/* global jsPDF */
/** ==================================================================== 
 * jsPDF XMP metadata plugin
 * Copyright (c) 2016 Jussi Utunen, u-jussi@suomi24.fi
 * 
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * ====================================================================
 */
/**
* @name xmp_metadata
* @module
*/
(function (jsPDFAPI) {
    'use strict';

    var postPutResources = function () {
        var xmpmeta_beginning = '<x:xmpmeta xmlns:x="adobe:ns:meta/">';
        var rdf_beginning = '<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><rdf:Description rdf:about="" xmlns:jspdf="' + this.internal.__metadata__.namespaceuri + '"><jspdf:metadata>';
        var rdf_ending = '</jspdf:metadata></rdf:Description></rdf:RDF>';
        var xmpmeta_ending = '</x:xmpmeta>';
        var utf8_xmpmeta_beginning = unescape(encodeURIComponent(xmpmeta_beginning));
        var utf8_rdf_beginning = unescape(encodeURIComponent(rdf_beginning));
        var utf8_metadata = unescape(encodeURIComponent(this.internal.__metadata__.metadata));
        var utf8_rdf_ending = unescape(encodeURIComponent(rdf_ending));
        var utf8_xmpmeta_ending = unescape(encodeURIComponent(xmpmeta_ending));

        var total_len = utf8_rdf_beginning.length + utf8_metadata.length + utf8_rdf_ending.length + utf8_xmpmeta_beginning.length + utf8_xmpmeta_ending.length;
        
        this.internal.__metadata__.metadata_object_number = this.internal.newObject();
        this.internal.write('<< /Type /Metadata /Subtype /XML /Length ' + total_len + ' >>');
        this.internal.write('stream');
        this.internal.write(utf8_xmpmeta_beginning + utf8_rdf_beginning + utf8_metadata + utf8_rdf_ending + utf8_xmpmeta_ending);
        this.internal.write('endstream');
        this.internal.write('endobj');
    };

    var putCatalog = function () {
        if (this.internal.__metadata__.metadata_object_number) {
            this.internal.write('/Metadata ' + this.internal.__metadata__.metadata_object_number + ' 0 R');
        }
    };

	/**
	* Adds XMP formatted metadata to PDF
	*
	* @name addMetadata
	* @function
	* @param {String} metadata The actual metadata to be added. The metadata shall be stored as XMP simple value. Note that if the metadata string contains XML markup characters "<", ">" or "&", those characters should be written using XML entities.
	* @param {String} namespaceuri Sets the namespace URI for the metadata. Last character should be slash or hash.
	* @returns {jsPDF} jsPDF-instance
	*/
    jsPDFAPI.addMetadata = function (metadata, namespaceuri) {
        if (typeof this.internal.__metadata__ === 'undefined') {
            this.internal.__metadata__ = {
                metadata :  metadata,
                namespaceuri : namespaceuri || "http://jspdf.default.namespaceuri/"
            };
            this.internal.events.subscribe(
                'putCatalog',
                putCatalog
            );

            this.internal.events.subscribe(
                'postPutResources',
                postPutResources
            );
        }
        return this;
    };
}(jsPDF.API));
