using System.Collections.Generic;
using System.Globalization;
using System.Text;
using System.Text.RegularExpressions;

namespace TruckScale.Common
{
    /// <summary>
    /// 将数字转为大写
    /// <remarks>https://www.cnblogs.com/goldli/p/14105832.html</remarks>
    /// </summary>
    class ConvertToChineseMoney
    {
        private static Dictionary<char, string> _dic;
        private static Dictionary<int, string> _units;

        private void Init()
        {
            _dic = new Dictionary<char, string>
            {
                {‘0‘, "零"},
                {‘1‘, "壹"},
                {‘2‘, "贰"},
                {‘3‘, "叁"},
                {‘4‘, "肆"},
                {‘5‘, "伍"},
                {‘6‘, "陆"},
                {‘7‘, "柒"},
                {‘8‘, "捌"},
                {‘9‘, "玖"}
            };
            _units = new Dictionary<int, string> 
            {
                {1,""},
                {2,"拾"},
                {3,"佰"},
                {4,"仟"},
                {5,"万"},
                {6,"拾"},
                {7,"佰"},
                {8,"仟"},
                {9,"亿"},
                {10,"拾"},
                {11,"佰"},
                {12,"仟"},
                {13,"万"},
                {14,"亿"}
            };
        }

        private ConvertToChineseMoney()
        {
            Init();
        }

        public static ConvertToChineseMoney Ins { get; } = new ConvertToChineseMoney();

        /// <summary>
        /// 对整数部分进行操作
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        private string ConvertIntegers(string source)
        {
            /*
             示例：
                120 5002
                1002 5002
                100 5002
             */
            var totalLen = source.Length;   //总长度
            var g = totalLen / 4;   //中国数字以４个数字为一组。　这里取模。结果为　多出　的部分.
            var r = totalLen % 4;   //取模后，得到的余数

            var parts = new string[r > 0 ? g + 1 : g];
            if (r > 0)  //此时表示　不能整除
            {
                parts[0] = source.Substring(0, r);  //取出 

                for (var i = 0; i < g; i++)
                {
                    parts[i + 1] = source.Substring(i * 4 + r, 4);  //取出
                }
            }
            else
            {
                for (var i = 0; i < parts.Length ; i++)
                {
                    parts[i] = source.Substring(i * 4, 4);  //取出
                }
            }

            var result = new StringBuilder();

            for (var i = 0; i < parts.Length; i++)
            {
                var part = parts[i];
                var m0 = Regex.Match(part, "0{2,}");   //查找是否存在多个连续 0 的情况
                if (m0.Success) //存在连续的多个 0, 如: 1002
                {
                    var index = m0.Index;

                    /*
                     -----------------简化代码见下面-----------------
                    if (index == 0) // 00　开头
                    {
                        result.Append("零");
                        totalLen -= 2;
                        // 00后面的部分
                        for (var n = index + 2; n < 4; n++)
                        {
                            result.Append($"{_dic[part[n]]}{_units[totalLen]}");
                            totalLen--;
                        }
                    }
                    else
                    {
                        // 00前面的部分
                        for (var n = 0; n < index; n++)
                        {
                            result.Append($"{_dic[part[n]]}{_units[totalLen]}");
                            totalLen--;
                        }
                        result.Append("零");
                        totalLen-=2;
                        // 00后面的部分
                        for (var n = index + 2; n < 4; n++)
                        {
                            result.Append($"{_dic[part[n]]}{_units[totalLen]}");
                            totalLen--;
                        }
                    }
                    */

                    if (index > 0)
                    {
                        for (var n = 0; n < index; n++)
                        {
                            result.Append($"{_dic[part[n]]}{_units[totalLen]}");
                            totalLen--;
                        }
                    }

                    result.Append("零");
                    totalLen -= m0.Length;
                    
                    for (var n = index + m0.Length; n < 4; n++)
                    {
                        result.Append($"{_dic[part[n]]}{_units[totalLen]}");
                        totalLen--;
                    }
                }
                else
                {
                    var x = part.Length;
                    var y = part.TrimEnd(‘0‘).Length;//数字尾部的 0
                    if (y == 0)
                    {
                        result.Append("零");     //0.95 的 0
                        totalLen--;
                    }
                    else if (y != x)
                    {
                        for (var m = 0; m < y; m++)
                        {
                            result.Append($"{_dic[part[m]]}{(part[m] == ‘0‘ ? "" : _units[totalLen])}");    //part[m] == ‘0‘ 零后面不需要 进制单位
                            totalLen--;
                        }

                        result.Append($"{_units[4 * (parts.Length - i - 1) + 1]}");
                        totalLen--;
                    }
                    else
                    {
                        for (var m = 0; m < y; m++)
                        {
                            result.Append($"{_dic[part[m]]}{(part[m] == ‘0‘ ? "" : _units[totalLen])}"); 
                            totalLen--;
                        }
                    }
                }
            }

            return result.ToString();
        }

        public string Convert(double d)
        {
            var ret = new StringBuilder();

            var source = d.ToString(CultureInfo.CurrentCulture);
            var dotIndex = source.IndexOf(‘.‘);

            if (dotIndex > 0)//有小数
            {
                var integerPart = source.Substring(0, dotIndex);
                ret.Append(ConvertIntegers(integerPart))
                    .Append("点");
                
                var decimalPart = source.Substring(dotIndex + 1, source.Length - dotIndex -1);
                foreach (var c in decimalPart)
                {
                    ret.Append($"{_dic[c]}");
                }
            }
            else
            {
                ret.Append(ConvertIntegers(source));
            }

            return ret.ToString();
        }

    }
}

            var s1 = ConvertToChineseMoney.Ins.Convert(278449980.95);
            var s2 = ConvertToChineseMoney.Ins.Convert(0.95);
            var s3 = ConvertToChineseMoney.Ins.Convert(1205020);
            var s4 = ConvertToChineseMoney.Ins.Convert(1205002);
            var s5 = ConvertToChineseMoney.Ins.Convert(1200052);
            var s6 = ConvertToChineseMoney.Ins.Convert(10025002);
            var s76 = ConvertToChineseMoney.Ins.Convert(100001734);