<?php

declare(strict_types=1);

namespace AdsDestroyer\Core;

/**
 * Lightweight dependency injection container.
 * 
 * This container provides a simple way to manage service dependencies
 * and lazy loading of services. It supports both factory functions
 * and direct object instances.
 * 
 * @since 1.0.0
 */
final class ServiceContainer {
    
    /**
     * Registered services.
     * 
     * @var array<string, callable|object>
     */
    private array $services = [];
    
    /**
     * Register a service factory or instance.
     * 
     * @since 1.0.0
     * @param string $id Service identifier.
     * @param callable|object $service Service factory or instance.
     * @throws \InvalidArgumentException If service ID is empty.
     */
    public function set(string $id, $service): void {
        if (empty($id)) {
            throw new \InvalidArgumentException('Service ID cannot be empty');
        }
        
        $this->services[$id] = $service;
    }
    
    /**
     * Get a service by ID, lazily instantiating if necessary.
     * 
     * @since 1.0.0
     * @param string $id Service identifier.
     * @return mixed Service instance.
     * @throws \RuntimeException If service is not found.
     */
    public function get(string $id) {
        if (!isset($this->services[$id])) {
            throw new \RuntimeException(
                sprintf('Service not found: %s', sanitize_key($id))
            );
        }
        
        $entry = $this->services[$id];
        
        // If it's a factory function, call it and cache the result
        if (is_callable($entry)) {
            $instance = $entry();
            $this->services[$id] = $instance;
            return $instance;
        }
        
        return $entry;
    }
}