Support default values from OpenAPI spec in generated models

openapi-generator/src/main/kotlin/org/jellyfin/openapi/builder/api/OperationBuilder.kt

@@ -5,19 +5,18 @@ import com.squareup.kotlinpoet.FunSpec
 import com.squareup.kotlinpoet.KModifier
 import com.squareup.kotlinpoet.MemberName
 import com.squareup.kotlinpoet.ParameterSpec
-import com.squareup.kotlinpoet.ParameterizedTypeName
 import com.squareup.kotlinpoet.ParameterizedTypeName.Companion.plusParameter
 import com.squareup.kotlinpoet.buildCodeBlock
 import org.jellyfin.openapi.builder.Builder
 import org.jellyfin.openapi.builder.extra.DeprecatedAnnotationSpecBuilder
 import org.jellyfin.openapi.builder.extra.DescriptionBuilder
+import org.jellyfin.openapi.builder.extra.defaultValue
 import org.jellyfin.openapi.constants.Classes
 import org.jellyfin.openapi.constants.Packages
 import org.jellyfin.openapi.constants.Strings
 import org.jellyfin.openapi.constants.Types
 import org.jellyfin.openapi.model.ApiServiceOperation
 import org.jellyfin.openapi.model.ApiServiceOperationParameter
-import org.jellyfin.openapi.model.CustomDefaultValue
 import org.jellyfin.openapi.model.IntRangeValidation
 import org.jellyfin.openapi.model.ParameterValidation
 
@@ -44,30 +43,7 @@ open class OperationBuilder(
 	protected fun buildParameter(
 		data: ApiServiceOperationParameter,
 	) = ParameterSpec.builder(data.name, data.type).apply {
-		// Determine class name without parameters
+		defaultValue(data)
-		val typeClassName = when (data.type) {
-			is ClassName -> data.type
-			is ParameterizedTypeName -> data.type.rawType
-			else -> null
-		}
-
-		// Set default value
-		when (data.defaultValue) {
-			is String -> defaultValue("%S", data.defaultValue)
-			is Int -> defaultValue("%L", data.defaultValue)
-			is Boolean -> defaultValue("%L", data.defaultValue)
-			is CustomDefaultValue -> defaultValue(data.defaultValue.build())
-			// Set value to null by default for nullable values
-			null -> when {
-				typeClassName == Types.COLLECTION ->
-					defaultValue("%M()", MemberName("kotlin.collections", "emptyList"))
-				typeClassName == Types.LIST ->
-					defaultValue("%M()", MemberName("kotlin.collections", "emptyList"))
-				typeClassName == Types.MAP ->
-					defaultValue("%M()", MemberName("kotlin.collections", "emptyMap"))
-				data.type.isNullable -> defaultValue("%L", "null")
-			}
-		}
 
 		// Add description
 		descriptionBuilder.build(data.description)?.let {

openapi-generator/src/main/kotlin/org/jellyfin/openapi/builder/extra/defaultValueExtensions.kt

@@ -0,0 +1,57 @@
+package org.jellyfin.openapi.builder.extra
+
+import com.squareup.kotlinpoet.ClassName
+import com.squareup.kotlinpoet.MemberName
+import com.squareup.kotlinpoet.ParameterSpec
+import com.squareup.kotlinpoet.ParameterizedTypeName
+import com.squareup.kotlinpoet.TypeName
+import org.jellyfin.openapi.constants.Types
+import org.jellyfin.openapi.model.ApiServiceOperationParameter
+import org.jellyfin.openapi.model.CustomDefaultValue
+import org.jellyfin.openapi.model.ObjectApiModelProperty
+
+fun ParameterSpec.Builder.defaultValue(
+	type: TypeName,
+	defaultValue: Any?,
+	allowEmptyCollection: Boolean,
+) {
+	// Determine class name without parameters
+	val typeClassName = when (type) {
+		is ClassName -> type
+		is ParameterizedTypeName -> type.rawType
+		else -> null
+	}
+
+	// Set default value
+	when (defaultValue) {
+		is String -> defaultValue("%S", defaultValue)
+		is Int -> defaultValue("%L", defaultValue)
+		is Boolean -> defaultValue("%L", defaultValue)
+		is CustomDefaultValue -> defaultValue(defaultValue.build())
+		// Set value to null by default for nullable values
+		null -> when {
+			typeClassName == Types.COLLECTION && allowEmptyCollection ->
+				defaultValue("%M()", MemberName("kotlin.collections", "emptyList"))
+
+			typeClassName == Types.LIST && allowEmptyCollection ->
+				defaultValue("%M()", MemberName("kotlin.collections", "emptyList"))
+
+			typeClassName == Types.MAP && allowEmptyCollection ->
+				defaultValue("%M()", MemberName("kotlin.collections", "emptyMap"))
+
+			type.isNullable -> defaultValue("%L", "null")
+		}
+	}
+}
+
+fun ParameterSpec.Builder.defaultValue(parameter: ApiServiceOperationParameter) = defaultValue(
+	type = parameter.type,
+	defaultValue = parameter.defaultValue,
+	allowEmptyCollection = true,
+)
+
+fun ParameterSpec.Builder.defaultValue(property: ObjectApiModelProperty) = defaultValue(
+	type = property.type,
+	defaultValue = property.defaultValue,
+	allowEmptyCollection = false,
+)

openapi-generator/src/main/kotlin/org/jellyfin/openapi/builder/model/ObjectModelBuilder.kt

@@ -13,6 +13,7 @@ import org.jellyfin.openapi.builder.Builder
 import org.jellyfin.openapi.builder.extra.DeprecatedAnnotationSpecBuilder
 import org.jellyfin.openapi.builder.extra.DescriptionBuilder
 import org.jellyfin.openapi.builder.extra.TypeSerializerBuilder
+import org.jellyfin.openapi.builder.extra.defaultValue
 import org.jellyfin.openapi.constants.Packages
 import org.jellyfin.openapi.constants.Strings
 import org.jellyfin.openapi.constants.Types
@@ -32,8 +33,7 @@ class ObjectModelBuilder(
 			data.properties.forEach { property ->
 				// Create constructor parameter
 				addParameter(ParameterSpec.builder(property.name, property.type).apply {
-					// Set value to null by default for nullable values
+					defaultValue(property)
-					if (property.type.isNullable) defaultValue("%L", "null")
 				}.build())
 
 				// Create class property

openapi-generator/src/main/kotlin/org/jellyfin/openapi/builder/openapi/OpenApiModelBuilder.kt

@@ -36,6 +36,7 @@ class OpenApiModelBuilder(
 						ObjectApiModelProperty(
 							name = name,
 							originalName = originalName,
+							defaultValue = property.default,
 							type = openApiTypeBuilder.build(ModelTypePath(data.name, name), property),
 							description = property.description,
 							deprecated = property.deprecated == true

openapi-generator/src/main/kotlin/org/jellyfin/openapi/model/ObjectApiModelProperty.kt

@@ -5,6 +5,7 @@ import com.squareup.kotlinpoet.TypeName
 data class ObjectApiModelProperty(
 	val name: String,
 	val originalName: String,
+	val defaultValue: Any?,
 	val type: TypeName,
 	val description: String?,
 	val deprecated: Boolean