//
// Created by Grishka on 15.08.2018.
//

#ifndef LIBTGVOIP_JNIUTILITIES_H
#define LIBTGVOIP_JNIUTILITIES_H

#include "../../Buffers.h"
#include <functional>
#include <jni.h>
#include <cstdarg>
#include <string>

extern JavaVM* sharedJVM;

namespace tgvoip
{
namespace jni
{

    inline void DoWithJNI(std::function<void(JNIEnv*)> f)
    {
        JNIEnv* env = NULL;
        bool didAttach = false;
        sharedJVM->GetEnv((void**)&env, JNI_VERSION_1_6);
        if (!env)
        {
            sharedJVM->AttachCurrentThread(&env, NULL);
            didAttach = true;
        }

        f(env);

        if (didAttach)
        {
            sharedJVM->DetachCurrentThread();
        }
    }

    inline void AttachAndCallVoidMethod(jmethodID method, jobject obj, ...)
    {
        if (!method || !obj)
            return;
        va_list va;
        va_start(va, obj);
        DoWithJNI([&va, method, obj](JNIEnv* env) {
            env->CallVoidMethodV(obj, method, va);
        });
        va_end(va);
    }

    inline std::string JavaStringToStdString(JNIEnv* env, jstring jstr)
    {
        if (!jstr)
            return "";
        const char* jchars = env->GetStringUTFChars(jstr, NULL);
        std::string str(jchars);
        env->ReleaseStringUTFChars(jstr, jchars);
        return str;
    }

    inline jbyteArray BufferToByteArray(JNIEnv* env, Buffer& buf)
    {
        jbyteArray arr = env->NewByteArray((jsize)buf.Length());
        jbyte* elements = env->GetByteArrayElements(arr, NULL);
        std::memcpy(elements, *buf, buf.Length());
        env->ReleaseByteArrayElements(arr, elements, 0);
        return arr;
    }

}
}

#endif // LIBTGVOIP_JNIUTILITIES_H