using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Web;
using ThoughtWorks.QRCode.Codec;
using ThoughtWorks.QRCode.Codec.Data;

namespace VRS.Util
{
    /// <summary>
    /// 二维码工具
    /// </summary>
    public static class QRCodeHelper
    {
        /// <summary>
        /// 读取图片文件，识别二维码
        /// </summary>
        /// <param name="filePath">图片文件路劲</param>
        /// <returns>识别结果字符串</returns>
        public static string CodeDecoder(string filePath)
        {
            string decoderStr;
            bool isGreen = false;
            try
            {
                if (!System.IO.File.Exists(filePath))//判断有没有需要读取的主文件夹，如果不存在，终止  
                    return null;

                Bitmap bitMap = new Bitmap(Image.FromFile(filePath));//实例化位图对象，把文件实例化为带有颜色信息的位图对象  

                for (int i = bitMap.Height / 3, h = bitMap.Height; i < h; i++)
                {
                    for (int j = 0, w = bitMap.Width; j < w; j++)
                    {
                        var color = bitMap.GetPixel(j, i);
                        if (IsGreen(color))
                        {
                            isGreen = true;
                            break;
                        }
                    }
                    if (isGreen)
                        break;
                }

                QRCodeDecoder decoder = new QRCodeDecoder();//实例化QRCodeDecoder  

                //通过.decoder方法把颜色信息转换成字符串信息  
                decoderStr = decoder.decode(new QRCodeBitmapImage(bitMap), System.Text.Encoding.UTF8);
            }
            catch (Exception ex)
            {
                return ex.Message;
            }

            if (!isGreen)
                return "warning";
            else
                return decoderStr;//返回字符串信息  
        }

        public static bool IsGreen(Color color)
        {
            return (color.G > color.R * 5) && (color.G > color.B * 5);
        }
    }
}