From 4eced65dbf3906c724209c2354f5d448b2c3d92d Mon Sep 17 00:00:00 2001
From: Ladd Hoffman <ladd.hoffman@swarmsolutions.com>
Date: Thu, 2 Feb 2023 21:54:37 -0600
Subject: [PATCH] Add basic virtual machine concept

---
 forum-network/src/classes/vm.js            | 65 ++++++++++++++++++++++
 forum-network/src/index.html               |  2 +-
 forum-network/src/tests/scripts/vm.test.js | 42 ++++++++++++++
 forum-network/src/tests/vm.test.html       | 32 +++++++++++
 4 files changed, 140 insertions(+), 1 deletion(-)
 create mode 100644 forum-network/src/classes/vm.js
 create mode 100644 forum-network/src/tests/scripts/vm.test.js
 create mode 100644 forum-network/src/tests/vm.test.html

diff --git a/forum-network/src/classes/vm.js b/forum-network/src/classes/vm.js
new file mode 100644
index 0000000..ee6f1a6
--- /dev/null
+++ b/forum-network/src/classes/vm.js
@@ -0,0 +1,65 @@
+import { Action } from './action.js';
+
+class ContractRecord {
+  constructor(id, instance) {
+    this.id = id;
+    this.instance = instance;
+  }
+}
+
+export class VMHandle {
+  constructor(vm, sender) {
+    this.vm = vm;
+    this.sender = sender;
+    this.actions = {
+      call: new Action('call'),
+    };
+  }
+
+  /**
+   * @param {string} id Contract ID
+   * @param {string} method
+   */
+  callContract(id, method, ...args) {
+    const instance = this.vm.getContractInstance(id);
+    const fn = instance[method];
+    if (!fn) throw new Error(`Contract ${id} method ${method} not found!`);
+    this.actions.call.log(this.sender, instance, method);
+    return fn.call(instance, this.sender, ...args);
+  }
+}
+
+export class VM {
+  constructor() {
+    this.contracts = new Map();
+  }
+
+  /**
+   * @param {string} id
+   * @param {class} ContractClass
+   * @param {any[]} ...args Passed to contractClass constructor after `vm`
+   */
+  addContract(id, ContractClass, ...args) {
+    const instance = new ContractClass(this, ...args);
+    const contract = new ContractRecord(id, instance);
+    this.contracts.set(id, contract);
+  }
+
+  getHandle(sender) {
+    return new VMHandle(this, sender);
+  }
+
+  /**
+   * @param {string} id
+   */
+  getContract(id) {
+    return this.contracts.get(id);
+  }
+
+  /**
+   * @param {string} id
+   */
+  getContractInstance(id) {
+    return this.getContract(id)?.instance;
+  }
+}
diff --git a/forum-network/src/index.html b/forum-network/src/index.html
index 0051aba..7f6fa7b 100644
--- a/forum-network/src/index.html
+++ b/forum-network/src/index.html
@@ -24,8 +24,8 @@
   </ul>
   <ul>
     <li><a href="./tests/forum-network.test.html">Forum Network</a></li>
+    <li><a href="./tests/vm.test.html">VM</a></li>
   </ul>
-  <h3>Tertiary</h3>
   <ul>
     <li><a href="./tests/basic.test.html">Basic Sequencing</a></li>
     <li><a href="./tests/wdag.test.html">WDAG</a></li>
diff --git a/forum-network/src/tests/scripts/vm.test.js b/forum-network/src/tests/scripts/vm.test.js
new file mode 100644
index 0000000..69e4c8d
--- /dev/null
+++ b/forum-network/src/tests/scripts/vm.test.js
@@ -0,0 +1,42 @@
+import { Actor } from '../../classes/actor.js';
+import { Box } from '../../classes/box.js';
+import { Scene } from '../../classes/scene.js';
+import { VM } from '../../classes/vm.js';
+
+const rootElement = document.getElementById('scene');
+const rootBox = new Box('rootBox', rootElement).flex();
+window.scene = new Scene('VM test', rootBox).withSequenceDiagram();
+
+const testContractId = 'test-contract-id';
+class TestContract extends Actor {
+  constructor(vm, value) {
+    super('TestContract');
+    this.vm = vm;
+    this.value = value;
+  }
+
+  hello(sender) {
+    return `${sender.name} ${this.value}`;
+  }
+}
+
+describe('VM', () => {
+  let vm;
+  let sender;
+  let vmHandle;
+
+  before(() => {
+    vm = (window.vm = new VM());
+    sender = new Actor('Sender');
+    vm.addContract(testContractId, TestContract, 'world');
+    vmHandle = vm.getHandle(sender);
+  });
+
+  it('Should exist', () => {
+    should.exist(vm);
+  });
+
+  it('Call a contract method', () => {
+    vmHandle.callContract(testContractId, 'hello').should.equal('Sender world');
+  });
+});
diff --git a/forum-network/src/tests/vm.test.html b/forum-network/src/tests/vm.test.html
new file mode 100644
index 0000000..8aeff12
--- /dev/null
+++ b/forum-network/src/tests/vm.test.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+
+<head>
+  <title>VM</title>
+  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  <link rel="stylesheet" href="https://unpkg.com/mocha/mocha.css" />
+  <link type="text/css" rel="stylesheet" href="../index.css" />
+</head>
+
+<body>
+  <h2><a href="../">DGF Tests</a></h2>
+  <div id="mocha"></div>
+  <div id="scene"></div>
+</body>
+<script src="https://cdnjs.cloudflare.com/ajax/libs/radash/10.7.0/radash.js"
+  integrity="sha512-S207zKWG3iqXqe6msO7/Mr8X3DzzF4u8meFlokHjGtBPTGUhgzVo0lpcqEy0GoiMUdcoct+H+SqzoLsxXbynzg=="
+  crossorigin="anonymous" referrerpolicy="no-referrer"></script>
+<script src="https://unpkg.com/mocha/mocha.js"></script>
+<script src="https://unpkg.com/chai/chai.js"></script>
+<script type="module" src="./scripts/vm.test.js"></script>
+<script defer class="mocha-init">
+  mocha.setup({
+    ui: 'bdd',
+    globals: ['vm', '__REACT_DEVTOOLS_*'],
+  });
+  mocha.checkLeaks();
+  window.should = chai.should();
+</script>
+<script defer class="mocha-exec">
+  // TODO: Weird race condition -- resolve this in a better way
+  setTimeout(() => mocha.run(), 1000);
+</script>