Pull the emoji list from unicode.org (#612)

- Removing unused information (names and descriptions) from the Emoji class
- Creating a Gradle task that generates a more efficient res/raw/emojis.txt file from the most recent Unicode standard
- Saving recently used emoji preferences as emoji values rather than names
- Migrating old user preferences to the new system

build.gradle

@@ -103,6 +103,14 @@ tasks.register('buildKeyboardFont') {
   }
 }
 
+tasks.register('genEmojis') {
+  println "\nGenerating res/raw/emojis.txt"
+  exec {
+    workingDir = projectDir
+    commandLine "python", "gen_emoji.py"
+  }
+}
+
 tasks.withType(Test).configureEach {
   dependsOn 'genLayoutsList'
   dependsOn 'checkKeyboardLayouts'

gen_emoji.py

@@ -0,0 +1,38 @@
+import urllib.request
+import os.path
+
+EMOJIS_PATH = 'res/raw/emojis.txt'
+EMOJI_TEST_PATH = 'emoji-test.txt'
+EMOJI_TEST_URL = 'https://unicode.org/Public/emoji/latest/emoji-test.txt'
+
+def rawEmojiFromCodes(codes):
+    return ''.join([chr(int(c, 16)) for c in codes])
+
+def getEmojiTestContents():
+    if os.path.exists(EMOJI_TEST_PATH):
+        print(f'Using existing {EMOJI_TEST_PATH}')
+    else:
+        print(f'Downloading {EMOJI_TEST_URL}')
+        urllib.request.urlretrieve(EMOJI_TEST_URL, EMOJI_TEST_PATH)
+    return open(EMOJI_TEST_PATH, mode='r', encoding='UTF-8').read()
+
+
+emoji_list = []
+group_indices = []
+for line in getEmojiTestContents().splitlines():
+    if line.startswith('# group:'):
+        if len(group_indices) == 0 or len(emoji_list) > group_indices[-1]:
+            group_indices.append(len(emoji_list))
+    elif not line.startswith('#') and 'fully-qualified' in line:
+        codes = line.split(';')[0].split()
+        emoji_list.append(rawEmojiFromCodes(codes))
+
+with open(EMOJIS_PATH, 'w', encoding='UTF-8') as emojis:
+    for e in emoji_list:
+        emojis.write(f'{e}\n')
+    emojis.write('\n')
+
+    emojis.write(' '.join([str(g) for g in group_indices]))
+    emojis.write('\n')
+
+print(f'Parsed {len(emoji_list)} emojis in {len(group_indices)}')