Improve copy and pasting

src/buffer.go

@@ -164,6 +164,70 @@ func (buffer *Buffer) GetSelectedText() string {
 	}
 }
 
+func (buffer *Buffer) CopyText() (string, int) {
+	if buffer.Selection == nil {
+		// Copy line
+		copiedText := ""
+
+		// Add current letter to copied text
+		if buffer.CursorPos < len(buffer.Contents) {
+			copiedText = string(buffer.Contents[buffer.CursorPos])
+		}
+
+		// Find end of line
+		for i := buffer.CursorPos + 1; i < len(buffer.Contents); i++ {
+			currentLetter := buffer.Contents[i]
+
+			copiedText += string(currentLetter)
+			if currentLetter == '\n' {
+				break
+			}
+		}
+
+		// Find start of line
+		for i := buffer.CursorPos - 1; i >= 0; i-- {
+			currentLetter := buffer.Contents[i]
+			if currentLetter != '\n' {
+				copiedText = string(currentLetter) + copiedText
+			} else {
+				break
+			}
+		}
+
+		return copiedText, 0
+	} else {
+		// Copy selection
+		return buffer.GetSelectedText(), 1
+	}
+}
+
+func (buffer *Buffer) PasteText(window *Window, text string) {
+	str := buffer.Contents
+
+	// Remove selected text
+	if buffer.Selection != nil {
+		edge1, edge2 := buffer.GetSelectionEdges()
+		if edge2 == len(buffer.Contents) {
+			edge2 = len(buffer.Contents) - 1
+		}
+
+		str = str[:edge1] + str[edge2+1:]
+		buffer.Contents = str
+		window.SetCursorPos(edge1)
+		buffer.Selection = nil
+	}
+
+	index := buffer.CursorPos
+
+	if index == len(str) {
+		str += text
+	} else {
+		str = str[:index] + text + str[index:]
+	}
+	buffer.Contents = str
+	window.SetCursorPos(buffer.CursorPos + len(text))
+}
+
 func GetOpenFileBuffer(filename string) *Buffer {
 	// Replace tilde with home directory
 	if filename != "~" && strings.HasPrefix(filename, "~/") {