<?php

namespace fphammerle\helpers;

class HtmlHelper
{
    public static function encode($string)
    {
        return htmlspecialchars($string, ENT_QUOTES | ENT_SUBSTITUTE);
    }

    private static function _renderTagAttributes(array $attributes = [])
    {
        return StringHelper::implode(' ', ArrayHelper::mapIfSet(
            $attributes,
            function($k, $v) {
                if($v === true) {
                    return sprintf('%s="%s"', $k, $k);
                } elseif($v === false) {
                    return null;
                } else {
                    return sprintf('%s="%s"', $k, self::encode($v));
                }
                }
            ));
    }

    public static function voidTag($tag_name, array $attributes = [])
    {
        if($tag_name === null) {
            return null;
        } elseif(!is_string($tag_name)) {
            throw new \InvalidArgumentException(
                sprintf('expected string or null as tag name, %s given', gettype($tag_name))
                );
        } else {
            return sprintf(
                '<%s%s />',
                $tag_name,
                StringHelper::prepend(' ', self::_renderTagAttributes($attributes))
                );
        }
    }

    public static function startTag($tag_name, array $attributes = [])
    {
        if($tag_name === null) {
            return null;
        } elseif(!is_string($tag_name)) {
            throw new \InvalidArgumentException(
                sprintf('expected string or null as tag name, %s given', gettype($tag_name))
                );
        } else {
            return sprintf(
                '<%s%s>',
                $tag_name,
                StringHelper::prepend(' ', self::_renderTagAttributes($attributes))
                );
        }
    }

    public static function endTag($name)
    {
        if($name === null) {
            return null;
        } elseif(!is_string($name)) {
            throw new \InvalidArgumentException(
                sprintf('expected string or null as name, %s given', gettype($name))
                );
        } else {
            return '</' . $name . '>';
        }
    }

    public static function nonVoidTag($tag_name, $content, array $attributes = [])
    {
        // @see https://www.w3.org/TR/html-markup/syntax.html#syntax-elements
        return StringHelper::embed(
            self::startTag($tag_name, $attributes),
            $content,
            self::endTag($tag_name)
            );
    }

    public static function time($dt, $content, array $attributes = [])
    {
        if($dt instanceof \DateTime) {
            $attr = $dt->format(\DateTime::W3C);
        } elseif($dt instanceof \DateInterval) {
            $attr = DateTimeHelper::iso($dt);
        } else {
            $attr = $dt;
        }

        return self::nonVoidTag(
            'time',
            is_callable($content) ? $content($dt) : $content,
            array_merge(
                ['datetime' => $attr],
                ArrayHelper::map($attributes, function($v) use ($dt) {
                    return is_callable($v) ? $v($dt) : $v;
                    })
                )
            );
    }
}