From 95833bd2c194e8d0c72ae472302f0689ee4a06aa Mon Sep 17 00:00:00 2001
From: Tim Evans <timevans666@gmail.com>
Date: Mon, 20 Jul 2026 16:22:13 +0100
Subject: [PATCH] feat: VANITY d6-pool rule-pack

---
 src/dice/rulepacks/index.js     |  3 ++-
 src/dice/rulepacks/vanity-d6.js | 31 +++++++++++++++++++++++++++
 tests/dice/vanity-d6.test.js    | 37 +++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 src/dice/rulepacks/vanity-d6.js
 create mode 100644 tests/dice/vanity-d6.test.js

diff --git a/src/dice/rulepacks/index.js b/src/dice/rulepacks/index.js
index aefe47f..bbb0d95 100644
--- a/src/dice/rulepacks/index.js
+++ b/src/dice/rulepacks/index.js
@@ -1,7 +1,8 @@
 import { yearZero } from './year-zero.js';
 import { cocD100 } from './coc-d100.js';
+import { vanityD6 } from './vanity-d6.js';
 
-const packs = new Map([[yearZero.id, yearZero], [cocD100.id, cocD100]]);
+const packs = new Map([[yearZero.id, yearZero], [cocD100.id, cocD100], [vanityD6.id, vanityD6]]);
 
 export function getRulePack(id) { return packs.get(id) || null; }
 export function registerRulePack(pack) { packs.set(pack.id, pack); }
diff --git a/src/dice/rulepacks/vanity-d6.js b/src/dice/rulepacks/vanity-d6.js
new file mode 100644
index 0000000..049897c
--- /dev/null
+++ b/src/dice/rulepacks/vanity-d6.js
@@ -0,0 +1,31 @@
+// VANITY (Draft 13) core roll: 5-6 = Success; Stumble = 0 successes with 2+ ones.
+export const vanityD6 = {
+  id: 'vanity-d6',
+  label: 'd6 Pool (VANITY)',
+  params: [{ key: 'difficulty', label: 'Successes needed', default: 1 }],
+  interpret(results, params = {}) {
+    let successes = 0, ones = 0;
+    for (const r of results) {
+      if (r.value >= 5) successes += 1;
+      if (r.value === 1) ones += 1;
+    }
+    const difficulty = params.difficulty ?? 1;
+    const isSuccess = successes >= difficulty;
+    return {
+      successes,
+      ones,
+      difficulty,
+      isSuccess,
+      stumble: successes === 0 && ones >= 2,
+      twist: ones >= 1,
+      style: successes > difficulty,
+      canPush: true,
+    };
+  },
+  summary(v) {
+    const base = `${v.successes} success${v.successes === 1 ? '' : 'es'}`;
+    const verdict = v.isSuccess ? '' : ' — fail';
+    const stumble = v.stumble ? ' · STUMBLE (+1 Bane)' : (v.twist ? ' · a 1 (GM twist)' : '');
+    return `${base}${verdict}${stumble}`;
+  },
+};
diff --git a/tests/dice/vanity-d6.test.js b/tests/dice/vanity-d6.test.js
new file mode 100644
index 0000000..994e4eb
--- /dev/null
+++ b/tests/dice/vanity-d6.test.js
@@ -0,0 +1,37 @@
+import { describe, it, expect } from 'vitest';
+import { vanityD6 } from '../../src/dice/rulepacks/vanity-d6.js';
+import { getRulePack } from '../../src/dice/rulepacks/index.js';
+
+const pool = (...vals) => vals.map((v) => ({ sides: 6, value: v }));
+
+describe('vanity-d6 rule-pack', () => {
+  it('counts 5s and 6s as successes', () => {
+    const v = vanityD6.interpret(pool(6, 5, 2), { difficulty: 1 });
+    expect(v.successes).toBe(2);
+    expect(v.isSuccess).toBe(true);
+    expect(v.style).toBe(true); // more successes than needed
+  });
+  it('stumbles on zero successes with two or more 1s', () => {
+    const v = vanityD6.interpret(pool(1, 1, 3), { difficulty: 1 });
+    expect(v.successes).toBe(0);
+    expect(v.ones).toBe(2);
+    expect(v.stumble).toBe(true);
+    expect(v.isSuccess).toBe(false);
+  });
+  it('a lone 1 is a GM twist, not a stumble', () => {
+    const v = vanityD6.interpret(pool(1, 4, 4), { difficulty: 1 });
+    expect(v.twist).toBe(true);
+    expect(v.stumble).toBe(false);
+  });
+  it('respects the difficulty (successes needed)', () => {
+    const v = vanityD6.interpret(pool(6, 2, 2), { difficulty: 2 });
+    expect(v.successes).toBe(1);
+    expect(v.isSuccess).toBe(false);
+  });
+  it('defaults difficulty to 1, summarises, and is registered', () => {
+    const v = vanityD6.interpret(pool(5, 3));
+    expect(v.difficulty).toBe(1);
+    expect(vanityD6.summary(v)).toContain('1 success');
+    expect(getRulePack('vanity-d6')).toBe(vanityD6);
+  });
+});