Composition area: Only paste HTML that originated in Signal

Co-authored-by: Chris Svenningsen <chris@carbonfive.com>

ts/quill/util.ts

@@ -1,6 +1,7 @@
 // Copyright 2020 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
+import emojiRegex from 'emoji-regex';
 import Delta from 'quill-delta';
 import { LeafBlot, DeltaOperation } from 'quill';
 import Op from 'quill-delta/dist/Op';
@@ -195,3 +196,67 @@ export const getDeltaToRemoveStaleMentions = (
 
   return new Delta(newOps);
 };
+
+export const insertMentionOps = (
+  incomingOps: Array<Op>,
+  bodyRanges: Array<BodyRangeType>
+): Array<Op> => {
+  const ops = [...incomingOps];
+
+  // Working backwards through bodyRanges (to avoid offsetting later mentions),
+  // Shift off the op with the text to the left of the last mention,
+  // Insert a mention based on the current bodyRange,
+  // Unshift the mention and surrounding text to leave the ops ready for the next range
+  bodyRanges
+    .sort((a, b) => b.start - a.start)
+    .forEach(({ start, length, mentionUuid, replacementText }) => {
+      const op = ops.shift();
+
+      if (op) {
+        const { insert } = op;
+
+        if (typeof insert === 'string') {
+          const left = insert.slice(0, start);
+          const right = insert.slice(start + length);
+
+          const mention = {
+            uuid: mentionUuid,
+            title: replacementText,
+          };
+
+          ops.unshift({ insert: right });
+          ops.unshift({ insert: { mention } });
+          ops.unshift({ insert: left });
+        } else {
+          ops.unshift(op);
+        }
+      }
+    });
+
+  return ops;
+};
+
+export const insertEmojiOps = (incomingOps: Array<Op>): Array<Op> => {
+  return incomingOps.reduce((ops, op) => {
+    if (typeof op.insert === 'string') {
+      const text = op.insert;
+      const re = emojiRegex();
+      let index = 0;
+      let match: RegExpExecArray | null;
+
+      // eslint-disable-next-line no-cond-assign
+      while ((match = re.exec(text))) {
+        const [emoji] = match;
+        ops.push({ insert: text.slice(index, match.index) });
+        ops.push({ insert: { emoji } });
+        index = match.index + emoji.length;
+      }
+
+      ops.push({ insert: text.slice(index, text.length) });
+    } else {
+      ops.push(op);
+    }
+
+    return ops;
+  }, [] as Array<Op>);
+};