Add emojis to autocomplete

Improve autocomplete:
 - Add space after autocompleted item
 - Emotes starting with `:` can now be autocompleted properly (i.e. emojis)

src/widgets/resizingtextedit.cpp

@@ -29,11 +29,41 @@ int ResizingTextEdit::heightForWidth(int) const
     return margins.top() + document()->size().height() + margins.bottom() + 5;
 }
 
-QString ResizingTextEdit::textUnderCursor() const
+QString ResizingTextEdit::textUnderCursor(bool *hadSpace) const
 {
-    QTextCursor tc = textCursor();
-    tc.select(QTextCursor::WordUnderCursor);
-    return tc.selectedText();
+    auto currentText = this->toPlainText();
+
+    QTextCursor tc = this->textCursor();
+
+    auto textUpToCursor = currentText.left(tc.selectionStart());
+
+    auto words = textUpToCursor.splitRef(' ');
+    if (words.size() == 0) {
+        return QString();
+    }
+
+    bool first = true;
+    QString lastWord;
+    for (auto it = words.crbegin(); it != words.crend(); ++it) {
+        auto word = *it;
+
+        if (first && word.isEmpty()) {
+            first = false;
+            if (hadSpace != nullptr) {
+                *hadSpace = true;
+            }
+            continue;
+        }
+
+        lastWord = word.toString();
+        break;
+    }
+
+    if (lastWord.isEmpty()) {
+        return QString();
+    }
+
+    return lastWord;
 }
 
 void ResizingTextEdit::keyPressEvent(QKeyEvent *event)
@@ -105,8 +135,17 @@ void ResizingTextEdit::insertCompletion(const QString &completion)
         return;
     }
 
+    bool hadSpace = false;
+    auto prefix = this->textUnderCursor(&hadSpace);
+
+    int prefixSize = prefix.size();
+
+    if (hadSpace) {
+        ++prefixSize;
+    }
+
     QTextCursor tc = this->textCursor();
-    tc.select(QTextCursor::SelectionType::WordUnderCursor);
+    tc.movePosition(QTextCursor::PreviousCharacter, QTextCursor::KeepAnchor, prefixSize);
     tc.insertText(completion);
     this->setTextCursor(tc);
 }

src/widgets/resizingtextedit.hpp

@@ -25,7 +25,10 @@ protected:
 
 private:
     QCompleter *completer = nullptr;
-    QString textUnderCursor() const;
+
+    // hadSpace is set to true in case the "textUnderCursor" word was after a space
+    QString textUnderCursor(bool *hadSpace = nullptr) const;
+
     bool nextCompletion = false;
 
 private slots: