Alice, a wholesale seller of Holi-themed items, has been explaining the benefits of a Simple Payment Channel to local shopkeepers in HoliVille. These shopkeepers visit Alice's warehouse to purchase Holi-themed costumes, masks, and other accessories for their shops. The process of purchasing these items can be cumbersome and time-consuming, especially when dealing with multiple shopkeepers.

Alice explained how a customer, John, who owns a local shop in HoliVille, would deposit 100 wei into the smart contract. John lists payments for a variety of Holi-themed items, such as costumes (10 wei each) and masks (20 wei each). When John closes the channel, the total amount of 30 wei is transferred to Alice for the items purchased, and the remaining 70 wei is transferred back to John. This process, Alice explained, would make transactions faster, more convenient, and more cost-effective for both Alice and the local shopkeepers in HoliVille.

You're tasked with creating a Simple Payment Channel smart contract for Alice's wholesale business. This contract will enable local shopkeepers to deposit, list payments for Holi-themed items, and close channels directly with Alice, simplifying transactions and improving the overall shopping experience for both parties..

Input:

constructor(address recipientAddress): The constructor function should initialize the contract by setting the wholesale seller’s address as the owner and the recipient of the contract. The recipientAddress parameter sets the address that will receive the payments.

deposit() payable : This payable function should allow the local shopkeeper to deposit funds into the Simple Payment Channel. The function should check if the amount sent is greater than 0.

listPayment(uint256 amount) : This function should allow the local shopkeeper to list a new payment. The user should only be able to list a maximum of their deposited amount. The corresponding amount in wei should be reserved for the listed payment.

closeChannel() : This function should allow either the local shopkeeper or the wholesale seller to close the Simple Payment Channel. The function should check if the sender or the recipient is calling this function. All remaining funds in the channel should be transferred to the caller.

Output:

checkBalance() returns (uint): This function should return the current balance in the Simple Payment Channel.

getAllPayments() returns (uint[]): This function should return an array of all the payments listed in the Simple Payment Channel. Each element in the array represents the amount of a listed payment.