(function (window, document, $, undefined) {

    var possibleCharacters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
    
    var defaults = {
        selector: "#captcha",
        text: null,
        randomText: true,
        randomColours: true,
        width: 300,
        height: 200,
        colour1: null,
        colour2: null,
        font: 'bold 48px "Comic Sans MS", cursive, sans-serif',
    	onError: function() { 
    		alert('Captcha inválido.'); 
    	} 
    };

    var CAPTCHA = function (config) {

        var that = this;

        this._settings = $.extend({}, defaults, config || {});

        this._container = $(this._settings.selector);

        var canvasWrapper = $('<div>').appendTo(this._container);

//        this._canvas = $('<canvas>').appendTo(canvasWrapper).width(this._settings.width).height(this._settings.height);
        this._canvas = $('<canvas>').appendTo(canvasWrapper).width(220).height(75);

        var controlWrapper = $('<div>').appendTo(this._container);

        this._input = $('<input>').addClass('form-control')
        				.attr('id','txtCaptcha').attr('placeholder','Código de Seguridad').attr('type','text').attr('autocomplete','off')
                        .on('keypress', function (e) {
                            if (e.which == 13) {
                                that.validate(that._input.val());
                            }
                        })
                        .appendTo(controlWrapper);

//        this._button = $('<button>').text('submit')
//        				.addClass('validate')
//				        .on('submit', function () { that.validate(that._input.val()); })
//				        .appendTo(controlWrapper);
        
        if (this._canvas != null && this._canvas.get(0) != null){
        	this._context = this._canvas.get(0).getContext("2d");
        }

    };

  
    
    CAPTCHA.prototype = {

        generate: function () {

            var context = this._context;

            //if there's no text, set the flag to randomly generate some
            if (this._settings.text == null || this._settings.text == '') {
                this._settings.randomText = true;
            }

            if (this._settings.randomText) {
                this._generateRandomText();
            }

            if (this._settings.randomColours) {
//                this._settings.colour1 = this._generateRandomColour();
//                this._settings.colour2 = this._generateRandomColour();
                this._settings.colour1 = "rgb(112,184,255)";
                this._settings.colour2 = "rgb(0,107,215)";
            }

            var gradient1 = context.createLinearGradient(0, 0, this._settings.width, 0);
            gradient1.addColorStop(0, this._settings.colour1);
            gradient1.addColorStop(1, this._settings.colour2);

            context.fillStyle = gradient1;
            context.fillRect(0, 0, this._settings.width, this._settings.height);

            var gradient2 = context.createLinearGradient(0, 0, this._settings.width, 0);
//            gradient2.addColorStop(0, this._settings.colour2);
//            gradient2.addColorStop(1, this._settings.colour1);
            gradient2.addColorStop(0, "rgb(255,255,255)");
            gradient2.addColorStop(1, "rgb(255,255,255)");

            context.font = this._settings.font;
            context.fillStyle = gradient2;

            context.setTransform((Math.random() / 10) + 0.9,    //scalex
                                0.1 - (Math.random() / 5),      //skewx
                                0.1 - (Math.random() / 5),      //skewy
                                (Math.random() / 10) + 0.9,     //scaley
                                (Math.random() * 20) + 10,      //transx
                                100);                           //transy

            context.fillText(this._settings.text, 0, 0);

            context.setTransform(1, 0, 0, 1, 0, 0);

            var numRandomCurves = Math.floor((Math.random() * 6) + 5);

            for (var i = 0; i < 3; i++) {
                this._drawRandomCurve();
            }
        },

        validate: function (userText) {
        	if ( typeof(userText) !== "undefined" && userText !== null ) {
        		var str1 = '',str2 = '', i = 0, j = 0, tmp1_len = userText.length, tmp2_len = this._settings.text.length, c;
                
            	for (; i < tmp1_len; i += 1) {
    	              c = userText.charCodeAt(i);
    	              str1 += c.toString(16);
    	        }
            	
            	for (; j < tmp2_len; j += 1) {
    	              c = this._settings.text.charCodeAt(j);
    	              str2 += c.toString(16);
    	        }
            	
                if ((userText === this._settings.text) || (str1 === str2)) {
                    this._settings.onSuccess();
                    return true;
                } else {
//                        this.generate();
                	this._settings.onError();
                	return false;
                }
        	}
        	else {
        		alert("Capcha is undefined");
        		this._settings.onError();
            	return false;
        	}
        },

        _drawRandomCurve: function () {

            var ctx = this._context;

            var gradient1 = ctx.createLinearGradient(0, 0, this._settings.width, 0);
            gradient1.addColorStop(0, Math.random() < 0.5 ? this._settings.colour1 : this._settings.colour2);
            gradient1.addColorStop(1, Math.random() < 0.5 ? this._settings.colour1 : this._settings.colour2);

            ctx.lineWidth = Math.floor((Math.random() * 4) + 2);
            ctx.strokeStyle = gradient1;
            ctx.beginPath();
            ctx.moveTo(Math.floor((Math.random() * this._settings.width)), Math.floor((Math.random() * this._settings.height)));
            ctx.bezierCurveTo(Math.floor((Math.random() * this._settings.width)), Math.floor((Math.random() * this._settings.height)),
                Math.floor((Math.random() * this._settings.width)), Math.floor((Math.random() * this._settings.height)),
                Math.floor((Math.random() * this._settings.width)), Math.floor((Math.random() * this._settings.height)));
            ctx.stroke();
        },

        _generateRandomText: function () {
            this._settings.text = '';
            var length = Math.floor((Math.random() * 3) + 6);
            for (var i = 0; i < length; i++) {
                this._settings.text += possibleCharacters.charAt(Math.floor(Math.random() * possibleCharacters.length));
            }
        },

        _generateRandomColour: function () {
//        	var rgb ="rgb(" + Math.floor((Math.random() * 255)) + ", " + Math.floor((Math.random() * 255)) + ", " + Math.floor((Math.random() * 255)) + ")";
//            alert(rgb);
//        	return rgb;
//            COLOR LIGHTBLUE
        	return "rgb(141,178,215)";
        }
    };

    window.CAPTCHA = CAPTCHA || {};

}(window, document, jQuery));