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

/// <summary>
///ICSVWriterReader 的摘要说明
/// </summary>
public class ICSVWriterReader
{
    // C# 读写CSV文件到DataTable
    public interface ICSVWriterReaderDo
    {//define a interface  
        string CSVFile { get; set; } //csv file  
        DataTable Read();//read csv to DataTable.  
        DataTable ReadTitle();//read csv to DataTable. 
        bool Write(DataTable dt); //convert datatable to csv 
        string WritelineString(DataTable dt);//返回表对应csv的字符串
    }

    public class CSVHelper : ICSVWriterReader
    {
        private string _csvFile;

        public CSVHelper(string csvFile)
        {
            this._csvFile = csvFile;
        }

        #region ICSVWriterReader Members

        public string CSVFile
        {
            get { return _csvFile; }
            set { _csvFile = value; }
        }

       
        /// <summary>
        /// 读取CSV文件返回table，出错则返回对应错误 CSV格式分隔符,
        /// </summary>
        /// <param name="Result"></param>
        /// <param name="Table"></param>
        public void Read(out string Result , out DataTable Table)
        {
            Table = new DataTable();
            Result = "True";
            FileInfo fi = new FileInfo(this._csvFile);
            if (fi == null || !fi.Exists)
                Result = "文件不存在！" + this._csvFile;

            //StreamReader reader = new StreamReader(this._csvFile, Encoding.GetEncoding("GB2312"));
            StreamReader reader = new StreamReader(this._csvFile, Encoding.GetEncoding("UTF-8"));

            string line = string.Empty; int lineNumber = 0;
            
            try
            {


                while ((line = reader.ReadLine()) != null)
                {
                    if (lineNumber == 0)
                    {//Create Tole  
                        Table = CreateDataTable(line);
                        if (Table.Columns.Count == 0)
                            Result = "首行出错！";
                    }
                    else
                    {
                        bool isSuccess = CreateDataRow(ref Table, line);
                        if (!isSuccess)
                            Result = "第" + lineNumber + "出错！";
                    }
                    lineNumber++;
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
            reader.Close();
        }


        public void Read(out string Result, out DataTable Table, string tag)
        {
            Table = new DataTable();
            Result = "True";
            FileInfo fi = new FileInfo(this._csvFile);
            if (fi == null || !fi.Exists)
                Result = "文件不存在！" + this._csvFile;

            StreamReader reader = new StreamReader(this._csvFile, Encoding.GetEncoding("GB2312"));
            //StreamReader reader = new StreamReader(this._csvFile, Encoding.GetEncoding("UTF-8"));

            string line = string.Empty; int lineNumber = 0;

            try
            {


                while ((line = reader.ReadLine()) != null)
                {
                    if (lineNumber == 0)
                    {//Create Tole  
                        Table = CreateDataTable(line);
                        if (Table.Columns.Count == 0)
                            Result = "首行出错！";
                    }
                    else
                    {
                        bool isSuccess = CreateDataRow(ref Table, line);
                        if (!isSuccess)
                            Result = "第" + lineNumber + "出错！";
                    }
                    lineNumber++;
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
            reader.Close();
        }

        /// <summary>
        /// 读取CSV文件返回table，出错则返回对应错误 CSV格式分隔符；
        /// </summary>
        /// <param name="Result"></param>
        /// <param name="Table"></param>
        public void ReadTitle(out string Result, out DataTable Table)
        {
            Table = new DataTable();
            Result = "True";
            FileInfo fi = new FileInfo(this._csvFile);
            if (fi == null || !fi.Exists)
                Result = "文件不存在！" + this._csvFile;

            StreamReader reader = new StreamReader(this._csvFile, Encoding.GetEncoding("GB2312"));

            string line = string.Empty; int lineNumber = 0;

            try
            {


                while ((line = reader.ReadLine()) != null)
                {
                    if (lineNumber == 0)
                    {//Create Tole  
                        Table = CreateDataTableTitle(line);
                        if (Table.Columns.Count == 0)
                            Result = "首行出错！";
                    }
                    else
                    {
                        bool isSuccess = CreateDataRowTitle(ref Table, line);
                        if (!isSuccess)
                            Result = "第" + lineNumber + "出错！";
                    }
                    lineNumber++;
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
            reader.Close();
        }

        /// <summary>
        /// 传入表datatable返回对应csv格式的字符串
        /// </summary>
        /// <param name="dt">需要转换的表</param>
        /// <returns>生成的对应的csv格式的字符串</returns>
        public bool Write(DataTable dt)
        {
            FileInfo fi = new FileInfo(this._csvFile);
            if (fi == null) return false;

            if (dt == null || dt.Columns.Count == 0 || dt.Rows.Count == 0) return false;

            StreamWriter writer = new StreamWriter(this._csvFile, false, System.Text.Encoding.Default);
            
            string line = string.Empty;

            line = CreateTitle(dt);
            writer.WriteLine(line);

            foreach (DataRow dr in dt.Rows)
            {
                line = CretreLine(dr);
                writer.WriteLine(line);                
            }

            writer.Close();

            return true;
        }

        private DataTable CreateDataTable(string line)
        {
            DataTable dt = new DataTable();
            int i =0;
            foreach (string field in
                read_csv(line)[0])
            {
                i++;
                //如果标题为空则为第几列
                if (field == "")
                {
                    dt.Columns.Add("NO"+i.ToString());
                }
                else
                {
                    dt.Columns.Add(field);
                }
            }

            return dt;
        }

        private bool CreateDataRow(ref DataTable dt, string line)
        {
            DataRow dr = dt.NewRow();

            string[] fileds = read_csv(line)[0];

            if (fileds.Length == 0 || fileds.Length != dt.Columns.Count) return false;

            for (int i = 0; i < fileds.Length; i++)
            {
                dr[i] = fileds[i];
            }

            dt.Rows.Add(dr);
            return true;
        }

        /// <summary>
        /// 传入封号分割的CSV生成表头如：xxx;xxx
        /// </summary>
        /// <param name="line">字符串</param>
        /// <returns></returns>
        private DataTable CreateDataTableTitle(string line)
        {
            DataTable dt = new DataTable();
            int i = 0;
            foreach (string field in
                read_csvTitle(line)[0])
            {
                i++;
                //如果标题为空则为第几列
                if (field == "")
                {
                    dt.Columns.Add("NO" + i.ToString());
                }
                else
                {
                    dt.Columns.Add(field);
                }
            }

            return dt;
        }

        private bool CreateDataRowTitle(ref DataTable dt, string line)
        {
            DataRow dr = dt.NewRow();

            string[] fileds = read_csvTitle(line)[0];

            if (fileds.Length == 0 || fileds.Length != dt.Columns.Count) return false;

            for (int i = 0; i < fileds.Length; i++)
            {
                dr[i] = fileds[i];
            }

            dt.Rows.Add(dr);
            return true;
        }

        private string CreateTitle(DataTable dt)
        {
            string line = string.Empty;

            for (int i = 0; i < dt.Columns.Count; i++)
            { 
                if (dt.Columns[i].ColumnName.ToString().IndexOf(",") != -1)
                {
                    line = line + "\"" + dt.Columns[i].ColumnName + "\",";
                }
                else
                {
                    line = line + dt.Columns[i].ColumnName + ",";
                }
            }

            line = line.Substring(0, line.Length - 1);

            return line;
        }

        private string CretreLine(DataRow dr)
        {
            string line = "";

            for (int i = 0; i < dr.ItemArray.Length; i++)
            {
                if (dr[i].ToString().IndexOf(",") != -1)
                {
                    line = line + "\"" + dr[i] + "\",";
                }
                else
                {
                    line = line + dr[i] + ",";
                }
            }

            line = line.Substring(0, line.Length - 1);

            return line;
        }

        /// <summary>
        /// 读取CSV文件到数组中，如xxx;xxx;xxx
        /// </summary>
        /// <param name="text">传入需要读取的CSV文件</param>
        /// <returns></returns>
        public static string[][] read_csvTitle(string text)
        {
            if (text == null)
                return null;
            var text_array = new List<string[]>();
            var line = new List<string>();
            var field = new StringBuilder();
            //是否在双引号内
            bool in_quata = false;
            //字段是否开始
            bool field_start = true;
            for (int i = 0; i < text.Length; i++)
            {
                char ch = text[i];
                if (in_quata)
                {
                    //如果已经处于双引号范围内
                    if (ch == '\"')
                    {
                        //如果是两个引号，则当成一个普通的引号处理
                        if (i < text.Length - 1 && text[i + 1] == '\"')
                        {
                            field.Append('\"');
                            i++;
                        }
                        else
                            //否则退出引号范围
                            in_quata = false;
                    }
                    else //双引号范围内的任何字符（除了双引号）都当成普通字符
                    {
                        field.Append(ch);
                    }
                }
                else
                {
                    switch (ch)
                    {
                        case ';': //新的字段开始
                            line.Add(field.ToString());
                            field.Remove(0, field.Length);
                            field_start = true;
                            break;
                        case '\"'://引号的处理
                            if (field_start)
                                in_quata = true;
                            else
                                field.Append(ch);
                            break;
                        case '\r': //新的记录行开始
                            if (field.Length > 0 || field_start)
                            {
                                line.Add(field.ToString());
                                field.Remove(0, field.Length);
                            }
                            text_array.Add(line.ToArray());
                            line.Clear();
                            field_start = true;
                            //在 window 环境下，\r\n通常是成对出现，所以要跳过
                            if (i < text.Length - 1 && text[i + 1] == '\n')
                                i++;
                            break;
                        default:
                            field_start = false;
                            field.Append(ch);
                            break;
                    }
                }
            }
            //文件结束
            if (field.Length > 0 || field_start)
                line.Add(field.ToString());
            if (line.Count > 0)
                text_array.Add(line.ToArray());
            return text_array.ToArray();
        }

        /// <summary>
        /// 读取CSV文件到数组中，如xxx,xxx,xxx
        /// </summary>
        /// <param name="text">传入需要读取的CSV文件</param>
        /// <returns></returns>
        public static string[][] read_csv(string text)
        {
            if (text == null)
                return null;
            var text_array = new List<string[]>();
            var line = new List<string>();
            var field = new StringBuilder();
            //是否在双引号内
            bool in_quata = false;
            //字段是否开始
            bool field_start = true;
            for (int i = 0; i < text.Length; i++)
            {
                char ch = text[i];
                if (in_quata)
                {
                    //如果已经处于双引号范围内
                    if (ch == '\"')
                    {
                        //如果是两个引号，则当成一个普通的引号处理
                        if (i < text.Length - 1 && text[i + 1] == '\"')
                        {
                            field.Append('\"');
                            i++;
                        }
                        else
                            //否则退出引号范围
                            in_quata = false;
                    }
                    else //双引号范围内的任何字符（除了双引号）都当成普通字符
                    {
                        field.Append(ch);
                    }
                }
                else
                {
                    switch (ch)
                    {
                        case ',': //新的字段开始
                            line.Add(field.ToString());
                            field.Remove(0, field.Length);
                            field_start = true;
                            break;
                        case '\"'://引号的处理
                            if (field_start)
                                in_quata = true;
                            else
                                field.Append(ch);
                            break;
                        case '\r': //新的记录行开始
                            if (field.Length > 0 || field_start)
                            {
                                line.Add(field.ToString());
                                field.Remove(0, field.Length);
                            }
                            text_array.Add(line.ToArray());
                            line.Clear();
                            field_start = true;
                            //在 window 环境下，\r\n通常是成对出现，所以要跳过
                            if (i < text.Length - 1 && text[i + 1] == '\n')
                                i++;
                            break;
                        default:
                            field_start = false;
                            field.Append(ch);
                            break;
                    }
                }
            }
            //文件结束
            if (field.Length > 0 || field_start)
                line.Add(field.ToString());
            if (line.Count > 0)
                text_array.Add(line.ToArray());
            return text_array.ToArray();
        }

        #endregion
    }
}