using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.SS.Util;
using NPOI.XSSF.UserModel;
using SAGA.DotNetUtils.NPOI;
using SAGA.DotNetUtils.Extend;

namespace SAGA.DotNetUtils.NPOI
{
    /// <summary>
    /// NPOI操作帮助类
    /// </summary>
    public class NPOIHelper
    {
        /// <summary>  
        /// DataTable导出到Excel文件  
        /// </summary>  
        /// <param name="dtSource">源DataTable</param>  
        /// <param name="strHeaderText">表头文本</param>  
        /// <param name="strFileName">保存位置</param>  
        public static void Export(DataTable dtSource, string strHeaderText, string strFileName)
        {
            using (MemoryStream ms = Export(dtSource, strHeaderText))
            {
                using (FileStream fs = new FileStream(strFileName, FileMode.Create, FileAccess.Write))
                {
                    byte[] data = ms.ToArray();
                    fs.Write(data, 0, data.Length);
                    fs.Flush();
                }
            }
        }

        /// <summary>  
        /// DataTable导出到Excel的MemoryStream  
        /// </summary>  
        /// <param name="dtSource">源DataTable</param>  
        /// <param name="strHeaderText">表头文本</param>  
        public static MemoryStream Export(DataTable dtSource, string strHeaderText)
        {
            XSSFWorkbook workbook = new XSSFWorkbook();
            ISheet sheet = workbook.CreateSheet();

            ICellStyle dateStyle = workbook.CreateCellStyle();
            IDataFormat format = workbook.CreateDataFormat();
            dateStyle.DataFormat = format.GetFormat("yyyy-MM-dd");

            #region 取得每列的列宽（最大宽度）
            int[] arrColWidth = new int[dtSource.Columns.Count];
            foreach (DataColumn item in dtSource.Columns)
            {
                //GBK对应的code page是CP936
                arrColWidth[item.Ordinal] = Encoding.GetEncoding(936).GetBytes(item.ColumnName.ToString()).Length;
            }
            for (int i = 0; i < dtSource.Rows.Count; i++)
            {
                for (int j = 0; j < dtSource.Columns.Count; j++)
                {
                    int intTemp = Encoding.GetEncoding(936).GetBytes(dtSource.Rows[i][j].ToString()).Length;
                    if (intTemp > arrColWidth[j])
                    {
                        arrColWidth[j] = intTemp;
                    }
                }
            }
            #endregion

            int rowIndex = 0;

            foreach (DataRow row in dtSource.Rows)
            {
                #region 新建表，填充表头，填充列头，样式
                if (rowIndex == 65535 || rowIndex == 0)
                {
                    if (rowIndex != 0)
                    {
                        sheet = workbook.CreateSheet();
                    }

                    #region 表头及样式
                    {
                        IRow headerRow = sheet.CreateRow(0);
                        headerRow.HeightInPoints = 25;
                        headerRow.CreateCell(0).SetCellValue(strHeaderText);

                        ICellStyle headStyle = workbook.CreateCellStyle();
                        headStyle.Alignment = HorizontalAlignment.Center;
                        IFont font = workbook.CreateFont();
                        font.FontHeightInPoints = 20;
                        font.Boldweight = 700;
                        headStyle.SetFont(font);

                        headerRow.GetCell(0).CellStyle = headStyle;

                        sheet.AddMergedRegion(new CellRangeAddress(0, 0, 0, dtSource.Columns.Count - 1));
                    }
                    #endregion


                    #region 列头及样式
                    {
                        IRow headerRow = sheet.CreateRow(1);
                        ICellStyle headStyle = workbook.CreateCellStyle();
                        headStyle.Alignment = HorizontalAlignment.Center;
                        IFont font = workbook.CreateFont();
                        font.FontHeightInPoints = 10;
                        font.Boldweight = 700;
                        headStyle.SetFont(font);


                        foreach (DataColumn column in dtSource.Columns)
                        {
                            headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
                            headerRow.GetCell(column.Ordinal).CellStyle = headStyle;

                            //设置列宽  
                            sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + 1) * 256);

                        }
                    }
                    #endregion

                    rowIndex = 2;
                }
                #endregion


                #region 填充内容
                ICellStyle contentStyle = workbook.CreateCellStyle();
                contentStyle.Alignment = HorizontalAlignment.Left;
                IRow dataRow = sheet.CreateRow(rowIndex);
                foreach (DataColumn column in dtSource.Columns)
                {
                    ICell newCell = dataRow.CreateCell(column.Ordinal);
                    newCell.CellStyle = contentStyle;

                    string drValue = row[column].ToString();

                    switch (column.DataType.ToString())
                    {
                        case "System.String"://字符串类型  
                            newCell.SetCellValue(drValue);
                            break;
                        case "System.DateTime"://日期类型  
                            DateTime dateV;
                            DateTime.TryParse(drValue, out dateV);
                            newCell.SetCellValue(dateV);

                            newCell.CellStyle = dateStyle;//格式化显示  
                            break;
                        case "System.Boolean"://布尔型  
                            bool boolV = false;
                            bool.TryParse(drValue, out boolV);
                            newCell.SetCellValue(boolV);
                            break;
                        case "System.Int16"://整型  
                        case "System.Int32":
                        case "System.Int64":
                        case "System.Byte":
                            int intV = 0;
                            int.TryParse(drValue, out intV);
                            newCell.SetCellValue(intV);
                            break;
                        case "System.Decimal"://浮点型  
                        case "System.Double":
                            double doubV = 0;
                            double.TryParse(drValue, out doubV);
                            newCell.SetCellValue(doubV);
                            break;
                        case "System.DBNull"://空值处理  
                            newCell.SetCellValue("");
                            break;
                        default:
                            newCell.SetCellValue("");
                            break;
                    }

                }
                #endregion

                rowIndex++;
            }


            using (MemoryStream ms = new MemoryStream())
            {
                workbook.Write(ms);
                ms.Flush();
                ms.Position = 0;

                //sheet.Dispose();
                //workbook.Dispose();//一般只用写这一个就OK了，他会遍历并释放所有资源，但当前版本有问题所以只释放sheet  
                return ms;
            }

        }


        /// <summary>  
        /// 用于Web导出  
        /// </summary>  
        /// <param name="dtSource">源DataTable</param>  
        /// <param name="strHeaderText">表头文本</param>  
        /// <param name="strFileName">文件名</param>  
        //public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName)
        //{

        //    HttpContext curContext = HttpContext.Current;

        //    // 设置编码和附件格式  
        //    curContext.Response.ContentType = "application/vnd.ms-excel";
        //    curContext.Response.ContentEncoding = Encoding.UTF8;
        //    curContext.Response.Charset = "";
        //    curContext.Response.AppendHeader("Content-Disposition",
        //        "attachment;filename=" + HttpUtility.UrlEncode(strFileName + ".xls", Encoding.UTF8));

        //    curContext.Response.BinaryWrite(Export(dtSource, strHeaderText).GetBuffer());
        //    curContext.Response.End();

        //}


        /// <summary>读取excel  
        /// 默认第一行为标头  
        /// 导出某一张表
        /// </summary>  
        /// <param name="strFileName">excel文档路径</param>  
        /// <returns></returns>  
        public static DataTable ImportAppointSheet(XSSFWorkbook hssfworkbook, int index)
        {
            ISheet sheet = hssfworkbook.GetSheetAt(index);
            if (sheet == null) return null;
            DataTable dt = new DataTable(sheet.SheetName);

            IRow headerRow = sheet.GetRow(0);
            if (headerRow == null) return dt;
            if (headerRow.Cells.Count==0)
            {
                headerRow = sheet.GetRow(1);
            }
            int cellCount = headerRow.LastCellNum;

            for (int j = 0; j < cellCount; j++)
            {
                ICell cell = headerRow.GetCell(j);
                dt.Columns.Add(cell.ToStr());
            }

            for (int i = (sheet.FirstRowNum + 1); i <= sheet.LastRowNum; i++)
            {
                IRow row = sheet.GetRow(i);
                if(row==null)continue;
                DataRow dataRow = dt.NewRow();

                for (int j = row.FirstCellNum; j < cellCount; j++)
                {
                    if (row.GetCell(j) != null)
                        dataRow[j] = row.GetCell(j).ToString();
                }

                dt.Rows.Add(dataRow);
            }
            return dt;
        }
        /// <summary>
        /// 导出整个Excel
        /// </summary>
        /// <param name="strFileName"></param>
        /// <returns></returns>
        public static DataSet Import(string strFileName)
        {
            DataSet ds = new DataSet();

            XSSFWorkbook hssfworkbook;
            using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
            {
                hssfworkbook = new XSSFWorkbook(file);
            }
            var sheetCount = hssfworkbook.Count;
            for (int i = 0; i < sheetCount; i++)
            {
                DataTable dt = ImportAppointSheet(hssfworkbook, i);
                if (dt != null)
                    ds.Tables.Add(dt);
            }

            return ds;
        }
        /// <summary>
        /// 将Excel数据转换为实体列表
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static List<T> ConvertExcelSheetToModel<T>(string filePath)
        {
            var datas = new List<T>();
            var type = typeof(T);
            var sheetInfo = type.GetAttribute<SheetInfoAttribute>();
            if (sheetInfo == null) return datas;
            var fileName = filePath;
            if (!File.Exists(fileName)) return datas;

            using (var fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read))
            {
                IWorkbook workbook = null; //新建IWorkbook对象

                var fileExtension = Path.GetExtension(fileName);

                if (fileExtension == ".xlsx") // 2007版本
                {
                    workbook = new XSSFWorkbook(fileStream); //xlsx数据读入workbook
                }
                else if (fileExtension == ".xls") // 2003版本
                {
                    workbook = new HSSFWorkbook(fileStream); //xls数据读入workbook
                }

                ISheet sheet = sheetInfo.SheetName == "" ? workbook.GetSheetAt(0) : workbook.GetSheet(sheetInfo.SheetName);

                IRow row;
               // List<int> showIndex = new List<int> { 1, 2, 3, 4 };

                for (int i = sheetInfo.RowStartIndex; i < sheet.LastRowNum; i++)
                {
                    row = sheet.GetRow(i);
                    if (row != null)
                    {
                        datas.Add(ForeachClassProperties<T>(row));
                    }
                }

                workbook.Close();
            }
            return datas;
        }
        /// <summary>
        /// C#反射遍历对象属性
        /// </summary>
        /// <typeparam name="T">对象类型</typeparam>
        /// <param name="model">对象</param>
        public static T ForeachClassProperties<T>(IRow row)
        {
            Type t = typeof(T);
            var model = Activator.CreateInstance<T>();
            PropertyInfo[] PropertyList = t.GetProperties();
            foreach (PropertyInfo item in PropertyList)
            {
                var index = item.GetCustomAttribute<CellIndexAttribute>()?.Index;
                ICell cell = row.GetCell(index ?? 0);
                if (cell == null)
                {
                    item.SetValue(model, "");
                    continue;
                }
                if (cell.IsMergedCell)
                {
                    //row.Sheet.
                    var sheet = row.Sheet;
                    for (int i = 0; i < sheet.NumMergedRegions; i++)
                    {
                        var range = sheet.GetMergedRegion(i);
                        if (range.IsInRange(cell.RowIndex, cell.ColumnIndex))
                        {
                            var useRow = row.Sheet.GetRow(range.FirstRow);
                            item.SetValue(model, useRow.GetCell(range.FirstColumn) + "");
                            break;
                        }
                    }                  
                }
                else
                {
                    item.SetValue(model, row.GetCell(index ?? 0) + "");
                }             
            }
            return model;
        }
    }
    public class SheetInfoAttribute : Attribute
    {
        public string FilePath { get; set; }
        public string SheetName { get; set; }
        public int RowStartIndex { get; set; }
    }
    public class CellIndexAttribute : Attribute
    {
        public CellIndexAttribute(int index)
        {
            Index = index;
        }
        public int Index { get; set; }
    }

    public static class RefletcExtend
    {
        public static T GetAttribute<T>(this Type type) where T : Attribute
        {
            return (T)type.GetCustomAttributes(typeof(T), false).FirstOrDefault();
        }
    }
}