Add support for IntelliJ's "Reformat Code" command

.editorconfig

@@ -5,5 +5,8 @@ indent_size = 4
 indent_style = space
 insert_final_newline = true
 
+[*.md]
+indent_size = 2
+
 [*.yml]
 indent_size = 2

CHANGELOG.md

@@ -6,6 +6,9 @@
 
 - Very simple parser, which should provide just enough of a basis to add basic editor functionality like code
   formatting and auto indentation.
+- Support for IntelliJ's "Reformat Code" command. Currently, this does the following:
+  - Indent blocks
+  - Normalize spacing between tokens on 1 line
 
 ## [0.1.3-alpha] - 2023-03-30
 

README.md

@@ -31,6 +31,7 @@ using [Simon Brown](https://twitter.com/simonbrown)'s [C4 model](https://c4model
 
 * Basic syntax highlighting for the Structurizr DSL language. Files with the `.dsl` extension are considered to be
   Structurizr DSL files.
+* Automatically indent and normalize spacing with IntelliJ's "Reformat Code" command.
 * More to come! Please refer to the [TODO section](https://github.com/dirkgroot/structurizr-dsl-intellij-plugin#todo) of
   the README for a list of features that will likely be added.
 
@@ -73,7 +74,7 @@ using [Simon Brown](https://twitter.com/simonbrown)'s [C4 model](https://c4model
 - ☑️ syntax highlighting
     - ✅ token based
     - 🔳 annotator based
-- 🔳 reformat code
+- ✅ reformat code
 - 🔳 auto indentation
 - 🔳 go to definition
 - 🔳 rename refactoring for identifiers

src/main/kotlin/nl/dirkgroot/structurizr/dsl/lang/SDBlock.kt

@@ -0,0 +1,54 @@
+package nl.dirkgroot.structurizr.dsl.lang
+
+import com.intellij.formatting.*
+import com.intellij.lang.ASTNode
+import com.intellij.psi.TokenType.WHITE_SPACE
+import com.intellij.psi.formatter.common.AbstractBlock
+import com.intellij.psi.tree.TokenSet
+import nl.dirkgroot.structurizr.dsl.psi.SDTypes.*
+
+class SDBlock(
+    node: ASTNode,
+    private val spacingBuilder: SpacingBuilder,
+    private val indent: Indent = Indent.getNoneIndent(),
+    wrap: Wrap = Wrap.createWrap(WrapType.NONE, false),
+    alignment: Alignment = Alignment.createAlignment()
+) : AbstractBlock(node, wrap, alignment) {
+    override fun buildChildren(): MutableList<Block> {
+        val result = mutableListOf<Block>()
+        var child = myNode.firstChildNode
+        while (child != null) {
+            if (child.elementType != WHITE_SPACE && child.elementType != CRLF) {
+                val indent = if (child.elementType in INDENT_TOKEN_TYPES && myNode.treeParent != null)
+                    Indent.getNormalIndent(true)
+                else
+                    Indent.getNoneIndent()
+                val block = SDBlock(child, spacingBuilder, indent)
+                result.add(block)
+            }
+            child = child.treeNext
+        }
+        return result
+    }
+
+    override fun getIndent() = indent
+
+    override fun getSpacing(child1: Block?, child2: Block) = spacingBuilder.getSpacing(this, child1, child2)
+
+    override fun isLeaf() = myNode.firstChildNode == null
+
+    companion object {
+        private val INDENT_TOKEN_TYPES = TokenSet.create(
+            BLOCK_COMMENT,
+            BLOCK_STATEMENT,
+            EXPLICIT_RELATIONSHIP,
+            IDENTIFIER_REFERENCES,
+            IMPLICIT_RELATIONSHIP,
+            KEY_VALUE_PAIR,
+            LINE_COMMENT,
+            PROPERTY_BLOCK_STATEMENT,
+            SCRIPT_BLOCK,
+            SINGLE_LINE_STATEMENT,
+        )
+    }
+}

src/main/kotlin/nl/dirkgroot/structurizr/dsl/lang/SDFormattingModelBuilder.kt

@@ -0,0 +1,23 @@
+package nl.dirkgroot.structurizr.dsl.lang
+
+import com.intellij.formatting.*
+import com.intellij.psi.codeStyle.CodeStyleSettings
+import nl.dirkgroot.structurizr.dsl.StructurizrDSLLanguage
+import nl.dirkgroot.structurizr.dsl.psi.SDTypes
+
+class SDFormattingModelBuilder : FormattingModelBuilder {
+    override fun createModel(formattingContext: FormattingContext): FormattingModel =
+        FormattingModelProvider.createFormattingModelForPsiFile(
+            formattingContext.containingFile,
+            SDBlock(formattingContext.node, createSpacingBuilder(formattingContext.codeStyleSettings)),
+            formattingContext.codeStyleSettings
+        )
+
+    private fun createSpacingBuilder(codeStyleSettings: CodeStyleSettings) =
+        SpacingBuilder(codeStyleSettings, StructurizrDSLLanguage)
+            .around(SDTypes.EQUALS).spaces(1)
+            .around(SDTypes.IDENTIFIER_NAME).spaces(1)
+            .before(SDTypes.ARGUMENT).spaces(1)
+            .before(SDTypes.BRACE1).spaces(1)
+            .between(SDTypes.KEY, SDTypes.VALUE).spaces(1)
+}

src/main/resources/META-INF/plugin.xml

@@ -15,6 +15,8 @@
                                        implementationClass="nl.dirkgroot.structurizr.dsl.syntax.StructurizrDSLSyntaxHighlighterFactory"/>
         <lang.parserDefinition language="StructurizrDSL"
                                implementationClass="nl.dirkgroot.structurizr.dsl.lang.StructurizrDSLParserDefinition"/>
+        <lang.formatter language="StructurizrDSL"
+                        implementationClass="nl.dirkgroot.structurizr.dsl.lang.SDFormattingModelBuilder"/>
     </extensions>
 
     <actions>

src/test/kotlin/nl/dirkgroot/structurizr/dsl/editing/formatter/FormatterTest.kt

@@ -0,0 +1,18 @@
+package nl.dirkgroot.structurizr.dsl.editing.formatter
+
+import com.intellij.openapi.command.WriteCommandAction
+import com.intellij.psi.codeStyle.CodeStyleManager
+import nl.dirkgroot.structurizr.dsl.support.StructurizrDSLCodeInsightTest
+
+abstract class FormatterTest : StructurizrDSLCodeInsightTest() {
+    protected fun assertFormattingResult(code: String, expectedResult: String) {
+        val file = fixture.addFileToProject("test.dsl", code)
+        fixture.openFileInEditor(file.virtualFile)
+
+        WriteCommandAction.writeCommandAction(project).run<Exception> {
+            CodeStyleManager.getInstance(project)
+                .reformatText(fixture.file, listOf(fixture.file.textRange))
+        }
+        fixture.checkResult(expectedResult)
+    }
+}

src/test/kotlin/nl/dirkgroot/structurizr/dsl/editing/formatter/IndentationTest.kt

@@ -0,0 +1,229 @@
+package nl.dirkgroot.structurizr.dsl.editing.formatter
+
+import org.junit.jupiter.api.Test
+
+class IndentationTest : FormatterTest() {
+    @Test
+    fun `block with single line element`() {
+        assertFormattingResult(
+            """
+                softwareSystem name description {
+                container Backend
+                }
+            """.trimIndent(),
+            """
+                softwareSystem name description {
+                    container Backend
+                }
+            """.trimIndent(),
+        )
+    }
+
+    @Test
+    fun `nested blocks`() {
+        assertFormattingResult(
+            """
+                softwareSystem name description {
+                container Backend {
+                component RestAPI
+                }
+                }
+            """.trimIndent(),
+            """
+                softwareSystem name description {
+                    container Backend {
+                        component RestAPI
+                    }
+                }
+            """.trimIndent(),
+        )
+    }
+
+    @Test
+    fun `property block`() {
+        assertFormattingResult(
+            """
+                properties {
+                a b
+                c d
+                }
+            """.trimIndent(),
+            """
+                properties {
+                    a b
+                    c d
+                }
+            """.trimIndent(),
+        )
+    }
+
+    @Test
+    fun `nested property block`() {
+        assertFormattingResult(
+            """
+                softwareSystem system {
+                properties {
+                a b
+                c d
+                }
+                }
+            """.trimIndent(),
+            """
+                softwareSystem system {
+                    properties {
+                        a b
+                        c d
+                    }
+                }
+            """.trimIndent(),
+        )
+    }
+
+    @Test
+    fun `block with assigned identifier`() {
+        assertFormattingResult(
+            """
+                systemIdentifier = softwareSystem system {
+                container backend
+                }
+            """.trimIndent(),
+            """
+                systemIdentifier = softwareSystem system {
+                    container backend
+                }
+            """.trimIndent(),
+        )
+    }
+
+    @Test
+    fun `script block`() {
+        assertFormattingResult(
+            """
+                !script kotlin {
+                println("Hello World")
+                }
+            """.trimIndent(),
+            """
+                !script kotlin {
+                println("Hello World")
+                }
+            """.trimIndent(),
+        )
+    }
+
+    @Test
+    fun `nested script block`() {
+        assertFormattingResult(
+            """
+                workspace {
+                !script kotlin {
+                println("Hello World")
+                }
+                }
+            """.trimIndent(),
+            """
+                workspace {
+                    !script kotlin {
+                println("Hello World")
+                }
+                }
+            """.trimIndent(),
+        )
+    }
+
+    @Test
+    fun `explicit relationships`() {
+        assertFormattingResult(
+            """
+                model {
+                    a = softwareSystem A
+                    b = softwareSystem B
+                a -> b Uses
+                }
+            """.trimIndent(),
+            """
+                model {
+                    a = softwareSystem A
+                    b = softwareSystem B
+                    a -> b Uses
+                }
+            """.trimIndent()
+        )
+    }
+
+    @Test
+    fun `implicit relationships`() {
+        assertFormattingResult(
+            """
+                model {
+                    a = softwareSystem A
+                    b = softwareSystem B {
+                    -> a Uses
+                    }
+                }
+            """.trimIndent(),
+            """
+                model {
+                    a = softwareSystem A
+                    b = softwareSystem B {
+                        -> a Uses
+                    }
+                }
+            """.trimIndent()
+        )
+    }
+
+    @Test
+    fun `line comments`() {
+        assertFormattingResult(
+            """
+                model {
+                # comment
+                }
+            """.trimIndent(),
+            """
+                model {
+                    # comment
+                }
+            """.trimIndent()
+        )
+    }
+
+    @Test
+    fun `block comments`() {
+        assertFormattingResult(
+            """
+                model {
+                /*
+                comment
+                */
+                }
+            """.trimIndent(),
+            """
+                model {
+                    /*
+                    comment
+                    */
+                }
+            """.trimIndent()
+        )
+    }
+
+    @Test
+    fun `identifier references`() {
+        assertFormattingResult(
+            """
+                animation {
+                a b c
+                d
+                }
+            """.trimIndent(),
+            """
+                animation {
+                    a b c
+                    d
+                }
+            """.trimIndent()
+        )
+    }
+}