/**
+ * Provides a DataSchema implementation which can be used to work with JSON data.
+ *
+ * @module dataschema
+ * @submodule dataschema-json
+ */
+
+/**
+ * JSON subclass for the DataSchema Utility.
+ * @class DataSchema.JSON
+ * @extends DataSchema.Base
+ * @static
+ */
+var LANG = Y.Lang,
+
+ SchemaJSON = {
+
+ /////////////////////////////////////////////////////////////////////////////
+ //
+ // DataSchema.JSON static methods
+ //
+ /////////////////////////////////////////////////////////////////////////////
+ /**
+ * Utility function converts JSON locator strings into walkable paths
+ *
+ * @method DataSchema.JSON.getPath
+ * @param locator {String} JSON value locator.
+ * @return {String[]} Walkable path to data value.
+ * @static
+ */
+ getPath: function(locator) {
+ var path = null,
+ keys = [],
+ i = 0;
+
+ if (locator) {
+ // Strip the ["string keys"] and [1] array indexes
+ locator = locator.
+ replace(/\[(['"])(.*?)\1\]/g,
+ function (x,$1,$2) {keys[i]=$2;return '.@'+(i++);}).
+ replace(/\[(\d+)\]/g,
+ function (x,$1) {keys[i]=parseInt($1,10)|0;return '.@'+(i++);}).
+ replace(/^\./,''); // remove leading dot
+
+ // Validate against problematic characters.
+ if (!/[^\w\.\$@]/.test(locator)) {
+ path = locator.split('.');
+ for (i=path.length-1; i >= 0; --i) {
+ if (path[i].charAt(0) === '@') {
+ path[i] = keys[parseInt(path[i].substr(1),10)];
+ }
+ }
+ }
+ else {
+ Y.log("Invalid locator: " + locator, "error", "dataschema-json");
+ }
+ }
+ return path;
+ },
+
+ /**
+ * Utility function to walk a path and return the value located there.
+ *
+ * @method DataSchema.JSON.getLocationValue
+ * @param path {String[]} Locator path.
+ * @param data {String} Data to traverse.
+ * @return {Object} Data value at location.
+ * @static
+ */
+ getLocationValue: function (path, data) {
+ var i = 0,
+ len = path.length;
+ for (;i<len;i++) {
+ if(!LANG.isUndefined(data[path[i]])) {
+ data = data[path[i]];
+ }
+ else {
+ data = undefined;
+ break;
+ }
+ }
+ return data;
+ },
+
+ /**
+ * Applies a given schema to given JSON data.
+ *
+ * @method apply
+ * @param schema {Object} Schema to apply.
+ * @param data {Object} JSON data.
+ * @return {Object} Schema-parsed data.
+ * @static
+ */
+ apply: function(schema, data) {
+ var data_in = data,
+ data_out = {results:[],meta:{}};
+
+ // Convert incoming JSON strings
+ if(!LANG.isObject(data)) {
+ try {
+ data_in = Y.JSON.parse(data);
+ }
+ catch(e) {
+ data_out.error = e;
+ return data_out;
+ }
+ }
+
+ if(LANG.isObject(data_in) && schema) {
+ // Parse results data
+ if(!LANG.isUndefined(schema.resultListLocator)) {
+ data_out = SchemaJSON._parseResults(schema, data_in, data_out);
+ }
+
+ // Parse meta data
+ if(!LANG.isUndefined(schema.metaFields)) {
+ data_out = SchemaJSON._parseMeta(schema.metaFields, data_in, data_out);
+ }
+ }
+ else {
+ Y.log("JSON data could not be schema-parsed: " + Y.dump(data) + " " + Y.dump(data), "error", "dataschema-json");
+ data_out.error = new Error("JSON schema parse failure");
+ }
+
+ return data_out;
+ },
+
+ /**
+ * Schema-parsed list of results from full data
+ *
+ * @method _parseResults
+ * @param schema {Object} Schema to parse against.
+ * @param json_in {Object} JSON to parse.
+ * @param data_out {Object} In-progress parsed data to update.
+ * @return {Object} Parsed data object.
+ * @static
+ * @protected
+ */
+ _parseResults: function(schema, json_in, data_out) {
+ var results = [],
+ path,
+ error;
+
+ if(schema.resultListLocator) {
+ path = SchemaJSON.getPath(schema.resultListLocator);
+ if(path) {
+ results = SchemaJSON.getLocationValue(path, json_in);
+ if (results === undefined) {
+ data_out.results = [];
+ error = new Error("JSON results retrieval failure");
+ }
+ else {
+ if(LANG.isArray(schema.resultFields) && LANG.isArray(results)) {
+ data_out = SchemaJSON._getFieldValues(schema.resultFields, results, data_out);
+ }
+ else {
+ data_out.results = [];
+ error = new Error("JSON Schema fields retrieval failure");
+ }
+ }
+ }
+ else {
+ error = new Error("JSON Schema results locator failure");
+ }
+
+ if (error) {
+ Y.log("JSON data could not be parsed: " + Y.dump(json_in), "error", "dataschema-json");
+ data_out.error = error;
+ }
+
+ }
+ return data_out;
+ },
+
+ /**
+ * Get field data values out of list of full results
+ *
+ * @method _getFieldValues
+ * @param fields {Array} Fields to find.
+ * @param array_in {Array} Results to parse.
+ * @param data_out {Object} In-progress parsed data to update.
+ * @return {Object} Parsed data object.
+ * @static
+ * @protected
+ */
+ _getFieldValues: function(fields, array_in, data_out) {
+ var results = [],
+ len = fields.length,
+ i, j,
+ field, key, path, parser,
+ simplePaths = [], complexPaths = [], fieldParsers = [],
+ result, record;
+
+ // First collect hashes of simple paths, complex paths, and parsers
+ for (i=0; i<len; i++) {
+ field = fields[i]; // A field can be a simple string or a hash
+ key = field.key || field; // Find the key
+
+ // Validate and store locators for later
+ path = SchemaJSON.getPath(key);
+ if (path) {
+ if (path.length === 1) {
+ simplePaths[simplePaths.length] = {key:key, path:path[0]};
+ } else {
+ complexPaths[complexPaths.length] = {key:key, path:path};
+ }
+ } else {
+ Y.log("Invalid key syntax: " + key, "warn", "dataschema-json");
+ }
+
+ // Validate and store parsers for later
+ //TODO: use Y.DataSchema.parse?
+ parser = (LANG.isFunction(field.parser)) ? field.parser : Y.Parsers[field.parser+''];
+ if (parser) {
+ fieldParsers[fieldParsers.length] = {key:key, parser:parser};
+ }
+ }
+
+ // Traverse list of array_in, creating records of simple fields,
+ // complex fields, and applying parsers as necessary
+ for (i=array_in.length-1; i>=0; --i) {
+ record = {};
+ result = array_in[i];
+ if(result) {
+ // Cycle through simpleLocators
+ for (j=simplePaths.length-1; j>=0; --j) {
+ // Bug 1777850: The result might be an array instead of object
+ record[simplePaths[j].key] = Y.DataSchema.Base.parse(
+ (LANG.isUndefined(result[simplePaths[j].path]) ?
+ result[j] : result[simplePaths[j].path]), simplePaths[j]);
+ }
+
+ // Cycle through complexLocators
+ for (j=complexPaths.length - 1; j>=0; --j) {
+ record[complexPaths[j].key] = Y.DataSchema.Base.parse(
+ (SchemaJSON.getLocationValue(complexPaths[j].path, result)), complexPaths[j] );
+ }
+
+ // Cycle through fieldParsers
+ for (j=fieldParsers.length-1; j>=0; --j) {
+ key = fieldParsers[j].key;
+ record[key] = fieldParsers[j].parser(record[key]);
+ // Safety net
+ if (LANG.isUndefined(record[key])) {
+ record[key] = null;
+ }
+ }
+ results[i] = record;
+ }
+ }
+ data_out.results = results;
+ return data_out;
+ },
+
+ /**
+ * Parses results data according to schema
+ *
+ * @method _parseMeta
+ * @param metaFields {Object} Metafields definitions.
+ * @param json_in {Object} JSON to parse.
+ * @param data_out {Object} In-progress parsed data to update.
+ * @return {Object} Schema-parsed meta data.
+ * @static
+ * @protected
+ */
+ _parseMeta: function(metaFields, json_in, data_out) {
+ if(LANG.isObject(metaFields)) {
+ var key, path;
+ for(key in metaFields) {
+ if (metaFields.hasOwnProperty(key)) {
+ path = SchemaJSON.getPath(metaFields[key]);
+ if (path && json_in) {
+ data_out.meta[key] = SchemaJSON.getLocationValue(path, json_in);
+ }
+ }
+ }
+ }
+ else {
+ data_out.error = new Error("JSON meta data retrieval failure");
+ }
+ return data_out;
+ }
+ };
+
+Y.DataSchema.JSON = Y.mix(SchemaJSON, Y.DataSchema.Base);
+