[PSDK-117] Implement Transfer Class

src/coinbase/coinbase.ts

@@ -13,6 +13,11 @@ import { InvalidAPIKeyFormat, InternalError, InvalidConfiguration } from "./erro
 export class Coinbase {
   apiClients: ApiClients = {};
 
+  /**
+   * Represents the number of Wei per Ether.
+   */
+  static readonly WEI_PER_ETHER: bigint = BigInt("1000000000000000000");
+
   /**
    * Initializes the Coinbase SDK.
    * @constructor

src/coinbase/errors.ts

@@ -55,3 +55,22 @@ export class InvalidConfiguration extends Error {
     }
   }
 }
+
+/**
+ * InvalidUnsignedPayload error is thrown when the unsigned payload is invalid.
+ */
+export class InvalidUnsignedPayload extends Error {
+  static DEFAULT_MESSAGE = "Invalid unsigned payload";
+
+  /**
+   * Initializes a new InvalidUnsignedPayload instance.
+   * @param message - The error message.
+   */
+  constructor(message: string = InvalidUnsignedPayload.DEFAULT_MESSAGE) {
+    super(message);
+    this.name = "InvalidUnsignedPayload";
+    if (Error.captureStackTrace) {
+      Error.captureStackTrace(this, InvalidUnsignedPayload);
+    }
+  }
+}

src/coinbase/transfer.ts

@@ -0,0 +1,147 @@
+import { ApiClients } from "./types";
+import { Coinbase } from "./coinbase";
+import { Transfer as TransferModel } from "../client/api";
+import { ethers } from "ethers";
+import { InvalidUnsignedPayload } from "./errors";
+
+/**
+ * A representation of a Transfer, which moves an amount of an Asset from
+ * a user-controlled Wallet to another Address. The fee is assumed to be paid
+ * in the native Asset of the Network.
+ */
+export class Transfer {
+  private model: TransferModel;
+  private client: ApiClients;
+  private transaction?: ethers.Transaction;
+
+  /**
+   * Initializes a new Transfer instance.
+   * @param {TransferModel} transferModel - The Transfer model.
+   * @param {ApiClients} client - The API clients.
+   */
+  constructor(transferModel: TransferModel, client: ApiClients) {
+    this.model = transferModel;
+    this.client = client;
+  }
+
+  /**
+   * Returns the ID of the Transfer.
+   * @returns {string} The Transfer ID.
+   */
+  public getId(): string {
+    return this.model.transfer_id;
+  }
+
+  /**
+   * Returns the Network ID of the Transfer.
+   * @returns {string} The Network ID.
+   */
+  public getNetworkId(): string {
+    return this.model.network_id;
+  }
+
+  /**
+   * Returns the Wallet ID of the Transfer.
+   * @returns {string} The Wallet ID.
+   */
+  public getWalletId(): string {
+    return this.model.wallet_id;
+  }
+
+  /**
+   * Returns the From Address ID of the Transfer.
+   * @returns {string} The From Address ID.
+   */
+  public getFromAddressId(): string {
+    return this.model.address_id;
+  }
+
+  /**
+   * Returns the Destination Address ID of the Transfer.
+   * @returns {string} The Destination Address ID.
+   */
+  public getDestinationAddressId(): string {
+    return this.model.destination;
+  }
+
+  /**
+   * Returns the Asset ID of the Transfer.
+   * @returns {string} The Asset ID.
+   */
+  public getAssetId(): string {
+    return this.model.asset_id;
+  }
+
+  /**
+   * Returns the Amount of the Transfer.
+   * @returns {string} The Amount of the Asset.
+   */
+  public getAmount(): bigint {
+    const amount = BigInt(this.model.amount);
+
+    if (this.getAssetId() === "ETH") {
+      return amount / Coinbase.WEI_PER_ETHER;
+    }
+    return BigInt(this.model.amount);
+  }
+
+  /**
+   * Returns the Unsigned Payload of the Transfer.
+   * @returns {string} The Unsigned Payload as a Hex string.
+   */
+  public getUnsignedPayload(): string {
+    return this.model.unsigned_payload;
+  }
+
+  /**
+   * Returns the Signed Payload of the Transfer.
+   * @returns {string | undefined} The Signed Payload as a Hex string, or undefined if not yet available.
+   */
+  public getSignedPayload(): string | undefined {
+    return this.model.signed_payload;
+  }
+
+  /**
+   * Returns the Transaction Hash of the Transfer.
+   * @returns {string | undefined} The Transaction Hash as a Hex string, or undefined if not yet available
+   */
+  public getTransactionhash(): string | undefined {
+    return this.model.transaction_hash;
+  }
+
+  /**
+   * Returns the Transaction of the Transfer.
+   * @returns {ethers.Transaction} The ethers.js Transaction object.
+   * @throws (InvalidUnsignedPayload) If the unsigned payload is invalid.
+   */
+  public getTransaction(): ethers.Transaction {
+    if (this.transaction) return this.transaction;
+
+    let transaction = new ethers.Transaction();
+
+    const rawPayload = this.getUnsignedPayload()
+      .match(/../g)
+      ?.map(byte => parseInt(byte, 16));
+    if (!rawPayload) {
+      throw new InvalidUnsignedPayload("Unable to parse unsigned payload");
+    }
+
+    // TODO: Add try catch block to wrap decoding.
+    const rawPayloadBytes = new Uint8Array(rawPayload);
+
+    const decoder = new TextDecoder();
+
+    const parsedPayload = JSON.parse(decoder.decode(rawPayloadBytes));
+
+    transaction.chainId = BigInt(parsedPayload["chainId"]);
+    transaction.nonce = BigInt(parsedPayload["nonce"]);
+    transaction.maxPriorityFeePerGas = BigInt(parsedPayload["maxPriorityFeePerGas"]);
+    transaction.maxFeePerGas = BigInt(parsedPayload["maxFeePerGas"]);
+    transaction.gasLimit = BigInt(parsedPayload["gas"]);
+    transaction.to = parsedPayload["to"];
+    transaction.value = BigInt(parsedPayload["value"]);
+    transaction.data = parsedPayload["input"];
+
+    return transaction;
+  }
+}

src/coinbase/user.ts

@@ -12,7 +12,7 @@ export class User {
 
   /**
    * Initializes a new User instance.
-   * @param {UserModel} user - The user model.
+   * @param {UserModel} user - The User model.
    * @param {ApiClients} client - The API clients.
    */
   constructor(user: UserModel, client: ApiClients) {