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<?php

    namespace Inteve\FeedGenerator\Utils;

    use Inteve\FeedGenerator\AssertException;
    use Inteve\FeedGenerator\IOutput;
    use Inteve\FeedGenerator\StaticClassException;


    class Helpers
    {
        public function __construct()
        {
            throw new StaticClassException('This is static class.');
        }


        /**
         * @param  bool
         * @param  string|NULL
         * @return void
         * @throws AssertException
         */
        public static function assert($value, $msg = NULL)
        {
            if ($value !== TRUE) {
                throw new AssertException($msg !== NULL ? $msg : "Assertion failed.");
            }
        }


        /**
         * @param  string
         * @return string
         */
        public static function escapeXml($s)
        {
            return htmlspecialchars(preg_replace('#[\x00-\x08\x0B\x0C\x0E-\x1F]+#', '', $s), ENT_QUOTES);
        }


        /**
         * Escapes URL parameter.
         * @param  string
         * @return string
         */
        public static function escapeUrl($s)
        {
            return rawurlencode($s);
        }


        /**
         * Formats XML tag
         * @param  string
         * @param  string|NULL
         * @param  array
         * @return string
         */
        public static function writeXml(IOutput $output, array $xml)
        {
            foreach ($xml as $tagName => $content) {
                if ($content === NULL || (is_array($content) && array_key_exists('content', $content) && $content['content'] === NULL)) {
                    continue;
                }

                $tag = $tagName;

                if (is_array($content) && isset($content['tag'])) {
                    $tag = $content['tag'];
                }

                // open tag
                $output->output('<' . $tag);

                if (is_array($content) && isset($content['attrs'])) {
                    foreach ($content['attrs'] as $attrName => $attrValue) {
                        if ($attrValue === NULL) {
                            continue;
                        }

                        $output->output(' ' . $attrName . '="' . self::escapeXml($attrValue) . '"');
                    }
                }

                $isEmpty = is_array($content) && !isset($content['content']);

                if ($isEmpty) {
                    $output->output(' /');
                }

                $output->output('>');

                if (!$isEmpty) {
                    // content
                    if (is_array($content) && isset($content['content'])) {
                        if (is_array($content['content'])) {
                            $output->output("\n");
                            self::writeXml($output, $content['content']);

                        } else {
                            $output->output(self::escapeXml($content['content']));
                        }

                    } else {
                        $output->output(self::escapeXml($content));
                    }

                    // close tag
                    $output->output('</' . $tag . ">");
                }

                $output->output("\n");
            }
        }
    }