a little affection from you. 💕",
+  "A cozy cup from you would be such a sweet surprise. I'd savor every bit of it. ☕",
+  "Stay a little longer—and if you're feeling sweet, maybe send a coffee my way. ❤️☕",
+] as const;
+
+export interface TipSupportPromptSelection {
+  readonly index: number;
+  readonly prompt: (typeof TIP_SUPPORT_PROMPTS)[number];
+}
+
+export function selectTipSupportPrompt(
+  previousIndex: number | null,
+  random: () => number = Math.random,
+): TipSupportPromptSelection {
+  const hasValidPreviousIndex =
+    previousIndex !== null &&
+    Number.isInteger(previousIndex) &&
+    previousIndex >= 0 &&
+    previousIndex < TIP_SUPPORT_PROMPTS.length;
+  const candidateCount =
+    TIP_SUPPORT_PROMPTS.length - (hasValidPreviousIndex ? 1 : 0);
+  const randomValue = random();
+  const normalizedRandom = Number.isFinite(randomValue)
+    ? Math.min(Math.max(randomValue, 0), 1 - Number.EPSILON)
+    : 0;
+  let index = Math.floor(normalizedRandom * candidateCount);
+
+  if (hasValidPreviousIndex && index >= previousIndex) index += 1;
+
+  return {
+    index,
+    prompt: TIP_SUPPORT_PROMPTS[index],
+  };
+}