<?php

/**

 * Atom Syndication Format PHP Library

 *

 * @package AtomLib

 * @link http://code.google.com/p/phpatomlib/

 *

 * @author Elias Torres <elias@torrez.us>

 * @version 0.4

 * @since 2.3.0

 */

/**

 * Structure that store common Atom Feed Properties

 *

 * @package AtomLib

 */

class AtomFeed {

	/**

	 * Stores Links

	 * @var array

	 * @access public

	 */

    var $links = array();

    /**

     * Stores Categories

     * @var array

     * @access public

     */

    var $categories = array();

	/**

	 * Stores Entries

	 *

	 * @var array

	 * @access public

	 */

    var $entries = array();

}

/**

 * Structure that store Atom Entry Properties

 *

 * @package AtomLib

 */

class AtomEntry {

	/**

	 * Stores Links

	 * @var array

	 * @access public

	 */

    var $links = array();

    /**

     * Stores Categories

     * @var array

	 * @access public

     */

    var $categories = array();

}

/**

 * AtomLib Atom Parser API

 *

 * @package AtomLib

 */

class AtomParser {

    var $NS = 'http://www.w3.org/2005/Atom';

    var $ATOM_CONTENT_ELEMENTS = array('content','summary','title','subtitle','rights');

    var $ATOM_SIMPLE_ELEMENTS = array('id','updated','published','draft');

    var $debug = false;

    var $depth = 0;

    var $indent = 2;

    var $in_content;

    var $ns_contexts = array();

    var $ns_decls = array();

    var $content_ns_decls = array();

    var $content_ns_contexts = array();

    var $is_xhtml = false;

    var $is_html = false;

    var $is_text = true;

    var $skipped_div = false;

    var $FILE = "php://input";

    var $feed;

    var $current;

	/**

	 * PHP5 constructor.

	 */

    function __construct() {

        $this->feed = new AtomFeed();

        $this->current = null;

        $this->map_attrs_func = array( __CLASS__, 'map_attrs' );

        $this->map_xmlns_func = array( __CLASS__, 'map_xmlns' );

    }

	/**

	 * PHP4 constructor.

	 */

	public function AtomParser() {

		self::__construct();

	}

	/**

	 * Map attributes to key="val"

	 *

	 * @param string $k Key

	 * @param string $v Value

	 * @return string

	 */

	public static function map_attrs($k, $v) {

		return "$k=\"$v\"";

	}

	/**

	 * Map XML namespace to string.

	 *

	 * @param indexish $p XML Namespace element index

	 * @param array $n Two-element array pair. [ 0 => {namespace}, 1 => {url} ]

	 * @return string 'xmlns="{url}"' or 'xmlns:{namespace}="{url}"'

	 */

	public static function map_xmlns($p, $n) {

		$xd = "xmlns";

		if( 0 < strlen($n[0]) ) {

			$xd .= ":{$n[0]}";

		}

		return "{$xd}=\"{$n[1]}\"";

	}

    function _p($msg) {

        if($this->debug) {

            print str_repeat(" ", $this->depth * $this->indent) . $msg ."\n";

        }

    }

    function error_handler($log_level, $log_text, $error_file, $error_line) {

        $this->error = $log_text;

    }

    function parse() {

        set_error_handler(array(&$this, 'error_handler'));

        array_unshift($this->ns_contexts, array());

        if ( ! function_exists( 'xml_parser_create_ns' ) ) {

        	trigger_error( __( "PHP's XML extension is not available. Please contact your hosting provider to enable PHP's XML extension." ) );

        	return false;

        }

        $parser = xml_parser_create_ns();

        xml_set_object($parser, $this);

        xml_set_element_handler($parser, "start_element", "end_element");

        xml_parser_set_option($parser,XML_OPTION_CASE_FOLDING,0);

        xml_parser_set_option($parser,XML_OPTION_SKIP_WHITE,0);

        xml_set_character_data_handler($parser, "cdata");

        xml_set_default_handler($parser, "_default");

        xml_set_start_namespace_decl_handler($parser, "start_ns");

        xml_set_end_namespace_decl_handler($parser, "end_ns");

        $this->content = '';

        $ret = true;

        $fp = fopen($this->FILE, "r");

        while ($data = fread($fp, 4096)) {

            if($this->debug) $this->content .= $data;

            if(!xml_parse($parser, $data, feof($fp))) {

                trigger_error(sprintf(__('XML Error: %1$s at line %2$s')."\n",

                    xml_error_string(xml_get_error_code($parser)),

                    xml_get_current_line_number($parser)));

                $ret = false;

                break;

            }

        }

        fclose($fp);

        xml_parser_free($parser);

        restore_error_handler();

        return $ret;

    }

    function start_element($parser, $name, $attrs) {

        $tag = array_pop(explode(":", $name));

        switch($name) {

            case $this->NS . ':feed':

                $this->current = $this->feed;

                break;

            case $this->NS . ':entry':

                $this->current = new AtomEntry();

                break;

        };

        $this->_p("start_element('$name')");

        #$this->_p(print_r($this->ns_contexts,true));

        #$this->_p('current(' . $this->current . ')');

        array_unshift($this->ns_contexts, $this->ns_decls);

        $this->depth++;

        if(!empty($this->in_content)) {

            $this->content_ns_decls = array();

            if($this->is_html || $this->is_text)

                trigger_error("Invalid content in element found. Content must not be of type text or html if it contains markup.");

            $attrs_prefix = array();

            // resolve prefixes for attributes

            foreach($attrs as $key => $value) {

                $with_prefix = $this->ns_to_prefix($key, true);

                $attrs_prefix[$with_prefix[1]] = $this->xml_escape($value);

            }

            $attrs_str = join(' ', array_map($this->map_attrs_func, array_keys($attrs_prefix), array_values($attrs_prefix)));

            if(strlen($attrs_str) > 0) {

                $attrs_str = " " . $attrs_str;

            }

            $with_prefix = $this->ns_to_prefix($name);

            if(!$this->is_declared_content_ns($with_prefix[0])) {

                array_push($this->content_ns_decls, $with_prefix[0]);

            }

            $xmlns_str = '';

            if(count($this->content_ns_decls) > 0) {

                array_unshift($this->content_ns_contexts, $this->content_ns_decls);

                $xmlns_str .= join(' ', array_map($this->map_xmlns_func, array_keys($this->content_ns_contexts[0]), array_values($this->content_ns_contexts[0])));

                if(strlen($xmlns_str) > 0) {

                    $xmlns_str = " " . $xmlns_str;

                }

            }

            array_push($this->in_content, array($tag, $this->depth, "<". $with_prefix[1] ."{$xmlns_str}{$attrs_str}" . ">"));

        } else if(in_array($tag, $this->ATOM_CONTENT_ELEMENTS) || in_array($tag, $this->ATOM_SIMPLE_ELEMENTS)) {

            $this->in_content = array();

            $this->is_xhtml = $attrs['type'] == 'xhtml';

            $this->is_html = $attrs['type'] == 'html' || $attrs['type'] == 'text/html';

            $this->is_text = !in_array('type',array_keys($attrs)) || $attrs['type'] == 'text';

            $type = $this->is_xhtml ? 'XHTML' : ($this->is_html ? 'HTML' : ($this->is_text ? 'TEXT' : $attrs['type']));

            if(in_array('src',array_keys($attrs))) {

                $this->current->$tag = $attrs;

            } else {

                array_push($this->in_content, array($tag,$this->depth, $type));

            }

        } else if($tag == 'link') {

            array_push($this->current->links, $attrs);

        } else if($tag == 'category') {

            array_push($this->current->categories, $attrs);

        }

        $this->ns_decls = array();

    }

    function end_element($parser, $name) {

        $tag = array_pop(explode(":", $name));

        $ccount = count($this->in_content);

        # if we are *in* content, then let's proceed to serialize it

        if(!empty($this->in_content)) {

            # if we are ending the original content element

            # then let's finalize the content

            if($this->in_content[0][0] == $tag &&

                $this->in_content[0][1] == $this->depth) {

                $origtype = $this->in_content[0][2];

                array_shift($this->in_content);

                $newcontent = array();

                foreach($this->in_content as $c) {

                    if(count($c) == 3) {

                        array_push($newcontent, $c[2]);

                    } else {

                        if($this->is_xhtml || $this->is_text) {

                            array_push($newcontent, $this->xml_escape($c));

                        } else {

                            array_push($newcontent, $c);

                        }

                    }

                }

                if(in_array($tag, $this->ATOM_CONTENT_ELEMENTS)) {

                    $this->current->$tag = array($origtype, join('',$newcontent));

                } else {

                    $this->current->$tag = join('',$newcontent);

                }

                $this->in_content = array();

            } else if($this->in_content[$ccount-1][0] == $tag &&

                $this->in_content[$ccount-1][1] == $this->depth) {

                $this->in_content[$ccount-1][2] = substr($this->in_content[$ccount-1][2],0,-1) . "/>";

            } else {

                # else, just finalize the current element's content

                $endtag = $this->ns_to_prefix($name);

                array_push($this->in_content, array($tag, $this->depth, "</$endtag[1]>"));

            }

        }

        array_shift($this->ns_contexts);

        $this->depth--;

        if($name == ($this->NS . ':entry')) {

            array_push($this->feed->entries, $this->current);

            $this->current = null;

        }

        $this->_p("end_element('$name')");

    }

    function start_ns($parser, $prefix, $uri) {

        $this->_p("starting: " . $prefix . ":" . $uri);

        array_push($this->ns_decls, array($prefix,$uri));

    }

    function end_ns($parser, $prefix) {

        $this->_p("ending: #" . $prefix . "#");

    }

    function cdata($parser, $data) {

        $this->_p("data: #" . str_replace(array("\n"), array("\\n"), trim($data)) . "#");

        if(!empty($this->in_content)) {

            array_push($this->in_content, $data);

        }

    }

    function _default($parser, $data) {

        # when does this gets called?

    }

    function ns_to_prefix($qname, $attr=false) {

        # split 'http://www.w3.org/1999/xhtml:div' into ('http','//www.w3.org/1999/xhtml','div')

        $components = explode(":", $qname);

        # grab the last one (e.g 'div')

        $name = array_pop($components);

        if(!empty($components)) {

            # re-join back the namespace component

            $ns = join(":",$components);

            foreach($this->ns_contexts as $context) {

                foreach($context as $mapping) {

                    if($mapping[1] == $ns && strlen($mapping[0]) > 0) {

                        return array($mapping, "$mapping[0]:$name");

                    }

                }

            }

        }

        if($attr) {

            return array(null, $name);

        } else {

            foreach($this->ns_contexts as $context) {

                foreach($context as $mapping) {

                    if(strlen($mapping[0]) == 0) {

                        return array($mapping, $name);

                    }

                }

            }

        }

    }

    function is_declared_content_ns($new_mapping) {

        foreach($this->content_ns_contexts as $context) {

            foreach($context as $mapping) {

                if($new_mapping == $mapping) {

                    return true;

                }

            }

        }

        return false;

    }

    function xml_escape($string)

    {

             return str_replace(array('&','"',"'",'<','>'),

                array('&','"',''','<','>'),

                $string );

    }

}