/*
    Copyright (c) 2007-2010 iMatix Corporation

    This file is part of 0MQ.

    0MQ is free software; you can redistribute it and/or modify it under
    the terms of the Lesser GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    0MQ is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    Lesser GNU General Public License for more details.

    You should have received a copy of the Lesser GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <string.h>
#include <assert.h>
#include <errno.h>

#include "../../src/stdint.hpp"
#include "../c/zmq.h"

#include "org_zmq_Socket.h"

/** Handle to Java's Socket::socketHandle. */
static jfieldID socket_handle_fid = NULL;

/**
 * Make sure we have a valid pointer to Java's Socket::socketHandle.
 */
static void ensure_socket (JNIEnv *env,
			   jobject obj)
{
    if (socket_handle_fid == NULL) {
        jclass cls = env->GetObjectClass (obj);
	assert (cls);
	socket_handle_fid = env->GetFieldID (cls, "socketHandle", "J");
	assert (socket_handle_fid);
	env->DeleteLocalRef (cls);
    }
}

/**
 * Get the value of Java's Socket::socketHandle.
 */
static void *get_socket (JNIEnv *env,
			 jobject obj)
{
    ensure_socket (env, obj);
    void *s = (void*) env->GetLongField (obj, socket_handle_fid);
    return s;
}

/**
 * Set the value of Java's Socket::socketHandle.
 */
static void put_socket (JNIEnv *env,
			jobject obj,
			void *s)
{
    ensure_socket (env, obj);
    env->SetLongField (obj, socket_handle_fid, (jlong) s);
}

/**
 * Get the value of contextHandle for the Java Context associated with
 * this Java Socket object.
 */
static void *fetch_context (JNIEnv *env,
			    jobject context)
{
    static jmethodID get_context_handle_mid = NULL;

    if (get_context_handle_mid == NULL) {
        jclass cls = env->GetObjectClass (context);
	assert (cls);

	get_context_handle_mid = env->GetMethodID (cls,
						   "getContextHandle",
						   "()J");
	env->DeleteLocalRef (cls);
	assert (get_context_handle_mid);
    }

    void *zmq_ctx = (void*) env->CallLongMethod (context,
						 get_context_handle_mid);
    if (env->ExceptionCheck ()) {
        zmq_ctx = NULL;
    }

    assert (zmq_ctx);
    return zmq_ctx;
}

/**
 * Raise an exception that includes 0MQ's error message.
 */
static void raise_exception (JNIEnv *env, int err)
{
    //  Get exception class.
    jclass exception_class = env->FindClass ("java/lang/Exception");
    assert (exception_class);

    //  Get text description of the exception.
    const char *err_msg = zmq_strerror (err);

    //  Raise the exception.
    int rc = env->ThrowNew (exception_class, err_msg);
    env->DeleteLocalRef (exception_class);

    assert (rc == 0);
}

/**
 * Called to construct a Java Socket object.
 */
JNIEXPORT void JNICALL Java_org_zmq_Socket_construct (JNIEnv *env,
						      jobject obj,
						      jobject context,
						      jint type)
{
    void *s = get_socket (env, obj);
    assert (! s);

    void *zmq_ctx = fetch_context (env, context);
    s = zmq_socket (zmq_ctx, type);
    put_socket(env, obj, s);

    if (s == NULL) {
        raise_exception (env, errno);
	return;
    }
}

/**
 * Called to destroy a Java Socket object.
 */
JNIEXPORT void JNICALL Java_org_zmq_Socket_finalize (JNIEnv *env,
						     jobject obj)
{
    void *s = get_socket (env, obj);
    assert (s);

    int rc = zmq_close (s);
    put_socket (env, obj, NULL);
    assert (rc == 0);
}

/**
 * Called by Java's Socket::setsockopt(int option, long optval).
 */
JNIEXPORT void JNICALL Java_org_zmq_Socket_setsockopt__IJ (JNIEnv *env,
    jobject obj, jint option, jlong optval)
{
    switch (option) {
    case ZMQ_HWM:
    case ZMQ_LWM:
    case ZMQ_SWAP:
    case ZMQ_AFFINITY:
    case ZMQ_RATE:
    case ZMQ_RECOVERY_IVL:
    case ZMQ_MCAST_LOOP:
        {
            void *s = get_socket (env, obj);
            assert (s);

            int64_t value = optval;
            int rc = zmq_setsockopt (s, option, &value, sizeof (value));
            if (rc != 0)
                raise_exception (env, errno);
            return;
        }
    default:
        raise_exception (env, EINVAL);
        return;
    }
}

/**
 * Called by Java's Socket::setsockopt(int option, String optval).
 */
JNIEXPORT void JNICALL Java_org_zmq_Socket_setsockopt__ILjava_lang_String_2 (
    JNIEnv *env,
    jobject obj,
    jint option,
    jstring optval)
{
    switch (option) {
    case ZMQ_IDENTITY:
    case ZMQ_SUBSCRIBE:
    case ZMQ_UNSUBSCRIBE:
        {
            if (optval == NULL) {
                raise_exception (env, EINVAL);
                return;
            }

	    void *s = get_socket (env, obj);
	    assert (s);

            const char *value = env->GetStringUTFChars (optval, NULL);
            assert (value);
            int rc = zmq_setsockopt (s, option, value, strlen (value));
            env->ReleaseStringUTFChars (optval, value);
            if (rc != 0)
                raise_exception (env, errno);
            return;
        }
    default:
        raise_exception (env, EINVAL);
        return;
    }
}

/**
 * Called by Java's Socket::bind(String addr).
 */
JNIEXPORT void JNICALL Java_org_zmq_Socket_bind (JNIEnv *env,
						 jobject obj,
						 jstring addr)
{
    void *s = get_socket (env, obj);
    assert (s);

    if (addr == NULL) {
        raise_exception (env, EINVAL);
        return;
    }

    const char *c_addr = env->GetStringUTFChars (addr, NULL);
    if (c_addr == NULL) {
        raise_exception (env, EINVAL);
        return;
    }

    int rc = zmq_bind (s, c_addr);
    env->ReleaseStringUTFChars (addr, c_addr);

    if (rc == -1)
        raise_exception (env, errno);
}

/**
 * Called by Java's Socket::connect(String addr).
 */
JNIEXPORT void JNICALL Java_org_zmq_Socket_connect (JNIEnv *env,
						    jobject obj,
						    jstring addr)
{
    void *s = get_socket (env, obj);
    assert (s);

    if (addr == NULL) {
        raise_exception (env, EINVAL);
        return;
    }

    const char *c_addr = env->GetStringUTFChars (addr, NULL);
    if (c_addr == NULL) {
        raise_exception (env, EINVAL);
        return;
    }

    int rc = zmq_connect (s, c_addr);
    env->ReleaseStringUTFChars (addr, c_addr);

    if (rc == -1)
        raise_exception (env, errno);
}

/**
 * Called by Java's Socket::send(byte [] msg, long flags).
 */
JNIEXPORT jboolean JNICALL Java_org_zmq_Socket_send (JNIEnv *env,
						     jobject obj,
						     jbyteArray msg,
						     jlong flags)
{
    void *s = get_socket (env, obj);
    assert (s);

    jsize size = env->GetArrayLength (msg); 
    jbyte *data = env->GetByteArrayElements (msg, 0);

    zmq_msg_t message;
    int rc = zmq_msg_init_size (&message, size);
    assert (rc == 0);
    memcpy (zmq_msg_data (&message), data, size);

    env->ReleaseByteArrayElements (msg, data, 0);

    rc = zmq_send (s, &message, (int) flags);
        
    if (rc == -1 && errno == EAGAIN) {
        rc = zmq_msg_close (&message);
        assert (rc == 0);
        return JNI_FALSE;
    }
    
    if (rc == -1) {
        raise_exception (env, errno);
        rc = zmq_msg_close (&message);
        assert (rc == 0);
        return JNI_FALSE;
    }

    rc = zmq_msg_close (&message);
    assert (rc == 0);
    return JNI_TRUE;
}

/**
 * Called by Java's Socket::flush().
 */
JNIEXPORT void JNICALL Java_org_zmq_Socket_flush (JNIEnv *env,
						  jobject obj)
{
    void *s = get_socket (env, obj);
    assert (s);

    int rc = zmq_flush (s);

    if (rc == -1) {
        raise_exception (env, errno);
        return ;
    }
}

/**
 * Called by Java's Socket::recv(long flags).
 */
JNIEXPORT jbyteArray JNICALL Java_org_zmq_Socket_recv (JNIEnv *env,
						       jobject obj,
						       jlong flags)
{
    void *s = get_socket (env, obj);
    assert (s);

    zmq_msg_t message;
    zmq_msg_init (&message);
    int rc = zmq_recv (s, &message, (int) flags);

    if (rc == -1 && errno == EAGAIN) {
        zmq_msg_close (&message);
        return NULL;
    }

    if (rc == -1) {
        raise_exception (env, errno);
        zmq_msg_close (&message);
        return NULL;
    }

    jbyteArray data = env->NewByteArray (zmq_msg_size (&message));
    assert (data);
    env->SetByteArrayRegion (data,
			     0,
			     zmq_msg_size (&message),
			     (jbyte*) zmq_msg_data (&message));

    return data;
}