using System.IO;
using System.Data;
using System;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.HSSF.Util;

namespace UAS_LabelMachine
{
    class ExcelHandler
    {
        DataHelper dh = new DataHelper();

        /// <summary>
        /// 导出Excel,返回文件在客户端的路径
        /// </summary>
        public string ExportExcel(DataTable dt, DataTable Captioon, string FolderPath, string FileName)
        {
            //创建一个内存流，用来接收转换成Excel的内容
            MemoryStream ms;
            ms = DataTableToExcel(dt, Captioon);
            //以系统当前时间命名文件，FileMode.Create表示创建文件，FileAccess.Write表示拥有写的权限
            string filePath = @FolderPath + "\\" + FileName + ".xls";
            FileStream fs = new FileStream(filePath, FileMode.Create, FileAccess.Write);
            byte[] data = ms.ToArray();
            fs.Write(data, 0, data.Length);
            fs.Flush();
            //释放当前Excel文件，否则打开文件的时候会显示文件被占用
            ms.Dispose();
            fs.Dispose();
            return filePath;
        }

        /// <summary>
        /// 导入Excel
        /// </summary>
        public void ImportExcel(DataTable DataTable, string TableName)
        {
            int columnNum = DataTable.Columns.Count;
            int rowNum = DataTable.Columns.Count;
            string[] field = new string[columnNum];
            for (int i = 0; i < columnNum; i++)
            {
                field[i] = DataTable.Rows[0][i].ToString();
            }
        }

        /// <summary>
        /// 将DataTable形式的数据转成Excel格式的，然后用字节流的形式写入文件
        /// </summary>
        /// <param name="DataTable"></param>
        /// <returns></returns>
        public MemoryStream DataTableToExcel(DataTable DataTable, DataTable Captioon)
        {
            //创建内存流
            MemoryStream ms = new MemoryStream();
            //创建一个Book，相当于一个Excel文件
            HSSFWorkbook book = new HSSFWorkbook();
            //Excel中的Sheet
            ISheet sheet = book.CreateSheet("sheet1");
            //获取行数量和列数量
            int rowNum = DataTable.Rows.Count;
            int columnNum = DataTable.Columns.Count;
            //设置列的宽度，根据首行的列的内容的长度来设置
            for (int i = 0; i < columnNum; i++)
            {
                int dataLength;
                //如果内容比标题短则取标题长度
                if (DataTable.Rows[0][i].ToString().Length < DataTable.Columns[i].ColumnName.Length)
                {
                    dataLength = DataTable.Columns[i].ColumnName.Length;
                    dataLength = dataLength * 600;
                }
                else
                {
                    dataLength = DataTable.Rows[0][i].ToString().Length;
                    dataLength = dataLength * 500;
                }
                if (dataLength > 50000)
                    dataLength = 50000;
                sheet.SetColumnWidth(i, dataLength);
            }
            ICellStyle style = book.CreateCellStyle();
            style.FillForegroundColor = HSSFColor.PALE_BLUE.index;
            style.FillPattern = FillPatternType.BIG_SPOTS;
            style.FillBackgroundColor = HSSFColor.LIGHT_GREEN.index;
            //设置边框
            style.BorderBottom = BorderStyle.THICK;
            style.BorderLeft = BorderStyle.THICK;
            style.BorderRight = BorderStyle.THICK;
            style.BorderTop = BorderStyle.THICK;
            //首先画好第一行带颜色的，单独写出来，避免写在循环里面
            int rowindex = 0;
            if (Captioon.Rows[0]["es_engenable"].ToString() == "-1")
            {
                IRow row0 = sheet.CreateRow(rowindex);
                for (int i = 0; i < Captioon.Rows.Count; i++)
                {
                    row0.CreateCell(i).SetCellValue(Captioon.Rows[i]["esd_engcaption"].ToString());
                    row0.Cells[i].CellStyle = style;
                    row0.Cells[i].CellStyle.VerticalAlignment = VerticalAlignment.CENTER;
                    row0.Cells[i].CellStyle.Alignment = HorizontalAlignment.CENTER;
                }
                rowindex = rowindex + 1;
            }
            if (Captioon.Rows[0]["es_chineseenable"].ToString() == "-1")
            {
                IRow row1 = sheet.CreateRow(rowindex);
                for (int i = 0; i < Captioon.Rows.Count; i++)
                {
                    row1.CreateCell(i).SetCellValue(Captioon.Rows[i]["esd_caption"].ToString());

                    row1.Cells[i].CellStyle = style;
                    row1.Cells[i].CellStyle.VerticalAlignment = VerticalAlignment.CENTER;
                    row1.Cells[i].CellStyle.Alignment = HorizontalAlignment.CENTER;
                }
                rowindex = rowindex + 1;
            }
            //冻结第一行
            sheet.CreateFreezePane(0, rowindex, 0, rowindex);

            IRow row = sheet.CreateRow(rowindex);

            row.HeightInPoints = 20;

            //将DataTable的值循环赋值给book，Aligment设置居中
            //之前已经画了带颜色的第一行，所以从i=1开始画
            for (int i = 0; i < rowNum; i++)
            {
                row = sheet.CreateRow(i + rowindex);
                row.HeightInPoints = 20;
                for (int j = 0; j < columnNum; j++)
                {
                    row.CreateCell(j);
                    row.Cells[j].SetCellValue(DataTable.Rows[i][j].ToString());
                    row.GetCell(j).CellStyle.VerticalAlignment = VerticalAlignment.CENTER;
                }
            }
            for (int i = 0; i < DataTable.Columns.Count; i++)
            {
                sheet.AutoSizeColumn(i);
            }
            //将book的内容写入内存流中返回
            book.Write(ms);
            return ms;
        }
    }
}