refactor: edge and rectangle in separate packages

cmd/09/rectangle/rectangle.go

@@ -0,0 +1,83 @@
+// Package rectangle provides a model and methods for representing and manipulating rectangles.
+package rectangle
+
+import (
+	"math"
+
+	"github.com/StevanFreeborn/advent-of-code-2025/internal/position"
+)
+
+type Rectangle interface {
+	Corners() []position.Position
+	MaxRow() int
+	MaxColumn() int
+	MinRow() int
+	MinColumn() int
+	Area() int
+	Center() position.Position
+}
+
+type rectangle struct {
+	corners   []position.Position
+	maxRow    int
+	maxColumn int
+	minRow    int
+	minColumn int
+	area      int
+	center    position.Position
+}
+
+func From(cornerOne position.Position, cornerTwo position.Position) Rectangle {
+	thirdCorner := position.From(cornerOne.Row(), cornerTwo.Column())
+	fourthCorner := position.From(cornerTwo.Row(), cornerOne.Column())
+
+	corners := []position.Position{cornerOne, cornerTwo, thirdCorner, fourthCorner}
+	maxRow := math.Max(float64(cornerOne.Row()), float64(cornerTwo.Row()))
+	maxColumn := math.Max(float64(cornerOne.Column()), float64(cornerTwo.Column()))
+	minRow := math.Min(float64(cornerOne.Row()), float64(cornerTwo.Row()))
+	minColumn := math.Min(float64(cornerOne.Column()), float64(cornerTwo.Column()))
+
+	area := int((maxRow - minRow + 1) * (maxColumn - minColumn + 1))
+
+	centerRow := (maxRow + minRow) / 2
+	centerColumn := (maxColumn + minColumn) / 2
+	center := position.From(int(centerRow), int(centerColumn))
+
+	return rectangle{
+		corners:   corners,
+		maxRow:    int(maxRow),
+		maxColumn: int(maxColumn),
+		minRow:    int(minRow),
+		minColumn: int(minColumn),
+		area:      area,
+		center:    center,
+	}
+}
+
+func (r rectangle) Corners() []position.Position {
+	return r.corners
+}
+
+func (r rectangle) MaxRow() int {
+	return r.maxRow
+}
+
+func (r rectangle) MinRow() int {
+	return r.minRow
+}
+
+func (r rectangle) MaxColumn() int {
+	return r.maxColumn
+}
+
+func (r rectangle) MinColumn() int {
+	return r.minColumn
+}
+
+func (r rectangle) Area() int {
+	return r.area
+}
+
+func (r rectangle) Center() position.Position {
+	return r.center
+}

cmd/09/rectangle/rectangle_test.go

@@ -0,0 +1,105 @@
+package rectangle_test
+
+import (
+	"slices"
+	"testing"
+
+	"github.com/StevanFreeborn/advent-of-code-2025/cmd/09/rectangle"
+	"github.com/StevanFreeborn/advent-of-code-2025/internal/position"
+)
+
+func TestFrom(t *testing.T) {
+	cornerOne := position.From(1, 2)
+	cornerTwo := position.From(3, 4)
+
+	expectedCorners := []position.Position{
+		cornerOne,
+		cornerTwo,
+		position.From(1, 4),
+		position.From(3, 2),
+	}
+
+	result := rectangle.From(cornerOne, cornerTwo)
+
+	if slices.Equal(result.Corners(), expectedCorners) == false {
+		t.Errorf("Expected corners %v, but got %v", expectedCorners, result.Corners())
+	}
+}
+
+func TestMaxRow(t *testing.T) {
+	expectedMaxRow := 3
+
+	cornerOne := position.From(1, 2)
+	cornerTwo := position.From(3, 4)
+
+	result := rectangle.From(cornerOne, cornerTwo).MaxRow()
+
+	if result != expectedMaxRow {
+		t.Errorf("Expected max row %d, but got %d", expectedMaxRow, result)
+	}
+}
+
+func TestMinRow(t *testing.T) {
+	expectedMinRow := 1
+
+	cornerOne := position.From(1, 2)
+	cornerTwo := position.From(3, 4)
+
+	result := rectangle.From(cornerOne, cornerTwo).MinRow()
+
+	if result != expectedMinRow {
+		t.Errorf("Expected min row %d, but got %d", expectedMinRow, result)
+	}
+}
+
+func TestMaxColumn(t *testing.T) {
+	expectedMaxColumn := 4
+
+	cornerOne := position.From(1, 2)
+	cornerTwo := position.From(3, 4)
+
+	result := rectangle.From(cornerOne, cornerTwo).MaxColumn()
+
+	if result != expectedMaxColumn {
+		t.Errorf("Expected max column %d, but got %d", expectedMaxColumn, result)
+	}
+}
+
+func TestMinColumn(t *testing.T) {
+	expectedMinColumn := 2
+
+	cornerOne := position.From(1, 2)
+	cornerTwo := position.From(3, 4)
+
+	result := rectangle.From(cornerOne, cornerTwo).MinColumn()
+
+	if result != expectedMinColumn {
+		t.Errorf("Expected min column %d, but got %d", expectedMinColumn, result)
+	}
+}
+
+func TestArea(t *testing.T) {
+	expectedArea := 9
+
+	cornerOne := position.From(1, 2)
+	cornerTwo := position.From(3, 4)
+
+	result := rectangle.From(cornerOne, cornerTwo).Area()
+
+	if result != expectedArea {
+		t.Errorf("Expected area %d, but got %d", expectedArea, result)
+	}
+}
+
+func TestCenter(t *testing.T) {
+	expectedCenter := position.From(2, 3)
+
+	cornerOne := position.From(1, 2)
+	cornerTwo := position.From(3, 4)
+
+	result := rectangle.From(cornerOne, cornerTwo).Center()
+
+	if result != expectedCenter {
+		t.Errorf("Expected center %v, but got %v", expectedCenter, result)
+	}
+}