using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.IO;

namespace solarApp.Service
{
    //static class myHelper
    //{
      
    //}
    public static class csvHelper
    {

        public static void SaveCSV(DataTable dt, string fullPath)//table資料寫入csv
        {
            System.IO.FileInfo fi = new System.IO.FileInfo(fullPath);
            if (!fi.Directory.Exists)
            {
                fi.Directory.Create();
            }
            System.IO.FileStream fs = new System.IO.FileStream(fullPath, System.IO.FileMode.Create, System.IO.FileAccess.Write);
            System.IO.StreamWriter sw = new System.IO.StreamWriter(fs, System.Text.Encoding.UTF8);
            string data = "";

            for (int i = 0; i < dt.Columns.Count; i++)//寫入列名
            {
                data += dt.Columns[i].ColumnName.ToString();
                if (i < dt.Columns.Count - 1)
                {
                    data += ",";
                }
            }
            sw.WriteLine(data);

            for (int i = 0; i < dt.Rows.Count; i++) //寫入各行資料
            {
                data = "";
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    string str = dt.Rows[i][j].ToString();
                    str = str.Replace("\"", "\"\"");//替換英文冒號 英文冒號需要換成兩個冒號
                    if (str.Contains(',') || str.Contains('"')
                      || str.Contains('\r') || str.Contains('\n')) //含逗號 冒號 換行符的需要放到引號中
                    {
                        str = string.Format("\"{0}\"", str);
                    }

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

        public static DataTable OpenCSV(string filePath)//從csv讀取資料返回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);

            //記錄每次讀取的一行記錄
            string strLine = "";
            //記錄每行記錄中的各欄位內容
            string[] aryLine = null;
            string[] tableHead = null;
            //標示列數
            int columnCount = 0;
            //標示是否是讀取的第一行
            bool IsFirst = true;
            //逐行讀取CSV中的資料
            while ((strLine = sr.ReadLine()) != null)
            {
                if (IsFirst == true)
                {
                    tableHead = strLine.Split(',');
                    IsFirst = false;
                    columnCount = tableHead.Length;
                    //建立列
                    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);
                }
            }
            if (aryLine != null && aryLine.Length > 0)
            {
                dt.DefaultView.Sort = tableHead[0] + " " + "asc";
            }

            sr.Close();
            fs.Close();
            return dt;
        }
        /// 給定檔案的路徑，讀取檔案的二進位制資料，判斷檔案的編碼型別
        /// <param name="FILE_NAME">檔案路徑</param>
        /// <returns>檔案的編碼型別</returns>
        public static System.Text.Encoding GetType(string FILE_NAME)
        {
            //System.IO.FileStream fs = new System.IO.FileStream(FILE_NAME, System.IO.FileAccess.Read);
            using (FileStream fs = File.Create(FILE_NAME))
            {
                System.Text.Encoding r = GetType(fs);
                fs.Close();
                return r;
            }             
        }

        /// 通過給定的檔案流，判斷檔案的編碼型別
        /// <param name="fs">檔案流</param>
        /// <returns>檔案的編碼型別</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 }; //帶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;
        }

        /// 判斷是否是不帶 BOM 的 UTF8 格式
        /// <param name="data"></param>
        /// <returns></returns>
        private static bool IsUTF8Bytes(byte[] data)
        {
            int charByteCounter = 1;  //計算當前正分析的字元應還有的位元組數
            byte curByte; //當前分析的位元組.
            for (int i = 0; i < data.Length; i++)
            {
                curByte = data[i];
                if (charByteCounter == 1)
                {
                    if (curByte >= 0x80)
                    {
                        //判斷當前
                        while (((curByte <<= 1) & 0x80) != 0)
                        {
                            charByteCounter++;
                        }
                        //標記位首位若為非0 則至少以2個1開始 如:110XXXXX...........1111110X　
                        if (charByteCounter == 1 || charByteCounter > 6)
                        {
                            return false;
                        }
                    }
                }
                else
                {
                    //若是UTF-8 此時第一位必須為1
                    if ((curByte & 0xC0) != 0x80)
                    {
                        return false;
                    }
                    charByteCounter--;
                }
            }
            if (charByteCounter > 1)
            {
                throw new Exception("非預期的byte格式");
            }
            return true;
        }
    }

}