Add a modal for controls

index.html

@@ -20,9 +20,56 @@
       <div class="input">
         <div id="input-buttons"></div>
         <button id="clear-button">Clear</button>
+        <a id="controls-button" class="button open-modal" href="#controls">Controls</a>
       </div>
       <div id="state-graph"></div>
     </div>
+    <div id="controls" class="modal" hidden="hidden">
+      <div class="modal-content">
+        <h3>Controls</h3>
+        <table>
+          <thead>
+          <tr>
+            <th>Action</th>
+            <th>Desktop</th>
+          </tr>
+          </thead>
+          <tbody>
+          <tr>
+            <td>Pan</td>
+            <td>Left-click and drag</td>
+          </tr>
+          <tr>
+            <td>Zoom in/out</td>
+            <td>Mouse wheel</td>
+          </tr>
+          <tr>
+            <td>Create state</td>
+            <td>Double-click</td>
+          </tr>
+          <tr>
+            <td>Move state</td>
+            <td>Middle-click and drag</td>
+          </tr>
+          <tr>
+            <td>Edit/Delete state</td>
+            <td>Right-click</td>
+          </tr>
+          <tr>
+            <td>Create transition</td>
+            <td>Left-click and drag</td>
+          </tr>
+          <tr>
+            <td>Edit transition</td>
+            <td>Right-click</td>
+          </tr>
+          <tr>
+            <td>Delete transition</td>
+            <td>Right-click</td>
+          </tr>
+        </table>
+      </div>
+    </div>
     <script type="module" src="src/main.js"></script>
   </body>
 </html>

src/fsm.js

@@ -6,6 +6,7 @@ const IS_INVALID = 'is-invalid';
 
 const wordInput = /** @type {HTMLInputElement} */ (document.getElementById('word-input'));
 const buttons = /** @type {HTMLDivElement} */ (document.getElementById('input-buttons'));
+const controlsButton = /** @type {HTMLButtonElement} */ (document.getElementById('controls-button'));
 const clearButton = /** @type {HTMLButtonElement} */ (document.getElementById('clear-button'));
 const light = /** @type {HTMLDivElement} */ (document.getElementById('light'));
 
@@ -19,6 +20,11 @@ export function openAutomaton(states, editable = false) {
 
   const viewer = new GraphEditor();
   viewer.readonly = !editable;
+  if (editable) {
+    controlsButton.removeAttribute('hidden');
+  } else {
+    controlsButton.setAttribute('hidden', 'hidden');
+  }
   const graph = createGraph(states);
   viewer.addEventListener('change', () => {
     try {

src/main.js

@@ -1,5 +1,6 @@
 import { AUTOMATONS } from './examples.js';
 import { openAutomaton } from './fsm.js';
+import './modal.ts';
 
 const automatonSelector = /** @type {HTMLDivElement} */ (document.getElementById('automaton-selector'));
 const automatonCollection = /** @type {HTMLDivElement} */ (document.getElementById('automaton-collection'));

src/modal.ts

@@ -0,0 +1,34 @@
+let modal: HTMLElement | null = null;
+
+function openModal(event: Event) {
+  event.preventDefault();
+  const el = document.querySelector((event.target as HTMLElement).getAttribute('href')!)! as HTMLElement;
+  // @ts-expect-error reset
+  el.style.display = null;
+  el.removeAttribute('hidden');
+  el.setAttribute('aria-modal', 'true');
+  modal = el;
+  modal.addEventListener('click', closeModal);
+}
+
+function closeModal(event: Event) {
+  event.preventDefault();
+  if (modal === null) {
+    return;
+  }
+  modal.style.display = 'none';
+  modal.setAttribute('hidden', 'hidden');
+  modal.removeAttribute('aria-modal');
+  modal.removeEventListener('click', closeModal);
+  modal = null;
+}
+
+document.querySelectorAll('.open-modal').forEach((el) => {
+  el.addEventListener('click', openModal);
+});
+
+window.addEventListener('keydown', (event) => {
+  if (event.key === 'Escape' && modal !== null) {
+    closeModal(event);
+  }
+});

src/style.css

@@ -43,7 +43,7 @@ input {
   background-color: transparent;
   transition: border-color 0.25s;
 }
-button {
+button, .button {
   border-radius: 8px;
   border: 1px solid transparent;
   padding: 0.6em 1.2em;
@@ -53,8 +53,10 @@ button {
   background-color: #1a1a1a;
   cursor: pointer;
   transition: border-color 0.25s;
+  text-decoration: none;
+  color: inherit;
 }
-button:hover {
+button:hover, .button:hover {
   border-color: #646cff;
 }
 button:focus,
@@ -184,12 +186,47 @@ graph-editor {
   float: right;
 }
 
+table {
+  width: 100%;
+}
+th, td {
+  border-bottom: thin solid hsla(0, 0%, 100%, .12);
+  height: 48px;
+  padding: 0 16px;
+}
+
+.modal[hidden] {
+  display: none;
+}
+
+.modal {
+  position: fixed;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
+  background: rgba(0, 0, 0, .8);
+  animation: fadeIn .3s both
+}
+
+.modal-content {
+  overflow: auto;
+  width: 600px;
+  max-width: calc(100vw - 20px);
+  max-height: calc(100vh - 20px);
+  padding: 20px;
+  background-color: #1a1a1a;
+}
+
 @media (prefers-color-scheme: light) {
   :root {
     color: #213547;
     background-color: #ffffff;
   }
-  button {
+  button, .btn {
     background-color: #f9f9f9;
   }
   .context-menu {