Combination calculate + Combination Test

src/Combination.php

@@ -50,12 +50,21 @@ public function getItems(): array
         return $this->items;
     }
 
+    /**
+     * @param $itemIndex
+     * @return mixed|null
+     */
+    public function getItem($itemIndex): mixed
+    {
+        return $this->items[$itemIndex] ?? null;
+    }
+
     /**
      * @return int
      */
     public function countItems(): int
     {
-        return count( $this->getItems() );
+        return count($this->getItems());
     }
 
     /**
@@ -99,7 +108,7 @@ public function getPossibilities(): array
      */
     public function countPossibilities(): int
     {
-        return count( $this->getPossibilities() );
+        return count($this->getPossibilities());
     }
 
     /**
@@ -108,7 +117,26 @@ public function countPossibilities(): int
     public function calculate(): static
     {
         $this->possibilities = [];
-
+        if ($this->countItems()) {
+            $totalPossibilities = pow($this->countItems(), $this->getSelection());
+            $possibilitiesKeys = [];
+            for ($possibilityId = 0; $possibilityId < $totalPossibilities; $possibilityId++) {
+                $itemIndexes = BaseConvert::convert($possibilityId)->to($this->countItems())->setMinDigits($this->getSelection())->calculate()->getResultArray();
+                if (!$this->canRepetitions() && count($itemIndexes) !== count(array_unique($itemIndexes))) {
+                    continue;
+                }
+                $possibility = [];
+                foreach ($itemIndexes as $itemIndex) {
+                    $possibility[] = $this->getItem($itemIndex);
+                }
+                sort($possibility);
+                $possibilityKey = implode('-', $possibility);
+                if( !in_array($possibilityKey, $possibilitiesKeys) ){
+                    $possibilitiesKeys[] = $possibilityKey;
+                    $this->possibilities[] = $possibility;
+                }
+            }
+        }
         return $this;
     }
 }

tests/CombinationTest.php

@@ -0,0 +1,102 @@
+<?php
+
+namespace Graphita\Mathematics\Tests;
+
+use Graphita\Mathematics\Combination;
+use PHPUnit\Framework\TestCase;
+
+class CombinationTest extends TestCase
+{
+    public function testGetAndSetRepetitions()
+    {
+        $combination = new Combination();
+
+        $this->assertFalse($combination->canRepetitions());
+
+        $combination->setRepetitions(true);
+
+        $this->assertTrue($combination->canRepetitions());
+    }
+
+    public function testGetAndSetItems()
+    {
+        $combination = new Combination();
+
+        $this->assertIsArray($combination->getItems());
+        $this->assertEmpty($combination->getItems());
+        $this->assertEquals(0, $combination->countItems());
+
+        $combination->setItems([1, 2, 3]);
+
+        $this->assertIsArray($combination->getItems());
+        $this->assertCount(3, $combination->getItems());
+        $this->assertEquals(3, $combination->countItems());
+    }
+
+    public function testGetAndSetSelection()
+    {
+        $combination = new Combination();
+
+        $this->assertEquals(0, $combination->getSelection());
+
+        $combination->setSelection(2);
+
+        $this->assertEquals(2, $combination->getSelection());
+    }
+
+    public function testGetPossibilitiesWithoutItemsAndSelection()
+    {
+        $combination = new Combination();
+
+        $this->assertIsArray($combination->getPossibilities());
+        $this->assertEmpty($combination->getPossibilities());
+        $this->assertEquals(0, $combination->countPossibilities());
+
+        $combination->calculate();
+
+        $this->assertIsArray($combination->getPossibilities());
+        $this->assertEmpty($combination->getPossibilities());
+        $this->assertEquals(0, $combination->countPossibilities());
+    }
+
+    public function testGetPossibilitiesWithItemsAndWithoutSelection()
+    {
+        $combination = new Combination();
+        $combination->setItems([1, 2, 3]);
+
+        $this->assertIsArray($combination->getPossibilities());
+        $this->assertEmpty($combination->getPossibilities());
+        $this->assertEquals(0, $combination->countPossibilities());
+
+        $combination->calculate();
+
+        $this->assertIsArray($combination->getPossibilities());
+        $this->assertCount(1, $combination->getPossibilities());
+        $this->assertEquals(1, $combination->countPossibilities());
+    }
+
+    public function testGetPossibilitiesWithItemsAndSelection()
+    {
+        $combination = new Combination();
+        $combination->setItems([1, 2, 3]);
+        $combination->setSelection(2);
+        $combination->calculate();
+
+        $this->assertIsArray($combination->getPossibilities());
+        $this->assertCount(3, $combination->getPossibilities());
+        $this->assertEquals(3, $combination->countPossibilities());
+    }
+
+    public function testGetPossibilitiesWithItemsAndSelectionAndRepetitions()
+    {
+        $combination = new Combination();
+        $combination->setItems([1, 2, 3]);
+        $combination->setSelection(2);
+        $combination->setRepetitions(true);
+        $combination->calculate();
+
+        $this->assertIsArray($combination->getPossibilities());
+        $this->assertCount(6, $combination->getPossibilities());
+        $this->assertEquals(6, $combination->countPossibilities());
+    }
+}