feat: pay to a crypto address using atomic swap

[rolznz]

Closes #29

• Topup your debit card with your agent
• Possibly pay for x402/MPP endpoints?

yarn dev pay-crypto 0xXXXXXXXXXXXXXXXXXXXX -a 2 --currency USDC --network arbitrum
{
  "swap_id": "ddb301c6-df67-4dd3-91bb-5c08cd86062a",
  "status": "completed",
  "target": {
    "address": "0x78C01B70e43b7BD68c648cfa456D3c9Af99F67bC",
    "currency": "USDC",
    "network": "Arbitrum",
    "amount": 2
  }
}

Summary by CodeRabbit

• New Features

  • Introduced a new "pay-crypto" CLI command enabling cross-currency payments, allowing users to send cryptocurrency to blockchain addresses with configurable amounts and networks while validating address formats and supported currency pairs.

• Tests

  • Added test suite covering validation scenarios for the new command, including address formats, payment amounts, and supported currency-network combinations.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR adds a complete Lightning-to-EVM atomic swap feature. It introduces the Lendaswap SDK dependency, implements a swap orchestration module with pair discovery and validation, registers a new pay-crypto CLI command, and includes integration tests validating the full command flow with mock API responses.

Changes

Lightning to EVM Swap Feature

Layer / File(s)	Summary
Lendaswap SDK integration and swap orchestration src/lendaswap/swap.ts, package.json	Configures SDK client with in-memory storage, discovers supported Lightning→EVM token pairs via API, validates EVM addresses and currency/network combinations, constructs swap requests, and orchestrates the full swap lifecycle: subscription → invoice payment → claim triggering → status monitoring. Adds Lendaswap SDK dependency.
Pay-crypto CLI command implementation src/commands/pay-crypto.ts	Registers the pay-crypto command with commander, parsing recipient address (required) and --amount/--currency/--network options (with defaults). Validates inputs against supported pairs, invokes the swap via NWC wallet client, and outputs swap completion details.
CLI integration, registration, and validation tests src/index.ts, src/test/pay-crypto.test.ts	Wires the pay-crypto command into a new "Cross-Currency Payments" command group. Includes integration tests with a mock Lendaswap API server validating unsupported currency/network rejection, malformed address rejection, invalid amount rejection, and the happy-path reaching wallet-load validation.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 A swap from Lightning bright,
Through Lendaswap's SDK flight,
CLI commands now handle the load,
EVM tokens on the road,
Atomic magic done right! ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: adding a feature to pay to a crypto address using atomic swap, which is the primary focus of all modifications.
Linked Issues check	✅ Passed	The pull request implements the primary objective from issue #29 by adding functionality to pay with an atomic swap to a crypto address, including validation, swap creation, and invoice payment.
Out of Scope Changes check	✅ Passed	All changes are directly related to implementing the pay-crypto atomic swap feature: CLI command registration, swap logic, dependencies, and tests for the feature.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/pay-crypto

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[coderabbitai]

Actionable comments posted: 2

🧹 Nitpick comments (1)

src/lendaswap/swap.ts (1)

154-154: 💤 Low value

Consider making the referral code configurable.

The referral code is hardcoded. If this code identifies the integration partner or revenue share, it might need to vary by deployment context (staging vs production, different integrators, etc.).

Consider allowing override via environment variable or configuration parameter.

♻️ Optional enhancement to support environment override

+const REFERRAL_CODE = process.env.LENDASWAP_REFERRAL_CODE || "lnds_2c07e38f10a28d47";
+
 async function createPaymentSwap(params: {
   pair: SupportedPair;
   amount: number;
   targetAddress: string;
 }): Promise<LightningToEvmSwapResponse> {
   const client = await getClient();
   const targetAmount = toSmallestUnit(params.amount, params.pair.decimals);

   const targetAsset: Asset = {
     chain: params.pair.chain,
     tokenId: params.pair.tokenId,
   };

   const result = await client.createSwap({
     source: Asset.BTC_LIGHTNING,
     target: targetAsset,
     targetAmount,
     targetAddress: params.targetAddress,
     gasless: true,
-    referralCode: "lnds_2c07e38f10a28d47",
+    referralCode: REFERRAL_CODE,
   });

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@src/lendaswap/swap.ts` at line 154, The referralCode value is hardcoded in
swap.ts (referralCode: "lnds_2c07e38f10a28d47"); make it configurable by reading
a config or environment variable (e.g., process.env.LENDASWAP_REFERRAL_CODE) and
falling back to the current default; update the code that constructs the
payload/object containing referralCode (search for the referralCode symbol in
swap.ts) to use the config/env value and add a brief comment and a
unit/integration test or env-var mention in documentation to ensure deployments
can override it.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/lendaswap/swap.ts`:
- Around line 131-133: The toSmallestUnit(amount: number, decimals: number)
function can overflow Number.MAX_SAFE_INTEGER when amount * 10**decimals is
large; update it to either use BigInt/BigNumber math or validate inputs and
reject amounts that would exceed safe integer range. Specifically, compute or
estimate the scaled value bounds (e.g., via Number.MAX_SAFE_INTEGER /
10**decimals) and throw a clear error from toSmallestUnit when amount is too
large or decimals too high, or change the implementation to return a
BigInt/string using BigInt( Math.round(...) ) or a BigNumber library so you
preserve precision for values like 1e12 with 6+ decimals.
- Around line 1-11: The package version for `@lendasat/lendaswap-sdk-pure`
referenced by the imports (Asset, Client, InMemorySwapStorage,
InMemoryWalletStorage, LightningToEvmSwapResponse, SwapStatus,
SwapStatusHandler, toChain, toChainName) appears unpublished; update the
dependency in package.json to a published tag (e.g., a confirmed published
version such as 0.2.24 or the latest published), run npm install to update
lockfile, then verify that all imported symbols (Client, Asset, toChain,
toChainName, InMemorySwapStorage, InMemoryWalletStorage, etc.) still exist in
that released version and adjust imports if names changed, and finally re-run
your advisory/CVE scan against the chosen exact version.

---

Nitpick comments:
In `@src/lendaswap/swap.ts`:
- Line 154: The referralCode value is hardcoded in swap.ts (referralCode:
"lnds_2c07e38f10a28d47"); make it configurable by reading a config or
environment variable (e.g., process.env.LENDASWAP_REFERRAL_CODE) and falling
back to the current default; update the code that constructs the payload/object
containing referralCode (search for the referralCode symbol in swap.ts) to use
the config/env value and add a brief comment and a unit/integration test or
env-var mention in documentation to ensure deployments can override it.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 2c9f6e10-43eb-4156-9427-4f085878e8fc

📥 Commits

Reviewing files that changed from the base of the PR and between 3dcc22f and 38b8059.

⛔ Files ignored due to path filters (1)

• yarn.lock is excluded by !**/yarn.lock, !**/*.lock

📒 Files selected for processing (5)

• package.json
• src/commands/pay-crypto.ts
• src/index.ts
• src/lendaswap/swap.ts
• src/test/pay-crypto.test.ts