1 files changed, 128 insertions, 0 deletions
diff --git a/tools/ark/offboard-split-test.js b/tools/ark/offboard-split-test.js
new file mode 100644
index 0000000..561ee2b
--- /dev/null
+++ b/tools/ark/offboard-split-test.js
@@ -0,0 +1,128 @@
+// A partial on-chain send from Spending moves whole coins: the amount is
+// covered by coins that already add up to it, else split off via a self-send
+// that lands as one coin per input — all of them go, not one of the exact
+// size (Jarryd, 2026-10-23: three splits, no send). Local manager stub.
+// Run: bun tools/ark/offboard-split-test.js
+import assert from 'node:assert/strict';
+import puppeteer from '../puppeteer.js';
+import { generateMnemonic } from '@scure/bip39';
+import { wordlist } from '@scure/bip39/wordlists/english';
+
+const bundle = await Bun.build({ entrypoints: ['src/app.js'], target: 'browser', minify: true,
+  plugins: [{ name: 'offboard-split-test', setup(build) {
+    build.onLoad({ filter: /src\/app\.js$/ }, async ({ path }) => ({ loader: 'js', contents: await Bun.file(path).text() + `
+window.coopApp = { ui, wallet, ctx, render, enterWallet, get ready() { return !_bootDeciding; } };
+` }));
+    build.onLoad({ filter: /src\/features\/ark\.js$/ }, async ({ path }) => ({ loader: 'js', contents:
+      (await Bun.file(path).text()).replace("  return {\n    id: 'ark',", `
+  window.coopFeature = { setManager: (mgr) => { ark = mgr; }, offboard: doArkOffboard, exactCoins };
+  return {\n    id: 'ark',`) }));
+    build.onLoad({ filter: /src\/video-compress\.js$/ }, () => ({ loader: 'js', contents: 'export async function compressVideo(f) { return f; }' }));
+  } }] });
+assert(bundle.success, bundle.logs.join('\n'));
+const html = `<!doctype html><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1"><style>${await Bun.file('src/style.css').text()}</style><div id="app"></div><script type="module">${await bundle.outputs[0].text()}</script>`;
+const server = Bun.serve({ port: 0, fetch: (req) => new URL(req.url).pathname === '/'
+  ? new Response(html, { headers: { 'Content-Type': 'text/html' } }) : new Response(null, { status: 404 }) });
+const browser = await puppeteer.launch({ executablePath: '/usr/bin/google-chrome', headless: true, args: ['--no-sandbox'] });
+try {
+  const page = await browser.newPage(), errors = [];
+  page.on('pageerror', (e) => errors.push(e.message));
+  await page.setViewport({ width: 390, height: 844 });
+  const cdp = await page.createCDPSession();
+  await cdp.send('Network.enable');
+  await cdp.send('Network.setBlockedURLs', { urls: ['wss://*', 'ws://*'] });
+  await page.setRequestInterception(true);
+  page.on('request', (r) => r.url().startsWith(server.url.origin) || r.url().startsWith('data:') ? r.continue() : r.abort());
+  await page.evaluateOnNewDocument(() => {
+    localStorage.setItem('btc-wallet-network', 'regtest');
+    localStorage.setItem('btc-wallet-ark-provider:regtest', 'off');
+  });
+  await page.goto(server.url.href, { waitUntil: 'domcontentloaded' });
+  await page.waitForFunction(() => window.coopApp?.ready);
+  await page.evaluate(async (mn) => {
+    await coopApp.enterWallet(mn, '', { fresh: true, generated: true });
+    coopApp.ui.onb = null; localStorage.removeItem('btc-wallet-onb-step');
+    coopApp.wallet.scan = async () => {};
+    window.coopCalls = [];
+    window.coopManager = {
+      state: { vtxos: [], actions: [], movements: [], nextKeyIndex: 5 },
+      async offboardQuote() { return { chainSat: 736, serviceSat: 204, totalSat: 940, minSat: 1270 }; },
+      info: { network: 'regtest' }, _tipH: 100,
+      vtxos() { return this.state.vtxos; },
+      refreshFee() { return 0; }, unseenReceives() { return []; }, ackReceives() {},
+      address() { return 'test-ark-address'; },
+      // the real thing: largest inputs first until covered, one destination
+      // coin per input (the last carries the remainder), change on a new key;
+      // the destination coins land on the receive key at the next sync
+      async send(address, amount) {
+        coopCalls.push({ type: 'split', address, amount });
+        const free = this.state.vtxos.filter((v) => v.state === 'spendable').sort((a, b) => b.amountSat - a.amountSat);
+        const inputs = []; let sum = 0;
+        for (const v of free) { inputs.push(v); sum += v.amountSat; if (sum >= amount) break; }
+        let remaining = amount; const landing = [];
+        for (const v of inputs) {
+          const dest = Math.min(remaining, v.amountSat); remaining -= dest;
+          landing.push({ id: `dest-${v.id}`, amountSat: dest, state: 'spendable', keyIndex: 0 });
+          if (v.amountSat > dest) this.state.vtxos.push({ id: `change-${v.id}`, amountSat: v.amountSat - dest, state: 'spendable', keyIndex: this.state.nextKeyIndex++ });
+          v.state = 'spent';
+        }
+        this.pendingLanding = landing;
+        return 'send-1';
+      },
+      async sync() { if (this.pendingLanding) { this.state.vtxos.push(...this.pendingLanding); this.pendingLanding = null; } },
+      async startOffboard(spk, address, ids) {
+        coopCalls.push({ type: 'offboard', address, ids: ids || null });
+        return { txid: 'ab'.repeat(32), netSat: 1, feeSat: 1 };
+      },
+    };
+    coopFeature.setManager(coopManager);
+    coopApp.ui.screen = 'wallet'; coopApp.ui.tab = 'send'; coopApp.render();
+  }, generateMnemonic(wordlist));
+  const run = (coins, amount) => page.evaluate(async (coins, amount) => {
+    coopManager.state.vtxos = coins.map((c) => ({ state: 'spendable', keyIndex: 0, ...c }));
+    coopCalls.length = 0;
+    coopApp.ui.arkError = ''; coopApp.ui.arkOffboarded = null;
+    await coopFeature.offboard(amount, coopApp.wallet.derive(0, 1).address);
+    return { calls: coopCalls, err: coopApp.ui.arkError, done: !!coopApp.ui.arkOffboarded };
+  }, coins, amount);
+
+  // Jarryd's balance after one split: the halves add up, so nothing is split again
+  let r = await run([{ id: 'a', amountSat: 109958 }, { id: 'b', amountSat: 75042 }, { id: 'c', amountSat: 24958, keyIndex: 2 }], 185000);
+  assert.equal(r.err, '');
+  assert(r.done);
+  assert.deepEqual(r.calls.map((c) => c.type), ['offboard']);
+  assert.deepEqual([...r.calls[0].ids].sort(), ['a', 'b']);
+  console.log('✓ coins that already add up to the amount go as they are, no split');
+
+  // one coin of the exact size
+  r = await run([{ id: 'a', amountSat: 109958 }, { id: 'c', amountSat: 24958 }], 24958);
+  assert.deepEqual(r.calls, [{ type: 'offboard', address: r.calls[0].address, ids: ['c'] }]);
+  console.log('✓ a single coin of the exact size is the one that goes');
+
+  // Jarryd's first attempt: 185,000 out of 100,000 + 109,958 — nothing adds
+  // up, so a self-send splits it off and lands as two coins; both go
+  r = await run([{ id: 'a', amountSat: 100000 }, { id: 'b', amountSat: 109958 }], 185000);
+  assert.equal(r.err, '');
+  assert(r.done);
+  assert.deepEqual(r.calls.map((c) => c.type), ['split', 'offboard']);
+  assert.equal(r.calls[0].amount, 185000);
+  assert.deepEqual([...r.calls[1].ids].sort(), ['dest-a', 'dest-b']);
+  const left = await page.evaluate(() => coopManager.state.vtxos.filter((v) => v.state === 'spendable').map((v) => [v.id, v.amountSat, v.keyIndex]));
+  assert.deepEqual(left.filter(([id]) => id.startsWith('change')), [['change-a', 24958, 5]]);
+  console.log('✓ a split that lands as two coins sends both; the change stays behind');
+
+  // everything: no carving at all
+  r = await run([{ id: 'a', amountSat: 100000 }, { id: 'b', amountSat: 109958 }], 0);
+  assert.deepEqual(r.calls, [{ type: 'offboard', address: r.calls[0].address, ids: null }]);
+  console.log('✓ the whole balance goes without a split');
+
+  // the subset search: prefers few large coins, gives up on no fit
+  const sub = await page.evaluate(() => {
+    const coins = (a) => a.map((amountSat, i) => ({ id: 'c' + i, amountSat }));
+    const pick = (a, n) => { const r = coopFeature.exactCoins(coins(a), n); return r && r.map((v) => v.amountSat).sort((x, y) => y - x); };
+    return [pick([5000, 3000, 2000, 1000, 1000], 6000), pick([5000, 3000], 7000), pick([5000, 3000, 2000], 5000), pick([7000, 3000], 3000)];
+  });
+  assert.deepEqual(sub, [[5000, 1000], null, [5000], [3000]]);
+  console.log('✓ exactCoins finds a subset, the single coin, or nothing');
+  assert.deepEqual(errors, []);
+} finally { await browser.close(); server.stop(true); }