feat: add ToArray functionality for flattening Input objects

- Add ToArrayInterface for converting Input objects to flat arrays
- Add ToArray implementation with recursive object flattening
- Handle property name conflicts (later values overwrite earlier ones)
- Preserve arrays for SQL IN clause compatibility
- Ignore private/protected properties (public only)
- Add comprehensive test suite covering all edge cases

This enables SQL parameter binding from nested Input objects:
$params = $toArray($orderInput); // Flat array for SQL queries

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: koriym

src/ToArray.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Ray\InputQuery;
+
+use Override;
+use ReflectionClass;
+use ReflectionProperty;
+
+use function is_object;
+
+final class ToArray implements ToArrayInterface
+{
+    /**
+     * {@inheritDoc}
+     */
+    #[Override]
+    public function __invoke(object $input): array
+    {
+        return $this->extractProperties($input);
+    }
+
+    /** @return array<string, mixed> */
+    private function extractProperties(object $object): array
+    {
+        $result = [];
+        $reflection = new ReflectionClass($object);
+
+        foreach ($reflection->getProperties(ReflectionProperty::IS_PUBLIC) as $property) {
+            /** @var mixed $value */
+            $value = $property->getValue($object);
+            $name = $property->getName();
+
+            if (is_object($value)) {
+                // Recursively extract nested objects
+                $nestedProperties = $this->extractProperties($value);
+                /** @var mixed $nestedValue */
+                foreach ($nestedProperties as $nestedName => $nestedValue) {
+                    /** @psalm-suppress MixedAssignment */
+                    $result[$nestedName] = $nestedValue;
+                }
+
+                continue;
+            }
+
+            // Keep arrays and scalar values as-is
+            /** @psalm-suppress MixedAssignment */
+            $result[$name] = $value;
+        }
+
+        return $result;
+    }
+}

src/ToArrayInterface.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Ray\InputQuery;
+
+interface ToArrayInterface
+{
+    /**
+     * Convert Input object to flat associative array
+     *
+     * @param object $input Input object with #[Input] attributes
+     *
+     * @return array<string, mixed> Flat associative array
+     */
+    public function __invoke(object $input): array;
+}

tests/ToArrayTest.php

@@ -0,0 +1,173 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Ray\InputQuery;
+
+use PHPUnit\Framework\TestCase;
+use Ray\InputQuery\Attribute\Input;
+
+final class ToArrayTest extends TestCase
+{
+    private ToArrayInterface $toArray;
+
+    protected function setUp(): void
+    {
+        $this->toArray = new ToArray();
+    }
+
+    public function testSimpleObject(): void
+    {
+        $input = new class {
+            public function __construct(
+                #[Input]
+                public readonly string $name = 'John',
+                #[Input]
+                public readonly int $age = 30,
+            ) {
+            }
+        };
+
+        $result = ($this->toArray)($input);
+
+        $this->assertSame(['name' => 'John', 'age' => 30], $result);
+    }
+
+    public function testNestedObject(): void
+    {
+        $author = new class {
+            public function __construct(
+                #[Input]
+                public readonly string $name = 'John',
+                #[Input]
+                public readonly string $email = 'john@example.com',
+            ) {
+            }
+        };
+
+        $article = new class {
+            #[Input]
+            public readonly string $title;
+
+            #[Input]
+            public readonly object $author;
+
+            public function __construct()
+            {
+                $this->title = 'Hello World';
+                $this->author = new class {
+                    public function __construct(
+                        #[Input]
+                        public readonly string $name = 'John',
+                        #[Input]
+                        public readonly string $email = 'john@example.com',
+                    ) {
+                    }
+                };
+            }
+        };
+
+        $result = ($this->toArray)($article);
+
+        $this->assertSame([
+            'title' => 'Hello World',
+            'name' => 'John',
+            'email' => 'john@example.com',
+        ], $result);
+    }
+
+    public function testArrayProperty(): void
+    {
+        $input = new class {
+            /** @param array<int> $userIds */
+            public function __construct(
+                #[Input]
+                public readonly string $status = 'active',
+                #[Input]
+                public readonly array $userIds = [1, 2, 3],
+            ) {
+            }
+        };
+
+        $result = ($this->toArray)($input);
+
+        $this->assertSame([
+            'status' => 'active',
+            'userIds' => [1, 2, 3],
+        ], $result);
+    }
+
+    public function testPropertyNameConflict(): void
+    {
+        $order = new class {
+            #[Input]
+            public readonly string $id;
+
+            #[Input]
+            public readonly object $customer;
+
+            public function __construct()
+            {
+                $this->id = 'order-456';
+                $this->customer = new class {
+                    public function __construct(
+                        #[Input]
+                        public readonly string $id = 'customer-123',
+                        #[Input]
+                        public readonly string $name = 'John',
+                    ) {
+                    }
+                };
+            }
+        };
+
+        $result = ($this->toArray)($order);
+
+        // Later property overwrites earlier one
+        $this->assertSame([
+            'id' => 'customer-123',
+            'name' => 'John',
+        ], $result);
+    }
+
+    public function testPrivatePropertiesIgnored(): void
+    {
+        $input = new class {
+            public function __construct(
+                #[Input]
+                public readonly string $public = 'visible',
+                #[Input]
+                private readonly string $private = 'hidden',
+            ) {
+            }
+        };
+
+        $result = ($this->toArray)($input);
+
+        $this->assertSame(['public' => 'visible'], $result);
+        $this->assertArrayNotHasKey('private', $result);
+    }
+
+    public function testNullValues(): void
+    {
+        $input = new class {
+            public function __construct(
+                #[Input]
+                public readonly string $name = 'John',
+                #[Input]
+                public readonly string|null $email = null,
+                #[Input]
+                public readonly object|null $address = null,
+            ) {
+            }
+        };
+
+        $result = ($this->toArray)($input);
+
+        $this->assertSame([
+            'name' => 'John',
+            'email' => null,
+            'address' => null,
+        ], $result);
+    }
+}