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Swap: update to be compatible with ERC-20s (#189)
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@fadeev
fadeev authored Nov 14, 2023
1 parent 843d675 commit cc01f7f
Showing 1 changed file with 46 additions and 107 deletions.
153 changes: 46 additions & 107 deletions docs/developers/omnichain/tutorials/swap.md
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@ yarn
Run the following command to create a new omnichain contract called `Swap`.

```
npx hardhat omnichain Swap
npx hardhat omnichain Swap targetToken:address recipient:address
```

## Omnichain Contract
Expand Down Expand Up @@ -74,60 +74,56 @@ contract Swap is zContract {
bytes calldata message
) external virtual override onlySystem {
// highlight-start
uint32 targetChainID;
address recipient;
uint256 minAmountOut;
address targetTokenAddress;
bytes memory recipientAddress;
if (context.chainID == BITCOIN) {
targetChainID = BytesHelperLib.bytesToUint32(message, 0);
recipient = BytesHelperLib.bytesToAddress(message, 4);
targetTokenAddress = BytesHelperLib.bytesToAddress(message, 0);
recipientAddress = abi.encodePacked(
BytesHelperLib.bytesToAddress(message, 20)
);
} else {
(
uint32 targetChainID_,
address recipient_,
uint256 minAmountOut_
) = abi.decode(message, (uint32, address, uint256));
targetChainID = targetChainID_;
recipient = recipient_;
minAmountOut = minAmountOut_;
(address targetToken, bytes memory recipient) = abi.decode(
message,
(address, bytes)
);
targetTokenAddress = targetToken;
recipientAddress = recipient;
}
address targetZRC20 = systemContract.gasCoinZRC20ByChainId(
targetChainID
);
uint256 outputAmount = SwapHelperLib._doSwap(
systemContract.wZetaContractAddress(),
systemContract.uniswapv2FactoryAddress(),
systemContract.uniswapv2Router02Address(),
zrc20,
amount,
targetZRC20,
minAmountOut
targetTokenAddress,
0
);
(address gasZRC20, uint256 gasFee) = IZRC20(targetZRC20)
(address gasZRC20, uint256 gasFee) = IZRC20(targetTokenAddress)
.withdrawGasFee();
if (gasZRC20 != targetZRC20) revert WrongGasContract();
if (gasZRC20 != targetTokenAddress) revert WrongGasContract();
if (gasFee >= outputAmount) revert NotEnoughToPayGasFee();
IZRC20(targetZRC20).approve(targetZRC20, gasFee);
IZRC20(targetZRC20).withdraw(
abi.encodePacked(recipient),
IZRC20(targetTokenAddress).approve(targetTokenAddress, gasFee);
IZRC20(targetTokenAddress).withdraw(
recipientAddress,
outputAmount - gasFee
);
// highlight-end
}
}
```

The contract expects to receive three values in the `message`:
The contract expects to receive two values in the `message`:

- `targetChainID`: the ID of the destination chain
- `recipient`: the recipient address on the destination chain
- `minAmountOut`: and the minimum amount of tokens to receive on the destination
chain. For the purposes of this tutorial, we will set this value to 0.
- `address targetTokenAddress`: the address of the ZRC-20 version of the
destination token.
- `bytes memory recipientAddress`: the recipient address on the destination
chain. We're using `bytes`, because the recipient address can be either on an
EVM chain or Bitcoin.

When the contract is called from an EVM chain, the `message` is encoded as a
`bytes` array using the ABI encoding.
Expand All @@ -138,83 +134,22 @@ the message.
Use `context.chainID` to determine the connected chain from which the contract
is called.

If it's Bitcoin, the first 4 bytes of the `message` are the `targetChainID`
encoded as a `uint32`. Use `bytesToUint32` helper method to get the target chain
ID. To get the recipient address, use `bytesToAddress` helper method with an
offset of 4 bytes.
If it's Bitcoin, the first 20 bytes of the `message` are the
`targetTokenAddress` encoded as an `address`. Use `bytesToAddress` helper method
to get the target token address. To get the recipient address, use the same
helper method with an offset of 20 bytes and then use `abi.encodePacked` to
convert the address to `bytes`.

If it's an EVM chain, use `abi.decode` to decode the `message` into the
`targetChainID`, `recipient` and `minAmountOut` variables.
`targetToken` and `recipient` variables.

Use the `systemContract` to get the address of the ZRC-20 representation of the
gas coin on the destination chain.

Next, swap the incoming token for the gas coin on the destination chain. .
Next, swap the incoming token for the gas coin on the destination chain.
ZetaChain has liquidity pools with the ZRC-20 representation of the gas coin on
all connected chains. The `SwapHelperLib._doSwap` helper method to swap the
tokens.

Finally, withdraw the tokens to the recipient address on the destination chain.

## Modify the Interact Task

Modify the interact task to convert chain label (for example, `goerli_testnet`)
to chain ID (for example, `5`). Update the `prepareData` method with the values
which will be used to encode the `message`.

```ts title="tasks/interact.ts"
import { task } from "hardhat/config";
import { HardhatRuntimeEnvironment } from "hardhat/types";
import { parseEther } from "@ethersproject/units";
import { getAddress } from "@zetachain/protocol-contracts";
import { prepareData } from "@zetachain/toolkit/helpers";
// highlight-next-line
import { BigNumber } from "@ethersproject/bignumber";

const main = async (args: any, hre: HardhatRuntimeEnvironment) => {
const [signer] = await hre.ethers.getSigners();

// highlight-start
const targetChainID = hre.config.networks[args.destination]?.chainId;
if (targetChainID === undefined) {
throw new Error("Invalid destination network");
}
const minAmountOut = BigNumber.from("0");
// highlight-end

const data = prepareData(
args.contract,
// highlight-start
["uint32", "address", "uint256"],
[targetChainID, args.recipient, minAmountOut]
// highlight-end
);
const to = getAddress("tss", hre.network.name);
const value = parseEther(args.amount);

const tx = await signer.sendTransaction({ data, to, value });

if (args.json) {
console.log(JSON.stringify(tx, null, 2));
} else {
console.log(`🔑 Using account: ${signer.address}\n`);

console.log(`🚀 Successfully broadcasted a token transfer transaction on ${hre.network.name} network.
📝 Transaction hash: ${tx.hash}
`);
}
};

task("interact", "Interact with the contract", main)
.addParam("contract", "The address of the withdraw contract on ZetaChain")
.addParam("amount", "Amount of tokens to send")
.addFlag("json", "Output in JSON")
// highlight-start
.addParam("recipient")
.addParam("destination");
// highlight-end
```

## Create an Account and Request Tokens from the Faucet

Before proceeding with the next steps, make sure you have
Expand All @@ -237,30 +172,34 @@ npx hardhat deploy --network zeta_testnet

## Swap from an EVM Chain

Use the `interact` task to perform a cross-chain swap:
Use the `interact` task to perform a cross-chain swap. In this example, we're
swapping native gETH for for a ZRC-20 representation of tMATIC. The contract
will perform a swap and then withdraw tMATIC to Polygon Mumbai. To get the value
of the `--target-token` find the ZRC-20 contract address of the destination
token in the [docs](https://www.zetachain.com/docs/reference/testnet/).

```
px hardhat interact --contract 0x458bCAF5d95025cdd00f946f1C5F09623E856579 --amount 0.05 --network goerli_testnet --recipient 0x2cD3D070aE1BD365909dD859d29F387AA96911e1 --destination mumbai_testnet
npx hardhat interact --contract 0xcC02751bAA435E9A5cF3bd22F96a21d7C002E150 --amount 0.1 --target-token 0x48f80608B672DC30DC7e3dbBd0343c5F02C738Eb --recipient 0x2cD3D070aE1BD365909dD859d29F387AA96911e1 --network goerli_testnet
```

```
🔑 Using account: 0x2cD3D070aE1BD365909dD859d29F387AA96911e1
🚀 Successfully broadcasted a token transfer transaction on goerli_testnet network.
📝 Transaction hash: 0x47262aade728b9c8897bf4c8932c26774caf3b9ebd085cbc048dd9f6522ccf00
📝 Transaction hash: 0x7ebd2bff64cbc530c145a60e4830ba2ddc536bc62cf8c5566c900143b0e08baf
```

Track your cross-chain transaction:

```
npx hardhat cctx 0x47262aade728b9c8897bf4c8932c26774caf3b9ebd085cbc048dd9f6522ccf00
npx hardhat cctx 0x7ebd2bff64cbc530c145a60e4830ba2ddc536bc62cf8c5566c900143b0e08baf
```

```
✓ CCTXs on ZetaChain found.
✓ 0xee7ae0367ee5fa52e17ae0c01d8c929b009d0601a5078ddcb319910ddda493e0: 5 → 7001: OutboundMined (Remote omnichain contract call completed)
✓ 0xaa120bee04c86b1c5d16b1d47d69fd9a3c49fbed91ee15f4f59ef9eeef48ca88: 7001 → 80001: OutboundMined
✓ 0x5082897440218490193a724a22b7ed3f8744760956d857199e76bf2453f901b2: 5 → 7001: OutboundMined (Remote omnichain contract call completed)
✓ 0x3aebbba04cd284d2e87b9c8414f6946bdf933efad45076aba7c691e5a32895ba: 7001 → 80001: PendingOutbound → OutboundMined
```

## Swap from Bitcoin
Expand All @@ -269,12 +208,12 @@ Use the `send-btc` task to send Bitcoin to the TSS address with a memo. The memo
should contain the following:

- Omnichain contract address on ZetaChain:
`458bCAF5d95025cdd00f946f1C5F09623E856579`
- Target chain ID: `00000005`
`cC02751bAA435E9A5cF3bd22F96a21d7C002E150`
- Target token address: `48f80608B672DC30DC7e3dbBd0343c5F02C738Eb`
- Recipient address: `2cD3D070aE1BD365909dD859d29F387AA96911e1`

```
npx hardhat send-btc --amount 0.001 --memo 458bCAF5d95025cdd00f946f1C5F09623E856579000000052cD3D070aE1BD365909dD859d29F387AA96911e1 --recipient tb1qy9pqmk2pd9sv63g27jt8r657wy0d9ueeh0nqur
npx hardhat send-btc --amount 0.001 --memo cC02751bAA435E9A5cF3bd22F96a21d7C002E15048f80608B672DC30DC7e3dbBd0343c5F02C738Eb2cD3D070aE1BD365909dD859d29F387AA96911e1 --recipient tb1qy9pqmk2pd9sv63g27jt8r657wy0d9ueeh0nqur
```

## Source Code
Expand Down

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