<%@ WebHandler Language="C#" Class="importXlsx" %>

using System;
using System.Web;
using System.Runtime.Serialization.Json;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Web.Services.Protocols;
using System.Security.Cryptography;
using System.Text;
using System.Web.SessionState;
using System.Data;
using System.Collections.Generic;
using NPOI;
using NPOI.HPSF;
using NPOI.HSSF;
using NPOI.HSSF.UserModel;
using NPOI.XSSF;
using NPOI.XSSF.UserModel;
using NPOI.POIFS;
using NPOI.Util;
using System.IO;

public class importXlsx : IHttpHandler {

    authPermission objAuth = new authPermission();

    public void ProcessRequest (HttpContext context) {
        string xlsxFileCode = globalClass.CreateRandomCode(12);
        string xlsxFileName = xlsxFileCode + ".xlsx";
        string projPath = "uploads/xlsx/";


        result objRet = new result();
        DataContractJsonSerializer json = new DataContractJsonSerializer(objRet.GetType());
        context.Response.ContentType = "application/json;charset=utf-8";


        if (objAuth.isLogin() == false) {
            objRet.ret = "no";
            objRet.err_code = "9999";
            objRet.message = "尚未登入!";
            json.WriteObject(context.Response.OutputStream, objRet);
            return;
        }

        string base64_string = (context.Request["base64"] == null) ? "" : context.Request["base64"].ToString();

        if (base64_string == "") {
            objRet.ret = "no";
            objRet.err_code = "0003";
            objRet.message = "無base64檔案!";
            json.WriteObject(context.Response.OutputStream, objRet);
            return;
        }

        string filePath = string.Format("BackEnd/uploads/xlsx/{0}.xlsx", xlsxFileCode);

        string path = System.Web.HttpContext.Current.Server.MapPath("~/");

        globalClass.Base64ToFile(base64_string, path + filePath);

        //globalClass.Base64ToAzure(base64_string, projPath + xlsxFileName);

        XSSFWorkbook workbook = new XSSFWorkbook(globalClass.Base64ToStream(base64_string));

        XSSFSheet sheet = (XSSFSheet)workbook.GetSheetAt(0);
        DataTable dt = new DataTable(xlsxFileCode);

        XSSFRow headerRow = (XSSFRow)sheet.GetRow(0);

        int asciiA = 1;
        foreach (XSSFCell headerCell in headerRow) {
            dt.Columns.Add("A" + asciiA.ToString());
            objRet.columns.Add(headerCell.ToString());
            col newCol = new col();
            newCol.data = "A" + asciiA.ToString();
            newCol.visible = "true";
            newCol.title = headerCell.ToString();
            objRet.cols.Add(newCol);
            asciiA++;
        }

        int rowIndex = 0;
        int rowNum = 0;
        int py = sheet.PhysicalNumberOfRows;

        foreach (XSSFRow row in sheet) {

            DataRow dataRow = dt.NewRow();

            string hasData = "N";

            foreach (XSSFCell cell in row.Cells) {
                if (cell.ToString() != "")
                {
                    hasData = "Y";
                    break;
                }
            }

            if (hasData == "Y" && rowIndex != 0) {
                dataRow.ItemArray = row.Cells.ToArray();

                dt.Rows.Add(dataRow);
                rowNum++;
            }

            rowIndex++;
        }

        int totalRowNum = rowNum;

        DataTable dt2 = dt.Clone();

        if (totalRowNum < 6)
        {
            foreach (DataRow row in dt.Rows)
            {
                dt2.ImportRow(row);
            }
        }
        else {
            for (int i = 0; i < 3; i++) {
                dt2.ImportRow(dt.Rows[i]);
            }

            for (int i = (totalRowNum - 3); i < totalRowNum; i++) {
                dt2.ImportRow(dt.Rows[i]);
            }
        }

        string datatableJsonString = "";
        datatableJsonString = JsonConvert.SerializeObject(dt2);
        objRet.data = datatableJsonString;
        objRet.ret = "yes";
        objRet.totalRecNum = totalRowNum;
        objRet.xlsxSerial = xlsxFileCode;
        json.WriteObject(context.Response.OutputStream, objRet);
        return;
    }

    public bool IsReusable {
        get {
            return false;
        }
    }

    public class result {
        public string ret = "no";
        public string err_code = "0000";
        public string message = "";
        public string xlsxSerial = "";
        public int totalRecNum = 0;
        public List<string> columns = new List<string>();
        public List<col> cols = new List<col>();
        public string data = "";
    }

    public class col {
        public string data = "";
        public string visible = "";
        public string title = "";
    }

}