<?php
 /*
 * @package		Tech Fry Library
 * @license		https://www.gnu.org/licenses/gpl-3.0.en.html
 */

namespace TechFry\Library;

defined('_JEXEC') or die;

class TfDom
{
    public static function get_dom($html)
    {
        $html = mb_convert_encoding($html, "HTML-ENTITIES", 'UTF-8');
        
        $dom = new \domDocument;
        $dom->preserveWhiteSpace = false;
        $dom->loadHTML($html, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
        
        return $dom;
    }
    
    // 01. Function to get array of HTML elements
    public static function get_html($html, $tag, $attr = null, $attr_value = null)
    {
        $dom = self::get_dom($html);
        
        $contents = $dom->getElementsByTagName($tag); // Array of Content
        if ($contents->length == 0)
        { 
            return false;
        }
        
        foreach ($contents as $content)
        {
            if ($attr != null)
            {
                if ($content->getAttribute($attr) == $attr_value)
                {
                    $html_arr[] = $dom->saveHtml($content);
                }
            }
            elseif ($attr == null)
            {
                $html_arr[] = $dom->saveHTML($content);
            }
        }
        
        return $html_arr;
    }
    
    // 02. Function to get array of values
    public static function get_value($html, $tag, $attr = null, $attr_value = null)
    {
        $dom = self::get_dom($html);
         
        $contents = $dom->getElementsByTagName($tag); // Array of Content
        if ($contents->length == 0)
        { 
            return false;
        }
        
        foreach ($contents as $content)
        {
            if ($attr != null)
            {
                if ($content->getAttribute($attr) == $attr_value)
                {
                    $values[] = $content->nodeValue;
                }
            }
            elseif ($attr == null)
            {
                $values[] = $content->nodeValue;
            }
        }
        
        return $values;
    }
            
    // 03. Function to get array of attribute values
    public static function get_attr($html, $tag, $target, $attr = null, $attr_value = null)
    {
        $dom = self::get_dom($html);
        
        $contents = $dom->getElementsByTagName($tag); // Array of Content
        
        if ($contents->length == 0)
        {
            return false;
        }
        
        foreach ($contents as $content)
        {
            if ($attr != null)
            {
                if ($content->getAttribute($attr) == $attr_value)
                {
                    $attr_values[] = $content->getAttribute($target);
                }
            }
            elseif ($attr == null)
            {
                $attr_values[] = $content->getAttribute($target);
            }
        }
        
        return $attr_values;
    }
    
    // 04. Function to remove all attributes from HTML except some
	public static function rem_attr($html, $noremove = array())
	{
        $dom = self::get_dom($html);
        
        $xpath = new \DOMXPath($dom);
        $nodes = $xpath->query('//@*');
        
        foreach ($nodes as $node)
        {
            if (!in_array($node->nodeName, $noremove))
            {
                $node->parentNode->removeAttribute($node->nodeName);
            }
        }
        
        return $dom->saveHTML();
	}
	        
	// 05. Function to add attribute to specific tag
	public static function add_attr($html, $tag, $attr, $attr_value)
    {
        $dom = self::get_dom($html);
	    
        $nodes = $dom->getElementsByTagName($tag);
        
        if (is_array($attr_value))
        {
            foreach ($nodes as $k => $node)
            {   
                $node->setAttribute($attr, $attr_value[$k]);
            }
        }
        else
        {
            foreach ($nodes as $node)
            {   
                $node->setAttribute($attr, $attr_value);
            }
        }
        
        return $dom->saveHTML();
	}
            
    // 06. Function to remove complete element
	public static function rem_element($html, $tag, $attr = null, $attr_value = null)
	{
        $dom = self::get_dom($html);
        
        $list = $dom->getElementsByTagName($tag);
        
        for ($i = $list->length; --$i >= 0;)
        {
            $node = $list->item($i);
            
            if ($attr != null)
            {
                if ($node->getAttribute($attr) == $attr_value)
                {
                    $node->parentNode->removeChild($node);
                }
            }
            elseif ($attr == null)
            {
                $node->parentNode->removeChild($node);
            }
        }

        return $dom->saveHTML();
    }
	
	// 07. Function to get array of names of unique tags in html
	public static function get_tags($html)
	{
	    $dom = self::get_dom($html);
	    
	    $elements = $dom->getElementsByTagName('*');
	    $tag_names[] = array();
	    
	    foreach ($elements as $element)
	    {
	        if (!in_array($element->tagName, $tag_names))
	        {
	            $tag_names[] = $element->tagName;
	        }
	    }
	    
	    return $tag_names;
	}
	
	// 08.
	public static function get_html_by_value($html, $tag, $value = '')
    {
        $dom = self::get_dom($html);
        
        $contents = $dom->getElementsByTagName($tag); // Array of Content
        if ($contents->length == 0)
        { 
            return false;
        }
        
        foreach ($contents as $content)
        {
            if (!empty($value))
            {
                if (strpos($content->nodeValue, $value) !== false)
                {
                    $html_arr[] = $dom->saveHtml($content);
                }
            }
            elseif (empty($value))
            {
                $html_arr[] = $dom->saveHTML($content);
            }
        }
        
        return $html_arr;
    }
}