From 9fe20ee5ef5528364d0a497e4e50e7a6f69142c5 Mon Sep 17 00:00:00 2001
From: Adam Soltys <adam@coinos.io>
Date: Tue, 15 Jul 2025 12:51:33 -0700
Subject: basic wallet

---
 src/routes/+layout.svelte       |  21 +--
 src/routes/+page.svelte         | 281 ++++++++++++++++++++++++++++++++++++++--
 src/routes/create/+page.svelte  |  44 -------
 src/routes/created/+page.svelte |   0
 4 files changed, 278 insertions(+), 68 deletions(-)
 delete mode 100644 src/routes/create/+page.svelte
 delete mode 100644 src/routes/created/+page.svelte

(limited to 'src/routes')

diff --git a/src/routes/+layout.svelte b/src/routes/+layout.svelte
index 1729999..ceb238b 100644
--- a/src/routes/+layout.svelte
+++ b/src/routes/+layout.svelte
@@ -4,14 +4,15 @@
 	let { children } = $props();
 </script>
 
-<div class="container mx-auto mt-10 space-y-5 rounded-2xl bg-gray-100 p-8 text-xl shadow-lg">
-	<div class="flex">
-		<a href="/" class="mx-auto text-2xl">Bitcoin Wallet</a>
-	</div>
-
-	{@render children()}
-</div>
+	<div
+		class="container mx-auto max-w-3xl space-y-5 rounded-2xl bg-gray-100 p-8 text-xl shadow-lg"
+	>
+		<div class="flex items-center justify-center gap-2">
+			<img src="/bitcoin.svg" />
+			<div>
+				<a href="/" class="mx-auto text-2xl">Bitcoin Wallet</a>
+			</div>
+		</div>
 
-<div class="my-4 flex">
-	<a href="https://github.com/asoltys/paper" class="mx-auto">Source code</a>
-</div>
+		{@render children()}
+	</div>
diff --git a/src/routes/+page.svelte b/src/routes/+page.svelte
index 44bcb6a..db8986d 100644
--- a/src/routes/+page.svelte
+++ b/src/routes/+page.svelte
@@ -1,14 +1,267 @@
-<div class="flex flex-wrap justify-center gap-2">
-	<a
-		href="/create"
-		class="flex w-full justify-center gap-2 rounded-2xl border bg-white p-4 md:w-60"
-	>
-		<img src="/random.svg" class="w-8" />
-		<div class="my-auto">Generate</div>
-	</a>
-
-	<a href="/type" class="flex w-full justify-center gap-2 rounded-2xl border bg-white p-4 md:w-60">
-		<img src="/type.svg" class="w-8" />
-		<div class="my-auto">Import</div>
-	</a>
-</div>
+<script>
+	import { hex } from '@scure/base';
+	import { HDKey } from '@scure/bip32';
+	import * as btc from '@scure/btc-signer';
+	import { goto } from '$app/navigation';
+	import { onMount, tick } from 'svelte';
+	import { focus } from '$lib';
+	import { generateMnemonic, mnemonicToSeedSync } from '@scure/bip39';
+	import { wordlist } from '@scure/bip39/wordlists/english';
+
+	import { getAddress, p2wpkh } from '@scure/btc-signer/payment';
+
+	let NET = 'bitcoin';
+	const versions = {
+		bitcoin: {
+			private: 0x0488ade4,
+			public: 0x0488b21e
+		},
+		regtest: {
+			private: 0x04358394,
+			public: 0x043587cf
+		}
+	}[NET];
+
+	const network = {
+		bitcoin: {
+			bech32: 'bc',
+			pubKeyHash: 0x00,
+			scriptHash: 0x05,
+			wif: 0x80
+		},
+		regtest: {
+			bech32: 'bcrt',
+			pubKeyHash: 0x6f,
+			scriptHash: 0xc4,
+			wif: 0xef
+		}
+	}[NET];
+
+	let fees, rate;
+	let utxos = [];
+
+	let api = 'https://mempool.space/api';
+	let amt = $state(800);
+	// let destination = $state('bc1qqz6nlwxwmfqw0v864p5sggqst2xf0mevtyc579');
+	// let password = $state('123');
+	// let mnemonic = $state(
+	// 	'lizard armor follow dinner quarter talent truly among column rebuild arrest mix'
+	// );
+	// let withdrawing = $state(true);
+	let destination = $state();
+	let password = $state();
+	let mnemonic = $state();
+	let withdrawing = $state();
+
+	let balance = $state();
+	let pending = $state();
+
+	let loading = $state();
+
+	let generate = async () => {
+		mnemonic = await generateMnemonic(wordlist);
+	};
+
+	onMount(async () => {
+		// setTimeout(checkBalance, 1000);
+
+		if (NET === 'regtest') {
+			fees = { fastestFee: 281, halfHourFee: 271, hourFee: 256, economyFee: 44, minimumFee: 22 };
+		} else {
+			fees = await fetch(`${api}/v1/fees/recommended`).then((r) => r.json());
+		}
+
+		rate = fees['halfHourFee'];
+	});
+
+	let getHex = async (txid) => {
+		if (txid instanceof Uint8Array) txid = hex.encode(txid);
+		return hex.decode(await fetch(`${api}/tx/${txid}/hex`).then((r) => r.text()));
+	};
+
+	let node = $derived.by(() => {
+		if (!mnemonic) return;
+		const seed = mnemonicToSeedSync(mnemonic, password);
+		const root = HDKey.fromMasterSeed(seed, versions);
+		return root.derive(`m/84'/0'/0'/0/0`);
+	});
+
+	let address = $derived(node ? p2wpkh(node.publicKey).address : undefined);
+	let txid = $state();
+
+	let checkBalance = async (e) => {
+		e?.preventDefault();
+		loading = true;
+		utxos = await fetch(`${api}/address/${address}/utxo`).then((r) => r.json());
+
+		balance = 0;
+		pending = 0;
+
+		for (let { value, status } of utxos) {
+			if (status.confirmed) balance += value;
+			else pending += value;
+		}
+
+		loading = false;
+	};
+
+	let send = async () => {
+		let sats = 100000000;
+		let b = (n) => (Number(n) / sats).toFixed(8);
+		let inputs = [];
+		let outputs = [];
+		let fee, tx;
+
+		let i = 0;
+		let total = 0n;
+		let amount = BigInt(amt);
+
+		while (total < amount) {
+			total += BigInt(utxos[i].value);
+			i++;
+			if (i > utxos.length) throw new Error('insufficient funds');
+		}
+
+		let change = total - amount;
+
+		tx = new btc.Transaction();
+
+		for await (let { input, vout, txid } of utxos.slice(0, i)) {
+			tx.addInput({
+				txid,
+				index: vout,
+				nonWitnessUtxo: await getHex(txid),
+				sequence: 0xfffffffd
+			});
+		}
+
+		tx.addOutputAddress(destination, amount, network);
+		tx.addOutputAddress(address, change, network);
+
+		console.log(tx.unsignedTx.length);
+
+		while (i <= utxos.length) {
+			fee = BigInt(rate) * BigInt(tx.unsignedTx.length * 2);
+
+			if (fee <= change) {
+				let q = new btc.Transaction();
+				for (let i = 0; i < tx.inputsLength; i++) {
+					let input = tx.getInput(i);
+
+					let nonWitnessUtxo = await getHex(input.txid);
+					q.addInput({ ...input, nonWitnessUtxo });
+				}
+				q.addOutput(tx.getOutput(0));
+				q.addOutputAddress(address, change - fee, network);
+				tx = q;
+
+				break;
+			} else {
+				if (i === utxos.length) {
+					if (fee > amount) throw new Error('insufficient funds');
+					else {
+						let q = new btc.Transaction();
+						for (let i = 0; i < tx.inputsLength; i++) {
+							let input = tx.getInput(i);
+
+							let nonWitnessUtxo = await getHex(input.txid);
+							q.addInput({ ...input, nonWitnessUtxo });
+						}
+
+						q.addOutputAddress(destination, total - fee, network);
+
+						tx = q;
+						break;
+					}
+				}
+
+				let { txid, vout } = utxos[++i];
+				tx.addInput({
+					hash: txid,
+					index: vout,
+					nonWitnessUtxo: await getHex(txid)
+				});
+			}
+		}
+
+		let privkey = node.privateKey;
+		for (let i = 0; i < tx.inputsLength; i++) {
+			tx.signIdx(privkey, 0);
+			let input = tx.getInput(i);
+			let utxo = input.nonWitnessUtxo.outputs[input.index];
+
+			inputs = [
+				...inputs,
+				{
+					address: btc.Address(network).encode(btc.OutScript.decode(utxo.script)),
+					amount: b(utxo.amount)
+				}
+			];
+		}
+
+		outputs = tx.outputs.map((o) => ({
+			address: btc.Address(network).encode(btc.OutScript.decode(o.script)),
+			amount: b(o.amount)
+		}));
+
+		tx.finalize();
+
+		txid = await fetch(`${api}/tx`, {
+			method: 'POST',
+			body: tx.hex
+		}).then((r) => r.text());
+	};
+</script>
+
+<form class="space-y-5" onsubmit={checkBalance}>
+	<div class="flex items-center gap-2">
+		<textarea use:focus class="textarea grow" placeholder="Seed phrase" bind:value={mnemonic}
+		></textarea>
+		<button type="button" class="btn flex gap-1" onclick={generate}>
+			<img src="/random.svg" class="w-8" />
+			<div>Generate</div>
+		</button>
+	</div>
+
+	<input class="input w-full" placeholder="Passphrase" bind:value={password} />
+
+	{#if address}
+		<div class="flex items-center gap-2">
+			<div>
+				Address: {address}
+			</div>
+
+			<button type="submit" class="btn ml-auto"> Check balance </button>
+		</div>
+	{/if}
+</form>
+
+{#if loading}
+	<div>
+		<div class="loading loading-spinner"></div>
+	</div>
+{:else if typeof balance !== 'undefined'}
+	<div class="flex items-center gap-2">
+		<div>
+			Balance: {balance} sats
+			{#if pending}
+				<span class="text-orange-600">({pending} pending)</span>
+			{/if}
+		</div>
+		{#if balance + pending > 0}
+			<button type="submit" class="btn ml-auto" onclick={() => (withdrawing = true)}>
+				Withdraw</button
+			>
+		{/if}
+	</div>
+{/if}
+
+{#if txid}
+	<a href={`https://mempool.space/tx/${txid}`}>{txid}</a>
+{:else if withdrawing}
+	<input class="input w-full" placeholder="Destination address" bind:value={destination} />
+
+	<input class="input w-full" placeholder="Amount" bind:value={amt} />
+
+	<button type="submit" class="btn ml-auto" onclick={send}> Send</button>
+{/if}
diff --git a/src/routes/create/+page.svelte b/src/routes/create/+page.svelte
deleted file mode 100644
index 1d09990..0000000
--- a/src/routes/create/+page.svelte
+++ /dev/null
@@ -1,44 +0,0 @@
-<script>
-	import { goto } from '$app/navigation';
-	import { onMount, tick } from 'svelte';
-	import { mnemonic, focus } from '$lib';
-	import { generateMnemonic } from '@scure/bip39';
-	import { wordlist } from '@scure/bip39/wordlists/english';
-	import Mnemonic from '$lib/Mnemonic.svelte';
-
-	let password;
-
-	let submitted;
-	let bm;
-	onMount(async () => {
-		$mnemonic = await generateMnemonic(wordlist);
-	});
-
-	let submit = async () => {
-		submitted = true;
-		await tick();
-
-		goto('/created');
-	};
-</script>
-
-<Mnemonic mnemonic={$mnemonic} />
-
-<form class="space-y-5 text-center" on:submit|preventDefault={submit}>
-	<div>
-		<input
-			use:focus
-			name="password"
-			class="rounded-2xl bg-white p-4 text-2xl"
-			placeholder="Passphrase"
-			bind:value={password}
-		/>
-	</div>
-
-	<button
-		type="submit"
-		class="mx-auto flex w-full justify-center gap-2 rounded-2xl border bg-white p-4 md:w-60"
-	>
-		<div class="my-auto">Submit</div>
-	</button>
-</form>
diff --git a/src/routes/created/+page.svelte b/src/routes/created/+page.svelte
deleted file mode 100644
index e69de29..0000000
-- 
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