Added modifyDateTime scalar function (#1543)

Author: norberttech

src/core/etl/src/Flow/ETL/Function/ModifyDateTime.php

@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Flow\ETL\Function;
+
+use Flow\ETL\Row;
+
+final class ModifyDateTime extends ScalarFunctionChain
+{
+    public function __construct(
+        private readonly mixed $reference,
+        private readonly string|ScalarFunction $modifier,
+    ) {
+    }
+
+    public function eval(Row $row) : mixed
+    {
+        $value = (new Parameter($this->reference))->asInstanceOf($row, \DateTimeInterface::class);
+        $modifier = (new Parameter($this->modifier))->asString($row);
+
+        if ($modifier === null || $value === null) {
+            return null;
+        }
+
+        if (!$value instanceof \DateTime && !$value instanceof \DateTimeImmutable) {
+            return null;
+        }
+
+        return $value->modify($modifier);
+    }
+}

src/core/etl/src/Flow/ETL/Function/ScalarFunctionChain.php

@@ -372,6 +372,11 @@ public function mod(ScalarFunction|int|float $value) : self
         return new Mod($this, $value);
     }
 
+    public function modifyDateTime(string|ScalarFunction $modifier) : self
+    {
+        return new ModifyDateTime($this, $modifier);
+    }
+
     public function multiply(ScalarFunction|int|float $value) : self
     {
         return new Multiply($this, $value);

src/core/etl/tests/Flow/ETL/Tests/Integration/Function/ModifyDateTimeTest.php

@@ -0,0 +1,87 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Flow\ETL\Tests\Integration\Function;
+
+use function Flow\ETL\DSL\data_frame;
+use function Flow\ETL\DSL\{array_get, concat, from_array, lit, ref, to_memory};
+use Flow\ETL\Memory\ArrayMemory;
+use Flow\ETL\Tests\FlowTestCase;
+
+final class ModifyDateTimeTest extends FlowTestCase
+{
+    public function test_concat_on_non_string_value() : void
+    {
+        $rows = (data_frame())
+            ->read(
+                from_array(
+                    [
+                        ['id' => 1, 'created_at' => new \DateTimeImmutable('2025-01-01')],
+                        ['id' => 2, 'created_at' => new \DateTimeImmutable('2025-02-01')],
+                    ]
+                )
+            )
+            ->withEntry('expiration_at', ref('created_at')->modifyDateTime('last day of this month'))
+            ->fetch()
+            ->toArray();
+
+        self::assertEquals(
+            [
+                ['id' => 1, 'created_at' => new \DateTimeImmutable('2025-01-01'), 'expiration_at' => new \DateTimeImmutable('2025-01-31')],
+                ['id' => 2, 'created_at' => new \DateTimeImmutable('2025-02-01'), 'expiration_at' => new \DateTimeImmutable('2025-02-28')],
+            ],
+            $rows,
+        );
+    }
+
+    public function test_concat_on_nulls() : void
+    {
+        (data_frame())
+            ->read(
+                from_array(
+                    [
+                        ['id' => 1, 'array' => ['field' => 'value']],
+                        ['id' => 2],
+                    ]
+                )
+            )
+            ->withEntry('concat', concat(lit(null), lit(null)))
+            ->drop('array')
+            ->write(to_memory($memory = new ArrayMemory()))
+            ->run();
+
+        self::assertSame(
+            [
+                ['id' => 1, 'concat' => ''],
+                ['id' => 2, 'concat' => ''],
+            ],
+            $memory->dump()
+        );
+    }
+
+    public function test_concat_on_stringable_value() : void
+    {
+        (data_frame())
+            ->read(
+                from_array(
+                    [
+                        ['id' => 1, 'array' => ['field' => 'value']],
+                        ['id' => 2],
+                    ]
+                )
+            )
+            ->withEntry('concat', concat(ref('id'), '-', array_get(ref('array'), 'field')))
+            ->drop('array')
+            ->write(to_memory($memory = new ArrayMemory()))
+            ->run();
+
+        self::assertSame(
+            [
+                ['id' => 1, 'concat' => '1-value'],
+                ['id' => 2, 'concat' => '2-'],
+            ],
+            $memory->dump()
+        );
+    }
+}

src/core/etl/tests/Flow/ETL/Tests/Unit/Function/ModifyDateTimeTest.php

@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Flow\ETL\Tests\Unit\Function;
+
+use function Flow\ETL\DSL\{date_entry, datetime_entry, lit, ref, row};
+use Flow\ETL\Tests\FlowTestCase;
+
+final class ModifyDateTimeTest extends FlowTestCase
+{
+    public function test_modify_date() : void
+    {
+        self::assertEquals(
+            new \DateTimeImmutable('2025-01-01 12:00:00 +00:00'),
+            ref('datetime')->modifyDateTime('noon')->eval(
+                row(
+                    date_entry('datetime', '2025-01-01'),
+                )
+            )
+        );
+    }
+
+    public function test_modify_datetime() : void
+    {
+        self::assertEquals(
+            new \DateTimeImmutable('2025-01-01 00:00:00 +00:00'),
+            ref('datetime')->modifyDateTime('midnight')->eval(
+                row(
+                    datetime_entry('datetime', '2025-01-01 10:00:23 +00:00'),
+                )
+            )
+        );
+    }
+
+    public function test_modify_using_invalid_modifier() : void
+    {
+        self::assertNull(
+            ref('datetime')->modifyDateTime(lit(1))->eval(
+                row(
+                    datetime_entry('datetime', '2025-01-01 10:00:23 +00:00'),
+                )
+            )
+        );
+    }
+}