using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;
using Font = DocumentFormat.OpenXml.Spreadsheet.Font;
using X14 = DocumentFormat.OpenXml.Office2010.Excel;
using X15 = DocumentFormat.OpenXml.Office2013.Excel;
using X18 = DocumentFormat.OpenXml.Office2021.Excel;

namespace PlaylistManager
{
    internal class XLSX
    {
        internal static void Serialize(string filename, DataTable table)
        {
            if (table == null) throw new Exception("Data was empty");

            using (SpreadsheetDocument document = SpreadsheetDocument.Create(filename, SpreadsheetDocumentType.Workbook))
            {
                FillDocument(document, table);
            }
        }

        internal static string Serialize(DataTable table)
        {
            if (table == null) throw new Exception("Data was empty");

            MemoryStream ms = new MemoryStream();
            using (SpreadsheetDocument document = SpreadsheetDocument.Create(ms, SpreadsheetDocumentType.Workbook))
            {
                FillDocument(document, table);
            }
            ms.Seek(0, SeekOrigin.Begin);
            return Encoding.UTF8.GetString(ms.ToArray());
        }

        private static SpreadsheetDocument FillDocument(SpreadsheetDocument document, DataTable table)
        {


            // Create Content
            SheetData sheetData = new SheetData();
            Row xlrow = new Row();
            foreach (DataColumn col in table.Columns)
            {
                xlrow.Append(CreateCell(col.ColumnName, 2U));
            }
            sheetData.Append(xlrow);

            foreach (DataRow row in table.Rows)
            {
                xlrow = new Row();
                foreach (DataColumn col in table.Columns)
                {
                    xlrow.Append(CreateCell(row[col.ColumnName], col.DataType));
                }
                sheetData.Append(xlrow);
            }

            // Generate WorksheetPart Content 
            Worksheet worksheet1 = new Worksheet() { MCAttributes = new MarkupCompatibilityAttributes() { Ignorable = "x14ac" } };
            worksheet1.AddNamespaceDeclaration("r", "http://schemas.openxmlformats.org/officeDocument/2006/relationships");
            worksheet1.AddNamespaceDeclaration("mc", "http://schemas.openxmlformats.org/markup-compatibility/2006");
            worksheet1.AddNamespaceDeclaration("x14ac", "http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac");
            worksheet1.Append(sheetData);

            WorkbookPart workbookPart1 = document.AddWorkbookPart();
            workbookPart1.Workbook = new Workbook();
            workbookPart1.Workbook.Sheets = new Sheets(new Sheet() { Name = "Sheet1", SheetId = (UInt32Value)1U, Id = "rId1" });

            WorkbookStylesPart workbookStylesPart1 = workbookPart1.AddNewPart<WorkbookStylesPart>("rId3");
            workbookStylesPart1.Stylesheet = CreateStylesheet();

            WorksheetPart worksheetPart1 = workbookPart1.AddNewPart<WorksheetPart>("rId1");
            worksheetPart1.Worksheet = worksheet1;
            document.Save();
            return document;
        }

        private static Cell CreateCell(string Text, uint StyleIndex = 0U)
        {
            return CreateCell(Text, typeof(string), StyleIndex);
        }

        private static Cell CreateCell(object? value, Type type, uint StyleIndex = 0U)
        {
            Cell cell = new Cell();
            cell.StyleIndex = StyleIndex;
            if (value == null || value == DBNull.Value)
            {
                cell.DataType = CellValues.String;
                cell.CellValue = new CellValue("");
            }
            else if (type == typeof(int) || type == typeof(uint))
            {
                cell.DataType = CellValues.Number;
                cell.CellValue = new CellValue((int)value);
            }
            else if (type == typeof(float) || type == typeof(double))
            {
                cell.DataType = CellValues.Number;
                cell.CellValue = new CellValue((double)value);
            }
            else if (type == typeof(decimal))
            {
                cell.DataType = CellValues.Number;
                cell.CellValue = new CellValue((decimal)value);
            }
            else if (type == typeof(bool) || type == typeof(Boolean))
            {
                cell.DataType = CellValues.Boolean;
                cell.CellValue = new CellValue((bool)value);
            }
            else if (type == typeof(DateTime) || type == typeof(DateOnly) || type == typeof(TimeOnly))
            {
                cell.StyleIndex = 1U; // Style mit passendem Numberformat 
                cell.DataType = CellValues.Date;
                cell.CellValue = new CellValue(((DateTime)value));
            }
            else if (type == typeof(DateTimeOffset))
            {
                cell.DataType = CellValues.Date;
                cell.CellValue = new CellValue((DateTimeOffset)value);
            }
            else if (type == typeof(string) || type == typeof(String))
            {
                cell.DataType = CellValues.String;
                cell.CellValue = new CellValue((string)value);
            }
            else
            {
                throw new NotSupportedException($"Unsupported Column type: {type}");
            }
            return cell;
        }

        private static Stylesheet CreateStylesheet()
        {

            uint iExcelIndex = 164;
            Stylesheet stylesheet = new Stylesheet();

            stylesheet.Fonts = new Fonts(
                new Font()
                {
                    Color = new() { Theme = (UInt32Value)1U },
                    FontSize = new() { Val = 11D },
                    FontName = new() { Val = "Calibri" },
                    FontFamilyNumbering = new() { Val = 2 },
                    FontScheme = new FontScheme() { Val = FontSchemeValues.Minor },
                },
                new Font()
                {
                    Bold = new(),
                    Color = new() { Theme = (UInt32Value)1U },
                    FontSize = new() { Val = 11D },
                    FontName = new() { Val = "Calibri" },
                    FontFamilyNumbering = new() { Val = 2 },
                    FontScheme = new FontScheme() { Val = FontSchemeValues.Minor },
                }
                )
            { KnownFonts = true };

            stylesheet.Fills = new Fills(new Fill());// { Count = (UInt32Value)0U };

            stylesheet.Borders = new Borders(new Border());

            // ---- CELL STYLE FORMATS ----
            NumberingFormat nfDateTime = new NumberingFormat()
            {
                NumberFormatId = iExcelIndex++,
                FormatCode = StringValue.FromString("yyyy-MM-dd HH:mm:ss"),
            };

            stylesheet.NumberingFormats = new NumberingFormats(nfDateTime);


            stylesheet.CellStyleFormats = new CellStyleFormats(
                new CellFormat()
                {
                    NumberFormatId = (UInt32Value)0U,
                    FontId = (UInt32Value)0U,
                    BorderId = (UInt32Value)0U,
                }
                );

            // ---- CELL FORMATS ----
            // NumberFormatID: https://github.com/closedxml/closedxml/wiki/NumberFormatId-Lookup-Table
            stylesheet.CellFormats = new CellFormats(
                new CellFormat()
                {
                    NumberFormatId = (UInt32Value)0U,
                    FontId = (UInt32Value)0U,
                    BorderId = (UInt32Value)0U,
                    FormatId = (UInt32Value)0U
                },

                // Mit Datumsformat
                new CellFormat()
                {
                    NumberFormatId = nfDateTime.NumberFormatId,
                    FontId = (UInt32Value)0U,
                    BorderId = (UInt32Value)0U,
                    FormatId = (UInt32Value)0U
                },

                // Bold (Header)
                new CellFormat()
                {
                    NumberFormatId = (UInt32Value)0U,
                    FontId = (UInt32Value)1U,
                    BorderId = (UInt32Value)0U,
                    FormatId = (UInt32Value)0U,
                    ApplyFont = true
                }
                ); ;

            stylesheet.CellStyles = new CellStyles(
                new CellStyle()
                {
                    Name = "Normal",
                    FormatId = (UInt32Value)0U,
                    BuiltinId = (UInt32Value)0U
                }
                );

            return stylesheet;
        }


    }
}