Refactor assertion context

src/commonMain/kotlin/io/github/optimumcode/json/schema/JsonSchema.kt

@@ -3,6 +3,7 @@ package io.github.optimumcode.json.schema
 import io.github.optimumcode.json.pointer.JsonPointer
 import io.github.optimumcode.json.schema.internal.AssertionWithPath
 import io.github.optimumcode.json.schema.internal.DefaultAssertionContext
+import io.github.optimumcode.json.schema.internal.DefaultReferenceResolver
 import io.github.optimumcode.json.schema.internal.JsonSchemaAssertion
 import io.github.optimumcode.json.schema.internal.RefId
 import io.github.optimumcode.json.schema.internal.SchemaLoader
@@ -27,7 +28,7 @@ public class JsonSchema internal constructor(
    * All reported errors will be reported to [ErrorCollector.onError]
    */
   public fun validate(value: JsonElement, errorCollector: ErrorCollector): Boolean {
-    val context = DefaultAssertionContext(JsonPointer.ROOT, references)
+    val context = DefaultAssertionContext(JsonPointer.ROOT, DefaultReferenceResolver(references))
     return assertion.validate(value, context, errorCollector)
   }
 

src/commonMain/kotlin/io/github/optimumcode/json/schema/internal/AnnotationCollector.kt

@@ -0,0 +1,157 @@
+package io.github.optimumcode.json.schema.internal
+
+import kotlin.jvm.JvmStatic
+import kotlin.reflect.KClass
+import kotlin.reflect.cast
+
+internal interface AnnotationCollector {
+  fun <T : Any> annotate(key: AnnotationKey<T>, value: T)
+  fun <T : Any> annotated(key: AnnotationKey<T>): T?
+  fun <T : Any> aggregatedAnnotation(key: AnnotationKey<T>): T?
+}
+
+internal fun interface Aggregator<T : Any> {
+  fun aggregate(a: T, b: T): T?
+}
+
+internal class AnnotationKey<T : Any> private constructor(
+  private val name: String,
+  internal val type: KClass<T>,
+  internal val aggregator: Aggregator<T>,
+) {
+  override fun equals(other: Any?): Boolean {
+    if (this === other) return true
+    if (other == null || this::class != other::class) return false
+
+    other as AnnotationKey<*>
+
+    if (name != other.name) return false
+    if (type != other.type) return false
+
+    return true
+  }
+
+  override fun hashCode(): Int {
+    var result = name.hashCode()
+    result = 31 * result + type.hashCode()
+    return result
+  }
+
+  override fun toString(): String = "$name(${type.simpleName})"
+
+  companion object {
+    internal val NOT_AGGREGATABLE: (Any, Any) -> Nothing? = { _, _ -> null }
+
+    private fun <T : Any> notAggragatable(): (T, T) -> T? = NOT_AGGREGATABLE
+
+    @JvmStatic
+    inline fun <reified T : Any> create(name: String): AnnotationKey<T> = create(name, T::class)
+
+    @JvmStatic
+    inline fun <reified T : Any> createAggregatable(name: String, noinline aggregator: (T, T) -> T): AnnotationKey<T> =
+      createAggregatable(name, T::class, aggregator)
+
+    @JvmStatic
+    fun <T : Any> create(name: String, type: KClass<T>): AnnotationKey<T> = AnnotationKey(name, type, notAggragatable())
+
+    @JvmStatic
+    fun <T : Any> createAggregatable(
+      name: String,
+      type: KClass<T>,
+      aggregator: (T, T) -> T,
+    ): AnnotationKey<T> = AnnotationKey(name, type, aggregator)
+  }
+}
+
+internal class DefaultAnnotationCollector : AnnotationCollector {
+  private lateinit var _annotations: MutableMap<AnnotationKey<*>, Any>
+  private lateinit var _aggregatedAnnotations: MutableMap<AnnotationKey<*>, Any>
+
+  override fun <T : Any> annotate(key: AnnotationKey<T>, value: T) {
+    annotations()[key] = value
+  }
+
+  override fun <T : Any> annotated(key: AnnotationKey<T>): T? {
+    if (!::_annotations.isInitialized) {
+      return null
+    }
+    return _annotations[key]?.let { key.type.cast(it) }
+  }
+
+  override fun <T : Any> aggregatedAnnotation(key: AnnotationKey<T>): T? {
+    if (!::_aggregatedAnnotations.isInitialized && !::_annotations.isInitialized) {
+      return null
+    }
+    val currentLevelAnnotation: T? = annotated(key)
+    if (!::_aggregatedAnnotations.isInitialized) {
+      return currentLevelAnnotation
+    }
+    return _aggregatedAnnotations[key]?.let {
+      val aggregatedAnnotation: T = key.type.cast(it)
+      if (currentLevelAnnotation == null) {
+        aggregatedAnnotation
+      } else {
+        key.aggregator.aggregate(currentLevelAnnotation, aggregatedAnnotation)
+      }
+    } ?: currentLevelAnnotation
+  }
+
+  fun applyAnnotations() {
+    if (::_annotations.isInitialized && _annotations.isNotEmpty()) {
+      aggregateAnnotations(_annotations) { aggregatedAnnotations() }
+      _annotations.clear()
+    }
+  }
+
+  fun resetAnnotations() {
+    if (::_annotations.isInitialized && _annotations.isNotEmpty()) {
+      _annotations.clear()
+    }
+  }
+
+  fun propagateToParent(parent: DefaultAnnotationCollector) {
+    if (!::_aggregatedAnnotations.isInitialized) {
+      return
+    }
+    aggregateAnnotations(_aggregatedAnnotations) { parent.aggregatedAnnotations() }
+  }
+
+  private inline fun aggregateAnnotations(
+    source: MutableMap<AnnotationKey<*>, Any>,
+    destination: () -> MutableMap<AnnotationKey<*>, Any>,
+  ) {
+    source.forEach { (key, value) ->
+      if (key.aggregator === AnnotationKey.NOT_AGGREGATABLE) {
+        return@forEach
+      }
+      val aggregatedAnnotations = destination()
+      val oldValue: Any? = aggregatedAnnotations[key]
+      if (oldValue != null) {
+        // Probably there is a mistake in the architecture
+        // Need to think on how to change that to avoid unchecked cast
+        @Suppress("UNCHECKED_CAST")
+        val aggregator: Aggregator<Any> = key.aggregator as Aggregator<Any>
+        val aggregated = aggregator.aggregate(key.type.cast(oldValue), key.type.cast(value))
+        if (aggregated != null) {
+          aggregatedAnnotations[key] = aggregated
+        }
+      } else {
+        aggregatedAnnotations[key] = value
+      }
+    }
+  }
+
+  private fun annotations(): MutableMap<AnnotationKey<*>, Any> {
+    if (!::_annotations.isInitialized) {
+      _annotations = hashMapOf()
+    }
+    return _annotations
+  }
+
+  private fun aggregatedAnnotations(): MutableMap<AnnotationKey<*>, Any> {
+    if (!::_aggregatedAnnotations.isInitialized) {
+      _aggregatedAnnotations = hashMapOf()
+    }
+    return _aggregatedAnnotations
+  }
+}