<?php

declare(strict_types=1);

namespace ROITheme\Infrastructure\DI;

use ROITheme\Domain\Component\ComponentRepositoryInterface;
use ROITheme\Application\Contracts\ValidationServiceInterface;
use ROITheme\Application\Contracts\CacheServiceInterface;

/**
 * Dependency Injection Container
 *
 * Singleton container that manages all service instances.
 * Provides centralized access to dependencies throughout the application.
 *
 * @package ROITheme\Infrastructure\DI
 */
final class DIContainer
{
    private static ?DIContainer $instance = null;

    /** @var array<string, object> */
    private array $services = [];

    /**
     * Private constructor to prevent direct instantiation
     */
    private function __construct()
    {
        // Initialize services here
    }

    /**
     * Get singleton instance
     *
     * @return self
     */
    public static function getInstance(): self
    {
        if (self::$instance === null) {
            self::$instance = new self();
        }

        return self::$instance;
    }

    /**
     * Prevent cloning
     */
    private function __clone()
    {
    }

    /**
     * Prevent unserialization
     *
     * @throws \Exception
     */
    public function __wakeup(): void
    {
        throw new \Exception('Cannot unserialize singleton');
    }

    /**
     * Get Component Repository
     *
     * @return ComponentRepositoryInterface
     */
    public function getComponentRepository(): ComponentRepositoryInterface
    {
        if (!isset($this->services['component_repository'])) {
            // Placeholder - will be replaced in Phase 5
            throw new \RuntimeException('ComponentRepository not implemented yet. Will be available in Phase 5.');
        }

        return $this->services['component_repository'];
    }

    /**
     * Get Validation Service
     *
     * @return ValidationServiceInterface
     */
    public function getValidationService(): ValidationServiceInterface
    {
        if (!isset($this->services['validation_service'])) {
            // Placeholder - will be replaced in Phase 5
            throw new \RuntimeException('ValidationService not implemented yet. Will be available in Phase 5.');
        }

        return $this->services['validation_service'];
    }

    /**
     * Get Cache Service
     *
     * @return CacheServiceInterface
     */
    public function getCacheService(): CacheServiceInterface
    {
        if (!isset($this->services['cache_service'])) {
            // Placeholder - will be replaced in Phase 5
            throw new \RuntimeException('CacheService not implemented yet. Will be available in Phase 5.');
        }

        return $this->services['cache_service'];
    }

    /**
     * Register a service
     *
     * @param string $key Service identifier
     * @param object $service Service instance
     * @return void
     */
    public function set(string $key, object $service): void
    {
        $this->services[$key] = $service;
    }

    /**
     * Check if service exists
     *
     * @param string $key Service identifier
     * @return bool
     */
    public function has(string $key): bool
    {
        return isset($this->services[$key]);
    }

    /**
     * Get a service by key
     *
     * @param string $key Service identifier
     * @return object|null
     */
    public function get(string $key): ?object
    {
        return $this->services[$key] ?? null;
    }

    /**
     * Reset container (useful for testing)
     *
     * @return void
     */
    public static function reset(): void
    {
        self::$instance = null;
    }
}