/**
 * @docauthor Jason Johnston <jason@sencha.com>
 *
 * A file upload field which has custom styling and allows control over the button text and other
 * features of {@link Ext.form.field.Text text fields} like {@link Ext.form.field.Text#emptyText empty text}.
 * It uses a hidden file input element behind the scenes to allow user selection of a file and to
 * perform the actual upload during {@link Ext.form.Basic#submit form submit}.
 *
 * Because there is no secure cross-browser way to programmatically set the value of a file input,
 * the standard Field `setValue` method is not implemented. The `{@link #getValue}` method will return
 * a value that is browser-dependent; some have just the file name, some have a full path, some use
 * a fake path.
 *
 * **IMPORTANT:** File uploads are not performed using normal 'Ajax' techniques; see the description for
 * {@link Ext.form.Basic#hasUpload} for details.
 *
 * # Example Usage
 *
 *     @example
 *     Ext.create('Ext.form.Panel', {
 *         title: 'Upload a Photo',
 *         width: 400,
 *         bodyPadding: 10,
 *         frame: true,
 *         renderTo: Ext.getBody(),
 *         items: [{
 *             xtype: 'filefield',
 *             name: 'photo',
 *             fieldLabel: 'Photo',
 *             labelWidth: 50,
 *             msgTarget: 'side',
 *             allowBlank: false,
 *             anchor: '100%',
 *             buttonText: 'Select Photo...'
 *         }],
 *
 *         buttons: [{
 *             text: 'Upload',
 *             handler: function() {
 *                 var form = this.up('form').getForm();
 *                 if(form.isValid()){
 *                     form.submit({
 *                         url: 'photo-upload.php',
 *                         waitMsg: 'Uploading your photo...',
 *                         success: function(fp, o) {
 *                             Ext.Msg.alert('Success', 'Your photo "' + o.result.file + '" has been uploaded.');
 *                         }
 *                     });
 *                 }
 *             }
 *         }]
 *     });
 */
Ext.define('Ext.form.field.File', {
    extend: 'Ext.form.field.Trigger',
    alias: ['widget.filefield', 'widget.fileuploadfield'],
    alternateClassName: ['Ext.form.FileUploadField', 'Ext.ux.form.FileUploadField', 'Ext.form.File'],
    requires: [
        'Ext.form.field.FileButton'
    ],

    //<locale>
    /**
     * @cfg {String} buttonText
     * The button text to display on the upload button. Note that if you supply a value for
     * {@link #buttonConfig}, the buttonConfig.text value will be used instead if available.
     */
    buttonText: 'Browse...',
    //</locale>

    /**
     * @cfg {Boolean} buttonOnly
     * True to display the file upload field as a button with no visible text field. If true, all
     * inherited Text members will still be available.
     */
    buttonOnly: false,

    /**
     * @cfg {Number} buttonMargin
     * The number of pixels of space reserved between the button and the text field. Note that this only
     * applies if {@link #buttonOnly} = false.
     */
    buttonMargin: 3,
    
    /**
     * @cfg {Boolean} clearOnSubmit
     * True to clear the selected file value when the form this field belongs to
     * is submitted to the server.
     */
    clearOnSubmit: true,

    /**
     * @cfg {Object} buttonConfig
     * A standard {@link Ext.button.Button} config object.
     */

    /**
     * @event change
     * Fires when the underlying file input field's value has changed from the user selecting a new file from the system
     * file selection dialog.
     * @param {Ext.ux.form.FileUploadField} this
     * @param {String} value The file value returned by the underlying file input field
     */

    /**
     * @property {Ext.Element} fileInputEl
     * A reference to the invisible file input element created for this upload field. Only populated after this
     * component is rendered.
     */

    /**
     * @property {Ext.button.Button} button
     * A reference to the trigger Button component created for this upload field. Only populated after this component is
     * rendered.
     */

    /**
     * @cfg {String} [fieldBodyCls='x-form-file-wrap']
     * An extra CSS class to be applied to the body content element in addition to {@link #baseBodyCls}.
     */
    fieldBodyCls: Ext.baseCSSPrefix + 'form-file-wrap',

    /**
     * @cfg {Boolean} readOnly
     * Unlike with other form fields, the readOnly config defaults to true in File field.
     */
    readOnly: true,

    /**
     * Do not show hand pointer over text field since file choose dialog is only shown when clicking in the button
     * @private
     */
    triggerNoEditCls: '',

    // private
    componentLayout: 'triggerfield',

    // private. Extract the file element, button outer element, and button active element.
    childEls: ['browseButtonWrap'],

    // private
    onRender: function() {
        var me = this,
            id = me.id,
            inputEl;

        me.callParent(arguments);

        inputEl = me.inputEl;
        inputEl.dom.name = ''; //name goes on the fileInput, not the text input

                
        // render the button here. This isn't ideal, however it will be 
        // rendered before layouts are resumed, also we modify the DOM
        // below anyway
        me.button = new Ext.form.field.FileButton(Ext.apply({
            renderTo: id + '-browseButtonWrap',
            id: id + '-button',
            ui: me.ui,
            disabled: me.disabled,
            text: me.buttonText,
            style: me.buttonOnly ? '' : 'margin-left:' + me.buttonMargin + 'px',
            inputName: me.getName(),
            listeners: {
                scope: me,
                change: me.onFileChange
            }
        }, me.buttonConfig));
        me.fileInputEl = me.button.fileInputEl;
        
        if (me.buttonOnly) {
            me.inputCell.setDisplayed(false);
        }

        // Ensure the trigger cell is sized correctly upon render
        me.browseButtonWrap.dom.style.width = (me.browseButtonWrap.dom.lastChild.offsetWidth + me.button.getEl().getMargin('lr')) + 'px';
        if (Ext.isIE) {
            me.button.getEl().repaint();
        }
    },

    /**
     * Gets the markup to be inserted into the subTplMarkup.
     */
    getTriggerMarkup: function() {
        return '<td id="' + this.id + '-browseButtonWrap"></td>';
    },

    /**
     * @private Event handler fired when the user selects a file.
     */
    onFileChange: function(buttom, e, value) {
        this.lastValue = null; // force change event to get fired even if the user selects a file with the same name
        Ext.form.field.File.superclass.setValue.call(this, value);
    },

    /**
     * Overridden to do nothing
     * @method
     */
    setValue: Ext.emptyFn,

    reset : function(){
        var me = this,
            clear = me.clearOnSubmit;
        if (me.rendered) {
            me.button.reset(clear);
            me.fileInputEl = me.button.fileInputEl;
            if (clear) {
                me.inputEl.dom.value = '';
            }
        }
        me.callParent();
    },
    
    onShow: function(){
        this.callParent();
        // If we started out hidden, the button may have a messed up layout
        // since we don't act like a container
        this.button.updateLayout();    
    },

    onDisable: function(){
        this.callParent();
        this.button.disable();
    },

    onEnable: function(){
        this.callParent();
        this.button.enable();
    },

    isFileUpload: function() {
        return true;
    },

    extractFileInput: function() {
        var fileInput = this.button.fileInputEl.dom;
        this.reset();
        return fileInput;
    },
    
    restoreInput: function(el) {
        var button = this.button;
        button.restoreInput(el);
        this.fileInputEl = button.fileInputEl;
    },

    onDestroy: function(){
        Ext.destroyMembers(this, 'button');
        delete this.fileInputEl;
        this.callParent();
    }
});