using Microsoft.Win32;
using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Markup;

namespace DyeingComputer.UserClass
{
    internal class CSV
    {
        /// <summary>
        /// 将DataTable中数据写入到CSV文件中
        /// </summary>
        /// <param name="dt">提供保存数据的DataTable</param>
        /// <param name="strFormat">CSV的文件路径</param>
        public static void SaveCSV(DataTable dt,string strFormat)
        {
            FileInfo fi = new FileInfo(strFormat);
            if (!fi.Directory.Exists)
            {
                fi.Directory.Create();
            }
            FileStream fs = new FileStream(strFormat, System.IO.FileMode.Create, System.IO.FileAccess.Write);
            //StreamWriter sw = new StreamWriter(fs, System.Text.Encoding.Default);
            StreamWriter sw = new StreamWriter(fs, System.Text.Encoding.UTF8);
            string data = "";
            //写出列名称
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                data += dt.Columns[i].ColumnName.ToString();
                if (i < dt.Columns.Count - 1)
                {
                    data += ",";
                }
            }
            sw.WriteLine(data);
            //写出各行数据
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                data = "";
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    string str = dt.Rows[i][j].ToString();
                    str = str.Replace("\"", "\"\"");//替换英文冒号 英文冒号需要换成两个冒号
                    if (str.Contains(',') || str.Contains('"')
                        || str.Contains('\r') || str.Contains('\n')) //含逗号 冒号 换行符的需要放到引号中
                    {
                        str = string.Format("\"{0}\"", str);
                    }

                    data += str;
                    if (j < dt.Columns.Count - 1)
                    {
                        data += ",";
                    }
                }
                sw.WriteLine(data);
            }
            sw.Close(); fs.Close();
        }      

        #region CSV文件读取
        /// <summary>
        /// 将CSV文件的数据读取到DataTable中
        /// </summary>
        /// <param name="fileName">CSV文件路径</param>
        /// <returns>返回读取了CSV数据的DataTable</returns>
        public static DataTable OpenCSV(string filePath)//从csv读取数据返回table
        {
            System.Text.Encoding encoding = GetType(filePath); //Encoding.ASCII;//
            DataTable dt = new DataTable();
            System.IO.FileStream fs = new System.IO.FileStream(filePath, System.IO.FileMode.Open, System.IO.FileAccess.Read);
            System.IO.StreamReader sr = new System.IO.StreamReader(fs, encoding);

            //记录每次读取的一行记录
            string strLine = "";
            //记录每行记录中的各字段内容
            string[] aryLine = null;
            string[] tableHead = null;
            //标示列数
            int columnCount = 0;
            //标示是否是读取的第一行
            bool IsFirst = true;
            //逐行读取CSV中的数据
            int readCol = 0;
            while ((strLine = sr.ReadLine()) != null)
            {
                if (readCol > 0)
                {
                    if (IsFirst == true)
                    {
                        tableHead = strLine.Split(',');
                        IsFirst = false;
                        columnCount = tableHead.Length;
                        //创建列
                        for (int i = 0; i < columnCount; i++)
                        {
                            DataColumn dc = new DataColumn(tableHead[i]);
                            dt.Columns.Add(dc);
                        }
                    }
                    else
                    {
                        aryLine = strLine.Split(',');
                        DataRow dr = dt.NewRow();
                        for (int j = 0; j < columnCount; j++)
                        {
                            dr[j] = aryLine[j];
                        }
                        dt.Rows.Add(dr);
                    }
                }
                readCol++;
            }
            if (aryLine != null && aryLine.Length > 0)
            {
                dt.DefaultView.Sort = tableHead[0] + " " + "asc";
            }

            sr.Close();
            fs.Close();
            return dt;
        }
        /// 给定文件的路径，读取文件的二进制数据，判断文件的编码类型
        /// <param name="FILE_NAME">文件路径</param>
        /// <returns>文件的编码类型</returns>

        public static System.Text.Encoding GetType(string FILE_NAME)
        {
            System.IO.FileStream fs = new System.IO.FileStream(FILE_NAME, System.IO.FileMode.Open,
                System.IO.FileAccess.Read);
            System.Text.Encoding r = GetType(fs);
            fs.Close();
            return r;
        }

        /// 通过给定的文件流，判断文件的编码类型
        /// <param name="fs">文件流</param>
        /// <returns>文件的编码类型</returns>
        public static System.Text.Encoding GetType(System.IO.FileStream fs)
        {
            byte[] Unicode = new byte[] { 0xFF, 0xFE, 0x41 };
            byte[] UnicodeBIG = new byte[] { 0xFE, 0xFF, 0x00 };
            byte[] UTF8 = new byte[] { 0xEF, 0xBB, 0xBF }; //带BOM
            System.Text.Encoding reVal = System.Text.Encoding.Default;

            System.IO.BinaryReader r = new System.IO.BinaryReader(fs, System.Text.Encoding.Default);
            int i;
            int.TryParse(fs.Length.ToString(), out i);
            byte[] ss = r.ReadBytes(i);
            if (IsUTF8Bytes(ss) || (ss[0] == 0xEF && ss[1] == 0xBB && ss[2] == 0xBF))
            {
                reVal = System.Text.Encoding.UTF8;
            }
            else if (ss[0] == 0xFE && ss[1] == 0xFF && ss[2] == 0x00)
            {
                reVal = System.Text.Encoding.BigEndianUnicode;
            }
            else if (ss[0] == 0xFF && ss[1] == 0xFE && ss[2] == 0x41)
            {
                reVal = System.Text.Encoding.Unicode;
            }
            r.Close();
            return reVal;
        }

        /// 判断是否是不带 BOM 的 UTF8 格式
        /// <param name="data"></param>
        /// <returns></returns>
        private static bool IsUTF8Bytes(byte[] data)
        {
            int charByteCounter = 1;  //计算当前正分析的字符应还有的字节数
            byte curByte; //当前分析的字节.
            for (int i = 0; i < data.Length; i++)
            {
                curByte = data[i];
                if (charByteCounter == 1)
                {
                    if (curByte >= 0x80)
                    {
                        //判断当前
                        while (((curByte <<= 1) & 0x80) != 0)
                        {
                            charByteCounter++;
                        }
                        //标记位首位若为非0 则至少以2个1开始 如:110XXXXX...........1111110X　
                        if (charByteCounter == 1 || charByteCounter > 6)
                        {
                            return false;
                        }
                    }
                }
                else
                {
                    //若是UTF-8 此时第一位必须为1
                    if ((curByte & 0xC0) != 0x80)
                    {
                        return false;
                    }
                    charByteCounter--;
                }
            }
            if (charByteCounter > 1)
            {
                throw new Exception("非预期的byte格式");
            }
            return true;
        }
        #endregion
    
    }
}