ClosedXML-ClosedXML/ClosedXML/Excel/ConditionalFormats/Save/XLCFDataBarConverterExtension.cs

using ClosedXML.Extensions;
using DocumentFormat.OpenXml.Office.Excel;
using DocumentFormat.OpenXml.Office2010.Excel;
using System.Collections.Generic;

namespace ClosedXML.Excel
{
    internal class XLCFDataBarConverterExtension : IXLCFConverterExtension
    {
        private static readonly IReadOnlyDictionary<DocumentFormat.OpenXml.Spreadsheet.ConditionalFormatValueObjectValues, ConditionalFormattingValueObjectTypeValues> CFValueToTypeMap =
            new Dictionary<DocumentFormat.OpenXml.Spreadsheet.ConditionalFormatValueObjectValues, ConditionalFormattingValueObjectTypeValues>
            {
                { DocumentFormat.OpenXml.Spreadsheet.ConditionalFormatValueObjectValues.Max, ConditionalFormattingValueObjectTypeValues.Max },
                { DocumentFormat.OpenXml.Spreadsheet.ConditionalFormatValueObjectValues.Min, ConditionalFormattingValueObjectTypeValues.Min },
                { DocumentFormat.OpenXml.Spreadsheet.ConditionalFormatValueObjectValues.Number, ConditionalFormattingValueObjectTypeValues.Numeric },
                { DocumentFormat.OpenXml.Spreadsheet.ConditionalFormatValueObjectValues.Percent, ConditionalFormattingValueObjectTypeValues.Percent },
                { DocumentFormat.OpenXml.Spreadsheet.ConditionalFormatValueObjectValues.Percentile, ConditionalFormattingValueObjectTypeValues.Percentile },
                { DocumentFormat.OpenXml.Spreadsheet.ConditionalFormatValueObjectValues.Formula, ConditionalFormattingValueObjectTypeValues.Formula },
            };

        public ConditionalFormattingRule Convert(IXLConditionalFormat cf, XLWorkbook.SaveContext context)
        {
            ConditionalFormattingRule conditionalFormattingRule = new ConditionalFormattingRule()
            {
                Type = DocumentFormat.OpenXml.Spreadsheet.ConditionalFormatValues.DataBar,
                Id = ((XLConditionalFormat)cf).Id.WrapInBraces()
            };

            DataBar dataBar = new DataBar()
            {
                MinLength = 0,
                MaxLength = 100,
                Gradient = true,
                ShowValue = !cf.ShowBarOnly
            };

            var cfMin = BuildValueObject(cf, 1, ConditionalFormattingValueObjectTypeValues.AutoMin);
            var cfMax = BuildValueObject(cf, 2, ConditionalFormattingValueObjectTypeValues.AutoMax);

            var barAxisColor = new BarAxisColor { Rgb = XLColor.Black.Color.ToHex() };

            var negativeFillColor = new NegativeFillColor { Rgb = cf.Colors[1].Color.ToHex() };
            if (cf.Colors.Count == 2)
            {
                negativeFillColor = new NegativeFillColor { Rgb = cf.Colors[2].Color.ToHex() };
            }

            dataBar.Append(cfMin);
            dataBar.Append(cfMax);

            dataBar.Append(negativeFillColor);
            dataBar.Append(barAxisColor);

            conditionalFormattingRule.Append(dataBar);

            return conditionalFormattingRule;
        }

        /// <summary>
        /// Builds a single x14 conditional formatting value object (cfvo) for a data bar threshold.
        /// </summary>
        /// <param name="cf">The conditional format the data bar belongs to.</param>
        /// <param name="index">1-based threshold index (1 = minimum, 2 = maximum).</param>
        /// <param name="automaticType">
        /// Type emitted for an automatic bound: autoMin for the minimum, autoMax for the maximum.
        /// </param>
        /// <remarks>
        /// A threshold without an explicit content type is an automatic bound (autoMin/autoMax).
        /// A min/max threshold is the lowest/highest value; both it and the automatic bound are
        /// self-describing and carry no formula. Only value based thresholds (num/percent/percentile/
        /// formula) emit an xm:f formula. Writing a formula for a min/max threshold makes strict
        /// readers such as WPS lock the bar to that value (see issue #2843).
        /// </remarks>
        private static ConditionalFormattingValueObject BuildValueObject(IXLConditionalFormat cf, int index, ConditionalFormattingValueObjectTypeValues automaticType)
        {
            cf.Values.TryGetValue(index, out var value);
            var formulaText = value?.Value;

            if (!cf.ContentTypes.TryGetValue(index, out var contentType))
            {
                return new ConditionalFormattingValueObject { Type = automaticType };
            }

            var type = GetCFType(contentType.ToOpenXml());
            var valueObject = new ConditionalFormattingValueObject { Type = type };

            if (type == ConditionalFormattingValueObjectTypeValues.Min ||
                type == ConditionalFormattingValueObjectTypeValues.Max)
            {
                // A min/max threshold with no value is an automatic bound (autoMin/autoMax);
                // with a value it is the lowest/highest value. Neither carries a formula.
                if (formulaText == null)
                {
                    valueObject.Type = automaticType;
                }

                return valueObject;
            }

            if (formulaText != null)
            {
                valueObject.Append(new Formula { Text = formulaText });
            }

            return valueObject;
        }

        private static ConditionalFormattingValueObjectTypeValues GetCFType(DocumentFormat.OpenXml.Spreadsheet.ConditionalFormatValueObjectValues value)
        {
            return CFValueToTypeMap[value];
        }
    }
}