import { ToolAnnotations } from "@modelcontextprotocol/sdk/types.js";
import { getDefaultProvider, Wallet, Contract, ethers } from '@coti-io/coti-ethers';
import { getCurrentAccountKeys, getNetwork } from "../shared/account.js";
import { ERC20_ABI } from "../constants/abis.js";
import { decryptUint } from "@coti-io/coti-sdk-typescript";
import { z } from "zod";
/**
* Tool definition for checking ERC20 token allowance on the COTI blockchain
*/
export const GET_ERC20_ALLOWANCE: ToolAnnotations = {
title: "Get ERC20 Allowance",
name: "get_erc20_allowance",
description:
"Check how many tokens a spender is allowed to use. " +
"This is used for checking the current allowance a spender has for an owner's tokens. " +
"Requires token contract address, owner address, and spender address as input. " +
"Returns the allowance amount.",
inputSchema: {
token_address: z.string().describe("ERC20 token contract address on COTI blockchain"),
owner_address: z.string().describe("Address of the token owner"),
spender_address: z.string().describe("Address of the spender to check allowance for"),
},
};
/**
* Type guard for validating get ERC20 allowance arguments
* @param args - Arguments to validate
* @returns True if arguments are valid for get ERC20 allowance operation
*/
export function isGetERC20AllowanceArgs(args: unknown): args is { token_address: string, owner_address: string, spender_address: string } {
return (
typeof args === "object" &&
args !== null &&
"token_address" in args &&
typeof (args as { token_address: string }).token_address === "string" &&
"owner_address" in args &&
typeof (args as { owner_address: string }).owner_address === "string" &&
"spender_address" in args &&
typeof (args as { spender_address: string }).spender_address === "string"
);
}
/**
* Handler for the getERC20Allowance tool
* @param args The arguments for the tool
* @returns The tool response
*/
export async function getERC20AllowanceHandler(args: Record<string, unknown> | undefined): Promise<any> {
if (!isGetERC20AllowanceArgs(args)) {
throw new Error("Invalid arguments for get_erc20_allowance");
}
const { token_address, owner_address, spender_address } = args;
const results = await performGetERC20Allowance(token_address, owner_address, spender_address);
return {
content: [{ type: "text", text: results }],
isError: false,
};
}
/**
* Retrieves the allowance for an ERC20 token spender on the COTI blockchain
* @param token_address - Address of the ERC20 token contract
* @param owner_address - Address of the token owner
* @param spender_address - Address of the spender to check allowance for
* @returns A formatted message with the allowance details
*/
export async function performGetERC20Allowance(token_address: string, owner_address: string, spender_address: string) {
try {
const currentAccountKeys = getCurrentAccountKeys();
const provider = getDefaultProvider(getNetwork());
const wallet = new Wallet(currentAccountKeys.privateKey, provider);
wallet.setAesKey(currentAccountKeys.aesKey);
const tokenContract = new Contract(token_address, ERC20_ABI, wallet);
const symbolResult = await tokenContract.symbol();
const decimalsResult = await tokenContract.decimals();
const allowanceResult = await tokenContract.allowance(owner_address, spender_address);
const decryptedAllowance = decryptUint(allowanceResult, currentAccountKeys.aesKey);
const formattedAllowance = decryptedAllowance ? ethers.formatUnits(decryptedAllowance, decimalsResult) : "Unable to decrypt";
return `ERC20 Token Allowance:\nToken: ${symbolResult}\nOwner: ${owner_address}\nSpender: ${spender_address}\nAllowance: ${formattedAllowance}`;
} catch (error) {
console.error('Error getting ERC20 allowance:', error);
throw new Error(`Failed to get ERC20 allowance: ${error instanceof Error ? error.message : String(error)}`);
}
}
