/*
 *
 * Copyright (c) 2006-2011 Sam Collett (http://www.texotela.co.uk)
 * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)
 * and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses.
 * 
 * Version 1.3
 * Demo: http://www.texotela.co.uk/code/jquery/numeric/
 *
 */
(function($) {
/*
 * Allows only valid characters to be entered into input boxes.
 * Note: fixes value when pasting via Ctrl+V, but not when using the mouse to paste
  *      side-effect: Ctrl+A does not work, though you can still use the mouse to select (or double-click to select all)
 *
 * @name     numeric
 * @param    config      { decimal : "." , negative : true }
 * @param    callback     A function that runs if the number is not valid (fires onblur)
 * @author   Sam Collett (http://www.texotela.co.uk)
 * @example  $(".numeric").numeric();
 * @example  $(".numeric").numeric(","); // use , as separater
 * @example  $(".numeric").numeric({ decimal : "," }); // use , as separator
 * @example  $(".numeric").numeric({ negative : false }); // do not allow negative values
 * @example  $(".numeric").numeric(null, callback); // use default values, pass on the 'callback' function
 *
 */
$.fn.numeric = function(config, callback)
{
    if(typeof config === 'boolean')
    {
        config = { decimal: config };
    }
    config = config || {};
    // if config.negative undefined, set to true (default is to allow negative numbers)
    if(typeof config.negative == "undefined") config.negative = true;
    // set decimal point
    var decimal = (config.decimal === false) ? "" : config.decimal || ".";
    // allow negatives
    var negative = (config.negative === true) ? true : false;
    // callback function
    var callback = typeof callback == "function" ? callback : function(){};
    // set data and methods
    return this.data("numeric.decimal", decimal).data("numeric.negative", negative).data("numeric.callback", callback).keypress($.fn.numeric.keypress).keyup($.fn.numeric.keyup).blur($.fn.numeric.blur);
}

$.fn.numeric.keypress = function(e)
{
    // get decimal character and determine if negatives are allowed
    var decimal = $.data(this, "numeric.decimal");
    var negative = $.data(this, "numeric.negative");
    // get the key that was pressed
    var key = e.charCode ? e.charCode : e.keyCode ? e.keyCode : 0;
    // allow enter/return key (only when in an input box)
    if(key == 13 && this.nodeName.toLowerCase() == "input")
    {
        return true;
    }
    else if(key == 13)
    {
        return false;
    }
    var allow = false;
    // allow Ctrl+A
    if((e.ctrlKey && key == 97 /* firefox */) || (e.ctrlKey && key == 65) /* opera */) return true;
    // allow Ctrl+X (cut)
    if((e.ctrlKey && key == 120 /* firefox */) || (e.ctrlKey && key == 88) /* opera */) return true;
    // allow Ctrl+C (copy)
    if((e.ctrlKey && key == 99 /* firefox */) || (e.ctrlKey && key == 67) /* opera */) return true;
    // allow Ctrl+Z (undo)
    if((e.ctrlKey && key == 122 /* firefox */) || (e.ctrlKey && key == 90) /* opera */) return true;
    // allow or deny Ctrl+V (paste), Shift+Ins
    if((e.ctrlKey && key == 118 /* firefox */) || (e.ctrlKey && key == 86) /* opera */
    || (e.shiftKey && key == 45)) return true;
    // if a number was not pressed
    if(key < 48 || key > 57)
    {
        /* '-' only allowed at start and if negative numbers allowed */
        if(this.value.indexOf("-") != 0 && negative && key == 45 && (this.value.length == 0 || ($.fn.getSelectionStart(this)) == 0)) return true;
        /* only one decimal separator allowed */
        if(decimal && key == decimal.charCodeAt(0) && this.value.indexOf(decimal) != -1)
        {
            allow = false;
        }
        // check for other keys that have special purposes
        if(
            key != 8 /* backspace */ &&
            key != 9 /* tab */ &&
            key != 13 /* enter */ &&
            key != 35 /* end */ &&
            key != 36 /* home */ &&
            key != 37 /* left */ &&
            key != 39 /* right */ &&
            key != 46 /* del */
        )
        {
            allow = false;
        }
        else
        {
            // for detecting special keys (listed above)
            // IE does not support 'charCode' and ignores them in keypress anyway
            if(typeof e.charCode != "undefined")
            {
                // special keys have 'keyCode' and 'which' the same (e.g. backspace)
                if(e.keyCode == e.which && e.which != 0)
                {
                    allow = true;
                    // . and delete share the same code, don't allow . (will be set to true later if it is the decimal point)
                    if(e.which == 46) allow = false;
                }
                // or keyCode != 0 and 'charCode'/'which' = 0
                else if(e.keyCode != 0 && e.charCode == 0 && e.which == 0)
                {
                    allow = true;
                }
            }
        }
        // if key pressed is the decimal and it is not already in the field
        if(decimal && key == decimal.charCodeAt(0))
        {
            if(this.value.indexOf(decimal) == -1)
            {
                allow = true;
            }
            else
            {
                allow = false;
            }
        }
    }
    else
    {
        allow = true;
    }
    return allow;
}

$.fn.numeric.keyup = function(e)
{
    var val = this.value;
    if(val.length > 0)
    {
        // get carat (cursor) position
        var carat = $.fn.getSelectionStart(this);
        // get decimal character and determine if negatives are allowed
        var decimal = $.data(this, "numeric.decimal");
        var negative = $.data(this, "numeric.negative");
        
        // prepend a 0 if necessary
        if(decimal != "")
        {
            // find decimal point
            var dot = val.indexOf(decimal);
            // if dot at start, add 0 before
            if(dot == 0)
            {
                this.value = "0" + val;
            }
            // if dot at position 1, check if there is a - symbol before it
            if(dot == 1 && val.charAt(0) == "-")
            {
                this.value = "-0" + val.substring(1);
            }
            val = this.value;
        }
        
        // if pasted in, only allow the following characters
        var validChars = [0,1,2,3,4,5,6,7,8,9,'-',decimal];
        // get length of the value (to loop through)
        var length = val.length;
        // loop backwards (to prevent going out of bounds)
        for(var i = length - 1; i >= 0; i--)
        {
            var ch = val.charAt(i);
            // remove '-' if it is in the wrong place
            if(i != 0 && ch == "-")
            {
                val = val.substring(0, i) + val.substring(i + 1);
            }
            // remove character if it is at the start, a '-' and negatives aren't allowed
            else if(i == 0 && !negative && ch == "-")
            {
                val = val.substring(1);
            }
            var validChar = false;
            // loop through validChars
            for(var j = 0; j < validChars.length; j++)
            {
                // if it is valid, break out the loop
                if(ch == validChars[j])
                {
                    validChar = true;
                    break;
                }
            }
            // if not a valid character, or a space, remove
            if(!validChar || ch == " ")
            {
                val = val.substring(0, i) + val.substring(i + 1);
            }
        }
        // remove extra decimal characters
        var firstDecimal = val.indexOf(decimal);
        if(firstDecimal > 0)
        {
            for(var i = length - 1; i > firstDecimal; i--)
            {
                var ch = val.charAt(i);
                // remove decimal character
                if(ch == decimal)
                {
                    val = val.substring(0, i) + val.substring(i + 1);
                }
            }
        }
        // set the value and prevent the cursor moving to the end
        this.value = val;
        $.fn.setSelection(this, carat);
    }
}

$.fn.numeric.blur = function()
{
    var decimal = $.data(this, "numeric.decimal");
    var callback = $.data(this, "numeric.callback");
    var val = this.value;
    if(val != "")
    {
        var re = new RegExp("^\\d+$|\\d*" + decimal + "\\d+");
        if(!re.exec(val))
        {
            callback.apply(this);
        }
    }
}

$.fn.removeNumeric = function()
{
    return this.data("numeric.decimal", null).data("numeric.negative", null).data("numeric.callback", null).unbind("keypress", $.fn.numeric.keypress).unbind("blur", $.fn.numeric.blur);
}

// Based on code from http://javascript.nwbox.com/cursor_position/ (Diego Perini <dperini@nwbox.com>)
$.fn.getSelectionStart = function(o)
{
    if (o.createTextRange)
    {
        var r = document.selection.createRange().duplicate();
        r.moveEnd('character', o.value.length);
        if (r.text == '') return o.value.length;
        return o.value.lastIndexOf(r.text);
    } else return o.selectionStart;
}

// set the selection, o is the object (input), p is the position ([start, end] or just start)
$.fn.setSelection = function(o, p)
{
    // if p is number, start and end are the same
    if(typeof p == "number") p = [p, p];
    // only set if p is an array of length 2
    if(p && p.constructor == Array && p.length == 2)
    {
        if (o.createTextRange)
        {
            var r = o.createTextRange();
            r.collapse(true);
            r.moveStart('character', p[0]);
            r.moveEnd('character', p[1]);
            r.select();
        }
        else if(o.setSelectionRange)
        {
            o.focus();
            o.setSelectionRange(p[0], p[1]);
        }
    }
}

})(jQuery);