Near Cetificate Devoloper - Demo

Vietnamese gambling game: Gourd-Fish-Shrimp-Crab On NEAR

How to play

Instead of showing one to six pips, the sides of the dice have pictures of a fish, a prawn, a crab, a rooster, a calabash gourd,and a stag.We have 3 dice. Players place wagers on a board that has the six pictures The bettor will get their money back plus the corresponding amount of profit if the bet is correct If two (or three) dice correspond with a bet, the bettor receives tow (or three) times their money For instance, if one were to place $3 on fish, and the dealer rolls 1 fish, 1 crab and 1 stag, then the bettor would receive $3 while keeping the $3 they had bet

About Contract

It's need to be mentioned that it is a pure dapp project, which means there is no centralized backend nor data server, all persistent information is stored and mananged on NEAR chain by a contract.

Contract Structure

// information about bets allocation
#[derive(BorshDeserialize, BorshSerialize)]
pub struct BetInfo {
    pub fish: u128, 
    pub prawn: u128, 
    pub crab: u128, 
    pub rooster: u128, 
    pub gourd: u128, 
    pub stag: u128,
}

#[near_bindgen]
#[derive(BorshDeserialize, BorshSerialize)]
pub struct GourdCrab {
    pub owner_id: AccountId,
    pub accounts: UnorderedMap<AccountId, Balance>, // balance of user
    pub bets: UnorderedMap<AccountId,BetInfo>,      // bets in the room
    pub bet_level: Balance, 
}

Contract Interface

//****************/
//***** INIT *****/
//****************/

/// initialization of this contract
#[init]
    pub fn new(
        owner_id: AccountId,
        bet_level: U128, 
    ) -> Self;


//***************************/
//***** OWNER FUNCTIONS *****/
//***************************/

pub fn set_bet_level(&mut self, bet_level: U128);

pub fn deposit(&mut self); 

pub fn betting(
    &mut self, 
    num_fish: u128, 
    num_prawn: u128,
    num_crab: u128,
    num_rooster: u128, 
    num_gourd: u128,
    num_stag: u128);

pub fn cancel_betting(&mut self);

// roll the dice and calculate the payoff
pub fn rolling(&mut self);

// get account's balance
pub fn get_balance(&self, account_id: AccountId) -> u128;

Quick Start

To run this project locally:

1. Prerequisites: Make sure you've installed Node.js ≥ 12

Now you'll have a local development environment backed by the NEAR TestNet!

Go ahead and play with the app and the code. As you make code changes, the app will automatically reload.

Exploring The Code

The "contract" code lives in the /src folder. See the README there for more info.

Preparation

Every smart contract in NEAR has its own associated account. When you run yarn dev, your smart contract gets deployed to the live NEAR TestNet with a throwaway account. When you're ready to make it permanent, here's how.

Install near-cli (optional)

near-cli is a command line interface (CLI) for interacting with the NEAR blockchain. It was installed to the local node_modules folder when you ran yarn install, but for best ergonomics you may want to install it globally:

yarn install --global near-cli

Or, if you'd rather use the locally-installed version, you can prefix all near commands with npx

Ensure that it's installed with near --version (or npx near --version)

How to run

After you clone the project, go to the project folder

Step 1: Login

Each account on NEAR can have at most one contract deployed to it. If you've already created an account such as your-name.testnet, you can deploy your contract to NCD-GroupA-Demo.your-name.testnet. Assuming you've already created an account on NEAR Wallet, here's how to create NCD-GroupA-Demo.your-name.testnet:

1. Authorize NEAR CLI, following the commands it gives you:

   near login

2. Create a subaccount (replace YOUR-NAME below with your actual account name):

   near create-account subacc.YOUR-NAME.testnet --masterAccount YOUR-NAME.testnet

3. Export account to variable export ACCOUNT_ID=<YOUR_ACCOUNT_ID>

Step 2: build and testing

./build.sh
./test.sh

Step 3: deploy!

./deploy.sh

Step 4: Call contract from Near CLI

./call.sh <METHOD_NAME> <ARGs>

For example, both account_id1 = demo10.tlgk.testnet and account_id2 = demo10.kiendemo.testnet want to bet. You will get the following script

First, init contract:

./call.sh new '{"owner_id":"demo10.tlgk.testnet", "bet_level":"1000000000000000000000000"}'

deposit some money and place a bet. for instance, account_id1 want place 1 crab and 2 rooster, account_id2 want place 1 fish and 1 praw

./call.sh deposit '{}' --amount 40
./call.sh betting '{"num_fish": 0, "num_prawn": 0, "num_crab": 1,  "num_rooster": 2, "num_gourd": 0, "num_stag": 0}'

./call2.sh deposit '{}' --amount 40
./call2.sh betting '{"num_fish": 1, "num_prawn": 1, "num_crab": 0,  "num_rooster": 0,  "num_gourd": 0, "num_stag":0}'

You can check Bets by scripts:

./call.sh get_bet '{"account_id":"demo10.kiendemo.testnet"}'
./call.sh get_bet '{"account_id":"demo10.kiendemo.testnet"}'

Now, rolling dices

./call.sh rolling '{}'

You can check balance. ./call.sh get_balance '{"account_id":"demo10.tlgk.testnet"}' ./call.sh get_balance '{"account_id":"demo10.kiendemo.testnet"}'

Troubleshooting

On Windows, if you're seeing an error containing EPERM it may be related to spaces in your path. Please see this issue for more details.