fix: fetch initialization

modules/openid-federation-client/src/commonMain/kotlin/com/sphereon/oid/fed/client/fetch/Fetch.kt

@@ -1,31 +1,49 @@
 package com.sphereon.oid.fed.client.fetch
 
+import io.ktor.client.*
+import io.ktor.client.call.*
+import io.ktor.client.request.*
+import io.ktor.http.*
 import kotlin.jvm.JvmStatic
 
 interface ICallbackService<PlatformCallbackType> {
     fun register(platformCallback: PlatformCallbackType): ICallbackService<PlatformCallbackType>
 }
 
 interface IFetchService {
+    fun getHttpClient(): HttpClient
+}
+
+interface IFetchServiceInternal {
     suspend fun fetchStatement(
         endpoint: String
     ): String
 }
 
-interface IFetchCallbackService : ICallbackService<IFetchService>, IFetchService
+interface IFetchCallbackService : ICallbackService<IFetchService>, IFetchService, IFetchServiceInternal
 
 expect fun fetchService(): IFetchCallbackService
 
 object FetchServiceObject : IFetchCallbackService {
     @JvmStatic
     private lateinit var platformCallback: IFetchService
+    private lateinit var httpClient: HttpClient
 
     override suspend fun fetchStatement(endpoint: String): String {
-        return platformCallback.fetchStatement(endpoint)
+        return this.httpClient.get(endpoint) {
+            headers {
+                append(HttpHeaders.Accept, "application/entity-statement+jwt")
+            }
+        }.body()
+    }
+
+    override fun getHttpClient(): HttpClient {
+        return this.platformCallback.getHttpClient()
     }
 
     override fun register(platformCallback: IFetchService): IFetchCallbackService {
         this.platformCallback = platformCallback
+        this.httpClient = this.platformCallback.getHttpClient()
         return this
     }
 }

modules/openid-federation-client/src/commonMain/kotlin/com/sphereon/oid/fed/client/trustchain/TrustChain.kt

@@ -41,6 +41,7 @@ class TrustChain(private val fetchService: IFetchCallbackService) {
 
         val decodedEntityConfiguration = mapper.decodeJWTComponents(entityConfigurationJwt)
 
+
         // need to verify JWT
 
         val entityStatement: EntityConfigurationStatement =
@@ -59,7 +60,7 @@ class TrustChain(private val fetchService: IFetchCallbackService) {
                     entityIdentifier,
                     trustAnchors,
                     chain,
-                    decodedEntityConfiguration.header.kid,
+                    decodedEntityConfiguration.header.kid!!,
                     cache
                 )
             if (result != null) {