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
+}