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

namespace AutoTurnOver.Common
{
    /// <summary>
    /// csv操作类
    /// </summary>
    public class CsvFileHelper
    {
        /// <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="fileName">CSV的文件路径</param>
        /// <param name="isShowColumnName">是否写出列名</param>
        public static void SaveCSV(DataTable dt, string fullPath, bool isShowColumnName = true)
        {
            FileInfo fi = new FileInfo(fullPath);
            if (!fi.Directory.Exists)
            {
                fi.Directory.Create();
            }
            FileStream fs = isShowColumnName ? new FileStream(fullPath, System.IO.FileMode.Create, System.IO.FileAccess.Write) : new FileStream(fullPath, System.IO.FileMode.Append, 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
            if (isShowColumnName)
            {
                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();
                    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();
        }

        /// <summary>
        /// 将DataTable转成csv字符串
        /// </summary>
        /// <param name="table"></param>
        /// <returns></returns>
        public static string ToCSV(DataTable table)
        {
            var result = new StringBuilder();
            for (int i = 0; i < table.Columns.Count; i++)
            {
                result.Append(table.Columns[i].ColumnName.ToString());
                result.Append(i == table.Columns.Count - 1 ? "\n" : ",");
            }
            foreach (DataRow row in table.Rows)
            {
                for (int i = 0; i < table.Columns.Count; i++)
                {
                    string str = row[i].ToString();
                    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);
                    }
                    result.Append(str);
                    result.Append(i == table.Columns.Count - 1 ? "\n" : ",");
                }
            }
            return result.ToString();
        }
    }
}
