Engine.php

<?php

/*
 * This file is part of the Patron package.
 *
 * (c) Olivier Laviale <olivier.laviale@gmail.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Patron;

use ICanBoogie\Accessor\AccessorTrait;
use ICanBoogie\Debug;
use ICanBoogie\Render;
use ICanBoogie\Render\TemplateName;

define('WDPATRON_DELIMIT_MACROS', false);

/**
 * Patron engine.
 *
 * @property-read MarkupCollection $markups
 * @property-read FunctionCollection $functions
 */
class Engine
{
	use AccessorTrait;

	const PREFIX = 'p:';

	protected $trace_templates = false;

	/**
	 * @var MarkupCollection
	 */
	private $markups;

	protected function get_markups()
	{
		return $this->markups;
	}

	/**
	 * @var FunctionCollection
	 */
	private $functions;

	protected function get_functions()
	{
		return $this->functions;
	}

	/**
	 * Expression evaluator.
	 *
	 * @var Evaluator
	 */
	private $evaluator;

	/**
	 * Initializes the {@link $evaluator} property, and a bunch of functions.
	 *
	 * @param MarkupCollection $markups
	 * @param FunctionCollection $functions
	 */
	public function __construct(MarkupCollection $markups, FunctionCollection $functions)
	{
		$this->markups = $markups;
		$this->functions = $functions;
		$this->evaluator = new Evaluator($this);
		$this->template_resolver = Render\get_template_resolver();

		$this->init_context();
	}

	public function __clone()
	{
		$this->init_context();
	}

	/**
	 * Evaluate an expression relative to a context.
	 *
	 * @param mixed $context
	 * @param string $expression
	 * @param bool $silent
	 */
	public function evaluate($expression, $silent=false, $context=null)
	{
		$evaluator = $this->evaluator;

		return $evaluator($context ?: $this->context, $expression, $silent);
	}

	/**
	 * @return Engine
	 *
	 * @deprecated
	 */
	static public function get_singleton()
	{
		return get_patron();
	}

	/*
	**

	SYSTEM

	**
	*/

	protected $trace = [];
	protected $errors = [];

	public function trace_enter($a)
	{
		array_unshift($this->trace, $a);
	}

	public function trace_exit()
	{
		array_shift($this->trace);
	}

	public function error($alert, array $args=[])
	{
		if ($alert instanceof \ICanBoogie\Exception\Config)
		{
			$this->errors[] = '<div class="alert alert-danger">' . $alert->getMessage() . '</div>';

			return;
		}
		else if ($alert instanceof \Exception)
		{
			$alert = class_exists('ICanBoogie\Debug') ? Debug::format_alert($alert) : (string) $alert;
		}
		else
		{
			$alert = \ICanBoogie\format($alert, $args);
		}

		#
		#
		#

		$trace_html = null;

		if ($this->trace)
		{
			$i = count($this->trace);
			$root = $_SERVER['DOCUMENT_ROOT'];
			$root_length = strlen($root);

			foreach ($this->trace as $trace)
			{
				list($which, $message) = $trace;

				if ($which == 'file')
				{
					if (strpos($message, $root_length) === 0)
					{
						$message = substr($message, $root_length);
					}
				}

				$trace_html .= sprintf('#%02d: in %s "%s"', $i--, $which, $message) . '<br />';
			}

			if ($trace_html)
			{
				$trace_html = '<pre>' . $trace_html . '</pre>';
			}
		}

		#
		#
		#

		$this->errors[] = '<div class="alert alert-danger">' . $alert . $trace_html . '</div>';
	}

	public function handle_exception(\Exception $e)
	{
		if ($e instanceof \ICanBoogie\HTTP\Exception)
		{
			throw $e;
		}
		else if ($e instanceof \ICanBoogie\ActiveRecord\Exception)
		{
			throw $e;
		}

		$this->error($e);
	}

	public function fetchErrors()
	{
		$rc = implode(PHP_EOL, $this->errors);

		$this->errors = [];

		return $rc;
	}

	public function get_file()
	{
		foreach ($this->trace as $trace)
		{
			list($which, $data) = $trace;

			if ($which == 'file')
			{
				return $data;
			}
		}
	}

	public function get_template_dir()
	{
		return dirname($this->get_file());
	}

	/*
	**

	TEMPLATES

	**
	*/

	protected $templates = [];

	public function addTemplate($name, $template)
	{
		if (isset($this->templates[$name]))
		{
			$this->error('The template %name is already defined ! !template', [

				'%name' => $name, '!template' => $template

			]);

			return;
		}

		$this->templates[$name] = $template;
	}

	protected function resolve_template($name)
	{
		$template_resolver = $this->template_resolver;
		$file = $this->get_file();

		if ($file)
		{
			// FIXME-20150721: use a decorator

			$template_resolver = clone $this->template_resolver;

			$basic_template_resolver = null;

			if ($template_resolver instanceof Render\BasicTemplateResolver)
			{
				$basic_template_resolver = $template_resolver;
			}
			else if ($template_resolver instanceof Render\TemplateResolverDecorator)
			{
				$basic_template_resolver = $template_resolver->find_renderer(Render\BasicTemplateResolver::class);
			}

			if ($basic_template_resolver)
			{
				$basic_template_resolver->add_path(dirname($file));
			}
		}

		$tries = [];
		$template_pathname = $template_resolver->resolve($name, [ '.patron', '.html' ], $tries);

		if ($template_pathname)
		{
			return $this->create_template_from_file($template_pathname);
		}

		$template_name = TemplateName::from($name);
		$template_pathname = $template_resolver->resolve($template_name->as_partial, [ '.patron', '.html' ], $tries);

		if ($template_pathname)
		{
			return $this->create_template_from_file($template_pathname);
		}

		throw new TemplateNotFound("Template not found: $name.", $tries);
	}

	protected function create_template_from_file($pathname)
	{
		$content = file_get_contents($pathname);
		$nodes = $this->get_compiled($content);

		return new Template($nodes, [ 'file' => $pathname ]);
	}

	protected function get_template($name)
	{
		if (isset($this->templates[$name]))
		{
			return $this->templates[$name];
		}

		return $this->resolve_template($name);
	}

	/**
	 * Calls a template.
	 *
	 * @param $name
	 * @param array $args
	 *
	 * @return string
	 */
	public function callTemplate($name, array $args=[])
	{
		$template = $this->get_template($name);

		if (!$template)
		{
			$er = 'Unknown template %name';
			$params = [ '%name' => $name ];

			if ($this->templates)
			{
				$er .= ', available templates: :list';
				$params[':list'] = implode(', ', array_keys($this->templates));
			}

			$this->error($er, $params);

			return null;
		}

		$this->trace_enter([ 'template', $name, $template ]);

		$this->context['self']['arguments'] = $args;

		$rc = $this($template);

		array_shift($this->trace);

		return $rc;
	}

	/*
	**

	CONTEXT

	**
	*/

	public $context;

	protected function init_context()
	{
		$this->context = new \BlueTihi\Context([ 'self' => null, 'this' => null ]);
	}

	/*
	**

	PUBLISH

	**
	*/

	protected function get_compiled($template)
	{
		static $compiler;

		if ($compiler === null)
		{
			$compiler = new Compiler();
		}

		return $compiler($template);
	}

	public function __invoke($template, $bind=null, array $options=[])
	{
		if (!$template)
		{
			return null;
		}

		if ($bind !== null)
		{
			$this->context['this'] = $bind;
		}

		$file = null;

		foreach ($options as $option => $value)
		{
			switch ((string) $option)
			{
				case 'variables':
				{
					foreach ($value as $k => $v)
					{
						$this->context[$k] = $v;
					}
				}
				break;

				case 'file':
				{
					$file = $value;
				}
				break;

				default:
				{
					trigger_error(\ICanBoogie\format('Suspicious option: %option :value', [

						'%option' => $option,
						':value' => $value

					]));
				}
				break;
			}
		}

		if (!($template instanceof Template))
		{
			if (is_array($template) && isset($template['file']))
			{
				$file = $template['file'];

				unset($template['file']);
			}

			if (!is_array($template))
			{
				$template = $this->get_compiled($template);
			}

			$template = new Template($template, [ 'file' => $file ]);
		}

		if ($template->file)
		{
			$this->trace_enter([ 'file', $template->file ]);
		}

		$rc = '';

		foreach ($template as $node)
		{
			if (!($node instanceof Node))
			{
				continue;
			}

			try
			{
				$rc .= $node($this, $this->context);
			}
			catch (\Exception $e)
			{
				if (class_exists('ICanBoogie\Debug'))
				{
					$rc .= Debug::format_alert($e);
				}
				else
				{
					$rc .= $e;
				}
			}

			$rc .= $this->fetchErrors();
		}

		$rc .= $this->fetchErrors();

		#
		#
		#

		if ($file)
		{
			array_shift($this->trace);
		}

		return $rc;
	}

	/*

	#
	# $context_markup is used to keep track of two variables associated with each markup :
	# self and this.
	#
	# 'self' is a reference to the markup itself, holding its name and the arguments with which
	# it was called, it is also used to store special markup data as for the foreach markup
	#
	# 'this' is a reference to the object of the markup, that being an array, an object or a value
	#
	#

	<p:articles>

		self.range.start
		self.range.limit
		self.range.count

		this = array of Articles

		<p:foreach>

			self.name = foreach
			self.arguments = []
			self.position
			self.key
			self.left

			this = an Article object

		</p:foreach>
	</p:articles>

	*/

	public $context_markup = []; // should be protected
}