/*
 * @Author: liyi
 * @LastEditors: liyi
 * @Date: 2021-03-31 14:57:30
 * @LastEditTime: 2021-03-31 15:02:58
 * @Description: 随机验证码
 * @FilePath: /undefined/Users/yili/Desktop/gVerify.js
 */
!(function (window, document) {
    function GVerify(options, canvasId) { //创建一个图形验证码对象，接收options对象为参数
        this.options = { //默认options参数值
            id: "", //容器Id
            canvasId, //canvas的ID
            width: "100", //默认canvas宽度
            height: "30", //默认canvas高度
            type: "blend", //图形验证码默认类型blend:数字字母混合类型、number:纯数字、letter:纯字母
            code: ""
        }

        if (Object.prototype.toString.call(options) == "[object Object]") {//判断传入参数类型
            for (var i in options) { //根据传入的参数，修改默认参数值
                this.options[i] = options[i];
            }
        } else {//传入单个对象就是id
            this.options.id = options;
        }

        this.options.numArr = "0,1,2,3,4,5,6,7,8,9".split(",");//数字
        this.options.letterArr = getAllLetter();//生成字母数组
        this._init();//初始化
        this.refresh();//生成验证码
    }

    GVerify.prototype = {
        /**版本号**/
        version: '1.0.0',

        /**初始化方法**/
        _init: function () {
            var con = document.getElementById(this.options.id);//获得验证码的DIV
            var canvas = document.getElementById(this.options.canvasId);//获得画布   IE不能支持canvas，可以增加excanvas.js插件，但是还是不支持createelement()的形式
            this.options.width = con.offsetWidth > 0 ? con.offsetWidth : "100";//如果有宽度就使用自己的，没有就默认100
            this.options.height = con.offsetHeight > 0 ? con.offsetHeight : "30";//如果有长度就使用自己的，没有就默认30
            canvas.id = this.options.canvasId;
            canvas.width = this.options.width;
            canvas.height = this.options.height;
            canvas.style.cursor = "pointer";
            canvas.innerHTML = "您的浏览器版本不支持canvas";
            con.appendChild(canvas);
            //    canvas.id = this.options.canvasId;//为兼容IE把这些去掉，还需要在HTML中写入canvas标签 <canvas id="verifyCanvas" width="100" height="40" style="cursor: pointer;"></canvas>
            //    canvas.width = this.options.width;
            //    canvas.height = this.options.height;
            //    canvas.style.cursor = "pointer";
            //    canvas.innerHTML = "您的浏览器版本不支持canvas";
            //    con.appendChild(canvas);
            var parent = this;//把this赋值parent
            canvas.onclick = function () {//验证码点击切换刷新
                parent.refresh();
            }
        },

        /**生成验证码**/
        refresh: function () {
            this.options.code = "";//定义验证码为""
            var canvas = document.getElementById(this.options.canvasId);//获得验证码画布
            if (canvas.getContext) {//
                var ctx = canvas.getContext('2d');//获得绘画对象
            } else {//
                return;
            }
            ctx.textBaseline = "middle";
            ctx.fillStyle = randomColor(180, 240);
            ctx.fillRect(0, 0, this.options.width, this.options.height);//绘制矩形  
            /* x:矩形起点横坐标（坐标原点为canvas的左上角，当然确切的来说是原始原点，后面写到变形的时候你就懂了，现在暂时不用关系）
             y:矩形起点纵坐标
             width:矩形长度
             height:矩形高度*/
            if (this.options.type == "blend") { //判断验证码类型 blend:数字字母混合类型、number:纯数字、letter:纯字母
                var txtArr = this.options.numArr.concat(this.options.letterArr);
            } else if (this.options.type == "number") {
                var txtArr = this.options.numArr;
            } else {
                var txtArr = this.options.letterArr;
            }
            for (var i = 1; i <= 4; i++) {
                var txt = txtArr[randomNum(0, txtArr.length)];//取得一个字符
                if(!txt) txt = 'a';
                this.options.code += txt;//连接验证码
                ctx.font = randomNum(this.options.height / 2, this.options.height) + 'px SimHei'; //随机生成字体大小
                ctx.fillStyle = randomColor(50, 160); //填充的样式 随机生成字体颜色        
                ctx.shadowOffsetX = randomNum(-3, 3);//阴影的横向位移量
                ctx.shadowOffsetY = randomNum(-3, 3);//阴影的纵向位移量
                ctx.shadowBlur = randomNum(-3, 3);//阴影的模糊范围（值越大越模糊）
                ctx.shadowColor = "rgba(0, 0, 0, 0.3)";//阴影的颜色
                var x = this.options.width / 5 * i;
                var y = this.options.height / 2;
                var deg = randomNum(-30, 30);
                /**设置旋转角度和坐标原点
                 * 
                 *  平移context.translate(x,y)
                 *    x:坐标原点向x轴方向平移x
                 *    y:坐标原点向y轴方向平移y
                 * 
                 * **/
                ctx.translate(x, y);
                ctx.rotate(deg * Math.PI / 180);//旋转context.rotate(angle)
                ctx.fillText(txt, 0, 0);//context.fillText(text,x,y)  
                /**恢复旋转角度和坐标原点**/
                ctx.rotate(-deg * Math.PI / 180);
                ctx.translate(-x, -y);
            }
            /**绘制干扰线**/
            for (var i = 0; i < 4; i++) {
                ctx.strokeStyle = randomColor(40, 180);//随机颜色
                ctx.beginPath();//路径  context.beginPath()
                ctx.moveTo(randomNum(0, this.options.width), randomNum(0, this.options.height));//绘制线段 context.moveTo(x,y)  context.lineTo(x,y)
                ctx.lineTo(randomNum(0, this.options.width), randomNum(0, this.options.height));
                ctx.stroke();
            }
            /**绘制干扰点**/
            for (var i = 0; i < this.options.width / 4; i++) {
                ctx.fillStyle = randomColor(0, 255);
                ctx.beginPath();
                ctx.arc(randomNum(0, this.options.width), randomNum(0, this.options.height), 1, 0, 2 * Math.PI);// 圆弧context.arc(x, y, radius, starAngle,endAngle, anticlockwise)
                ctx.fill();
            }
        },

        /**验证验证码**/
        validate: function (code) {
            var code = code.toLowerCase();
            var v_code = this.options.code.toLowerCase();
            //console.log(v_code);
            if (code == v_code) {
                return true;
            } else {
                this.refresh();
                return false;
            }
        }
    }
    /**生成字母数组**/
    function getAllLetter() {
        var letterStr = "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
        return letterStr.split(",");
    }
    /**生成一个随机数**/
    function randomNum(min, max) {
        //return Math.floor(Math.random() * (max - min) + min);
        if(max >= 256) max = 255;
        var byteArray = new Uint8Array(1);
        window.crypto.getRandomValues(byteArray);

        var range = max - min + 1;
        var max_range = 256;
        if (byteArray[0] >= Math.floor(max_range / range) * range)
            return randomNum(min, max);
        var retNum =     min + (byteArray[0] % range);
        if(retNum > max) {
            retNum = max - 1;
        }
        return retNum;
    }
    /**生成一个随机色**/
    function randomColor(min, max) {
        var r = randomNum(min, max);
        var g = randomNum(min, max);
        var b = randomNum(min, max);
        return "rgb(" + r + "," + g + "," + b + ")";
    }
    window.GVerify = GVerify;//设置为window对象
})(window, document);