<?php

/*
 * This file is part of Psy Shell.
 *
 * (c) 2012-2018 Justin Hileman
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Psy\Command;

use PhpParser\Node;
use PhpParser\Parser;
use Psy\Context;
use Psy\ContextAware;
use Psy\Input\CodeArgument;
use Psy\ParserFactory;
use Psy\VarDumper\Presenter;
use Psy\VarDumper\PresenterAware;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\VarDumper\Caster\Caster;

/**
 * Parse PHP code and show the abstract syntax tree.
 */
class ParseCommand extends Command implements ContextAware, PresenterAware
{
    /**
     * Context instance (for ContextAware interface).
     *
     * @var Context
     */
    protected $context;

    private $presenter;
    private $parserFactory;
    private $parsers;

    /**
     * {@inheritdoc}
     */
    public function __construct($name = null)
    {
        $this->parserFactory = new ParserFactory();
        $this->parsers       = [];

        parent::__construct($name);
    }

    /**
     * ContextAware interface.
     *
     * @param Context $context
     */
    public function setContext(Context $context)
    {
        $this->context = $context;
    }

    /**
     * PresenterAware interface.
     *
     * @param Presenter $presenter
     */
    public function setPresenter(Presenter $presenter)
    {
        $this->presenter = clone $presenter;
        $this->presenter->addCasters([
            'PhpParser\Node' => function (Node $node, array $a) {
                $a = [
                    Caster::PREFIX_VIRTUAL . 'type'       => $node->getType(),
                    Caster::PREFIX_VIRTUAL . 'attributes' => $node->getAttributes(),
                ];

                foreach ($node->getSubNodeNames() as $name) {
                    $a[Caster::PREFIX_VIRTUAL . $name] = $node->$name;
                }

                return $a;
            },
        ]);
    }

    /**
     * {@inheritdoc}
     */
    protected function configure()
    {
        $definition = [
            new CodeArgument('code', CodeArgument::REQUIRED, 'PHP code to parse.'),
            new InputOption('depth', '', InputOption::VALUE_REQUIRED, 'Depth to parse.', 10),
        ];

        if ($this->parserFactory->hasKindsSupport()) {
            $msg = 'One of PhpParser\\ParserFactory constants: '
                . \implode(', ', ParserFactory::getPossibleKinds())
                . " (default is based on current interpreter's version).";
            $defaultKind = $this->parserFactory->getDefaultKind();

            $definition[] = new InputOption('kind', '', InputOption::VALUE_REQUIRED, $msg, $defaultKind);
        }

        $this
            ->setName('parse')
            ->setDefinition($definition)
            ->setDescription('Parse PHP code and show the abstract syntax tree.')
            ->setHelp(
                <<<'HELP'
Parse PHP code and show the abstract syntax tree.

This command is used in the development of PsySH. Given a string of PHP code,
it pretty-prints the PHP Parser parse tree.

See https://github.com/nikic/PHP-Parser

It prolly won't be super useful for most of you, but it's here if you want to play.
HELP
            );
    }

    /**
     * {@inheritdoc}
     */
    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $code = $input->getArgument('code');
        if (\strpos('<?', $code) === false) {
            $code = '<?php ' . $code;
        }

        $parserKind = $this->parserFactory->hasKindsSupport() ? $input->getOption('kind') : null;
        $depth      = $input->getOption('depth');
        $nodes      = $this->parse($this->getParser($parserKind), $code);
        $output->page($this->presenter->present($nodes, $depth));

        $this->context->setReturnValue($nodes);
    }

    /**
     * Lex and parse a string of code into statements.
     *
     * @param Parser $parser
     * @param string $code
     *
     * @return array Statements
     */
    private function parse(Parser $parser, $code)
    {
        try {
            return $parser->parse($code);
        } catch (\PhpParser\Error $e) {
            if (\strpos($e->getMessage(), 'unexpected EOF') === false) {
                throw $e;
            }

            // If we got an unexpected EOF, let's try it again with a semicolon.
            return $parser->parse($code . ';');
        }
    }

    /**
     * Get (or create) the Parser instance.
     *
     * @param string|null $kind One of Psy\ParserFactory constants (only for PHP parser 2.0 and above)
     *
     * @return Parser
     */
    private function getParser($kind = null)
    {
        if (!\array_key_exists($kind, $this->parsers)) {
            $this->parsers[$kind] = $this->parserFactory->createParser($kind);
        }

        return $this->parsers[$kind];
    }
}
