Add formatting options

server/src/main/kotlin/org/javacs/kt/Configuration.kt

@@ -57,6 +57,18 @@ data class InlayHintsConfiguration(
     var chainedHints: Boolean = false
 )
 
+data class KtFmtConfiguration(
+    var style: String = "google",
+    var indent: Int = 4,
+    var maxWidth: Int = 100,
+    var continuationIndent: Int = 8,
+    var removeUnusedImports: Boolean = true,
+)
+
+data class FormattingConfiguration(
+    var formatter: String = "ktfmt",
+    var ktFmt: KtFmtConfiguration = KtFmtConfiguration()
+)
 
 fun getStoragePath(params: InitializeParams): Path? {
     params.initializationOptions?.let { initializationOptions ->
@@ -94,5 +106,6 @@ public data class Configuration(
     val scripts: ScriptsConfiguration = ScriptsConfiguration(),
     val indexing: IndexingConfiguration = IndexingConfiguration(),
     val externalSources: ExternalSourcesConfiguration = ExternalSourcesConfiguration(),
-    val inlayHints: InlayHintsConfiguration = InlayHintsConfiguration()
+    val inlayHints: InlayHintsConfiguration = InlayHintsConfiguration(),
+    val formatting: FormattingConfiguration = FormattingConfiguration(),
 )

server/src/main/kotlin/org/javacs/kt/KotlinTextDocumentService.kt

@@ -8,7 +8,7 @@ import org.javacs.kt.codeaction.codeActions
 import org.javacs.kt.completion.completions
 import org.javacs.kt.definition.goToDefinition
 import org.javacs.kt.diagnostic.convertDiagnostic
-import org.javacs.kt.formatting.formatKotlinCode
+import org.javacs.kt.formatting.FormattingService
 import org.javacs.kt.hover.hoverAt
 import org.javacs.kt.position.offset
 import org.javacs.kt.position.extractRange
@@ -45,6 +45,7 @@ class KotlinTextDocumentService(
 ) : TextDocumentService, Closeable {
     private lateinit var client: LanguageClient
     private val async = AsyncExecutor()
+    private val formattingService = FormattingService(config.formatting)
 
     var debounceLint = Debouncer(Duration.ofMillis(config.diagnostics.debounceTime))
     val lintTodo = mutableSetOf<URI>()
@@ -139,7 +140,7 @@ class KotlinTextDocumentService(
         val code = extractRange(params.textDocument.content, params.range)
         listOf(TextEdit(
             params.range,
-            formatKotlinCode(code, params.options)
+            formattingService.formatKotlinCode(code, params.options)
         ))
     }
 
@@ -215,7 +216,7 @@ class KotlinTextDocumentService(
         LOG.info("Formatting {}", describeURI(params.textDocument.uri))
         listOf(TextEdit(
             Range(Position(0, 0), position(code, code.length)),
-            formatKotlinCode(code, params.options)
+            formattingService.formatKotlinCode(code, params.options)
         ))
     }
 

server/src/main/kotlin/org/javacs/kt/KotlinWorkspaceService.kt

@@ -103,6 +103,22 @@ class KotlinWorkspaceService(
                 }
             }
 
+            // Update options for formatting
+            get("formatting")?.asJsonObject?.apply {
+                val formatting = config.formatting
+                get("formatter")?.asString?.let {
+                    formatting.formatter = it
+                }
+                get("ktfmt")?.asJsonObject?.apply {
+                    val ktfmt = formatting.ktFmt
+                    get("style")?.asString?.let { ktfmt.style = it }
+                    get("indent")?.asInt?.let { ktfmt.indent = it }
+                    get("maxWidth")?.asInt?.let { ktfmt.maxWidth = it }
+                    get("continuationIndent")?.asInt?.let { ktfmt.continuationIndent = it }
+                    get("removeUnusedImports")?.asBoolean?.let { ktfmt.removeUnusedImports = it }
+                }
+            }
+
             // Update options for inlay hints
             get("inlayHints")?.asJsonObject?.apply {
                 val inlayHints = config.inlayHints

server/src/main/kotlin/org/javacs/kt/formatting/Formatter.kt

@@ -1,14 +1,31 @@
 package org.javacs.kt.formatting
 
-import com.facebook.ktfmt.format.Formatter
-import com.facebook.ktfmt.format.FormattingOptions as KtfmtOptions
-import org.eclipse.lsp4j.FormattingOptions
-
-fun formatKotlinCode(
-    code: String,
-    options: FormattingOptions = FormattingOptions(4, true)
-): String = Formatter.format(KtfmtOptions(
-    style = KtfmtOptions.Style.GOOGLE,
-    blockIndent = options.tabSize,
-    continuationIndent = 2 * options.tabSize
-), code)
+import org.javacs.kt.Configuration
+import org.javacs.kt.FormattingConfiguration
+import org.eclipse.lsp4j.FormattingOptions as LspFromattingOptions
+
+private const val DEFAULT_INDENT = 4
+
+class FormattingService(private val config: FormattingConfiguration) {
+
+    private val formatter: Formatter get() = when (config.formatter) {
+        "ktfmt" -> KtFmtFormatter(config.ktFmt)
+        "none" -> NopFormatter
+        else -> KtFmtFormatter(config.ktFmt)
+    }
+
+    fun formatKotlinCode(
+        code: String,
+        options: LspFromattingOptions = LspFromattingOptions(DEFAULT_INDENT, true)
+    ): String = this.formatter.format(code, options)
+}
+
+
+interface Formatter {
+    fun format(code: String, options: LspFromattingOptions): String
+}
+
+object NopFormatter : Formatter {
+    override fun format(code: String, options: LspFromattingOptions): String = code
+}
+

server/src/main/kotlin/org/javacs/kt/formatting/KtFmtFormatter.kt

@@ -0,0 +1,28 @@
+package org.javacs.kt.formatting
+
+import org.javacs.kt.KtFmtConfiguration
+import com.facebook.ktfmt.format.Formatter as KtFmt
+import com.facebook.ktfmt.format.FormattingOptions as KtfmtOptions
+import org.eclipse.lsp4j.FormattingOptions as LspFormattingOptions
+
+class KtFmtFormatter(private val config: KtFmtConfiguration) : Formatter {
+    override fun format(
+        code: String,
+        options: LspFormattingOptions,
+    ): String {
+        val style = when (config.style) {
+            "google" -> KtfmtOptions.Style.GOOGLE
+            "facebook" -> KtfmtOptions.Style.FACEBOOK
+            "dropbox" -> KtfmtOptions.Style.DROPBOX
+            else -> KtfmtOptions.Style.GOOGLE
+        }
+        return KtFmt.format(KtfmtOptions(
+            style = style,
+            maxWidth = config.maxWidth,
+            blockIndent = options.tabSize.takeUnless { it == 0 } ?: config.indent,
+            continuationIndent = config.continuationIndent,
+            removeUnusedImports = config.removeUnusedImports,
+        ), code)
+    }
+}
+