/*
Script: GrowingInput.js
	Alters the size of an input depending on its content

	License:
		MIT-style license.

	Authors:
		Guillermo Rauch
*/

(function() {

    GrowingInput = new Class({

        Implements: [Options, Events],

        options: {
            min: 0,
            max: null,
            startWidth: 2,
            correction: 15,
            maxwidth: null
        },

        initialize: function(element, options) {
            this.setOptions(options);
            this.element = $(element).store('growing', this).set('autocomplete', 'off');
            this.calc = new Element('span', {
                'styles': {
                    'float': 'left',
                    'display': 'inline-block',
                    'position': 'absolute',
                    'left': -1000,
                    'top': -1000
                }
            }).inject(this.element, 'after');
            ['font-size', 'font-family', 'padding-left', 'padding-top', 'padding-bottom',
		 'padding-right', 'border-left', 'border-right', 'border-top', 'border-bottom',
		 'word-spacing', 'letter-spacing', 'text-indent', 'text-transform'].each(function(p) {
		     this.calc.setStyle(p, this.element.getStyle(p));
		 }, this);
            this.resize();
            var resize = this.resize.bind(this);
            this.element.addEvents({ blur: resize, keyup: resize, keydown: resize, keypress: resize });
        },

        calculate: function(chars) {
            if (chars) chars = chars.replace(/ /g, " ");
            this.calc.set('html', chars);
            var width = this.calc.getStyle('width').toInt();
            return (width ? width : this.options.startWidth) + this.options.correction;
        },

        resize: function() {

            this.lastvalue = this.value;
            this.value = this.element.value;
            var value = this.value;
            if ($chk(this.options.min) && this.value.length < this.options.min) {
                if ($chk(this.lastvalue) && (this.lastvalue.length <= this.options.min)) return;
                value = str_pad(this.value, this.options.min, '-');
            } else if ($chk(this.options.max) && this.value.length > this.options.max) {
                if ($chk(this.lastvalue) && (this.lastvalue.length >= this.options.max)) return;
                value = this.value.substr(0, this.options.max);
            }
            var w = this.calculate(value);
            if ($chk(this.options.maxwidth) && this.options.maxwidth != 0 && w > this.options.maxwidth) w = this.options.maxwidth;
            this.element.setStyle('width', w);

            if (Browser.Engine.name == 'gecko' || Browser.Engine.name == 'unknown') this.element.value = this.element.value;
            return this;
        }

    });

    var str_repeat = function(str, times) { return new Array(times + 1).join(str); };
    var str_pad = function(self, length, str, dir) {
        if (self.length >= length) return this;
        str = str || ' ';
        var pad = str_repeat(str, length - self.length).substr(0, length - self.length);
        if (!dir || dir == 'right') return self + pad;
        if (dir == 'left') return pad + self;
        return pad.substr(0, (pad.length / 2).floor()) + self + pad.substr(0, (pad.length / 2).ceil());
    };

})();