Kotlin rewrite, adding diagram options

5 files changed, 129 insertions, 0 deletions

diff --git a/src/main/kotlin/org/pacien/pandoc/filter/plantuml/Filter.kt b/src/main/kotlin/org/pacien/pandoc/filter/plantuml/Filter.kt
new file mode 100644
index 0000000..82a78b5
--- /dev/null
+++ b/src/main/kotlin/org/pacien/pandoc/filter/plantuml/Filter.kt
@@ -0,0 +1,57 @@
+package org.pacien.pandoc.filter.plantuml
+
+import com.fasterxml.jackson.databind.JsonNode
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.databind.node.ArrayNode
+import com.fasterxml.jackson.databind.node.ObjectNode
+import com.fasterxml.jackson.databind.node.TextNode
+import java.io.InputStream
+import java.io.OutputStream
+
+object Filter {
+  private val mapper = ObjectMapper()
+
+  private inline fun <T> T.conditionally(condition: Boolean, block: (T) -> T): T =
+    if (condition) block(this) else this
+
+  private inline fun <T, A> T.withNonNull(value: A?, block: (T, A) -> T): T =
+    if (value != null) block(this, value) else this
+
+  private fun JsonNode.isCodeBlock() = type() == "CodeBlock"
+  private fun JsonNode.isPlantUmlBlock() = isCodeBlock() && "puml" in classNames()
+
+  private fun Latex.resizeBox(attrs: Map<String, String>) =
+    resizeBox(attrs["width"] ?: "!", attrs["height"] ?: "!")
+
+  private fun Latex.setOptions(classes: List<String>, attrs: Map<String, String>) =
+    this
+      .conditionally("width" in attrs || "height" in attrs) { it -> it.resizeBox(attrs) }
+      .conditionally("centered" in classes, Latex::centering)
+      .withNonNull(attrs["caption"], Latex::caption)
+      .withNonNull(attrs["label"], Latex::label)
+      .conditionally("caption" in attrs || "label" in attrs, Latex::figure)
+
+  private fun arrayNodeOf(type: String, content: String): ArrayNode =
+    mapper.createArrayNode()
+      .add(TextNode.valueOf(type))
+      .add(TextNode.valueOf(content))
+
+  private fun renderPlantumlNode(node: ObjectNode) {
+    val puml = node.content()
+    val tikz = PlantUml.renderTikz(puml)
+    val block = tikz.setOptions(node.classNames(), node.attributeMap())
+    node.setBlock("RawBlock", arrayNodeOf("latex", block.raw()))
+  }
+
+  private fun walk(node: JsonNode): Unit = when {
+    node.isPlantUmlBlock() -> renderPlantumlNode(node as ObjectNode)
+    else -> node.forEach(Filter::walk)
+  }
+
+  fun filter(input: InputStream, output: OutputStream) {
+    mapper.readTree(input)?.let { tree ->
+      walk(tree)
+      mapper.writeValue(output, tree)
+    }
+  }
+}
diff --git a/src/main/kotlin/org/pacien/pandoc/filter/plantuml/Latex.kt b/src/main/kotlin/org/pacien/pandoc/filter/plantuml/Latex.kt
new file mode 100644
index 0000000..48ce087
--- /dev/null
+++ b/src/main/kotlin/org/pacien/pandoc/filter/plantuml/Latex.kt
@@ -0,0 +1,16 @@
+package org.pacien.pandoc.filter.plantuml
+
+fun Sequence<String>.toLatex() = Latex(this)
+
+class Latex(private val body: Sequence<String>) {
+  fun raw() = body.filterNot(String::isEmpty).joinToString("\n")
+
+  private fun surround(prefix: String, suffix: String) =
+    Latex(sequenceOf(prefix) + body + sequenceOf(suffix))
+
+  fun resizeBox(width: String, height: String) = surround("\\resizebox{$width}{$height}{", "}")
+  fun centering() = surround("\\centering", "")
+  fun label(label: String) = surround("", "\\label{$label}")
+  fun caption(caption: String) = surround("", "\\caption{$caption}")
+  fun figure() = surround("\\begin{figure}[h]", "\\end{figure}")
+}
diff --git a/src/main/kotlin/org/pacien/pandoc/filter/plantuml/Main.kt b/src/main/kotlin/org/pacien/pandoc/filter/plantuml/Main.kt
new file mode 100644
index 0000000..1ebe8f9
--- /dev/null
+++ b/src/main/kotlin/org/pacien/pandoc/filter/plantuml/Main.kt
@@ -0,0 +1,5 @@
+package org.pacien.pandoc.filter.plantuml
+
+fun main(args: Array<String>) {
+  Filter.filter(System.`in`, System.out)
+}
diff --git a/src/main/kotlin/org/pacien/pandoc/filter/plantuml/PandocNode.kt b/src/main/kotlin/org/pacien/pandoc/filter/plantuml/PandocNode.kt
new file mode 100644
index 0000000..8b3ddde
--- /dev/null
+++ b/src/main/kotlin/org/pacien/pandoc/filter/plantuml/PandocNode.kt
@@ -0,0 +1,30 @@
+package org.pacien.pandoc.filter.plantuml
+
+import com.fasterxml.jackson.databind.JsonNode
+import com.fasterxml.jackson.databind.node.ObjectNode
+import com.fasterxml.jackson.databind.node.TextNode
+
+// Structure of a content node:
+// {
+//   "t": "CodeBlock",
+//   "c": [
+//     [
+//       "",
+//       [ "puml", "otherClass" ],
+//       [ ["scale", "0.5"], ["key", "value"] ]
+//     ],
+//     "@startuml\n@enduml"
+//   ]
+// }
+
+fun JsonNode.type(): String = path("t").asText()
+fun JsonNode.classes(): JsonNode = path("c").path(0).path(1)
+fun JsonNode.classNames(): List<String> = classes().map(JsonNode::asText)
+fun JsonNode.attributes(): JsonNode = path("c").path(0).path(2)
+fun JsonNode.attributePair(): Pair<String, String> = Pair(path(0).asText(), path(1).asText())
+fun JsonNode.attributeMap(): Map<String, String> = attributes().associate(JsonNode::attributePair)
+fun JsonNode.content(): String = path("c").path(1).asText()
+
+fun ObjectNode.setBlockType(type: String) = apply { set("t", TextNode.valueOf(type)) }
+fun ObjectNode.setBlockContent(content: JsonNode) = apply { set("c", content) }
+fun ObjectNode.setBlock(type: String, content: JsonNode) = setBlockType(type).setBlockContent(content)
diff --git a/src/main/kotlin/org/pacien/pandoc/filter/plantuml/PlantUml.kt b/src/main/kotlin/org/pacien/pandoc/filter/plantuml/PlantUml.kt
new file mode 100644
index 0000000..2a8da1b
--- /dev/null
+++ b/src/main/kotlin/org/pacien/pandoc/filter/plantuml/PlantUml.kt
@@ -0,0 +1,21 @@
+package org.pacien.pandoc.filter.plantuml
+
+import net.sourceforge.plantuml.FileFormat
+import net.sourceforge.plantuml.FileFormatOption
+import net.sourceforge.plantuml.SourceStringReader
+import java.io.ByteArrayOutputStream
+
+object PlantUml {
+  private val OUTPUT_FORMAT = FileFormatOption(FileFormat.LATEX_NO_PREAMBLE)
+
+  private fun SourceStringReader.generateImage(outputFormat: FileFormatOption) =
+    ByteArrayOutputStream().use { buffer ->
+      generateImage(buffer, outputFormat)
+      buffer.toString().lineSequence()
+    }
+
+  fun renderTikz(plantuml: String) =
+    SourceStringReader(plantuml)
+      .generateImage(OUTPUT_FORMAT)
+      .toLatex()
+}