/*

YUI 3.10.3 (build 2fb5187)

Copyright 2013 Yahoo! Inc. All rights reserved.

Licensed under the BSD License.

http://yuilibrary.com/license/

*/

YUI.add('event-valuechange', function (Y, NAME) {

/**

Adds a synthetic `valuechange` event that fires when the `value` property of an

`<input>` or `<textarea>` node changes as a result of a keystroke, mouse

operation, or input method editor (IME) input event.

Usage:

    YUI().use('event-valuechange', function (Y) {

        Y.one('#my-input').on('valuechange', function (e) {

            Y.log('previous value: ' + e.prevVal);

            Y.log('new value: ' + e.newVal);

        });

    });

@module event-valuechange

**/

/**

Provides the implementation for the synthetic `valuechange` event. This class

isn't meant to be used directly, but is public to make monkeypatching possible.

Usage:

    YUI().use('event-valuechange', function (Y) {

        Y.one('#my-input').on('valuechange', function (e) {

            Y.log('previous value: ' + e.prevVal);

            Y.log('new value: ' + e.newVal);

        });

    });

@class ValueChange

@static

*/

var DATA_KEY = '_valuechange',

    VALUE    = 'value',

    config, // defined at the end of this file

// Just a simple namespace to make methods overridable.

VC = {

    // -- Static Constants -----------------------------------------------------

    /**

    Interval (in milliseconds) at which to poll for changes to the value of an

    element with one or more `valuechange` subscribers when the user is likely

    to be interacting with it.

    @property POLL_INTERVAL

    @type Number

    @default 50

    @static

    **/

    POLL_INTERVAL: 50,

    /**

    Timeout (in milliseconds) after which to stop polling when there hasn't been

    any new activity (keypresses, mouse clicks, etc.) on an element.

    @property TIMEOUT

    @type Number

    @default 10000

    @static

    **/

    TIMEOUT: 10000,

    // -- Protected Static Methods ---------------------------------------------

    /**

    Called at an interval to poll for changes to the value of the specified

    node.

    @method _poll

    @param {Node} node Node to poll.

    @param {Object} options Options object.

        @param {EventFacade} [options.e] Event facade of the event that

            initiated the polling.

    @protected

    @static

    **/

    _poll: function (node, options) {

        var domNode = node._node, // performance cheat; getValue() is a big hit when polling

            event   = options.e,

            newVal  = domNode && domNode.value,

            vcData  = node._data && node._data[DATA_KEY], // another perf cheat

            facade, prevVal;

        if (!domNode || !vcData) {

            Y.log('_poll: node #' + node.get('id') + ' disappeared; stopping polling and removing all notifiers.', 'warn', 'event-valuechange');

            VC._stopPolling(node);

            return;

        }

        prevVal = vcData.prevVal;

        if (newVal !== prevVal) {

            vcData.prevVal = newVal;

            facade = {

                _event       : event,

                currentTarget: (event && event.currentTarget) || node,

                newVal       : newVal,

                prevVal      : prevVal,

                target       : (event && event.target) || node

            };

            Y.Object.each(vcData.notifiers, function (notifier) {

                notifier.fire(facade);

            });

            VC._refreshTimeout(node);

        }

    },

    /**

    Restarts the inactivity timeout for the specified node.

    @method _refreshTimeout

    @param {Node} node Node to refresh.

    @param {SyntheticEvent.Notifier} notifier

    @protected

    @static

    **/

    _refreshTimeout: function (node, notifier) {

        // The node may have been destroyed, so check that it still exists

        // before trying to get its data. Otherwise an error will occur.

        if (!node._node) {

            Y.log('_stopPolling: node disappeared', 'warn', 'event-valuechange');

            return;

        }

        var vcData = node.getData(DATA_KEY);

        VC._stopTimeout(node); // avoid dupes

        // If we don't see any changes within the timeout period (10 seconds by

        // default), stop polling.

        vcData.timeout = setTimeout(function () {

            Y.log('timeout: #' + node.get('id'), 'info', 'event-valuechange');

            VC._stopPolling(node, notifier);

        }, VC.TIMEOUT);

        Y.log('_refreshTimeout: #' + node.get('id'), 'info', 'event-valuechange');

    },

    /**

    Begins polling for changes to the `value` property of the specified node. If

    polling is already underway for the specified node, it will not be restarted

    unless the `force` option is `true`

    @method _startPolling

    @param {Node} node Node to watch.

    @param {SyntheticEvent.Notifier} notifier

    @param {Object} options Options object.

        @param {EventFacade} [options.e] Event facade of the event that

            initiated the polling.

        @param {Boolean} [options.force=false] If `true`, polling will be

            restarted even if we're already polling this node.

    @protected

    @static

    **/

    _startPolling: function (node, notifier, options) {

        if (!node.test('input,textarea')) {

            Y.log('_startPolling: aborting poll on #' + node.get('id') + ' -- not an input or textarea', 'warn', 'event-valuechange');

            return;

        }

        var vcData = node.getData(DATA_KEY);

        if (!vcData) {

            vcData = {prevVal: node.get(VALUE)};

            node.setData(DATA_KEY, vcData);

        }

        vcData.notifiers || (vcData.notifiers = {});

        // Don't bother continuing if we're already polling this node, unless

        // `options.force` is true.

        if (vcData.interval) {

            if (options.force) {

                VC._stopPolling(node, notifier); // restart polling, but avoid dupe polls

            } else {

                vcData.notifiers[Y.stamp(notifier)] = notifier;

                return;

            }

        }

        // Poll for changes to the node's value. We can't rely on keyboard

        // events for this, since the value may change due to a mouse-initiated

        // paste event, an IME input event, or for some other reason that

        // doesn't trigger a key event.

        vcData.notifiers[Y.stamp(notifier)] = notifier;

        vcData.interval = setInterval(function () {

            VC._poll(node, vcData, options);

        }, VC.POLL_INTERVAL);

        Y.log('_startPolling: #' + node.get('id'), 'info', 'event-valuechange');

        VC._refreshTimeout(node, notifier);

    },

    /**

    Stops polling for changes to the specified node's `value` attribute.

    @method _stopPolling

    @param {Node} node Node to stop polling on.

    @param {SyntheticEvent.Notifier} [notifier] Notifier to remove from the

        node. If not specified, all notifiers will be removed.

    @protected

    @static

    **/

    _stopPolling: function (node, notifier) {

        // The node may have been destroyed, so check that it still exists

        // before trying to get its data. Otherwise an error will occur.

        if (!node._node) {

            Y.log('_stopPolling: node disappeared', 'info', 'event-valuechange');

            return;

        }

        var vcData = node.getData(DATA_KEY) || {};

        clearInterval(vcData.interval);

        delete vcData.interval;

        VC._stopTimeout(node);

        if (notifier) {

            vcData.notifiers && delete vcData.notifiers[Y.stamp(notifier)];

        } else {

            vcData.notifiers = {};

        }

        Y.log('_stopPolling: #' + node.get('id'), 'info', 'event-valuechange');

    },

    /**

    Clears the inactivity timeout for the specified node, if any.

    @method _stopTimeout

    @param {Node} node

    @protected

    @static

    **/

    _stopTimeout: function (node) {

        var vcData = node.getData(DATA_KEY) || {};

        clearTimeout(vcData.timeout);

        delete vcData.timeout;

    },

    // -- Protected Static Event Handlers --------------------------------------

    /**

    Stops polling when a node's blur event fires.

    @method _onBlur

    @param {EventFacade} e

    @param {SyntheticEvent.Notifier} notifier

    @protected

    @static

    **/

    _onBlur: function (e, notifier) {

        VC._stopPolling(e.currentTarget, notifier);

    },

    /**

    Resets a node's history and starts polling when a focus event occurs.

    @method _onFocus

    @param {EventFacade} e

    @param {SyntheticEvent.Notifier} notifier

    @protected

    @static

    **/

    _onFocus: function (e, notifier) {

        var node   = e.currentTarget,

            vcData = node.getData(DATA_KEY);

        if (!vcData) {

            vcData = {};

            node.setData(DATA_KEY, vcData);

        }

        vcData.prevVal = node.get(VALUE);

        VC._startPolling(node, notifier, {e: e});

    },

    /**

    Starts polling when a node receives a keyDown event.

    @method _onKeyDown

    @param {EventFacade} e

    @param {SyntheticEvent.Notifier} notifier

    @protected

    @static

    **/

    _onKeyDown: function (e, notifier) {

        VC._startPolling(e.currentTarget, notifier, {e: e});

    },

    /**

    Starts polling when an IME-related keyUp event occurs on a node.

    @method _onKeyUp

    @param {EventFacade} e

    @param {SyntheticEvent.Notifier} notifier

    @protected

    @static

    **/

    _onKeyUp: function (e, notifier) {

        // These charCodes indicate that an IME has started. We'll restart

        // polling and give the IME up to 10 seconds (by default) to finish.

        if (e.charCode === 229 || e.charCode === 197) {

            VC._startPolling(e.currentTarget, notifier, {

                e    : e,

                force: true

            });

        }

    },

    /**

    Starts polling when a node receives a mouseDown event.

    @method _onMouseDown

    @param {EventFacade} e

    @param {SyntheticEvent.Notifier} notifier

    @protected

    @static

    **/

    _onMouseDown: function (e, notifier) {

        VC._startPolling(e.currentTarget, notifier, {e: e});

    },

    /**

    Called when the `valuechange` event receives a new subscriber.

    @method _onSubscribe

    @param {Node} node

    @param {Subscription} sub

    @param {SyntheticEvent.Notifier} notifier

    @param {Function|String} [filter] Filter function or selector string. Only

        provided for delegate subscriptions.

    @protected

    @static

    **/

    _onSubscribe: function (node, sub, notifier, filter) {

        var _valuechange, callbacks, nodes;

        callbacks = {

            blur     : VC._onBlur,

            focus    : VC._onFocus,

            keydown  : VC._onKeyDown,

            keyup    : VC._onKeyUp,

            mousedown: VC._onMouseDown

        };

        // Store a utility object on the notifier to hold stuff that needs to be

        // passed around to trigger event handlers, polling handlers, etc.

        _valuechange = notifier._valuechange = {};

        if (filter) {

            // If a filter is provided, then this is a delegated subscription.

            _valuechange.delegated = true;

            // Add a function to the notifier that we can use to find all

            // nodes that pass the delegate filter.

            _valuechange.getNodes = function () {

                return node.all('input,textarea').filter(filter);

            };

            // Store the initial values for each descendant of the container

            // node that passes the delegate filter.

            _valuechange.getNodes().each(function (child) {

                if (!child.getData(DATA_KEY)) {

                    child.setData(DATA_KEY, {prevVal: child.get(VALUE)});

                }

            });

            notifier._handles = Y.delegate(callbacks, node, filter, null,

                notifier);

        } else {

            // This is a normal (non-delegated) event subscription.

            if (!node.test('input,textarea')) {

                return;

            }

            if (!node.getData(DATA_KEY)) {

                node.setData(DATA_KEY, {prevVal: node.get(VALUE)});

            }

            notifier._handles = node.on(callbacks, null, null, notifier);

        }

    },

    /**

    Called when the `valuechange` event loses a subscriber.

    @method _onUnsubscribe

    @param {Node} node

    @param {Subscription} subscription