Improve Cluster interface with getCenter(), count and iteratore

Author: smnandre

src/Map/src/Cluster/Cluster.php

@@ -16,22 +16,30 @@
 /**
  * Cluster representation.
  *
+ * @implements \IteratorAggregate<int, Point>
+ *
  * @author Simon André <[email protected]>
  */
-final class Cluster
+final class Cluster implements \Countable, \IteratorAggregate
 {
     /**
      * @var Point[]
      */
     private array $points = [];
 
-    private float $sumLat = 0.0;
-    private float $sumLng = 0.0;
-    private int $count = 0;
+    private float $sumLat;
+    private float $sumLng;
+    private int $count;
 
+    /**
+     * Initializes the cluster with an initial point.
+     */
     public function __construct(Point $initialPoint)
     {
-        $this->addPoint($initialPoint);
+        $this->points[] = $initialPoint;
+        $this->sumLat = $initialPoint->getLatitude();
+        $this->sumLng = $initialPoint->getLongitude();
+        $this->count = 1;
     }
 
     public function addPoint(Point $point): void
@@ -42,14 +50,12 @@ public function addPoint(Point $point): void
         ++$this->count;
     }
 
-    public function getCenterLat(): float
-    {
-        return $this->count > 0 ? $this->sumLat / $this->count : 0.0;
-    }
-
-    public function getCenterLng(): float
+    /**
+     * Returns the center of the cluster as a Point.
+     */
+    public function getCenter(): Point
     {
-        return $this->count > 0 ? $this->sumLng / $this->count : 0.0;
+        return new Point($this->sumLat / $this->count, $this->sumLng / $this->count);
     }
 
     /**
@@ -59,4 +65,20 @@ public function getPoints(): array
     {
         return $this->points;
     }
+
+    /**
+     * Returns the number of points in the cluster.
+     */
+    public function count(): int
+    {
+        return $this->count;
+    }
+
+    /**
+     * @return \Traversable<int, Point>
+     */
+    public function getIterator(): \Traversable
+    {
+        return new \ArrayIterator($this->points);
+    }
 }

src/Map/tests/Cluster/ClusterTest.php

@@ -22,14 +22,14 @@ public function testAddPointAndGetCenter(): void
         $point1 = new Point(10.0, 20.0);
         $cluster = new Cluster($point1);
 
-        $this->assertEquals(10.0, $cluster->getCenterLat());
-        $this->assertEquals(20.0, $cluster->getCenterLng());
+        $this->assertEquals(10.0, $cluster->getCenter()->getLatitude());
+        $this->assertEquals(20.0, $cluster->getCenter()->getLongitude());
 
         $point2 = new Point(12.0, 22.0);
         $cluster->addPoint($point2);
 
-        $this->assertEquals(11.0, $cluster->getCenterLat());
-        $this->assertEquals(21.0, $cluster->getCenterLng());
+        $this->assertEquals(11.0, $cluster->getCenter()->getLatitude());
+        $this->assertEquals(21.0, $cluster->getCenter()->getLongitude());
     }
 
     public function testGetPoints(): void
@@ -45,13 +45,35 @@ public function testGetPoints(): void
         $this->assertSame($point2, $points[1]);
     }
 
-    public function testEmptyCluster(): void
+    public function testCount(): void
+    {
+        $cluster = new Cluster(new Point(10.0, 20.0));
+        $this->assertCount(1, $cluster);
+
+        $cluster->addPoint(new Point(10.0, 20.0));
+        $this->assertCount(2, $cluster);
+    }
+
+    public function testIterator(): void
     {
         $point1 = new Point(10.0, 20.0);
-        $cluster = new Cluster($point1); // Start an empty cluster
-        $points = $cluster->getPoints();
-        $this->assertCount(1, $points);
-        $this->assertEquals(10.0, $cluster->getCenterLat());
-        $this->assertEquals(20.0, $cluster->getCenterLng());
+        $point2 = new Point(12.0, 22.0);
+        $cluster = new Cluster($point1);
+        $cluster->addPoint($point2);
+
+        $points = iterator_to_array($cluster);
+        $this->assertCount(2, $points);
+        $this->assertSame($point1, $points[0]);
+        $this->assertSame($point2, $points[1]);
+    }
+
+    public function testCreateCluster(): void
+    {
+        $point1 = new Point(10.0, 20.0);
+        $cluster = new Cluster($point1);
+
+        $this->assertCount(1, $cluster->getPoints());
+        $this->assertEquals(10.0, $cluster->getCenter()->getLatitude());
+        $this->assertEquals(20.0, $cluster->getCenter()->getLongitude());
     }
 }

src/Map/tests/Cluster/GridClusteringAlgorithmTest.php

@@ -29,8 +29,8 @@ public function testSinglePointCreatesSingleCluster(): void
         /** @var Cluster $cluster */
         $cluster = $clusters[0];
 
-        $this->assertEquals(10.0, $cluster->getCenterLat());
-        $this->assertEquals(20.0, $cluster->getCenterLng());
+        $this->assertEquals(10.0, $cluster->getCenter()->getLatitude());
+        $this->assertEquals(20.0, $cluster->getCenter()->getLongitude());
         $this->assertCount(1, $cluster->getPoints());
     }
 
@@ -48,8 +48,8 @@ public function testPointsInSameGridAreClusteredTogether(): void
         $cluster = $clusters[0];
 
         $this->assertCount(2, $cluster->getPoints());
-        $this->assertEqualsWithDelta(10.05, $cluster->getCenterLat(), 0.0001);
-        $this->assertEqualsWithDelta(20.05, $cluster->getCenterLng(), 0.0001);
+        $this->assertEqualsWithDelta(10.05, $cluster->getCenter()->getLatitude(), 0.0001);
+        $this->assertEqualsWithDelta(20.05, $cluster->getCenter()->getLongitude(), 0.0001);
     }
 
     public function testPointsInDifferentGridsAreNotClustered(): void

src/Map/tests/Cluster/MortonClusteringAlgorithmTest.php

@@ -29,8 +29,8 @@ public function testSinglePointCreatesSingleCluster(): void
         /** @var Cluster $cluster */
         $cluster = $clusters[0];
 
-        $this->assertEquals(10.0, $cluster->getCenterLat());
-        $this->assertEquals(20.0, $cluster->getCenterLng());
+        $this->assertEquals(10.0, $cluster->getCenter()->getLatitude());
+        $this->assertEquals(20.0, $cluster->getCenter()->getLongitude());
         $this->assertCount(1, $cluster->getPoints());
     }