fix(odt): markdown styles no longer shadow common styles of styles.xml

TriasDev.Templify.Tests/Helpers/OdtDocumentBuilder.cs

@@ -39,6 +39,7 @@ public sealed class OdtDocumentBuilder
     private readonly StringBuilder _footer = new StringBuilder();
     private readonly List<(string Name, byte[] Data)> _extraEntries = new List<(string, byte[])>();
     private string _automaticStyles = string.Empty;
+    private string _commonStyles = string.Empty;
     private bool _isTemplate;
     private bool _mimetypeFirst = true;
     private bool _includeMimetype = true;
@@ -126,6 +127,13 @@ public OdtDocumentBuilder AddAutomaticStyles(string xml)
         return this;
     }
 
+    /// <summary>Adds common (named) styles (raw XML) to the office:styles of styles.xml.</summary>
+    public OdtDocumentBuilder AddCommonStyles(string xml)
+    {
+        _commonStyles += xml;
+        return this;
+    }
+
     /// <summary>Adds an extra package entry (listed in the manifest).</summary>
     public OdtDocumentBuilder AddEntry(string name, byte[] data)
     {
@@ -176,7 +184,9 @@ public string BuildStylesXml()
         string footer = _footer.Length > 0 ? $"<style:footer>{_footer}</style:footer>" : string.Empty;
         return "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" +
                $"<office:document-styles {NamespaceDeclarations} office:version=\"1.3\">" +
-               "<office:styles><style:style style:name=\"Standard\" style:family=\"paragraph\" style:class=\"text\"/></office:styles>" +
+               "<office:styles><style:style style:name=\"Standard\" style:family=\"paragraph\" style:class=\"text\"/>" +
+               _commonStyles +
+               "</office:styles>" +
                "<office:automatic-styles><style:page-layout style:name=\"pm1\"/></office:automatic-styles>" +
                "<office:master-styles>" +
                $"<style:master-page style:name=\"Standard\" style:page-layout-name=\"pm1\">{header}{footer}</style:master-page>" +

TriasDev.Templify.Tests/Odt/OdtLibreOfficeRoundTripTests.cs

@@ -414,6 +414,25 @@ public void HeaderRegions_ProcessedDocumentOpensInLibreOffice()
         Assert.StartsWith("%PDF", Encoding.ASCII.GetString(pdf, 0, 4), StringComparison.Ordinal);
     }
 
+    [Fact]
+    public void MarkdownStyle_DoesNotShadowACommonStyle_InLibreOffice()
+    {
+        LibreOfficeRunner.RequireExecutable();
+
+        OdtDocumentBuilder template = new OdtDocumentBuilder()
+            .AddCommonStyles("<style:style style:name=\"T3\" style:family=\"text\"><style:text-properties fo:color=\"#ff0000\"/></style:style>")
+            .AddXml("<text:p><text:span text:style-name=\"T3\">red</text:span> {{Bold}}</text:p>");
+
+        byte[] output = ProcessToBytes(template, new Dictionary<string, object> { ["Bold"] = "**b**" });
+        OdtDocumentVerifier resaved = new OdtDocumentVerifier(LibreOfficeRunner.Convert(output, "odt", "odt", "odt"));
+
+        // LibreOffice still reads the red text with the common style, and only the markdown text as bold.
+        System.Xml.Linq.XElement red = resaved.Body.Descendants(OdtDocumentVerifier.Text + "span").Single(s => s.Value == "red");
+        Assert.Equal("T3", (string?)red.Attribute(OdtDocumentVerifier.Text + "style-name"));
+        Assert.Null(GetEffectiveProperty(resaved, "red", OdtDocumentVerifier.Fo + "font-weight"));
+        Assert.Equal("bold", GetEffectiveProperty(resaved, "b", OdtDocumentVerifier.Fo + "font-weight"));
+    }
+
     private static string? GetEffectiveProperty(OdtDocumentVerifier document, string text, System.Xml.Linq.XName property)
     {
         System.Xml.Linq.XElement? automaticStyles = document.ContentXml.Root!.Element(OdtDocumentVerifier.Office + "automatic-styles");

TriasDev.Templify.Tests/Odt/OdtMarkdownTests.cs

@@ -152,6 +152,38 @@ public void MarkdownInHeader_CreatesStyleInStylesXml()
         Assert.NotNull(TextProperties(output.ContentXml, bodySpan));
     }
 
+    [Fact]
+    public void NewStyleName_DoesNotShadowACommonStyleOfStylesXml()
+    {
+        // content.xml spans can reference common (named) styles of styles.xml. An automatic style with the same
+        // name takes precedence in LibreOffice, so the red "T3" text used to turn bold when markdown created T3.
+        (_, OdtDocumentVerifier output) = OdtTestHelper.Process(
+            new OdtDocumentBuilder()
+                .AddCommonStyles("<style:style style:name=\"T3\" style:family=\"text\"><style:text-properties fo:color=\"#ff0000\"/></style:style>"
+                    + "<text:list-style style:name=\"T4\"/>")
+                .AddXml("<text:p><text:span text:style-name=\"T3\">red</text:span> {{Bold}}</text:p>"),
+            new Dictionary<string, object> { ["Bold"] = "**b**" });
+
+        XElement bold = output.Body.Descendants(_text + "span").Single(s => s.Value == "b");
+        Assert.Equal("T5", (string?)bold.Attribute(_text + "style-name"));
+        Assert.Equal("bold", (string?)TextProperties(output.ContentXml, bold)!.Attribute(_fo + "font-weight"));
+        XElement red = output.Body.Descendants(_text + "span").Single(s => s.Value == "red");
+        Assert.Equal("T3", (string?)red.Attribute(_text + "style-name"));
+        Assert.Null(TextProperties(output.ContentXml, red));
+    }
+
+    [Fact]
+    public void HeaderStyles_MayReuseNamesOfContentStyles()
+    {
+        // Automatic styles are per part: a header style T1 in styles.xml and the content style T1 do not collide.
+        (_, OdtDocumentVerifier output) = OdtTestHelper.Process(
+            new OdtDocumentBuilder().AddHeaderParagraph("{{Value}}"),
+            new Dictionary<string, object> { ["Value"] = "~~s~~" });
+
+        XElement headerSpan = output.StylesXml!.Descendants(_text + "span").Single();
+        Assert.Equal("T1", (string?)headerSpan.Attribute(_text + "style-name"));
+    }
+
     [Fact]
     public void MarkdownInLoop_ReusesStyleForAllItems()
     {

TriasDev.Templify/OpenDocument/OdtPlaceholderProcessor.cs

@@ -31,6 +31,9 @@ public OdtPlaceholderProcessor(
         _warningCollector = warningCollector ?? throw new ArgumentNullException(nameof(warningCollector));
     }
 
+    /// <summary>Gets the automatic text styles created for markdown formatting.</summary>
+    public OdtTextStyles Styles => _styles;
+
     /// <summary>Gets the number of placeholders replaced so far.</summary>
     public int ReplacementCount { get; private set; }
 

TriasDev.Templify/OpenDocument/OdtTemplateEngine.cs

@@ -61,9 +61,16 @@ public void Process(OdtPackage package, IEvaluationContext context)
             throw new InvalidOdtPackageException("Invalid document: content.xml has no text body (office:text).");
         }
 
+        XDocument? styles = package.GetXml(OdtPackage.StylesEntry);
+
+        // content.xml can reference the common styles of styles.xml by name; markdown styles must not shadow them.
+        _placeholders.Styles.ReserveNames(
+            styles?.Root?.Elements(OdfNames.Office + "styles").Descendants()
+                .Select(e => (string?)e.Attribute(OdfNames.Style + "name")).OfType<string>()
+            ?? Enumerable.Empty<string>());
+
         ProcessBlocks(body.Elements().ToList(), context);
 
-        XDocument? styles = package.GetXml(OdtPackage.StylesEntry);
         List<XElement> headersAndFooters = styles?.Root != null
             ? GetHeadersAndFooters(styles.Root).ToList()
             : new List<XElement>();

TriasDev.Templify/OpenDocument/OdtTextStyles.cs

@@ -19,7 +19,9 @@ namespace TriasDev.Templify.OpenDocument;
 /// <para>
 /// A style is reused when the part already has an automatic text style with exactly the markdown
 /// properties (e.g. one created by an earlier replacement, or an identical one written by LibreOffice).
-/// New styles are named <c>T{n}</c> with the lowest number not used by any style of the part.
+/// New styles are named <c>T{n}</c> with the lowest number not used by any style of the part, nor by a
+/// reserved name: the common styles of <c>styles.xml</c> are visible from <c>content.xml</c>, and a span
+/// referencing a common style <c>T3</c> would take the formatting of an automatic style of the same name.
 /// </para>
 /// <para>
 /// The formatted span is nested inside the span holding the placeholder; ODF combines the properties
@@ -35,6 +37,12 @@ internal sealed class OdtTextStyles
     private static readonly XName _textProperties = OdfNames.Style + "text-properties";
 
     private readonly Dictionary<(XDocument Part, int Key), string> _cache = new Dictionary<(XDocument, int), string>();
+    private readonly HashSet<string> _reservedNames = new HashSet<string>(StringComparer.Ordinal);
+
+    /// <summary>
+    /// Reserves style names that new styles must not take (the names of the common styles of <c>styles.xml</c>).
+    /// </summary>
+    public void ReserveNames(IEnumerable<string> names) => _reservedNames.UnionWith(names);
 
     /// <summary>
     /// Gets the name of an automatic text style of <paramref name="part"/> that renders the formatting of
@@ -63,7 +71,7 @@ internal sealed class OdtTextStyles
 
         if (name == null)
         {
-            name = CreateUniqueName(part.Root);
+            name = CreateUniqueName(part.Root, _reservedNames);
             automaticStyles.Add(new XElement(
                 _styleElement,
                 new XAttribute(_styleName, name),
@@ -146,11 +154,12 @@ private static XElement GetOrCreateAutomaticStyles(XElement root)
         return automaticStyles;
     }
 
-    private static string CreateUniqueName(XElement root)
+    private static string CreateUniqueName(XElement root, HashSet<string> reservedNames)
     {
         HashSet<string> used = new HashSet<string>(
             root.Descendants().Select(e => (string?)e.Attribute(_styleName)).OfType<string>(),
             StringComparer.Ordinal);
+        used.UnionWith(reservedNames);
 
         for (int n = 1; ; n++)
         {