Merge pull request #2 from xiangpengm/master

add first contract

Author: KaKeimei

i18n/zh-CN/docusaurus-plugin-content-docs/current/contract/getting-started/first-contract.md

@@ -2,3 +2,147 @@
 sidebar_position: 2
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 # 编写第一个合约
+
+在上一节中我们使用scrypt-cli工具创建了一个demo工程，并且打入了MVC链的补丁，下面我们使用这个项目来部署合约到MVC测试网。
+
+## 示例合约
+
+demo工程中有生成一个Demo合约，源码位于src/contracts/demo.ts，合约逻辑为使用一段数据的hash值构造并部署合约，合约unlock时需要输入数据原文。
+
+```typescript
+import {
+    assert,
+    ByteString,
+    method,
+    prop,
+    sha256,
+    Sha256,
+    SmartContract,
+} from 'scrypt-ts'
+
+export class Demo extends SmartContract {
+    @prop()
+    hash: Sha256
+
+    constructor(hash: Sha256) {
+        super(...arguments)
+        this.hash = hash
+    }
+
+    @method()
+    public unlock(message: ByteString) {
+        assert(sha256(message) == this.hash, 'Hash does not match')
+    }
+}
+```
+
+
+## 部署并调用合约
+
+原项目中使用项目根目录下的deploy.ts来部署合约，原项目部署适配bsv测试网，下面详述如何改成mvc链
+
+### 安装依赖包
+
+- token-core-ts包封装了MVC链的Wallet和Provider，为scrypt-ts提供MVC链接入功能
+- meta-contact封装了MVC数据服务，提供接入的api
+- @bitcoin-js/tiny-secp256k1-asmjs，ecpair提供Bitcoin标准的Signer interface
+
+```bash
+npm install token-core-ts meta-contract @bitcoin-js/tiny-secp256k1-asmjs ecpair
+```
+
+### 更新deploy.ts文件
+
+```typescript
+import { Demo } from './src/contracts/demo'
+import { bsv, sha256, toByteString } from 'scrypt-ts'
+import { MvcWallet, MvcProvider } from 'token-core-ts'
+import * as ecc from '@bitcoin-js/tiny-secp256k1-asmjs'
+import ECPairFactory, { SignerAsync } from 'ecpair'
+const ECPair = ECPairFactory(ecc)
+import * as dotenv from 'dotenv'
+import { API_TARGET } from 'meta-contract'
+
+// Load the .env file
+dotenv.config()
+
+if (!process.env.PRIVATE_KEY) {
+    throw new Error(
+        'No "PRIVATE_KEY" found in .env, Please run "npm run genprivkey" to generate a private key'
+    )
+}
+
+const network = bsv.Networks.testnet
+
+const mvcProvider = new MvcProvider(API_TARGET.MVC, network, 1000, true)
+
+// Read the private key from the .env file.
+// The default private key inside the .env file is meant to be used for the Bitcoin testnet.
+// See https://scrypt.io/docs/bitcoin-basics/bsv/#private-keys
+const privateKey = bsv.PrivateKey.fromWIF(process.env.PRIVATE_KEY || '')
+const bip174Signer = ECPair.fromPrivateKey(privateKey.toBuffer())
+
+const mvcWallet = new MvcWallet(
+    bip174Signer as unknown as SignerAsync,
+    network,
+    mvcProvider
+)
+
+async function main() {
+    await Demo.loadArtifact()
+
+    // check balance
+    const balance = await mvcWallet.getBalance()
+    if (balance.confirmed + balance.unconfirmed === 0) {
+        console.log('use faucet get mvc testnet coin')
+        console.log('https://witnessonchain.com/faucet/tspace')
+        console.log(
+            'address: ',
+            (await mvcWallet.getDefaultAddress()).toString()
+        )
+        return
+    }
+    console.log('balance', balance)
+
+    // TODO: Adjust the amount of satoshis locked in the smart contract:
+    const amount = 1
+
+    const msg = toByteString('hello world', true)
+
+    const instance = new Demo(
+        // TODO: Adjust constructor parameter values:
+        sha256(msg)
+    )
+
+    // Connect to a signer.
+    await instance.connect(mvcWallet)
+
+    // Contract deployment.
+    const deployTx = await instance.deploy(amount)
+    console.log(
+        `Demo contract deployed: https://test.mvcscan.com/tx/${deployTx.id}`
+    )
+    // Call contract
+    const { tx, atInputIndex } = await instance.methods.unlock(msg)
+    console.log(
+        `Demo contract call at: https://test.mvcscan.com/tx/${tx.id} ${atInputIndex}`
+    )
+}
+
+main()
+```
+
+### 执行deploy.ts
+
+```bash
+npm run deploy
+```
+如果测试地址无测试代币请前往MVC测试网[水龙头](https://witnessonchain.com/faucet/space)领取。
+
+![Alt text](/img/scrypt-first-faucet.png)
+
+执行成功如下
+
+![Alt text](/img/scrypt-first-run-success.png)
+
+实例中合约部署在[baf27c3164aecb1e285ef154c2f802eac69ee17b8cea8eb013da2f9d8890dfca](https://test.mvcscan.com/tx/baf27c3164aecb1e285ef154c2f802eac69ee17b8cea8eb013da2f9d8890dfca)，在[d18d04c19108ae5c7baeefe7183b1ea07847ef58e23b560fc3d32abcf0bd8f17](https://test.mvcscan.com/tx/d18d04c19108ae5c7baeefe7183b1ea07847ef58e23b560fc3d32abcf0bd8f17)中被调用。