Add CoordinateSystem::first() and CoordinateSystem::last()

CHANGELOG.md

@@ -9,6 +9,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+## v6.2.0
+
+### Added
+
+- Add `CoordinateSystem::first()` and `CoordinateSystem::last()`
+
 ## v6.1.0
 
 ### Added

src/CoordinateSystem.php

@@ -2,6 +2,8 @@
 
 namespace Mll\Microplate;
 
+use Illuminate\Support\Arr;
+
 abstract class CoordinateSystem
 {
     /** @return list<string> */
@@ -74,6 +76,46 @@ public function all(): iterable
         }
     }
 
+    /**
+     * Returns the coordinates of the first row and first column.
+     *
+     * @return Coordinates<$this>
+     */
+    public function first(): Coordinates
+    {
+        $firstRow = Arr::first($this->rows());
+        if (! is_string($firstRow)) {
+            throw new \Exception('First row must be string.');
+        }
+
+        $firstColumn = Arr::first($this->columns());
+        if (! is_int($firstColumn)) {
+            throw new \Exception('First column must be string.');
+        }
+
+        return new Coordinates($firstRow, $firstColumn, $this);
+    }
+
+    /**
+     * Returns the coordinates of the last row and last column.
+     *
+     * @return Coordinates<$this>
+     */
+    public function last(): Coordinates
+    {
+        $lastRow = Arr::last($this->rows());
+        if (! is_string($lastRow)) {
+            throw new \Exception('Last row must be string.');
+        }
+
+        $lastColumn = Arr::last($this->columns());
+        if (! is_int($lastColumn)) {
+            throw new \Exception('Last column must be string.');
+        }
+
+        return new Coordinates($lastRow, $lastColumn, $this);
+    }
+
     public function rowsCount(): int
     {
         return count($this->rows());

tests/Unit/CoordinateSystemTest.php

@@ -0,0 +1,32 @@
+<?php declare(strict_types=1);
+
+namespace Mll\Microplate\Tests\Unit;
+
+use Mll\Microplate\CoordinateSystem;
+use Mll\Microplate\CoordinateSystem12Well;
+use Mll\Microplate\CoordinateSystem48Well;
+use Mll\Microplate\CoordinateSystem96Well;
+use PHPUnit\Framework\TestCase;
+
+final class CoordinateSystemTest extends TestCase
+{
+    /** @dataProvider firstLast */
+    public function testFirstLast(CoordinateSystem $coordinateSystem, string $expectedFirst, string $expectedLast): void
+    {
+        $actualFirst = $coordinateSystem->first();
+        self::assertSame($expectedFirst, $actualFirst->toString());
+        self::assertSame($coordinateSystem, $actualFirst->coordinateSystem);
+
+        $actualLast = $coordinateSystem->last();
+        self::assertSame($expectedLast, $actualLast->toString());
+        self::assertSame($coordinateSystem, $actualLast->coordinateSystem);
+    }
+
+    /** @return iterable<array{CoordinateSystem, string, string}> */
+    public static function firstLast(): iterable
+    {
+        yield [new CoordinateSystem12Well(), 'A1', 'C4'];
+        yield [new CoordinateSystem48Well(), 'A1', 'F8'];
+        yield [new CoordinateSystem96Well(), 'A1', 'H12'];
+    }
+}