1 files changed, 94 insertions, 0 deletions
diff --git a/src/components/emoji-input/suggestor.js b/src/components/emoji-input/suggestor.js
new file mode 100644
index 00000000..aec5c39d
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+++ b/src/components/emoji-input/suggestor.js
@@ -0,0 +1,94 @@
+import { debounce } from 'lodash'
+/**
+ * suggest - generates a suggestor function to be used by emoji-input
+ * data: object providing source information for specific types of suggestions:
+ * data.emoji - optional, an array of all emoji available i.e.
+ *   (state.instance.emoji + state.instance.customEmoji)
+ * data.users - optional, an array of all known users
+ * updateUsersList - optional, a function to search and append to users
+ *
+ * Depending on data present one or both (or none) can be present, so if field
+ * doesn't support user linking you can just provide only emoji.
+ */
+
+const debounceUserSearch = debounce((data, input) => {
+  data.updateUsersList(input)
+}, 500, { leading: true, trailing: false })
+
+export default data => input => {
+  const firstChar = input[0]
+  if (firstChar === ':' && data.emoji) {
+    return suggestEmoji(data.emoji)(input)
+  }
+  if (firstChar === '@' && data.users) {
+    return suggestUsers(data)(input)
+  }
+  return []
+}
+
+export const suggestEmoji = emojis => input => {
+  const noPrefix = input.toLowerCase().substr(1)
+  return emojis
+    .filter(({ displayText }) => displayText.toLowerCase().startsWith(noPrefix))
+    .sort((a, b) => {
+      let aScore = 0
+      let bScore = 0
+
+      // Make custom emojis a priority
+      aScore += a.imageUrl ? 10 : 0
+      bScore += b.imageUrl ? 10 : 0
+
+      // Sort alphabetically
+      const alphabetically = a.displayText > b.displayText ? 1 : -1
+
+      return bScore - aScore + alphabetically
+    })
+}
+
+export const suggestUsers = data => input => {
+  const noPrefix = input.toLowerCase().substr(1)
+  const users = data.users
+
+  const newUsers = users.filter(
+    user =>
+      user.screen_name.toLowerCase().startsWith(noPrefix) ||
+      user.name.toLowerCase().startsWith(noPrefix)
+
+    /* taking only 20 results so that sorting is a bit cheaper, we display
+     * only 5 anyway. could be inaccurate, but we ideally we should query
+     * backend anyway
+     */
+  ).slice(0, 20).sort((a, b) => {
+    let aScore = 0
+    let bScore = 0
+
+    // Matches on screen name (i.e. user@instance) makes a priority
+    aScore += a.screen_name.toLowerCase().startsWith(noPrefix) ? 2 : 0
+    bScore += b.screen_name.toLowerCase().startsWith(noPrefix) ? 2 : 0
+
+    // Matches on name takes second priority
+    aScore += a.name.toLowerCase().startsWith(noPrefix) ? 1 : 0
+    bScore += b.name.toLowerCase().startsWith(noPrefix) ? 1 : 0
+
+    const diff = (bScore - aScore) * 10
+
+    // Then sort alphabetically
+    const nameAlphabetically = a.name > b.name ? 1 : -1
+    const screenNameAlphabetically = a.screen_name > b.screen_name ? 1 : -1
+
+    return diff + nameAlphabetically + screenNameAlphabetically
+    /* eslint-disable camelcase */
+  }).map(({ screen_name, name, profile_image_url_original }) => ({
+    displayText: screen_name,
+    detailText: name,
+    imageUrl: profile_image_url_original,
+    replacement: '@' + screen_name + ' '
+  }))
+
+  // BE search users if there are no matches
+  if (newUsers.length === 0 && data.updateUsersList) {
+    debounceUserSearch(data, noPrefix)
+  }
+  return newUsers
+  /* eslint-enable camelcase */
+}