fix: type erasure breaking nested generics (#285)

json-schema/src/main/kotlin/io/bkbn/kompendium/json/schema/handler/SimpleObjectHandler.kt

@@ -13,6 +13,7 @@ import kotlin.reflect.KProperty
 import kotlin.reflect.KType
 import kotlin.reflect.KTypeParameter
 import kotlin.reflect.KTypeProjection
+import kotlin.reflect.full.createType
 import kotlin.reflect.full.memberProperties
 import kotlin.reflect.full.primaryConstructor
 
@@ -22,9 +23,12 @@ object SimpleObjectHandler {
     // cache[type.getSimpleSlug()] = ReferenceDefinition("RECURSION_PLACEHOLDER")
     val typeMap = clazz.typeParameters.zip(type.arguments).toMap()
     val props = clazz.memberProperties.associate { prop ->
-      val schema = when (typeMap.containsKey(prop.returnType.classifier)) {
-        true -> handleGenericProperty(prop, typeMap, cache)
-        false -> handleProperty(prop, cache)
+      val schema = when (prop.needsToInjectGenerics(typeMap)) {
+        true -> handleNestedGenerics(typeMap, prop, cache)
+        false -> when (typeMap.containsKey(prop.returnType.classifier)) {
+          true -> handleGenericProperty(prop, typeMap, cache)
+          false -> handleProperty(prop, cache)
+        }
       }
 
       prop.name to schema
@@ -48,6 +52,34 @@ object SimpleObjectHandler {
     }
   }
 
+  private fun KProperty<*>.needsToInjectGenerics(
+    typeMap: Map<KTypeParameter, KTypeProjection>
+  ): Boolean {
+    val typeSymbols = returnType.arguments.map { it.type.toString() }
+    return typeMap.any { (k, _) -> typeSymbols.contains(k.name) }
+  }
+
+  private fun handleNestedGenerics(
+    typeMap: Map<KTypeParameter, KTypeProjection>,
+    prop: KProperty<*>,
+    cache: MutableMap<String, JsonSchema>
+  ): JsonSchema {
+    val propClass = prop.returnType.classifier as KClass<*>
+    val types = prop.returnType.arguments.map {
+      val typeSymbol = it.type.toString()
+      typeMap.filterKeys { k -> k.name == typeSymbol }.values.first()
+    }
+    val constructedType = propClass.createType(types)
+    return SchemaGenerator.fromTypeToSchema(constructedType, cache).let {
+      if (it is TypeDefinition && it.type == "object") {
+        cache[constructedType.getSimpleSlug()] = it
+        ReferenceDefinition(prop.returnType.getReferenceSlug())
+      } else {
+        it
+      }
+    }
+  }
+
   private fun handleGenericProperty(
     prop: KProperty<*>,
     typeMap: Map<KTypeParameter, KTypeProjection>,