<?php
/**
 * @package   SureCartCore
 * @author    SureCart <support@surecart.com>
 * @copyright 2017-2019 SureCart
 * @license   https://www.gnu.org/licenses/gpl-2.0.html GPL-2.0
 * @link      https://surecart.com/
 */

namespace SureCartCore\Helpers;

use Closure;
use SureCartCore\Application\GenericFactory;
use SureCartCore\Exceptions\ClassNotFoundException;
use SureCartCore\Exceptions\ConfigurationException;

/**
 * Represent a generic handler - a Closure or a class method to be resolved from the service container
 */
class Handler {
	/**
	 * Injection Factory.
	 *
	 * @var GenericFactory
	 */
	protected $factory = null;

	/**
	 * Parsed handler
	 *
	 * @var array|Closure
	 */
	protected $handler = null;

	/**
	 * Constructor
	 *
	 * @param GenericFactory $factory
	 * @param string|Closure $raw_handler
	 * @param string         $default_method
	 * @param string         $namespace
	 */
	public function __construct( GenericFactory $factory, $raw_handler, $default_method = '', $namespace = '' ) {
		$this->factory = $factory;

		$handler = $this->parse( $raw_handler, $default_method, $namespace );

		if ( $handler === null ) {
			throw new ConfigurationException( 'No or invalid handler provided.' );
		}

		$this->handler = $handler;
	}

	/**
	 * Parse a raw handler to a Closure or a [class, method] array
	 *
	 * @param  string|Closure $raw_handler
	 * @param  string         $default_method
	 * @param  string         $namespace
	 * @return array|Closure|null
	 */
	protected function parse( $raw_handler, $default_method, $namespace ) {
		if ( $raw_handler instanceof Closure ) {
			return $raw_handler;
		}

		return $this->parseFromString( $raw_handler, $default_method, $namespace );
	}

	/**
	 * Parse a raw string handler to a [class, method] array
	 *
	 * @param  string $raw_handler
	 * @param  string $default_method
	 * @param  string $namespace
	 * @return array|null
	 */
	protected function parseFromString( $raw_handler, $default_method, $namespace ) {
		list( $class, $method ) = array_pad( preg_split( '/@|::/', $raw_handler, 2 ), 2, '' );

		if ( empty( $method ) ) {
			$method = $default_method;
		}

		if ( ! empty( $class ) && ! empty( $method ) ) {
			return [
				'class'     => $class,
				'method'    => $method,
				'namespace' => $namespace,
			];
		}

		return null;
	}

	/**
	 * Get the parsed handler
	 *
	 * @return array|Closure
	 */
	public function get() {
		return $this->handler;
	}

	/**
	 * Make an instance of the handler.
	 *
	 * @return object
	 */
	public function make() {
		$handler = $this->get();

		if ( $handler instanceof Closure ) {
			return $handler;
		}

		$namespace = $handler['namespace'];
		$class     = $handler['class'];

		try {
			$instance = $this->factory->make( $class );
		} catch ( ClassNotFoundException $e ) {
			try {
				$instance = $this->factory->make( $namespace . $class );
			} catch ( ClassNotFoundException $e ) {
				throw new ClassNotFoundException( 'Class not found - tried: ' . $class . ', ' . $namespace . $class );
			}
		}

		return $instance;
	}

	/**
	 * Execute the parsed handler with any provided arguments and return the result.
	 *
	 * @param  mixed , ...$arguments
	 * @return mixed
	 */
	public function execute() {
		$arguments = func_get_args();
		$instance  = $this->make();

		if ( $instance instanceof Closure ) {
			return call_user_func_array( $instance, $arguments );
		}

		return call_user_func_array( [ $instance, $this->get()['method'] ], $arguments );
	}
}