namespace IdeaCore.Services.Common

{

    public class ValidateCodeService : IValidateCodeService

    {

        private const string ValidateCodeKey = "ValidateCode";

        private const double Pi2 = 6.283185307179586476925286766559;

        private const string BackColor = "#dde3ec";

        /// <summary>

        /// 获取验证码的sessionkey

        /// </summary>

        /// <returns></returns>

        public string GetValidateCodeKey() {

            return ValidateCodeKey;

        }

        /// <summary>

        /// 生成验证码

        /// </summary>

        /// <param name="length"></param>

        /// <returns></returns>

        public string CreateValidateCode(int length)

        {

            string code = string.Empty;

            while (true)

            {

                var s = (Guid.NewGuid() + "").Substring(, );

                if (s == "" || s == "l" || s == "o" || s == "")

                {

                }

                else

                {

                    code += s;

                }

                if (code.Length >= length)

                {

                    break;

                }

            }

            return code;

        }

        /// <summary>

        /// 创建验证码的图片

        /// </summary>

        /// <param name="validateCode">验证码</param>

        public byte[] CreateValidateGraphic(string validateCode)

        {

            const int fSize = ;

            const int fWidth = fSize + ;

            int imageWidth = validateCode.Length * fWidth +  +  * ;

            const int imageHeight = fSize *  + ;

            Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };

            string[] fonts = { "Arial", "Georgia" };

            var image = new Bitmap(imageWidth, imageHeight);

            Graphics g = Graphics.FromImage(image);

            try

            {

                g.Clear(ColorTranslator.FromHtml(BackColor));

                var rand = new Random();

                ////给背景添加随机生成的燥点

                //Pen pen = new Pen(Color.RoyalBlue, 0);

                //    int c = 6 * 20; //杂点数量

                //    for (int i = 0; i < c; i++)

                //    {

                //        int x = rand.Next(image.Width);

                //        int y = rand.Next(image.Height);

                //        g.DrawRectangle(pen, x, y, 1, 1);

                //    }

                const int n1 = (imageHeight -  -  * );

                const int n2 = n1 / ;

                const int top1 = n2;

                const int top2 = n2 * ;

                //随机字体和颜色的验证码字符

                for (int i = ; i < validateCode.Length; i++)

                {

                    int cindex = rand.Next(colors.Length - );

                    int findex = rand.Next(fonts.Length - );

                    var f = new Font(fonts[findex], fSize, FontStyle.Bold);

                    Brush b = new SolidBrush(colors[cindex]);

                    var top = i %  ==  ? top2 : top1;

                    var left = i * fWidth;

                    if (i == ) { left += ; }

                    g.DrawString(validateCode.Substring(i, ), f, b, left, top);

                }

                //

                image = TwistImage(image, true, new Random().Next(, ), new Random().Next(, ));

                var stream = new MemoryStream();

                image.Save(stream, ImageFormat.Jpeg);

                //输出图片流

                return stream.ToArray();

            }

            finally

            {

                g.Dispose();

                image.Dispose();

            }

        }

        #region 产生波形滤镜效果

        /// <summary>

        /// 正弦曲线Wave扭曲图片（Edit By 51aspx.com）

        /// </summary>

        /// <param name="srcBmp">图片路径</param>

        /// <param name="bXDir">如果扭曲则选择为True</param>

        /// <param name="dMultValue"></param>

        /// <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param>

        /// <returns></returns>

        private static Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)

        {

            var destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);

            // 将位图背景填充为白色

            var graph = Graphics.FromImage(destBmp);

            graph.FillRectangle(new SolidBrush(ColorTranslator.FromHtml(BackColor)), , , destBmp.Width, destBmp.Height);

            graph.Dispose();

            double dBaseAxisLen = bXDir ? destBmp.Height : destBmp.Width;

            for (int i = ; i < destBmp.Width; i++)

            {

                for (int j = ; j < destBmp.Height; j++)

                {

                    var dx = bXDir ? (Pi2 * j) / dBaseAxisLen : (Pi2 * i) / dBaseAxisLen;

                    dx += dPhase;

                    var dy = Math.Cos(dx);

                    // 取得当前点的颜色

                    int nOldX = bXDir ? i + (int)(dy * dMultValue) : i;

                    int nOldY = bXDir ? j : j + (int)(dy * dMultValue);

                    var color = srcBmp.GetPixel(i, j);

                    if (nOldX >=  && nOldX < destBmp.Width

                     && nOldY >=  && nOldY < destBmp.Height)

                    {

                        destBmp.SetPixel(nOldX, nOldY, color);

                    }

                }

            }

            return destBmp;

        }

        #endregion

    }

}

/// <summary>

/// 获取验证码

/// </summary>

/// <returns></returns>

public FileContentResult GetValidateCode()

{

    var code = _validateCodeService.CreateValidateCode();

    var bytes = _validateCodeService.CreateValidateGraphic(code);

    HttpContext.Session.SetString(_validateCodeService.GetValidateCodeKey(), code);

    return File(bytes, @"image/jpeg");

}

/// <summary>

/// 验证验证码

/// </summary>

/// <param name="code"></param>

/// <returns></returns>

protected bool ValidateCode(string code) {

    if (string.IsNullOrEmpty(code)) {

        return false;

    }

    var sessionCode = HttpContext.Session.GetString("ValidateCode");

    return sessionCode != null && sessionCode == code.Trim();

}