resolves yuzutech#1268 support Structurizr themes

server/src/main/java/io/kroki/server/service/Structurizr.java

@@ -4,13 +4,18 @@
 import com.structurizr.dsl.StructurizrDslParserException;
 import com.structurizr.export.Diagram;
 import com.structurizr.export.plantuml.StructurizrPlantUMLExporter;
+import com.structurizr.view.Border;
 import com.structurizr.view.ComponentView;
 import com.structurizr.view.ContainerView;
 import com.structurizr.view.DeploymentView;
 import com.structurizr.view.DynamicView;
+import com.structurizr.view.ElementStyle;
+import com.structurizr.view.RelationshipStyle;
+import com.structurizr.view.Shape;
 import com.structurizr.view.SystemContextView;
 import com.structurizr.view.SystemLandscapeView;
 import com.structurizr.view.View;
+import com.structurizr.view.ViewSet;
 import io.kroki.server.decode.DiagramSource;
 import io.kroki.server.decode.SourceDecoder;
 import io.kroki.server.error.BadRequestException;
@@ -20,13 +25,22 @@
 import io.vertx.core.Handler;
 import io.vertx.core.Vertx;
 import io.vertx.core.buffer.Buffer;
+import io.vertx.core.json.Json;
+import io.vertx.core.json.JsonArray;
 import io.vertx.core.json.JsonObject;
 
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.stream.Collectors;
 
 public class Structurizr implements DiagramService {
 
@@ -37,6 +51,12 @@ public class Structurizr implements DiagramService {
   // same as PlantUML since we convert Structurizr DSL to PlantUML
   private static final List<FileFormat> SUPPORTED_FORMATS = Arrays.asList(FileFormat.PNG, FileFormat.SVG, FileFormat.JPEG, FileFormat.BASE64, FileFormat.TXT, FileFormat.UTXT);
 
+  private static final String aws = read("structurizr/amazon-web-services.json");
+  private static final String gcp = read("structurizr/google-cloud-platform.json");
+  private static final String k8s = read("structurizr/kubernetes.json");
+  private static final String azure = read("structurizr/microsoft-azure.json");
+  private static final String oracleCloud = read("structurizr/oracle-cloud-infrastructure.json");
+
   public Structurizr(Vertx vertx) {
     this.vertx = vertx;
     this.structurizrPlantUMLExporter = new StructurizrPlantUMLExporter();
@@ -79,7 +99,8 @@ static byte[] convert(String source, FileFormat fileFormat, StructurizrPlantUMLE
     StructurizrDslParser parser = new StructurizrDslParser();
     try {
       parser.parse(source);
-      Collection<View> views = parser.getWorkspace().getViews().getViews();
+      ViewSet viewSet = parser.getWorkspace().getViews();
+      Collection<View> views = viewSet.getViews();
       if (views.isEmpty()) {
         throw new BadRequestException("Empty diagram, does not have any view.");
       }
@@ -95,6 +116,14 @@ static byte[] convert(String source, FileFormat fileFormat, StructurizrPlantUMLE
         // take the first view if not specified
         selectedView = views.iterator().next();
       }
+      for (String url : viewSet.getConfiguration().getThemes()) {
+        if (url.startsWith("https://static.structurizr.com/themes/")) {
+          String themeContent = getThemeContent(url);
+          if (themeContent != null) {
+            applyTheme(viewSet, themeContent);
+          }
+        }
+      }
       final Diagram diagram;
       if (selectedView instanceof DynamicView) {
         diagram = structurizrPlantUMLExporter.export((DynamicView) selectedView);
@@ -123,4 +152,112 @@ static byte[] convert(String source, FileFormat fileFormat, StructurizrPlantUMLE
       throw new BadRequestException(message, e);
     }
   }
+
+  private static void applyTheme(ViewSet viewSet, String themeContent) {
+    Object value = Json.decodeValue(themeContent);
+    if (value instanceof JsonObject) {
+      List<ElementStyle> elementStyles = getElementStyles((JsonObject) value);
+      for (ElementStyle elementStyle : elementStyles) {
+        viewSet.getConfiguration().getStyles().add(elementStyle);
+      }
+      List<RelationshipStyle> relationshipStyles = getRelationshipStyle((JsonObject) value);
+      for (RelationshipStyle relationshipStyle : relationshipStyles) {
+        viewSet.getConfiguration().getStyles().add(relationshipStyle);
+      }
+    }
+  }
+
+  private static List<ElementStyle> getElementStyles(JsonObject value) {
+    List<ElementStyle> result = new ArrayList<>();
+    Object elementsObject = value.getValue("elements");
+    if (elementsObject instanceof JsonArray) {
+      for (Object elementObject : ((JsonArray) elementsObject).getList()) {
+        if (elementObject instanceof Map) {
+          JsonObject element = new JsonObject((Map<String, Object>) elementObject);
+          ElementStyle elementStyle = new ElementStyle(
+            element.getString("tag"),
+            element.getInteger("width"),
+            element.getInteger("height"),
+            element.getString("background", "#FFFFFF"), // remind: cannot pass a null value
+            element.getString("color", "#000000"), // remind: cannot pass a null value
+            element.getInteger("fontSize")
+          );
+          elementStyle.setBorder(getBorder(element));
+          elementStyle.setStroke(element.getString("stroke"));
+          elementStyle.setShape(getShape(element));
+          elementStyle.setIcon(element.getString("icon"));
+          elementStyle.setOpacity(element.getInteger("opacity"));
+          elementStyle.setMetadata(element.getBoolean("metadata"));
+          elementStyle.setDescription(element.getBoolean("description"));
+          result.add(elementStyle);
+        }
+      }
+    }
+    return result;
+  }
+
+  private static String getThemeContent(String url) {
+    if (url.contains("amazon-web-services")) {
+      return aws;
+    }
+    if (url.contains("google-cloud-platform")) {
+      return gcp;
+    }
+    if (url.contains("kubernetes")) {
+      return k8s;
+    }
+    if (url.contains("microsoft-azure")) {
+      return azure;
+    }
+    if (url.contains("oracle-cloud-infrastructure")) {
+      return oracleCloud;
+    }
+    return null;
+  }
+
+  private static List<RelationshipStyle> getRelationshipStyle(JsonObject value) {
+    List<RelationshipStyle> result = new ArrayList<>();
+    // remind: RelationshipStyle does not have a public constructor, as a result, we cannot instantiate it.
+    return result;
+  }
+
+  private static String read(String resource) {
+    InputStream input = Thread.currentThread().getContextClassLoader().getResourceAsStream(resource);
+    try {
+      if (input == null) {
+        throw new IOException("Unable to get resource: " + resource);
+      }
+      try (BufferedReader buffer = new BufferedReader(new InputStreamReader(input))) {
+        return buffer.lines().collect(Collectors.joining("\n"));
+      }
+    } catch (IOException e) {
+      throw new RuntimeException("Unable to initialize the Structurizr service", e);
+    }
+  }
+
+  private static Shape getShape(JsonObject element) {
+    String shapeValue = element.getString("shape");
+    if (shapeValue == null) {
+      return null;
+    }
+    try {
+      return Shape.valueOf(shapeValue);
+    } catch (IllegalArgumentException e) {
+      // ignore!
+      return null;
+    }
+  }
+
+  private static Border getBorder(JsonObject element) {
+    String borderValue = element.getString("border");
+    if (borderValue == null) {
+      return null;
+    }
+    try {
+      return Border.valueOf(borderValue);
+    } catch (IllegalArgumentException e) {
+      // ignore!
+      return null;
+    }
+  }
 }