/*!
 * Ext JS Library 3.0.0
 * Copyright(c) 2006-2009 Ext JS, LLC
 * licensing@extjs.com
 * http://www.extjs.com/license
 */
/**
 * @class Ext.data.Api
 * @extends Object
 * Ext.data.Api is a singleton designed to manage the data API including methods
 * for validating a developer's DataProxy API.  Defines variables for CRUD actions
 * create, read, update and destroy in addition to a mapping of RESTful HTTP methods
 * GET, POST, PUT and DELETE to CRUD actions.
 * @singleton
 */
Ext.data.Api = (function() {

    // private validActions.  validActions is essentially an inverted hash of Ext.data.Api.actions, where value becomes the key.
    // Some methods in this singleton (e.g.: getActions, getVerb) will loop through actions with the code <code>for (var verb in this.actions)</code>
    // For efficiency, some methods will first check this hash for a match.  Those methods which do acces validActions will cache their result here.
    // We cannot pre-define this hash since the developer may over-ride the actions at runtime.
    var validActions = {};

    return {
        /**
         * Defined actions corresponding to remote actions:
         * <pre><code>
actions: {
    create  : 'create',  // Text representing the remote-action to create records on server.
    read    : 'read',    // Text representing the remote-action to read/load data from server.
    update  : 'update',  // Text representing the remote-action to update records on server.
    destroy : 'destroy'  // Text representing the remote-action to destroy records on server.
}
         * </code></pre>
         * @property actions
         * @type Object
         */
        actions : {
            create  : 'create',
            read    : 'read',
            update  : 'update',
            destroy : 'destroy'
        },

        /**
         * Defined {CRUD action}:{HTTP method} pairs to associate HTTP methods with the
         * corresponding actions for {@link Ext.data.DataProxy#restful RESTful proxies}.
         * Defaults to:
         * <pre><code>
restActions : {
    create  : 'POST',
    read    : 'GET',
    update  : 'PUT',
    destroy : 'DELETE'
},
         * </code></pre>
         */
        restActions : {
            create  : 'POST',
            read    : 'GET',
            update  : 'PUT',
            destroy : 'DELETE'
        },

        /**
         * Returns true if supplied action-name is a valid API action defined in <code>{@link #actions}</code> constants
         * @param {String} action
         * @param {String[]}(Optional) List of available CRUD actions.  Pass in list when executing multiple times for efficiency.
         * @return {Boolean}
         */
        isAction : function(action) {
            return (Ext.data.Api.actions[action]) ? true : false;
        },

        /**
         * Returns the actual CRUD action KEY "create", "read", "update" or "destroy" from the supplied action-name.  This method is used internally and shouldn't generally
         * need to be used directly.  The key/value pair of Ext.data.Api.actions will often be identical but this is not necessarily true.  A developer can override this naming
         * convention if desired.  However, the framework internally calls methods based upon the KEY so a way of retreiving the the words "create", "read", "update" and "destroy" is
         * required.  This method will cache discovered KEYS into the private validActions hash.
         * @param {String} name The runtime name of the action.
         * @return {String||null} returns the action-key, or verb of the user-action or null if invalid.
         * @nodoc
         */
        getVerb : function(name) {
            if (validActions[name]) {
                return validActions[name];  // <-- found in cache.  return immediately.
            }
            for (var verb in this.actions) {
                if (this.actions[verb] === name) {
                    validActions[name] = verb;
                    break;
                }
            }
            return (validActions[name] !== undefined) ? validActions[name] : null;
        },

        /**
         * Returns true if the supplied API is valid; that is, check that all keys match defined actions
         * otherwise returns an array of mistakes.
         * @return {String[]||true}
         */
        isValid : function(api){
            var invalid = [];
            var crud = this.actions; // <-- cache a copy of the actions.
            for (var action in api) {
                if (!(action in crud)) {
                    invalid.push(action);
                }
            }
            return (!invalid.length) ? true : invalid;
        },

        /**
         * Returns true if the supplied verb upon the supplied proxy points to a unique url in that none of the other api-actions
         * point to the same url.  The question is important for deciding whether to insert the "xaction" HTTP parameter within an
         * Ajax request.  This method is used internally and shouldn't generally need to be called directly.
         * @param {Ext.data.DataProxy} proxy
         * @param {String} verb
         * @return {Boolean}
         */
        hasUniqueUrl : function(proxy, verb) {
            var url = (proxy.api[verb]) ? proxy.api[verb].url : null;
            var unique = true;
            for (var action in proxy.api) {
                if ((unique = (action === verb) ? true : (proxy.api[action].url != url) ? true : false) === false) {
                    break;
                }
            }
            return unique;
        },

        /**
         * This method is used internally by <tt>{@link Ext.data.DataProxy DataProxy}</tt> and should not generally need to be used directly.
         * Each action of a DataProxy api can be initially defined as either a String or an Object.  When specified as an object,
         * one can explicitly define the HTTP method (GET|POST) to use for each CRUD action.  This method will prepare the supplied API, setting
         * each action to the Object form.  If your API-actions do not explicitly define the HTTP method, the "method" configuration-parameter will
         * be used.  If the method configuration parameter is not specified, POST will be used.
         <pre><code>
new Ext.data.HttpProxy({
    method: "POST",     // <-- default HTTP method when not specified.
    api: {
        create: 'create.php',
        load: 'read.php',
        save: 'save.php',
        destroy: 'destroy.php'
    }
});

// Alternatively, one can use the object-form to specify the API
new Ext.data.HttpProxy({
    api: {
        load: {url: 'read.php', method: 'GET'},
        create: 'create.php',
        destroy: 'destroy.php',
        save: 'update.php'
    }
});
        </code></pre>
         *
         * @param {Ext.data.DataProxy} proxy
         */
        prepare : function(proxy) {
            if (!proxy.api) {
                proxy.api = {}; // <-- No api?  create a blank one.
            }
            for (var verb in this.actions) {
                var action = this.actions[verb];
                proxy.api[action] = proxy.api[action] || proxy.url || proxy.directFn;
                if (typeof(proxy.api[action]) == 'string') {
                    proxy.api[action] = {
                        url: proxy.api[action]
                    };
                }
            }
        },

        /**
         * Prepares a supplied Proxy to be RESTful.  Sets the HTTP method for each api-action to be one of
         * GET, POST, PUT, DELETE according to the defined {@link #restActions}.
         * @param {Ext.data.DataProxy} proxy
         */
        restify : function(proxy) {
            proxy.restful = true;
            for (var verb in this.restActions) {
                proxy.api[this.actions[verb]].method = this.restActions[verb];
            }
        }
    };
})();

/**
 * @class Ext.data.Api.Error
 * @extends Ext.Error
 * Error class for Ext.data.Api errors
 */
Ext.data.Api.Error = Ext.extend(Ext.Error, {
    constructor : function(message, arg) {
        this.arg = arg;
        Ext.Error.call(this, message);
    },
    name: 'Ext.data.Api'
});
Ext.apply(Ext.data.Api.Error.prototype, {
    lang: {
        'action-url-undefined': 'No fallback url defined for this action.  When defining a DataProxy api, please be sure to define an url for each CRUD action in Ext.data.Api.actions or define a default url in addition to your api-configuration.',
        'invalid': 'received an invalid API-configuration.  Please ensure your proxy API-configuration contains only the actions defined in Ext.data.Api.actions',
        'invalid-url': 'Invalid url.  Please review your proxy configuration.',
        'execute': 'Attempted to execute an unknown action.  Valid API actions are defined in Ext.data.Api.actions"'
    }
});
