<?php

declare(strict_types=1);

namespace App\Engine;

/**
 * Main class responsible for controlling the compilation process.
 *
 * @author Adam Pippin <hello@adampippin.ca>
 */
class Engine
{
	/**
	 * Compiler for processing documents.
	 *
	 * @var \App\Engine\ICompile
	 */
	protected $compile;

	/**
	 * Serializer to convert documents back to whatever line/disk format we
	 * want.
	 *
	 * @var \App\Serialize\ISerialize
	 */
	protected $serialize;

	/**
	 * Unserializer to convert line/disk format documents into documents.
	 *
	 * @var \App\Serialize\IUnserialize
	 */
	protected $unserialize;

	/**
	 * Represents the current document state after any operations called.
	 *
	 * @var \App\Dom\Document
	 */
	protected $document;

	/**
	 * Process a domdocument, applying some higher level operations such as
	 * stacking documents.
	 *
	 * @param  string   $input_file
	 * @param  IOptions $options
	 * @return string
	 */
	public function process(string $input_file, IOptions $options): string
	{
		$file_helper = new File([dirname(realpath($input_file))]);

		$files = [$input_file];
		$processed = [];

		for ($i = 0; $i < sizeof($files); $i++)
		{
			$document = $this->unserialize->unserialize(file_get_contents($file_helper->resolve($files[$i])));
			if (!in_array($files[$i], $processed))
			{
				$additional_files = [];
				try
				{
					$additional_files = $document->getMeta('stack');
				}
				catch (\Exception $ex)
				{
				}
				if (sizeof($additional_files))
				{
					$processed[] = $files[$i];
					array_splice($files, $i, 0, $additional_files);
					$i -= sizeof($additional_files);
					continue;
				}
			}
			echo '=> '.$files[$i].PHP_EOL;
			$this->compileDocument($document, $options);
		}

		return $this->getOutput();
	}

	/**
	 * Set the compiler to use.
	 *
	 * @param  ICompile $compiler
	 * @return Engine
	 */
	public function setCompiler(ICompile $compiler): Engine
	{
		$this->compile = $compiler;
		return $this;
	}

	/**
	 * Set the serializer to use.
	 *
	 * @param  \App\Serialize\ISerialize $serializer
	 * @return Engine
	 */
	public function setSerializer(\App\Serialize\ISerialize $serializer): Engine
	{
		$this->serialize = $serializer;
		return $this;
	}

	/**
	 * Set the unserializer to use.
	 *
	 * @param  \App\Serialize\IUnserialize $unserializer
	 * @return Engine
	 */
	public function setUnserializer(\App\Serialize\IUnserialize $unserializer): Engine
	{
		$this->unserialize = $unserializer;
		return $this;
	}

	/**
	 * Set the initial compiler state.
	 *
	 * @param  \App\Dom\Document $document
	 * @return Engine
	 */
	public function setInputDocument(\App\Dom\Document $document): Engine
	{
		$this->document = $document;
		$this->compile->setDocument($document);
		return $this;
	}

	/**
	 * Set the initial compiler state from a serialized string.
	 *
	 * @param  string $document_string
	 * @return Engine
	 */
	public function setInput(string $document_string): Engine
	{
		$document = $this->unserialize->unserialize($document_string);
		$this->setInputDocument($document);
		return $this;
	}

	/**
	 * Compile a new document, mutating current state.
	 *
	 * @param  string   $document_string
	 * @param  IOptions $options
	 * @return Engine
	 */
	public function compile(string $document_string, IOptions $options): Engine
	{
		$document = $this->unserialize->unserialize($document_string);
		$this->compileDocument($document, $options);
		return $this;
	}

	/**
	 * Compile a new document, mutating current state.
	 *
	 * @param  \App\Dom\Document $document
	 * @param  IOptions          $options
	 * @return Engine
	 */
	public function compileDocument(\App\Dom\Document $document, IOptions $options): Engine
	{
		$this->compile->compile($document, $options);
		return $this;
	}

	/**
	 * Get the document state after all applied compile() calls.
	 *
	 * @return \App\Dom\Document
	 */
	public function getOutputDocument(): \App\Dom\Document
	{
		return $this->compile->getDocument();
	}

	/**
	 * Get the document state after all applied compile() calls and serialize
	 * it, returning line/disk format.
	 *
	 * @return string
	 */
	public function getOutput(): string
	{
		$document = $this->getOutputDocument();
		return $this->serialize->serialize($document);
	}
}