<?php

namespace League\HTMLToMarkdown\Converter;

use League\HTMLToMarkdown\Configuration;
use League\HTMLToMarkdown\ConfigurationAwareInterface;
use League\HTMLToMarkdown\ElementInterface;

class CommentConverter implements ConverterInterface, ConfigurationAwareInterface
{
    /**
     * @var Configuration
     */
    protected $config;

    /**
     * @param Configuration $config
     */
    public function setConfig(Configuration $config)
    {
        $this->config = $config;
    }

    /**
     * @param ElementInterface $element
     *
     * @return string
     */
    public function convert(ElementInterface $element)
    {
        if ($this->shouldPreserve($element)) {
            return '<!--' . $element->getValue() . '-->';
        }
        return '';
    }

    /**
     * @return string[]
     */
    public function getSupportedTags()
    {
        return array('#comment');
    }

    /**
     * @param ElementInterface $element
     *
     * @return bool
     */
    private function shouldPreserve(ElementInterface $element)
    {
        $preserve = $this->config->getOption('preserve_comments');
        if ($preserve === true) {
            return true;
        }
        if (is_array($preserve)) {
            $value = trim($element->getValue());
            return in_array($value, $preserve);
        }
        return false;
    }
}