YUI.add('dataschema-xml', function (Y, NAME) {

/**

Provides a DataSchema implementation which can be used to work with XML data.

@module dataschema

@submodule dataschema-xml

**/

/**

Provides a DataSchema implementation which can be used to work with XML data.

See the `apply` method for usage.

@class DataSchema.XML

@extends DataSchema.Base

@static

**/

var Lang = Y.Lang,

    okNodeType = {

        1 : true,

        9 : true,

        11: true

    },

    SchemaXML;

SchemaXML = {

    ////////////////////////////////////////////////////////////////////////////

    //

    // DataSchema.XML static methods

    //

    ////////////////////////////////////////////////////////////////////////////

    /**

    Applies a schema to an XML data tree, returning a normalized object with

    results in the `results` property. Additional information can be parsed out

    of the XML for inclusion in the `meta` property of the response object.  If

    an error is encountered during processing, an `error` property will be

    added.

    Field data in the nodes captured by the XPath in _schema.resultListLocator_

    is extracted with the field identifiers described in _schema.resultFields_.

    Field identifiers are objects with the following properties:

      * `key`    : <strong>(required)</strong> The desired property name to use

            store the retrieved value in the result object.  If `locator` is

            not specified, `key` is also used as the XPath locator (String)

      * `locator`: The XPath locator to the node or attribute within each

            result node found by _schema.resultListLocator_ containing the

            desired field data (String)

      * `parser` : A function or the name of a function on `Y.Parsers` used

            to convert the input value into a normalized type.  Parser

            functions are passed the value as input and are expected to

            return a value.

      * `schema` : Used to retrieve nested field data into an array for

            assignment as the result field value.  This object follows the same

            conventions as _schema_.

    If no value parsing or nested parsing is needed, you can use XPath locators

    (strings) instead of field identifiers (objects) -- see example below.

    `response.results` will contain an array of objects with key:value pairs.

    The keys are the field identifier `key`s, and the values are the data

    values extracted from the nodes or attributes found by the field `locator`

    (or `key` fallback).

    To extract additional information from the XML, include an array of

    XPath locators in _schema.metaFields_.  The collected values will be

    stored in `response.meta` with the XPath locator as keys.

    @example

        var schema = {

                resultListLocator: '//produce/item',

                resultFields: [

                    {

                        locator: 'name',

                        key: 'name'

                    },

                    {

                        locator: 'color',

                        key: 'color',

                        parser: function (val) { return val.toUpperCase(); }

                    }

                ]

            };

        // Assumes data like

        // <inventory>

        //   <produce>

        //     <item><name>Banana</name><color>yellow</color></item>

        //     <item><name>Orange</name><color>orange</color></item>

        //     <item><name>Eggplant</name><color>purple</color></item>

        //   </produce>

        // </inventory>

        var response = Y.DataSchema.JSON.apply(schema, data);

        // response.results[0] is { name: "Banana", color: "YELLOW" }

    @method apply

    @param {Object} schema Schema to apply.  Supported configuration

        properties are:

      @param {String} [schema.resultListLocator] XPath locator for the

          XML nodes that contain the data to flatten into `response.results`

      @param {Array} [schema.resultFields] Field identifiers to

          locate/assign values in the response records. See above for

          details.

      @param {Array} [schema.metaFields] XPath locators to extract extra

          non-record related information from the XML data

    @param {XMLDocument} data XML data to parse

    @return {Object} An Object with properties `results` and `meta`

    @static

    **/

    apply: function(schema, data) {

        var xmldoc = data, // unnecessary variables

            data_out = { results: [], meta: {} };

        if (xmldoc && okNodeType[xmldoc.nodeType] && schema) {

            // Parse results data

            data_out = SchemaXML._parseResults(schema, xmldoc, data_out);

            // Parse meta data

            data_out = SchemaXML._parseMeta(schema.metaFields, xmldoc, data_out);

        } else {

            Y.log("XML data could not be schema-parsed: " + Y.dump(data) + " " + Y.dump(data), "error", "dataschema-xml");

            data_out.error = new Error("XML schema parse failure");

        }

        return data_out;

    },

    /**

     * Get an XPath-specified value for a given field from an XML node or document.

     *

     * @method _getLocationValue

     * @param field {String | Object} Field definition.

     * @param context {Object} XML node or document to search within.

     * @return {Object} Data value or null.

     * @static

     * @protected

     */

    _getLocationValue: function(field, context) {

        var locator = field.locator || field.key || field,

            xmldoc = context.ownerDocument || context,

            result, res, value = null;

        try {

            result = SchemaXML._getXPathResult(locator, context, xmldoc);

            while ((res = result.iterateNext())) {

                value = res.textContent || res.value || res.text || res.innerHTML || res.innerText || null;

            }

            // FIXME: Why defer to a method that is mixed into this object?

            // DSchema.Base is mixed into DSchema.XML (et al), so

            // DSchema.XML.parse(...) will work.  This supports the use case

            // where DSchema.Base.parse is changed, and that change is then

            // seen by all DSchema.* implementations, but does not support the

            // case where redefining DSchema.XML.parse changes behavior. In

            // fact, DSchema.XML.parse is never even called.

            return Y.DataSchema.Base.parse.call(this, value, field);

        } catch (e) {

            Y.log('SchemaXML._getLocationValue failed: ' + e.message);

        }

        return null;

    },

    /**

     * Fetches the XPath-specified result for a given location in an XML node

     * or document.

     *

     * @method _getXPathResult

     * @param locator {String} The XPath location.

     * @param context {Object} XML node or document to search within.

     * @param xmldoc {Object} XML document to resolve namespace.

     * @return {Object} Data collection or null.

     * @static

     * @protected

     */

    _getXPathResult: function(locator, context, xmldoc) {

        // Standards mode

        if (! Lang.isUndefined(xmldoc.evaluate)) {

            return xmldoc.evaluate(locator, context, xmldoc.createNSResolver(context.ownerDocument ? context.ownerDocument.documentElement : context.documentElement), 0, null);

        }

        // IE mode

        else {

            var values=[], locatorArray = locator.split(/\b\/\b/), i=0, l=locatorArray.length, location, subloc, m, isNth;

            // XPath is supported

            try {

                // this fixes the IE 5.5+ issue where childnode selectors begin at 0 instead of 1

                try {

                   xmldoc.setProperty("SelectionLanguage", "XPath");

                } catch (e) {}

                values = context.selectNodes(locator);

            }

            // Fallback for DOM nodes and fragments

            catch (e) {

                // Iterate over each locator piece

                for (; i<l && context; i++) {

                    location = locatorArray[i];

                    // grab nth child []

                    if ((location.indexOf("[") > -1) && (location.indexOf("]") > -1)) {

                        subloc = location.slice(location.indexOf("[")+1, location.indexOf("]"));

                        //XPath is 1-based while DOM is 0-based

                        subloc--;

                        context = context.children[subloc];

                        isNth = true;

                    }

                    // grab attribute value @

                    else if (location.indexOf("@") > -1) {

                        subloc = location.substr(location.indexOf("@"));

                        context = subloc ? context.getAttribute(subloc.replace('@', '')) : context;

                    }

                    // grab that last instance of tagName

                    else if (-1 < location.indexOf("//")) {

                        subloc = context.getElementsByTagName(location.substr(2));

                        context = subloc.length ? subloc[subloc.length - 1] : null;

                    }

                    // find the last matching location in children

                    else if (l != i + 1) {

                        for (m=context.childNodes.length-1; 0 <= m; m-=1) {

                            if (location === context.childNodes[m].tagName) {

                                context = context.childNodes[m];

                                m = -1;

                            }

                        }

                    }

                }

                if (context) {

                    // attribute

                    if (Lang.isString(context)) {

                        values[0] = {value: context};

                    }

                    // nth child

                    else if (isNth) {

                        values[0] = {value: context.innerHTML};

                    }

                    // all children

                    else {

                        values = Y.Array(context.childNodes, 0, true);

                    }

                }

            }

            // returning a mock-standard object for IE

            return {

                index: 0,

                iterateNext: function() {

                    if (this.index >= this.values.length) {return undefined;}

                    var result = this.values[this.index];

                    this.index += 1;

                    return result;

                },

                values: values

            };

        }

    },

    /**

     * Schema-parsed result field.

     *

     * @method _parseField

     * @param field {String | Object} Required. Field definition.

     * @param result {Object} Required. Schema parsed data object.

     * @param context {Object} Required. XML node or document to search within.

     * @static

     * @protected

     */

    _parseField: function(field, result, context) {

        var key = field.key || field,

            parsed;

        if (field.schema) {

            parsed = { results: [], meta: {} };

            parsed = SchemaXML._parseResults(field.schema, context, parsed);

            result[key] = parsed.results;

        } else {

            result[key] = SchemaXML._getLocationValue(field, context);

        }

    },

    /**

     * Parses results data according to schema

     *

     * @method _parseMeta

     * @param xmldoc_in {Object} XML document parse.

     * @param data_out {Object} In-progress schema-parsed data to update.

     * @return {Object} Schema-parsed data.

     * @static

     * @protected

     */

    _parseMeta: function(metaFields, xmldoc_in, data_out) {

        if(Lang.isObject(metaFields)) {

            var key,

                xmldoc = xmldoc_in.ownerDocument || xmldoc_in;

            for(key in metaFields) {

                if (metaFields.hasOwnProperty(key)) {

                    data_out.meta[key] = SchemaXML._getLocationValue(metaFields[key], xmldoc);

                }

            }

        }

        return data_out;

    },

    /**

     * Schema-parsed result to add to results list.

     *

     * @method _parseResult

     * @param fields {Array} Required. A collection of field definition.

     * @param context {Object} Required. XML node or document to search within.

     * @return {Object} Schema-parsed data.

     * @static

     * @protected

     */

    _parseResult: function(fields, context) {

        var result = {}, j;

        // Find each field value

        for (j=fields.length-1; 0 <= j; j--) {

            SchemaXML._parseField(fields[j], result, context);

        }

        return result;

    },

    /**

     * Schema-parsed list of results from full data

     *

     * @method _parseResults

     * @param schema {Object} Schema to parse against.

     * @param context {Object} XML node or document to parse.

     * @param data_out {Object} In-progress schema-parsed data to update.

     * @return {Object} Schema-parsed data.

     * @static

     * @protected

     */

    _parseResults: function(schema, context, data_out) {

        if (schema.resultListLocator && Lang.isArray(schema.resultFields)) {

            var xmldoc = context.ownerDocument || context,

                fields = schema.resultFields,

                results = [],

                node, nodeList, i=0;

            if (schema.resultListLocator.match(/^[:\-\w]+$/)) {

                nodeList = context.getElementsByTagName(schema.resultListLocator);

                // loop through each result node

                for (i = nodeList.length - 1; i >= 0; --i) {

                    results[i] = SchemaXML._parseResult(fields, nodeList[i]);

                }

            } else {

                nodeList = SchemaXML._getXPathResult(schema.resultListLocator, context, xmldoc);

                // loop through the nodelist

                while ((node = nodeList.iterateNext())) {

                    results[i] = SchemaXML._parseResult(fields, node);

                    i += 1;

                }

            }

            if (results.length) {

                data_out.results = results;

            } else {

                data_out.error = new Error("XML schema result nodes retrieval failure");

            }

        }

        return data_out;

    }

};

Y.DataSchema.XML = Y.mix(SchemaXML, Y.DataSchema.Base);

}, '@VERSION@', {"requires": ["dataschema-base"]});