promise.ts

import { util } from "./util";
import { env } from "./env";
import { u128 } from ".";

function encodeArgs<T>(t: T): Uint8Array {
  if (t instanceof Uint8Array) {
    return t;
  }
  return encode<T>(t);
}

// TODO: make a types file for reuse
type Balance = u128;
type Gas = u64;
type PublicKey = Uint8Array;
type AccountId = string;

/**
 * Batch actions from within an AssemblyScript contract
 *
 * (1) transfer money
 *
 * // assume Context.sender = "bob.testnet"
 * ContractPromiseBatch.create("alice.testnet").transfer(100); // send 100 N to "alice.testnet"
 *
 * (2) deploy a contract
 *
 * // assume contract is loaded, either included and encoded as base64 in the current
 * // contract itself or via input to a function call (requires some other changes in near-sdk-as)
 * const code = Uint8Array[1,2,3]; // regardless, you end up with the contract code somehow
 *
 * // assume Context.sender = "bob.testnet"
 *
 * ContractPromiseBatch
 *     .create("app-v1.bob.testnet")
 *     .create_account()
 *     .transfer(u128.from(100))
 *     .add_full_access_key(new Uint8Array(0)) // TODO: need signer public key as byte array
 *     .deploy_contract(code)
 *
 * (3) chain promises
 *
 * // assume Context.sender = "bob.testnet"
 *
 * let promise = ContractPromiseBatch.create("first-contract.bob.testnet")
 *
 * promise.then("first-contract.bob.testnet")
 *        .transfer(u128.from(10))
 *
 */
export class ContractPromiseBatch {
  id: u64;

  static create(accountId: AccountId): ContractPromiseBatch {
    const accountIdArr = util.stringToBytes(accountId);
    const id: u64 = env.promise_batch_create(
      accountIdArr.byteLength,
      accountIdArr.dataStart
    );

    // @ts-ignore: Typescript expects the object to have a function to match the type
    // Wheras as only cares about the fields.
    return {
      id,
    };
  }

  create_account(): ContractPromiseBatch {
    env.promise_batch_action_create_account(this.id);
    return this;
  }

  deploy_contract(code: Uint8Array): ContractPromiseBatch {
    env.promise_batch_action_deploy_contract(
      this.id,
      code.length,
      code.dataStart
    );
    return this;
  }

  function_call<T>(
    methodName: string,
    args: T,
    amount: Balance,
    gas: Gas
  ): ContractPromiseBatch {
    const method_name = util.stringToBytes(methodName);
    const amountArr = amount.toUint8Array();
    const argsArr = encodeArgs<T>(args);

    env.promise_batch_action_function_call(
      this.id,
      method_name.byteLength,
      method_name.dataStart,
      argsArr.byteLength,
      argsArr.dataStart,
      amountArr.dataStart,
      gas
    );
    return this;
  }

  transfer(amount: Balance): ContractPromiseBatch {
    const amountArr = amount.toUint8Array();
    env.promise_batch_action_transfer(this.id, amountArr.dataStart);
    return this;
  }

  stake(amount: Balance, publicKey: PublicKey): ContractPromiseBatch {
    const amountArr = amount.toUint8Array();
    env.promise_batch_action_stake(
      this.id,
      amountArr.dataStart,
      publicKey.byteLength,
      publicKey.dataStart
    );
    return this;
  }

  add_full_access_key(
    publicKey: PublicKey,
    nonce: u64 = 0
  ): ContractPromiseBatch {
    env.promise_batch_action_add_key_with_full_access(
      this.id,
      publicKey.byteLength,
      publicKey.dataStart,
      nonce
    );
    return this;
  }

  add_access_key(
    publicKey: PublicKey,
    allowance: Balance,
    receiverId: AccountId,
    methodNames: string[],
    nonce: u64 = 0
  ): ContractPromiseBatch {
    const allowanceArr = allowance.toUint8Array();
    const typedArray = util.stringToBytes(receiverId);
    const methodNamesArr = util.stringToBytes(methodNames.join(","));
    env.promise_batch_action_add_key_with_function_call(
      this.id,
      publicKey.byteLength,
      publicKey.dataStart,
      nonce,
      allowanceArr.dataStart,
      typedArray.byteLength,
      typedArray.dataStart,
      methodNamesArr.byteLength,
      methodNamesArr.dataStart
    );
    return this;
  }

  delete_key(publicKey: PublicKey): ContractPromiseBatch {
    env.promise_batch_action_delete_key(
      this.id,
      publicKey.byteLength,
      publicKey.dataStart
    );
    return this;
  }

  delete_account(beneficiaryId: AccountId): ContractPromiseBatch {
    const typedArray = util.stringToBytes(beneficiaryId);
    env.promise_batch_action_delete_account(
      this.id,
      typedArray.byteLength,
      typedArray.dataStart
    );
    return this;
  }

  then(accountId: AccountId): ContractPromiseBatch {
    const accountIdArr = util.stringToBytes(accountId);
    const id = env.promise_batch_then(
      this.id,
      accountIdArr.byteLength,
      accountIdArr.dataStart
    );
    // @ts-ignore: See above ignore comment
    return {
      id,
    };
  }
}