feat: add copy button plugin to chat interface

- Add a copy button plugin to the chat.js file
- Add CSS style for the copy button
- Add a new JS file for the copy button plugin

Author: mushonnip

client/css/style.css

@@ -619,4 +619,63 @@ a:-webkit-any-link {
     resize: vertical;
     max-height: 150px;
     min-height: 80px;
+}
+
+/* style for hljs copy */
+.hljs-copy-wrapper {
+    position: relative;
+    overflow: hidden
+}
+
+.hljs-copy-wrapper:hover .hljs-copy-button,
+.hljs-copy-button:focus {
+    transform: translateX(0)
+}
+
+.hljs-copy-button {
+    position: absolute;
+    transform: translateX(calc(100% + 1.125em));
+    top: 1em;
+    right: 1em;
+    width: 2rem;
+    height: 2rem;
+    text-indent: -9999px;
+    color: #fff;
+    border-radius: .25rem;
+    border: 1px solid #ffffff22;
+    background-color: #2d2b57;
+    background-image: url('data:image/svg+xml;utf-8,<svg width="16" height="16" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg"><path fill-rule="evenodd" clip-rule="evenodd" d="M6 5C5.73478 5 5.48043 5.10536 5.29289 5.29289C5.10536 5.48043 5 5.73478 5 6V20C5 20.2652 5.10536 20.5196 5.29289 20.7071C5.48043 20.8946 5.73478 21 6 21H18C18.2652 21 18.5196 20.8946 18.7071 20.7071C18.8946 20.5196 19 20.2652 19 20V6C19 5.73478 18.8946 5.48043 18.7071 5.29289C18.5196 5.10536 18.2652 5 18 5H16C15.4477 5 15 4.55228 15 4C15 3.44772 15.4477 3 16 3H18C18.7956 3 19.5587 3.31607 20.1213 3.87868C20.6839 4.44129 21 5.20435 21 6V20C21 20.7957 20.6839 21.5587 20.1213 22.1213C19.5587 22.6839 18.7957 23 18 23H6C5.20435 23 4.44129 22.6839 3.87868 22.1213C3.31607 21.5587 3 20.7957 3 20V6C3 5.20435 3.31607 4.44129 3.87868 3.87868C4.44129 3.31607 5.20435 3 6 3H8C8.55228 3 9 3.44772 9 4C9 4.55228 8.55228 5 8 5H6Z" fill="white"/><path fill-rule="evenodd" clip-rule="evenodd" d="M7 3C7 1.89543 7.89543 1 9 1H15C16.1046 1 17 1.89543 17 3V5C17 6.10457 16.1046 7 15 7H9C7.89543 7 7 6.10457 7 5V3ZM15 3H9V5H15V3Z" fill="white"/></svg>');
+    background-repeat: no-repeat;
+    background-position: center;
+    transition: background-color 200ms ease, transform 200ms ease-out
+}
+
+.hljs-copy-button:hover {
+    border-color: #ffffff44
+}
+
+.hljs-copy-button:active {
+    border-color: #ffffff66
+}
+
+.hljs-copy-button[data-copied="true"] {
+    text-indent: 0;
+    width: auto;
+    background-image: none
+}
+
+@media(prefers-reduced-motion) {
+    .hljs-copy-button {
+        transition: none
+    }
+}
+
+.hljs-copy-alert {
+    clip: rect(0 0 0 0);
+    clip-path: inset(50%);
+    height: 1px;
+    overflow: hidden;
+    position: absolute;
+    white-space: nowrap;
+    width: 1px
 }

client/html/index.html

@@ -56,6 +56,7 @@
             }
         </style>
         <script src="/assets/js/highlight.min.js"></script>
+        <script src="/assets/js/highlightjs-copy.min.js"></script>
         <script>window.conversation_id = `{{chat_id}}`</script>
         <title>ChatGPT</title>
     </head>

client/js/chat.js

@@ -8,6 +8,8 @@ const stop_generating   = document.querySelector(`.stop_generating`);
 const send_button       = document.querySelector(`#send-button`);
 let   prompt_lock       = false
 
+hljs.addPlugin(new CopyButtonPlugin());
+
 const format = (text) => {
     return text.replace(/(?:\r\n|\r|\n)/g, '<br>')
 }