moved selection into its own file

src/messages/selection.hpp

@@ -0,0 +1,64 @@
+#pragma once
+
+namespace chatterino {
+namespace messages {
+struct SelectionItem {
+    int messageIndex;
+    int charIndex;
+
+    SelectionItem()
+    {
+        messageIndex = charIndex = 0;
+    }
+
+    SelectionItem(int _messageIndex, int _charIndex)
+    {
+        this->messageIndex = _messageIndex;
+        this->charIndex = _charIndex;
+    }
+
+    bool isSmallerThan(const SelectionItem &other) const
+    {
+        return this->messageIndex < other.messageIndex ||
+               (this->messageIndex == other.messageIndex && this->charIndex < other.charIndex);
+    }
+
+    bool equals(const SelectionItem &other) const
+    {
+        return this->messageIndex == other.messageIndex && this->charIndex == other.charIndex;
+    }
+};
+
+struct Selection {
+    SelectionItem start;
+    SelectionItem end;
+    SelectionItem min;
+    SelectionItem max;
+
+    Selection()
+    {
+    }
+
+    Selection(const SelectionItem &start, const SelectionItem &end)
+        : start(start)
+        , end(end)
+        , min(start)
+        , max(end)
+    {
+        if (max.isSmallerThan(min)) {
+            std::swap(this->min, this->max);
+        }
+    }
+
+    bool isEmpty() const
+    {
+        return this->start.equals(this->end);
+    }
+
+    bool isSingleMessage() const
+    {
+        return this->min.messageIndex == this->max.messageIndex;
+    }
+};
+}
+}