feat: recursively flatten files

src/main/kotlin/XmlIncludeFlattener.kt

@@ -1,6 +1,7 @@
 package io.github.tacascer
 
 import io.github.oshai.kotlinlogging.KotlinLogging
+import org.jdom2.Document
 import org.jdom2.Element
 import org.jdom2.filter.Filters
 import org.jdom2.input.SAXBuilder
@@ -35,27 +36,37 @@ class XmlIncludeFlattener(private val input: Path, format: Format = Format.getPr
      * @throws Exception if an error occurs during processing
      */
     fun process(): String {
-        doProcess()
+        val output = process(inputDocument)
         return StringWriter().use {
-            outputter.output(inputDocument, it)
+            outputter.output(output, it)
             it.toString()
         }
     }
 
-    private fun doProcess() {
-        inputDocument.getDescendants(Filters.element()).filter { it.name == "include" }.forEach {
-            it.detach()
-            inlineInclude(it)
-        }
+    private fun process(inputDocument: Document): Document {
+        val output = inputDocument.clone()
+        val includeElements = output.getDescendants(Filters.element()).filter { it.name == "include" }
+        includeElements.forEach(Element::detach)
+        includeElements
+            .map { it.toDocument().inline() }
+            .forEach { includedDocument ->
+                output.rootElement.addContent(
+                    includedDocument.rootElement.getDescendants(Filters.element()).map(Element::clone)
+                )
+            }
+        return output
     }
 
-    private fun inlineInclude(include: Element) {
-        val includedSchema = include.getAttributeValue("schemaLocation")
+    private fun Element.toDocument(): Document {
+        val includedSchema = getAttributeValue("schemaLocation")
         logger.info { "Processing included schema: $includedSchema" }
         val includedDocument = saxBuilder.build(URI(includedSchema).toPath().inputStream())
-        includedDocument.rootElement.getDescendants(Filters.element()).toList().forEach {
-            it.detach()
-            inputDocument.rootElement.addContent(it)
-        }
+        return includedDocument
+    }
+
+    private fun Document.inline(): Document {
+        val inlinedDocument = process(this)
+        val output = inlinedDocument.clone()
+        return output
     }
 }

src/test/kotlin/XmlIncludeFlattenerTest.kt

@@ -1,4 +1,3 @@
-
 import io.github.tacascer.XmlIncludeFlattener
 import io.kotest.core.spec.style.FunSpec
 import io.kotest.engine.spec.tempdir
@@ -37,6 +36,48 @@ class XmlIncludeFlattenerTest : FunSpec({
             <xs:element name="sampleOne" type="xs:string" />
         </xs:schema>
         """.trimIndent()
-        XmlIncludeFlattener(includingFile).process().trimIndent() shouldBe  expectedText
+        XmlIncludeFlattener(includingFile).process().trimIndent() shouldBe expectedText
+    }
+
+    test("given one xsd that includes another xsd that includes another, then should return a single xsd with all elements") {
+        val testDir = tempdir()
+        val includingFile = testDir.toPath().resolve("sample.xsd").createFile()
+        val includedFile = testDir.toPath().resolve("sample_1.xsd").createFile()
+        val includedFile2 = testDir.toPath().resolve("sample_2.xsd").createFile()
+        @Language("XML") val includingFileText = """
+        <?xml version="1.0" encoding="UTF-8"?>
+        <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.sample.com">
+            <xs:include schemaLocation="${testDir.toPath().resolve("sample_1.xsd").toUri()}"/>
+            <xs:element name="sample" type="xs:string"/>
+        </xs:schema>
+        """.trimIndent()
+        includingFile.writeText(
+            includingFileText
+        )
+        @Language("XML") val includedFileText = """
+        <?xml version="1.0" encoding="UTF-8"?>
+        <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
+            <xs:include schemaLocation="${testDir.toPath().resolve("sample_2.xsd").toUri()}"/>
+            <xs:element name="sampleOne" type="xs:string"/>
+        </xs:schema>
+        """.trimIndent()
+        includedFile.writeText(includedFileText)
+        @Language("XML") val includedFile2Text = """
+        <?xml version="1.0" encoding="UTF-8"?>
+        <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
+            <xs:element name="sampleTwo" type="xs:string"/>
+        </xs:schema>
+        """.trimIndent()
+        includedFile2.writeText(includedFile2Text)
+
+        @Language("XML") val expectedText = """
+        <?xml version="1.0" encoding="UTF-8"?>
+        <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.sample.com">
+            <xs:element name="sample" type="xs:string" />
+            <xs:element name="sampleOne" type="xs:string" />
+            <xs:element name="sampleTwo" type="xs:string" />
+        </xs:schema>
+        """.trimIndent()
+        XmlIncludeFlattener(includingFile).process().trimIndent() shouldBe expectedText
     }
 })