<?php
/**
 * Minimal DI container (developer preview).
 *
 * Interface-compatible subset of PSR-11; the production build swaps this
 * for a scoped League\Container without touching call sites.
 *
 * @package AiRankSuite
 */

declare(strict_types=1);

namespace AiRankSuite;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

use InvalidArgumentException;

final class Container {

	/**
	 * Factory callables keyed by service id.
	 *
	 * @var array<string, callable>
	 */
	private array $factories = array();

	/**
	 * Resolved singletons keyed by service id.
	 *
	 * @var array<string, mixed>
	 */
	private array $instances = array();

	/**
	 * Register a shared service factory.
	 *
	 * @param string   $id      Service id (interface or class name).
	 * @param callable $factory Factory receiving the container.
	 */
	public function share( string $id, callable $factory ): void {
		$this->factories[ $id ] = $factory;
	}

	/**
	 * Whether a service id is known.
	 *
	 * @param string $id Service id.
	 */
	public function has( string $id ): bool {
		return isset( $this->factories[ $id ] ) || isset( $this->instances[ $id ] );
	}

	/**
	 * Resolve a service.
	 *
	 * @param string $id Service id.
	 * @return mixed
	 * @throws InvalidArgumentException When the id is unknown.
	 */
	public function get( string $id ): mixed {
		if ( isset( $this->instances[ $id ] ) ) {
			return $this->instances[ $id ];
		}
		if ( ! isset( $this->factories[ $id ] ) ) {
			throw new InvalidArgumentException( esc_html( "Unknown service: {$id}" ) );
		}
		$this->instances[ $id ] = ( $this->factories[ $id ] )( $this );
		return $this->instances[ $id ];
	}
}