using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;

namespace Oms.Application.Services.Orders.Templates;

/// <summary>
/// 为标准模板 Excel 增加表头必填标黄、枚举下拉等 OpenXML 增强。
/// </summary>
internal static class OrderTemplateExcelOpenXmlEnhancer
{
    private const uint DataValidationStartRow = 2;
    private const uint DataValidationEndRow = 5000;
    private const string RequiredHeaderFillRgb = "FFFFE5E5";
    private const string RequiredHeaderFontRgb = "FFC00000";

    public static byte[] Enhance(
        byte[] workbookBytes,
        IReadOnlyList<OrderTemplateFieldDefinition> fields,
        IReadOnlyList<OrderTemplateDictOption> dictOptions)
    {
        using var stream = new MemoryStream();
        stream.Write(workbookBytes, 0, workbookBytes.Length);
        stream.Position = 0;

        using (var document = SpreadsheetDocument.Open(stream, true))
        {
            var workbookPart = document.WorkbookPart
                ?? throw new InvalidOperationException("工作簿无效");

            var requiredHeaderStyleIndex = EnsureRequiredHeaderStyle(workbookPart);
            var dataSheetPart = GetWorksheetPart(workbookPart, OrderTemplateExcelGenerator.DataSheetName)
                ?? throw new InvalidOperationException("未找到下单数据工作表");

            ApplyRequiredHeaderHighlight(dataSheetPart.Worksheet, fields, requiredHeaderStyleIndex);
            ApplyColumnValidations(workbookPart, dataSheetPart, fields, dictOptions);

            dataSheetPart.Worksheet.Save();
            workbookPart.Workbook.Save();
        }

        return stream.ToArray();
    }

    private static void ApplyRequiredHeaderHighlight(
        Worksheet worksheet,
        IReadOnlyList<OrderTemplateFieldDefinition> fields,
        uint styleIndex)
    {
        var sheetData = worksheet.GetFirstChild<SheetData>()
            ?? throw new InvalidOperationException("工作表数据为空");

        var headerRow = sheetData.Elements<Row>().FirstOrDefault(x => x.RowIndex?.Value == 1)
            ?? throw new InvalidOperationException("未找到表头行");

        for (var columnIndex = 0; columnIndex < fields.Count; columnIndex++)
        {
            if (!fields[columnIndex].Required)
            {
                continue;
            }

            var cellReference = $"{ToColumnName(columnIndex)}1";
            var cell = headerRow.Elements<Cell>().FirstOrDefault(x => x.CellReference?.Value == cellReference)
                       ?? CreateCell(headerRow, cellReference, fields[columnIndex].Label);
            cell.StyleIndex = styleIndex;
        }
    }

    private static void ApplyColumnValidations(
        WorkbookPart workbookPart,
        WorksheetPart dataSheetPart,
        IReadOnlyList<OrderTemplateFieldDefinition> fields,
        IReadOnlyList<OrderTemplateDictOption> dictOptions)
    {
        var dictRangeByType = BuildDictTypeRanges(workbookPart, dictOptions);
        var validations = dataSheetPart.Worksheet.GetFirstChild<DataValidations>();
        if (validations == null)
        {
            validations = new DataValidations();
            dataSheetPart.Worksheet.Append(validations);
        }

        for (var columnIndex = 0; columnIndex < fields.Count; columnIndex++)
        {
            var field = fields[columnIndex];
            var formula = ResolveValidationFormula(field, dictRangeByType);
            if (string.IsNullOrWhiteSpace(formula))
            {
                continue;
            }

            var columnName = ToColumnName(columnIndex);
            var validation = new DataValidation
            {
                Type = DataValidationValues.List,
                AllowBlank = !field.Required,
                ShowInputMessage = true,
                ShowErrorMessage = true,
                ErrorTitle = "输入无效",
                Error = field.Required ? "请从下拉列表选择或填写有效值" : "请填写有效值",
                PromptTitle = field.Label,
                Prompt = BuildValidationPrompt(field),
                SequenceOfReferences = new ListValue<StringValue>
                {
                    InnerText = $"{columnName}{DataValidationStartRow}:{columnName}{DataValidationEndRow}"
                }
            };
            validation.Append(new Formula1(formula));
            validations.Append(validation);
        }

        validations.Count = (uint)validations.ChildElements.Count;
    }

    private static string? ResolveValidationFormula(
        OrderTemplateFieldDefinition field,
        IReadOnlyDictionary<string, string> dictRangeByType)
    {
        if (string.Equals(field.DataType, "boolean", StringComparison.OrdinalIgnoreCase))
        {
            return "\"true,false\"";
        }

        if (string.IsNullOrWhiteSpace(field.DictType))
        {
            return null;
        }

        if (dictRangeByType.TryGetValue(field.DictType, out var rangeFormula))
        {
            return rangeFormula;
        }

        return null;
    }

    private static string BuildValidationPrompt(OrderTemplateFieldDefinition field)
    {
        if (!string.IsNullOrWhiteSpace(field.Hint))
        {
            return field.Hint;
        }

        if (string.Equals(field.DataType, "boolean", StringComparison.OrdinalIgnoreCase))
        {
            return "填写 true 或 false";
        }

        return field.Required ? "必填" : "选填";
    }

    private static Dictionary<string, string> BuildDictTypeRanges(
        WorkbookPart workbookPart,
        IReadOnlyList<OrderTemplateDictOption> dictOptions)
    {
        var result = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
        if (dictOptions.Count == 0)
        {
            return result;
        }

        var dictSheetPart = GetWorksheetPart(workbookPart, OrderTemplateExcelGenerator.DictSheetName);
        if (dictSheetPart?.Worksheet == null)
        {
            return result;
        }

        var grouped = dictOptions
            .Where(x => !string.IsNullOrWhiteSpace(x.DictType) && !string.IsNullOrWhiteSpace(x.Code))
            .GroupBy(x => x.DictType, StringComparer.OrdinalIgnoreCase)
            .OrderBy(x => x.Key, StringComparer.OrdinalIgnoreCase)
            .ToList();

        var sheetData = dictSheetPart.Worksheet.GetFirstChild<SheetData>();
        sheetData?.RemoveAllChildren<Row>();
        sheetData ??= new SheetData();
        if (dictSheetPart.Worksheet.GetFirstChild<SheetData>() == null)
        {
            dictSheetPart.Worksheet.Append(sheetData);
        }

        var headerRow = new Row { RowIndex = 1 };
        sheetData.InsertAt(headerRow, 0);

        var columnIndex = 0;
        foreach (var group in grouped)
        {
            var columnName = ToColumnName(columnIndex);
            SetCellText(headerRow, $"{columnName}1", group.Key);

            var rowIndex = 2U;
            foreach (var option in group.OrderBy(x => x.Code, StringComparer.OrdinalIgnoreCase))
            {
                var row = sheetData.Elements<Row>().FirstOrDefault(x => x.RowIndex?.Value == rowIndex)
                          ?? CreateRow(sheetData, rowIndex);
                SetCellText(row, $"{columnName}{rowIndex}", option.Code);
                rowIndex++;
            }

            if (rowIndex == 2)
            {
                columnIndex++;
                continue;
            }

            var lastRow = rowIndex - 1;
            var escapedSheetName = OrderTemplateExcelGenerator.DictSheetName.Replace("'", "''");
            result[group.Key] = $"'{escapedSheetName}'!${columnName}$2:${columnName}${lastRow}";
            columnIndex++;
        }

        dictSheetPart.Worksheet.Save();
        return result;
    }

    private static uint EnsureRequiredHeaderStyle(WorkbookPart workbookPart)
    {
        var stylesPart = workbookPart.WorkbookStylesPart ?? workbookPart.AddNewPart<WorkbookStylesPart>();
        var stylesheet = stylesPart.Stylesheet;
        if (stylesheet == null)
        {
            stylesheet = new Stylesheet
            {
                Fonts = new Fonts(new Font()),
                Fills = new Fills(
                    new Fill { PatternFill = new PatternFill { PatternType = PatternValues.None } },
                    new Fill { PatternFill = new PatternFill { PatternType = PatternValues.Gray125 } }),
                Borders = new Borders(new Border()),
                CellStyleFormats = new CellStyleFormats(new CellFormat()),
                CellFormats = new CellFormats(new CellFormat())
            };
            stylesheet.Fonts.Count = 1;
            stylesheet.Fills.Count = 2;
            stylesheet.Borders.Count = 1;
            stylesheet.CellStyleFormats.Count = 1;
            stylesheet.CellFormats.Count = 1;
            stylesPart.Stylesheet = stylesheet;
        }

        var fills = stylesheet.Fills ?? new Fills { Count = 0 };
        stylesheet.Fills = fills;

        var fonts = stylesheet.Fonts ?? new Fonts { Count = 0 };
        stylesheet.Fonts = fonts;

        var borders = stylesheet.Borders ?? new Borders { Count = 0 };
        stylesheet.Borders = borders;

        var cellFormats = stylesheet.CellFormats ?? new CellFormats { Count = 0 };
        stylesheet.CellFormats = cellFormats;

        if (fills.Count?.Value is not > 0)
        {
            fills.Append(new Fill { PatternFill = new PatternFill { PatternType = PatternValues.None } });
            fills.Append(new Fill { PatternFill = new PatternFill { PatternType = PatternValues.Gray125 } });
            fills.Count = 2U;
        }

        if (fonts.Count?.Value is not > 0)
        {
            fonts.Append(new Font());
            fonts.Count = 1U;
        }

        if (borders.Count?.Value is not > 0)
        {
            borders.Append(new Border());
            borders.Count = 1U;
        }

        if (cellFormats.Count?.Value is not > 0)
        {
            cellFormats.Append(new CellFormat());
            cellFormats.Count = 1U;
        }

        var requiredFill = new Fill
        {
            PatternFill = new PatternFill
            {
                PatternType = PatternValues.Solid,
                ForegroundColor = new ForegroundColor { Rgb = RequiredHeaderFillRgb },
                BackgroundColor = new BackgroundColor { Indexed = 64 }
            }
        };
        fills.Append(requiredFill);
        var requiredFillId = (uint)fills.ChildElements.Count - 1;
        fills.Count = (uint)fills.ChildElements.Count;

        var headerFont = new Font(
            new Bold(),
            new Color { Rgb = RequiredHeaderFontRgb });
        fonts.Append(headerFont);
        var headerFontId = (uint)fonts.ChildElements.Count - 1;
        fonts.Count = (uint)fonts.ChildElements.Count;

        var headerFormat = new CellFormat
        {
            FontId = headerFontId,
            FillId = requiredFillId,
            BorderId = 0,
            ApplyFont = true,
            ApplyFill = true
        };
        cellFormats.Append(headerFormat);
        var headerFormatIndex = (uint)cellFormats.ChildElements.Count - 1;
        cellFormats.Count = (uint)cellFormats.ChildElements.Count;

        stylesheet.Save();
        return headerFormatIndex;
    }

    private static WorksheetPart? GetWorksheetPart(WorkbookPart workbookPart, string sheetName)
    {
        var sheet = workbookPart.Workbook.Sheets?.Elements<Sheet>()
            .FirstOrDefault(x => string.Equals(x.Name?.Value, sheetName, StringComparison.Ordinal));
        if (sheet?.Id?.Value == null)
        {
            return null;
        }

        return workbookPart.GetPartById(sheet.Id.Value) as WorksheetPart;
    }

    private static Cell CreateCell(Row row, string cellReference, string text)
    {
        var cell = new Cell
        {
            CellReference = cellReference,
            DataType = CellValues.String,
            CellValue = new CellValue(text)
        };
        row.Append(cell);
        return cell;
    }

    private static Row CreateRow(SheetData sheetData, uint rowIndex)
    {
        var row = new Row { RowIndex = rowIndex };
        sheetData.Append(row);
        return row;
    }

    private static void SetCellText(Row row, string cellReference, string text)
    {
        var cell = row.Elements<Cell>().FirstOrDefault(x => x.CellReference?.Value == cellReference)
                   ?? CreateCell(row, cellReference, text);
        cell.DataType = CellValues.String;
        cell.CellValue = new CellValue(text);
    }

    private static string ToColumnName(int columnIndex)
    {
        var dividend = columnIndex + 1;
        var columnName = string.Empty;
        while (dividend > 0)
        {
            var modulo = (dividend - 1) % 26;
            columnName = Convert.ToChar('A' + modulo) + columnName;
            dividend = (dividend - modulo) / 26;
        }

        return columnName;
    }
}