Add support for sending user emoji using autocomplete (#205)

* Add support for sending user emoji using autocomplete

What's included:
- An implementation for detecting user emojis
- Addition of user emojis to the emoji autocomplete in the command bar
- Translation of shortcodes into image tags on message sending

What's not included:
- Loading emojis from the active room, loading the user's global emoji packs, loading emoji from spaces
- Selecting custom emoji using the emoji picker

This is a predominantly proof-of-concept change, and everything here may be subject to
architectural review and reworking.

* Amending PR:  Allow sending multiple of the same emoji

* Amending PR:  Add support for emojis in edited messages

* Amend PR:  Apply requested revisions

This commit consists of several small changes, including:
- Fix crash when the user doesn't have the im.ponies.user_emotes account data entry
- Add mx-data-emoticon attribute to command bar emoji
- Rewrite alt text in the command bar interface
- Remove "vertical-align" attribute from sent emoji

* Amending PR:  Fix bugs (listed below)

- Fix bug where sending emoji w/ markdown off resulted in a crash
- Fix bug where alt text in the command bar was wrong

* Amending PR:  Add support for replacement of twemoji shortcodes

* Amending PR: Fix & refactor getAllEmoji -> getShortcodeToEmoji

* Amending PR: Fix bug: Sending two of the same emoji corrupts message

* Amending PR:  Stylistic fixes

src/client/state/RoomsInput.js

@@ -2,6 +2,7 @@ import EventEmitter from 'events';
 import { micromark } from 'micromark';
 import { gfm, gfmHtml } from 'micromark-extension-gfm';
 import encrypt from 'browser-encrypt-attachment';
+import { getShortcodeToEmoji } from '../../app/organisms/emoji-board/custom-emoji';
 import cons from './cons';
 import settings from './settings';
 
@@ -200,6 +201,54 @@ class RoomsInput extends EventEmitter {
     return this.roomIdToInput.get(roomId)?.isSending || false;
   }
 
+  // Apply formatting to a plain text message
+  //
+  // This includes inserting any custom emoji that might be relevant, and (only if the
+  // user has enabled it in their settings) formatting the message using markdown.
+  formatAndEmojifyText(text) {
+    const allEmoji = getShortcodeToEmoji(this.matrixClient);
+
+    // Start by applying markdown formatting (if relevant)
+    let formattedText;
+    if (settings.isMarkdown) {
+      formattedText = getFormattedBody(text);
+    } else {
+      formattedText = text;
+    }
+
+    // Check to see if there are any :shortcode-style-tags: in the message
+    Array.from(formattedText.matchAll(/\B:([\w-]+):\B/g))
+      // Then filter to only the ones corresponding to a valid emoji
+      .filter((match) => allEmoji.has(match[1]))
+      // Reversing the array ensures that indices are preserved as we start replacing
+      .reverse()
+      // Replace each :shortcode: with an <img/> tag
+      .forEach((shortcodeMatch) => {
+        const emoji = allEmoji.get(shortcodeMatch[1]);
+
+        // Render the tag that will replace the shortcode
+        let tag;
+        if (emoji.mxc) {
+          tag = `<img data-mx-emoticon="" src="${
+            emoji.mxc
+          }" alt=":${
+            emoji.shortcode
+          }:" title=":${
+            emoji.shortcode
+          }:" height="32" />`;
+        } else {
+          tag = emoji.unicode;
+        }
+
+        // Splice the tag into the text
+        formattedText = formattedText.substr(0, shortcodeMatch.index)
+          + tag
+          + formattedText.substr(shortcodeMatch.index + shortcodeMatch[0].length);
+      });
+
+    return formattedText;
+  }
+
   async sendInput(roomId) {
     const input = this.getInput(roomId);
     input.isSending = true;
@@ -214,13 +263,15 @@ class RoomsInput extends EventEmitter {
         body: input.message,
         msgtype: 'm.text',
       };
-      if (settings.isMarkdown) {
-        const formattedBody = getFormattedBody(input.message);
-        if (formattedBody !== input.message) {
-          content.format = 'org.matrix.custom.html';
-          content.formatted_body = formattedBody;
-        }
+
+      // Apply formatting if relevant
+      const formattedBody = this.formatAndEmojifyText(input.message);
+      if (formattedBody !== input.message) {
+        // Formatting was applied, and we need to switch to custom HTML
+        content.format = 'org.matrix.custom.html';
+        content.formatted_body = formattedBody;
       }
+
       if (typeof input.replyTo !== 'undefined') {
         content = bindReplyToContent(roomId, input.replyTo, content);
       }
@@ -348,14 +399,14 @@ class RoomsInput extends EventEmitter {
         rel_type: 'm.replace',
       },
     };
-    if (settings.isMarkdown) {
-      const formattedBody = getFormattedBody(editedBody);
-      if (formattedBody !== editedBody) {
-        content.formatted_body = ` * ${formattedBody}`;
-        content.format = 'org.matrix.custom.html';
-        content['m.new_content'].formatted_body = formattedBody;
-        content['m.new_content'].format = 'org.matrix.custom.html';
-      }
+
+    // Apply formatting if relevant
+    const formattedBody = this.formatAndEmojifyText(editedBody);
+    if (formattedBody !== editedBody) {
+      content.formatted_body = ` * ${formattedBody}`;
+      content.format = 'org.matrix.custom.html';
+      content['m.new_content'].formatted_body = formattedBody;
+      content['m.new_content'].format = 'org.matrix.custom.html';
     }
     if (isReply) {
       const evBody = mEvent.getContent().body;