<?php
/**
 * Minimal PSR-11-style service container.
 *
 * @package Bookline
 */

declare( strict_types=1 );

namespace Bookline;

use Closure;
use InvalidArgumentException;
use RuntimeException;

/**
 * Factory registration and singleton resolution. No third-party container.
 */
final class Container {

	/**
	 * Factories keyed by service id.
	 *
	 * @var array<string, Closure(self): mixed>
	 */
	private array $factories = [];

	/**
	 * Shared instances keyed by service id.
	 *
	 * @var array<string, mixed>
	 */
	private array $instances = [];

	/**
	 * Register a factory that returns a new instance each resolve.
	 *
	 * @param string  $id      Service id (usually a class name).
	 * @param Closure $factory Factory receiving the container.
	 */
	public function set( string $id, Closure $factory ): void {
		$this->factories[ $id ] = $factory;
		unset( $this->instances[ $id ] );
	}

	/**
	 * Register a singleton factory.
	 *
	 * @param string  $id      Service id.
	 * @param Closure $factory Factory receiving the container.
	 */
	public function singleton( string $id, Closure $factory ): void {
		$this->set(
			$id,
			function ( self $c ) use ( $id, $factory ) {
				if ( ! array_key_exists( $id, $this->instances ) ) {
					$this->instances[ $id ] = $factory( $c );
				}
				return $this->instances[ $id ];
			}
		);
	}

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

	/**
	 * Resolve a service.
	 *
	 * @param string $id Service id.
	 * @return mixed
	 *
	 * @throws InvalidArgumentException When the id is unknown.
	 * @throws RuntimeException         When resolution fails.
	 */
	public function get( string $id ): mixed {
		if ( ! $this->has( $id ) ) {
			throw new InvalidArgumentException(
				sprintf( 'Bookline container has no service "%s".', esc_html( $id ) )
			);
		}

		try {
			return ( $this->factories[ $id ] )( $this );
		} catch ( \Throwable $e ) {
			throw new RuntimeException(
				sprintf(
					'Failed to resolve Bookline service "%s": %s',
					esc_html( $id ),
					esc_html( $e->getMessage() )
				),
				0,
				$e
			);
		}
	}
}