#include <jni.h>

#include <string>

#include "state/state.hpp"

using namespace mesos::internal::state;

extern "C" {

/*
 * Class:     org_apache_mesos_state_Variable
 * Method:    value
 * Signature: ()[B
 */
JNIEXPORT jbyteArray JNICALL Java_org_apache_mesos_state_Variable_value
  (JNIEnv* env, jobject thiz)
{
  jclass clazz = env->GetObjectClass(thiz);

  jfieldID __variable = env->GetFieldID(clazz, "__variable", "J");

  Variable<std::string>* variable =
    (Variable<std::string>*) env->GetLongField(thiz, __variable);

  // byte[] value = ..;
  jbyteArray jvalue = env->NewByteArray((*variable)->size());
  env->SetByteArrayRegion(
      jvalue, 0, (*variable)->size(), (jbyte*) (*variable)->data());

  return jvalue;
}


/*
 * Class:     org_apache_mesos_state_Variable
 * Method:    mutate
 * Signature: ([B)Lorg/apache/mesos/state/Variable;
 */
JNIEXPORT jobject JNICALL Java_org_apache_mesos_state_Variable_mutate
  (JNIEnv* env, jobject thiz, jbyteArray jvalue)
{
  jclass clazz = env->GetObjectClass(thiz);

  jfieldID __variable = env->GetFieldID(clazz, "__variable", "J");

  // Create a copy of the old variable to support the immutable Java API.
  Variable<std::string>* variable = new Variable<std::string>(
      *((Variable<std::string>*) env->GetLongField(thiz, __variable)));

  jbyte* value = env->GetByteArrayElements(jvalue, NULL);
  jsize length = env->GetArrayLength(jvalue);

  // Update the value of the new copy.
  (*variable)->assign((const char*) value, length);

  env->ReleaseByteArrayElements(jvalue, value, 0);

  // Variable variable = new Variable();
  clazz = env->FindClass("org/apache/mesos/state/Variable");

  jmethodID _init_ = env->GetMethodID(clazz, "<init>", "()V");
  jobject jvariable = env->NewObject(clazz, _init_);

  env->SetLongField(jvariable, __variable, (jlong) variable);

  return jvariable;
}


/*
 * Class:     org_apache_mesos_state_Variable
 * Method:    finalize
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_org_apache_mesos_state_Variable_finalize
  (JNIEnv* env, jobject thiz)
{
  jclass clazz = env->GetObjectClass(thiz);

  jfieldID __variable = env->GetFieldID(clazz, "__variable", "J");

  Variable<std::string>* variable =
    (Variable<std::string>*) env->GetLongField(thiz, __variable);

  delete variable;
}

} // extern "C" {