Clean up lisp terminal code

src/main/kotlin/terminal/LispTerminal.kt

@@ -20,7 +20,10 @@ import java.util.concurrent.Executors
 
 class LispTerminal(configuration: TerminalConfiguration) {
 
-    private val terminal = configuration.terminal!!
+    private val terminal = configuration.terminal!!.apply {
+        addResizeListener { _, _ -> resize() }
+    }
+
     private val inputWriter = SafeOutputStream(configuration.inputWriter)
     private val outputReader = SafeInputStream(configuration.outputReader)
     private val controlSequenceHandler = ControlSequenceHandler()
@@ -33,29 +36,8 @@ class LispTerminal(configuration: TerminalConfiguration) {
     private var originColumn = 0
     private var originRow = 0
 
-    private val leadingEdge: TerminalPosition
-        @Synchronized get() {
-            val inputLength = inputLine.length
-            val totalColumns = terminalSize.columns
-            val rowDifference = inputLength / totalColumns
-            val columnDifference = inputLength % totalColumns
-
-            return TerminalPosition(originColumn + columnDifference, originRow + rowDifference)
-        }
-
-    private val isBufferFilled: Boolean
-        @Synchronized get() {
-            val row = leadingEdge.row
-            val column = leadingEdge.column
-
-            return row == terminalSize.rows - 1
-                    && column >= terminalSize.columns - 1
-                    && originRow <= 0
-        }
-
     init {
         setOriginToCurrentPosition()
-        terminal.addResizeListener { _, _ -> resize() }
     }
 
     @Synchronized
@@ -88,7 +70,17 @@ class LispTerminal(configuration: TerminalConfiguration) {
 
     @Synchronized
     private fun moveCursorToEndOfInput() {
-        terminal.cursorPosition = leadingEdge
+        terminal.cursorPosition = getLeadingEdge()
+    }
+
+    @Synchronized
+    private fun getLeadingEdge(): TerminalPosition {
+        val inputLength = inputLine.length
+        val totalColumns = terminalSize.columns
+        val rowDifference = inputLength / totalColumns
+        val columnDifference = inputLength % totalColumns
+
+        return TerminalPosition(originColumn + columnDifference, originRow + rowDifference)
     }
 
     fun start() {
@@ -363,13 +355,20 @@ class LispTerminal(configuration: TerminalConfiguration) {
     private fun doCharacter(character: Char) {
         val cursorPosition = terminal.cursorPosition
 
-        if (!isBufferFilled)
+        if (!isBufferFilled())
             if (isPossibleToMoveRight(cursorPosition))
                 insertCharacter(character, cursorPosition)
             else
                 appendCharacter(character, cursorPosition)
     }
 
+    @Synchronized
+    private fun isBufferFilled() = getLeadingEdge().let { leadingEdge ->
+        leadingEdge.row == terminalSize.rows - 1
+                && leadingEdge.column >= terminalSize.columns - 1
+                && originRow <= 0
+    }
+
     @Synchronized
     private fun insertCharacter(character: Char, cursorPosition: TerminalPosition) {
         val shiftedPosition = shiftPositionIfNewRowAdded(cursorPosition)
@@ -385,7 +384,7 @@ class LispTerminal(configuration: TerminalConfiguration) {
     @Synchronized
     private fun shiftPositionIfNewRowAdded(cursorPosition: TerminalPosition): TerminalPosition {
         val oldOriginRow = originRow
-        moveCursorRight(leadingEdge)
+        moveCursorRight(getLeadingEdge())
 
         return if (isNewRowAdded(oldOriginRow)) adjustCursorPosition(cursorPosition) else cursorPosition
     }