doc for writing your first contract with Hyperweb

docs/WRITING_FIRST_CONTRACT.md

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+# Writing Your First Contract
+
+This guide walks you through creating a simple "Hello World" contract using Hyperweb. This contract will set an initial greeting message and provide a way to retrieve it.
+
+## Prerequisites
+
+Before starting, ensure you have:
+- Set up the Hyperweb development environment (refer to the main [README](../README.md)).
+- Basic understanding of TypeScript and object-oriented programming.
+
+## Overview
+
+Our "Hello World" contract will:
+
+1. Set a greeting message when the contract is instantiated.
+2. Provide a method to retrieve the message.
+
+## Step 1: Create Your Contract Directory
+
+1. Navigate to the `src/` directory.
+2. Create a new folder named `hello-world`:
+
+   ```bash
+   mkdir src/hello-world
+   ```
+
+3. Inside the `hello-world` folder, create a file named `index.ts`:
+
+   ```bash
+   touch src/hello-world/index.ts
+   ```
+
+## Step 2: Implement the Hello World Contract
+
+In `src/hello-world/index.ts`, define the contract as follows:
+
+```ts
+export interface State {
+  get(key: string): string;
+  set(key: string, value: any): void;
+};
+
+default export class HelloWorldContract {
+    state: State;
+
+    constructor(state: State) {
+      this.state = state;
+      this.state.set('greet', "Hello, World!"); // Set initial greeting in constructor
+    }
+
+    // Retrieve the greeting message
+    greet(): string {
+      return this.state.get('greet');
+    }
+}
+```
+
+### Explanation
+
+- **Constructor**: Initializes the contract with the greeting message "Hello, World!".
+- **`greet`**: Returns the message stored in the state.
+
+## Step 3: Add the Contract to the Build Script
+
+To include your contract in the build process:
+
+1. Open `scripts/build.ts`.
+2. Add an entry for the `hello-world` contract:
+
+   ```ts
+   const configs: BuildConfig[] = [
+   // existing contracts
+    {
+      entryFile: 'src/hello-world',
+      outFile: 'dist/contracts/helloWorld.js',
+      externalPackages: []
+    }
+   ];
+   ```
+
+This configuration specifies the entry point and output file for the build process.
+
+## Step 4: Build the Contract
+
+Compile the contract:
+
+```bash
+yarn build
+```
+
+This will generate the bundled contract in `dist/contracts`, making it ready for deployment.
+
+## Step 5: Write Tests for the Hello World Contract
+
+Testing helps ensure the contract behaves as expected. In the `__tests__/` directory:
+
+1. Create `helloWorld.test.ts`:
+
+   ```bash
+   touch __tests__/helloWorld.test.ts
+   ```
+
+2. Write test cases for greeting retrieval:
+
+   ```js
+   import { DirectSecp256k1HdWallet } from '@cosmjs/proto-signing';
+   import { assertIsDeliverTxSuccess } from '@cosmjs/stargate';
+
+   import path from "path";
+   import fs from 'fs';
+   import { getSigningJsdClient, jsd } from 'hyperwebjs';
+   import { useChain, generateMnemonic } from 'starshipjs';
+   import { sleep } from '../test-utils/sleep';
+   import './setup.test';
+
+   describe('Hello World Contract Tests', () => {
+    let wallet, denom, address, queryClient, signingClient;
+    let chainInfo, getCoin, getRpcEndpoint, creditFromFaucet;
+    let contractCode, contractIndex;
+
+    let fee;
+
+    beforeAll(async () => {
+    ({
+      chainInfo,
+      getCoin,
+      getRpcEndpoint,
+      creditFromFaucet
+      } = useChain('hyperweb'));
+       denom = (await getCoin()).base;
+
+       // Initialize wallet
+       wallet = await DirectSecp256k1HdWallet.fromMnemonic(generateMnemonic(), {
+         prefix: chainInfo.chain.bech32_prefix
+       });
+       address = (await wallet.getAccounts())[0].address;
+       console.log(`contract creator address: ${address}`);
+
+       // Create custom cosmos interchain client
+       queryClient = await jsd.ClientFactory.createRPCQueryClient({
+         rpcEndpoint: await getRpcEndpoint()
+       });
+
+       signingClient = await getSigningJsdClient({
+         rpcEndpoint: await getRpcEndpoint(),
+         signer: wallet
+       });
+
+       // Set default fee
+       fee = { amount: [{ denom, amount: '100000' }], gas: '550000' };
+
+       await creditFromFaucet(address);
+       await sleep(2000); // Wait for faucet transfer
+    });
+
+    it('check balance', async () => {
+      const balance = await signingClient.getBalance(address, denom);
+      expect(balance.amount).toEqual("10000000000");
+      expect(balance.denom).toEqual(denom);
+    });
+
+    it('instantiate Hello World contract', async () => {
+      // Read contract code from external file
+      const contractPath = path.join(__dirname, '../dist/contracts/helloWorld.js');
+      contractCode = fs.readFileSync(contractPath, 'utf8');
+
+      const msg = jsd.jsd.MessageComposer.fromPartial.instantiate({
+        creator: address,
+        code: contractCode,
+      });
+
+      const result = await signingClient.signAndBroadcast(address, [msg], fee);
+      assertIsDeliverTxSuccess(result);
+
+      // Parse response to get the contract index
+      const response = jsd.jsd.MsgInstantiateResponse.fromProtoMsg(result.msgResponses[0]);
+      contractIndex = response.index;
+      expect(contractIndex).toBeGreaterThan(0);
+      console.log(`contract index: ${contractIndex}`);
+    });
+
+    it('query for initial greeting', async () => {
+      const msg = jsd.jsd.MessageComposer.fromPartial.eval({
+        creator: address,
+        index: contractIndex,
+        fnName: "greet",
+        arg: "",
+      });
+
+      const result = await signingClient.signAndBroadcast(address, [msg], fee);
+      assertIsDeliverTxSuccess(result);
+
+      const response = jsd.jsd.MsgEvalResponse.fromProtoMsg(result.msgResponses[0]);
+      expect(response.result).toEqual("Hello, World!");
+    });
+   });
+   ```
+
+3. Run the tests:
+
+   ```bash
+   yarn test
+   ```
+
+## Step 6: Deploy and Interact with the Contract
+
+With the contract built and tested, you can now deploy it to the Hyperweb blockchain:
+
+1. **Deploy**: Use Hyperweb’s deployment tools to deploy your contract.
+2. **Interact**: Call the `greet` method to retrieve the greeting message from the deployed contract.
+
+## Summary
+
+You've successfully created, built, tested, and deployed a simple "Hello World" contract using Hyperweb.
+This foundational contract will help as you move on to more complex contracts.
+For further information, refer to the Hyperweb documentation.