Remove java.awt dependency from non-GUI packages (#7)

* Replace java.awt.Point with custom Point class in non-GUI packages
* Fix GUI classes to use custom Point when interacting with domain model
* Add missing distance() method to custom Point class

The custom Point class was missing the distance() method that java.awt.Point provides, causing compilation errors in DefaultContext.kt that uses this method to calculate distances between points.

* Make Point class immutable and add comprehensive tests

- Changed Point class properties from var to val for immutability
- Added comprehensive test suite with 21 test cases covering:
  - Constructor variations (default and parameterized)
  - Immutability verification
  - Clone and copy operations
  - Equals and hashCode contracts
  - Distance calculations (horizontal, vertical, diagonal)
  - Edge cases (negative coordinates, large values)
  - Data class features (component access, copy with modifications)

This improves code quality and test coverage for SonarQube.

* Fix immutable Point class compilation errors

Made Point class properties truly immutable by changing them from var to val. Fixed code that was trying to mutate Point objects:

1. DefaultContext.swapXY() - Now returns a new Point with swapped coordinates
2. DefaultContext.bresenham() - Uses local var copies (p1Mut, p2Mut) instead of mutating parameters
3. Cell.Segment.transform() - Creates new Point instead of cloning and mutating

These changes maintain the original algorithm logic while respecting immutability.

Added BresenhamJoinTest.kt with 9 test cases covering:
- Horizontal line generation (straight line along x-axis)
- Vertical line generation (straight line along y-axis)
- Diagonal line at 45 degrees
- Shallow slope lines (more x than y movement)
- Steep slope lines (more y than x movement)
- Short distance handling (≤ √2 skips Bresenham)
- Negative coordinate handling
- Bidirectional line generation (forward/reverse)
- Point immutability preservation during join operations

Tests verify the Bresenham algorithm through the public joinCells API,
ensuring correct intermediate cell placement when connecting distant cells.

Addresses request in comment 2672984094.

* Remove clone() method from immutable Point class

Since Point is now an immutable data class, cloning is unnecessary.
Updated all usages to use Point instances directly:
- DefaultContext: Removed clone() calls in bresenhamJoin
- PointTest: Removed clone() test
- Array2DMapTest: Simplified point creation
- BresenhamJoinTest: Fixed tests to avoid negative coordinates and grid boundaries
- RailwayNetGridCanvas: Minor formatting cleanup

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Bedřich Hovorka <bedrich.hovorka@gmail.com>
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: 3 people

src/main/kotlin/cz/vutbr/fit/interlockSim/context/AbstractRailwayNetGrid.kt

@@ -11,7 +11,7 @@ package cz.vutbr.fit.interlockSim.context
 
 import cz.vutbr.fit.interlockSim.objects.cells.Cell
 import cz.vutbr.fit.interlockSim.util.Array2DMap
-import java.awt.Point
+import cz.vutbr.fit.interlockSim.util.Point
 import java.util.Iterator
 import java.util.Map.Entry
 import java.util.Set

src/main/kotlin/cz/vutbr/fit/interlockSim/context/Context.kt

@@ -12,7 +12,7 @@ package cz.vutbr.fit.interlockSim.context
 import cz.vutbr.fit.interlockSim.objects.cells.Cell.Segment
 import cz.vutbr.fit.interlockSim.objects.tracks.TrackBlock
 import cz.vutbr.fit.interlockSim.util.ExtendedUnorientedGraph
-import java.awt.Point
+import cz.vutbr.fit.interlockSim.util.Point
 import java.beans.PropertyChangeListener
 
 /**

src/main/kotlin/cz/vutbr/fit/interlockSim/context/DefaultContext.kt

@@ -31,14 +31,14 @@ import cz.vutbr.fit.interlockSim.sim.ShuntingLoop
 import cz.vutbr.fit.interlockSim.sim.SimulationException
 import cz.vutbr.fit.interlockSim.util.ExtendedUnorientedGraph
 import cz.vutbr.fit.interlockSim.util.HashMapGraph
+import cz.vutbr.fit.interlockSim.util.Point
 import cz.vutbr.fit.interlockSim.util.TreeMultiMap
 import cz.vutbr.fit.interlockSim.util.Util
 import jDisco.DiscoException
 import jDisco.Process
 import jDisco.Random
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
-import java.awt.Point
 import java.beans.PropertyChangeSupport
 import java.util.ArrayList
 import java.util.Collection
@@ -168,10 +168,8 @@ abstract class DefaultContext :
 	/**
 	 * Swap X and Y coordinates of a point (used in Bresenham algorithm)
 	 */
-	private fun swapXY(p: Point) {
-		val temp = p.x
-		p.x = p.y
-		p.y = temp
+	private fun swapXY(p: Point): Point {
+		return Point(p.y, p.x)
 	}
 
 	/**
@@ -286,8 +284,8 @@ abstract class DefaultContext :
 		trackBlock: TrackBlock
 	): Map<Point, TrackBlockPart>? {
 		if (pi1 == null || pi2 == null) throw IllegalArgumentException()
-		val p1 = pi1.clone() as Point
-		val p2 = pi2.clone() as Point
+		val p1 = pi1
+		val p2 = pi2
 
 		val keys: MutableList<Point> = ArrayList()
 		val b = bresenham(key1, key2, p1, p2, keys)
@@ -389,42 +387,44 @@ abstract class DefaultContext :
 	): Boolean {
 		assert(key1 != null && key2 != null && p1 != null && p2 != null)
 		assert(!key1.equals(p1) && !key2.equals(p2) && !key1.equals(p2) && !key2.equals(p1))
+		
+		// Make mutable copies since we need to modify them for the algorithm
+		var p1Mut = p1
+		var p2Mut = p2
 
-		if (p1.equals(p2)) {
-			points.add(p1) // snad je naklonovany
+		if (p1Mut.equals(p2Mut)) {
+			points.add(p1Mut) // snad je naklonovany
 			return false
 		}
 
-		var dx = Math.abs(p2.x - p1.x)
-		var dy = Math.abs(p2.y - p1.y)
+		var dx = Math.abs(p2Mut.x - p1Mut.x)
+		var dy = Math.abs(p2Mut.y - p1Mut.y)
 		val swapped = dy > dx
 
 		if (swapped) {
-			swapXY(p1)
-			swapXY(p2)
+			p1Mut = swapXY(p1Mut)
+			p2Mut = swapXY(p2Mut)
 			val temp = dx
 			dx = dy
 			dy = temp
 		}
 
-		val b = p1.x > p2.x
+		val b = p1Mut.x > p2Mut.x
 		if (b) {
-			val temp = p1
-			// assign to parameters is part of algorithm
-			p1.x = p2.x
-			p1.y = p2.y
-			p2.x = temp.x
-			p2.y = temp.y
+			val temp = p1Mut
+			// swap p1 and p2
+			p1Mut = Point(p2Mut.x, p2Mut.y)
+			p2Mut = Point(temp.x, temp.y)
 		}
 
 		var P = 2 * dy - dx // prediktor
 		val P1 = 2 * dy
 		val P2 = P1 - 2 * dx
-		var y = p1.y
+		var y = p1Mut.y
 
-		val step_y = if (p1.y > p2.y) -1 else 1 // smer kresleni
+		val step_y = if (p1Mut.y > p2Mut.y) -1 else 1 // smer kresleni
 
-		for (x in p1.x..p2.x) {
+		for (x in p1Mut.x..p2Mut.x) {
 			val newPoint = if (!swapped) Point(x, y) else Point(y, x)
 
 			if (newPoint.equals(key1) || newPoint.equals(key2) || used(newPoint)) {

src/main/kotlin/cz/vutbr/fit/interlockSim/context/DefaultRailWayNetGrid.kt

@@ -11,7 +11,7 @@ package cz.vutbr.fit.interlockSim.context
 
 import cz.vutbr.fit.interlockSim.objects.cells.Cell
 import cz.vutbr.fit.interlockSim.objects.cells.TrackBlockPart
-import java.awt.Point
+import cz.vutbr.fit.interlockSim.util.Point
 import java.util.AbstractSet
 import java.util.Iterator
 import java.util.Map

src/main/kotlin/cz/vutbr/fit/interlockSim/context/EditingContext.kt

@@ -11,7 +11,7 @@ package cz.vutbr.fit.interlockSim.context
 
 import cz.vutbr.fit.interlockSim.objects.cells.NodeCell
 import cz.vutbr.fit.interlockSim.objects.tracks.TrackBlock
-import java.awt.Point
+import cz.vutbr.fit.interlockSim.util.Point
 
 /**
  * Interface to shared functions of inner data model, which is allowed by editing

src/main/kotlin/cz/vutbr/fit/interlockSim/context/RailwayNetGrid.kt

@@ -10,7 +10,7 @@
 package cz.vutbr.fit.interlockSim.context
 
 import cz.vutbr.fit.interlockSim.objects.cells.Cell
-import java.awt.Point
+import cz.vutbr.fit.interlockSim.util.Point
 import java.util.Iterator
 import java.util.Map.Entry
 

src/main/kotlin/cz/vutbr/fit/interlockSim/gui/RailwayNetGridCanvas.kt

@@ -183,7 +183,7 @@ class RailwayNetGridCanvas :
 	private var state = State.EDITING
 	private var toolbarCellClass: Class<out NodeCell>? = null
 	private var toolbarArgs: Array<Any?>? = null
-	private var selectedKey: Point? = null
+	private var selectedKey: cz.vutbr.fit.interlockSim.util.Point? = null
 
 	init {
 		background = Color.BLACK
@@ -316,7 +316,8 @@ class RailwayNetGridCanvas :
 	}
 
 	// Mouse coordinate to grid coordinate conversion
-	private fun currentKey(e: MouseEvent): Point = Point(e.x / CELL_WIDTH, e.y / CELL_HEIGHT)
+	private fun currentKey(e: MouseEvent): cz.vutbr.fit.interlockSim.util.Point =
+		cz.vutbr.fit.interlockSim.util.Point(e.x / CELL_WIDTH, e.y / CELL_HEIGHT)
 
 	private fun cellOn(
 		x: Int,

src/main/kotlin/cz/vutbr/fit/interlockSim/gui/gridcanvas/GridCanvasEditingPopupMenu.kt

@@ -11,7 +11,6 @@ package cz.vutbr.fit.interlockSim.gui.gridcanvas
 
 import cz.vutbr.fit.interlockSim.objects.cells.NodeCell
 import cz.vutbr.fit.interlockSim.objects.tracks.TrackBlock
-import java.awt.Point
 import java.awt.event.ActionEvent
 
 /**
@@ -31,7 +30,7 @@ class GridCanvasEditingPopupMenu : GridCanvasPopupMenu() {
 		}
 	}
 
-	private var key: Point? = null
+	private var key: cz.vutbr.fit.interlockSim.util.Point? = null
 	private var nodeCell: NodeCell? = null
 	private var trackBlock: TrackBlock? = null
 
@@ -44,7 +43,7 @@ class GridCanvasEditingPopupMenu : GridCanvasPopupMenu() {
 	}
 
 	override fun reorganizeMenu(
-		key: Point,
+		key: cz.vutbr.fit.interlockSim.util.Point,
 		cell: NodeCell
 	) {
 		this.key = key

src/main/kotlin/cz/vutbr/fit/interlockSim/gui/gridcanvas/GridCanvasPopupMenu.kt

@@ -14,7 +14,6 @@ import cz.vutbr.fit.interlockSim.objects.cells.Cell
 import cz.vutbr.fit.interlockSim.objects.cells.NodeCell
 import cz.vutbr.fit.interlockSim.objects.cells.TrackBlockPart
 import cz.vutbr.fit.interlockSim.objects.tracks.TrackBlock
-import java.awt.Point
 import java.awt.event.ActionEvent
 import java.awt.event.MouseEvent
 import javax.swing.AbstractAction
@@ -54,7 +53,7 @@ abstract class GridCanvasPopupMenu : JPopupMenu() {
 	fun show(
 		canvas: RailwayNetGridCanvas,
 		e: MouseEvent,
-		key: Point?,
+		key: cz.vutbr.fit.interlockSim.util.Point?,
 		cell: Cell?
 	) {
 		assert(canvas != null && e != null) { "Canvas and event cannot be null" }
@@ -66,7 +65,7 @@ abstract class GridCanvasPopupMenu : JPopupMenu() {
 
 	// Reorganize menu based on the clicked cell type
 	private fun reorganizeMenu(
-		key: Point,
+		key: cz.vutbr.fit.interlockSim.util.Point,
 		cell: Cell
 	) {
 		when (cell) {
@@ -86,7 +85,7 @@ abstract class GridCanvasPopupMenu : JPopupMenu() {
 	protected abstract fun reorganizeMenu(line: TrackBlock)
 
 	protected abstract fun reorganizeMenu(
-		key: Point,
+		key: cz.vutbr.fit.interlockSim.util.Point,
 		cell: NodeCell
 	)
 

src/main/kotlin/cz/vutbr/fit/interlockSim/objects/cells/Cell.kt

@@ -9,7 +9,7 @@
  */
 package cz.vutbr.fit.interlockSim.objects.cells
 
-import java.awt.Point
+import cz.vutbr.fit.interlockSim.util.Point
 import java.util.Set
 
 /**
@@ -82,9 +82,7 @@ interface Cell {
 		 */
 		fun transform(from: Point): Point {
 			assert(from != null)
-			val tr = from.clone() as Point
-			tr.x += dx
-			tr.y += dy
+			val tr = Point(from.x + dx, from.y + dy)
 			assert(!from.equals(tr)) { this }
 			return tr
 		}