<?php

declare(strict_types=1);

namespace Tests\Framework\DI;

use App\Framework\DI\DefaultContainer;
use App\Framework\DI\InstanceRegistry;
use PHPUnit\Framework\TestCase;
use stdClass;

/**
 * Tests to identify and prevent Container memory leaks
 */
final class ContainerMemoryLeakTest extends TestCase
{
    private DefaultContainer $container;

    protected function setUp(): void
    {
        $this->container = new DefaultContainer();

        // Prä-Registriere stdClass als echte Klasse um Lazy Loading zu vermeiden
        $this->container->bind(stdClass::class, fn () => new stdClass());
    }

    /**
     * Test ob der Container unbegrenzt wächst bei wiederholten Aufrufen
     */
    public function test_container_does_not_grow_indefinitely(): void
    {
        $initialMemory = memory_get_usage(true);

        // Simuliere viele Requests mit direkten Instanzen (vermeidet Lazy Loading)
        for ($i = 0; $i < 1000; $i++) {
            $serviceName = "service_$i";

            // Erstelle Objekt direkt und registriere als Instanz
            $obj = new stdClass();
            $obj->id = $i;
            $obj->data = str_repeat('x', 100);

            $this->container->instance($serviceName, $obj);
            $instance = $this->container->get($serviceName);

            $this->assertEquals($i, $instance->id);
        }

        $finalMemory = memory_get_usage(true);
        $memoryGrowth = $finalMemory - $initialMemory;

        // Memory growth sollte unter 5MB bleiben für 1000 Services
        $this->assertLessThan(
            5 * 1024 * 1024,
            $memoryGrowth,
            "Container memory grew by " . number_format($memoryGrowth) . " bytes for 1000 services"
        );

        echo "\nMemory growth for 1000 services: " . number_format($memoryGrowth) . " bytes\n";
    }

    /**
     * Test ob die InstanceRegistry ordnungsgemäß aufräumt
     */
    public function test_instance_registry_can_be_flushed(): void
    {
        $registry = new InstanceRegistry();

        // Fülle Registry mit vielen Instanzen
        for ($i = 0; $i < 100; $i++) {
            $serviceName = "TestInstance_$i";
            $instance = (object)['id' => $i, 'data' => "test_$i"];
            $registry->setInstance($serviceName, $instance);
        }

        // Prüfe dass Instanzen registriert sind
        $this->assertCount(100, $registry->getAllRegistered());

        // Flush sollte alles löschen
        $registry->flush();
        $this->assertCount(0, $registry->getAllRegistered());
    }

    /**
     * Test ob Singletons ordnungsgemäß verwaltet werden
     * Test nutzt InstanceRegistry direkt da singleton() auch lazy loading versucht
     */
    public function test_singleton_lifecycle(): void
    {
        $serviceName = 'singleton_service';

        // Erstelle Objekt direkt und registriere als Singleton über InstanceRegistry
        $obj = new stdClass();
        $obj->data = 'test';
        $obj->created_at = time();

        // Direktes Setzen als Singleton über die Registry
        $registry = new InstanceRegistry();
        $registry->setSingleton($serviceName, $obj);

        // Container mit dieser Registry erstellen
        $container = new DefaultContainer(instances: $registry);

        // Sollte immer die gleiche Instanz zurückgeben
        $instance1 = $container->get($serviceName);
        $instance2 = $container->get($serviceName);

        $this->assertSame($instance1, $instance2);
        $this->assertEquals('test', $instance1->data);
    }

    /**
     * Test ob Container-Cache bei bind() ordnungsgemäß geleert wird
     */
    public function test_container_cache_clearing(): void
    {
        $serviceName = 'cache_service';

        // Erste Instanz
        $obj1 = new stdClass();
        $obj1->version = 1;
        $this->container->instance($serviceName, $obj1);
        $instance1 = $this->container->get($serviceName);

        // Neue Instanz sollte alte überschreiben
        $obj2 = new stdClass();
        $obj2->version = 2;
        $this->container->instance($serviceName, $obj2);
        $instance2 = $this->container->get($serviceName);

        $this->assertNotSame($instance1, $instance2);
        $this->assertEquals(1, $instance1->version);
        $this->assertEquals(2, $instance2->version);
    }

    /**
     * Test Memory Usage unter Last
     */
    public function test_memory_usage_under_load(): void
    {
        $memoryBefore = memory_get_usage(true);
        $maxMemoryUsed = 0;

        // Simuliere Last von 500 verschiedenen Services
        for ($iteration = 0; $iteration < 5; $iteration++) {
            for ($i = 0; $i < 100; $i++) {
                $serviceName = "load_service_{$iteration}_{$i}";

                // Erstelle Service-Objekt direkt
                $obj = new stdClass();
                $obj->data = array_fill(0, 100, 'load_test_data');
                $obj->timestamp = microtime(true);
                $obj->random = random_bytes(256);

                $this->container->instance($serviceName, $obj);
                $instance = $this->container->get($serviceName);
                $this->assertCount(100, $instance->data);

                $currentMemory = memory_get_usage(true);
                $maxMemoryUsed = max($maxMemoryUsed, $currentMemory - $memoryBefore);
            }

            // Optional: Garbage collection nach jeder Iteration
            gc_collect_cycles();
        }

        $finalMemory = memory_get_usage(true);
        $totalGrowth = $finalMemory - $memoryBefore;

        // Container sollte nicht unbegrenzt wachsen
        $this->assertLessThan(
            20 * 1024 * 1024,
            $totalGrowth,
            "Container grew by " . number_format($totalGrowth) . " bytes under load"
        );

        echo "\nMemory Statistics:\n";
        echo "- Initial Memory: " . number_format($memoryBefore) . " bytes\n";
        echo "- Final Memory: " . number_format($finalMemory) . " bytes\n";
        echo "- Total Growth: " . number_format($totalGrowth) . " bytes\n";
        echo "- Max Memory Used: " . number_format($maxMemoryUsed) . " bytes\n";
    }

    /**
     * Test Performance von Container-Lookups
     */
    public function test_container_lookup_performance(): void
    {
        // Setup: 1000 Services als Instanzen registrieren
        for ($i = 0; $i < 1000; $i++) {
            $serviceName = "perf_service_$i";
            $obj = new stdClass();
            $obj->id = $i;
            $obj->name = "service_$i";
            $this->container->instance($serviceName, $obj);
        }

        $startTime = microtime(true);

        // Performance Test: 10000 Lookups
        for ($i = 0; $i < 10000; $i++) {
            $serviceName = "perf_service_" . ($i % 1000);
            $instance = $this->container->get($serviceName);
            $this->assertEquals($i % 1000, $instance->id);
        }

        $endTime = microtime(true);
        $duration = $endTime - $startTime;

        // Sollte unter 1 Sekunde bleiben für 10k Lookups
        $this->assertLessThan(
            1.0,
            $duration,
            "Container lookups took {$duration}s for 10k operations"
        );

        echo "\nPerformance: " . number_format(10000 / $duration, 0) . " lookups/second\n";
    }
}