/* 
 * FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 * Copyright (C) 2007, Damjan Jovanovic <d a m j a n d o t j o v a t g m a i l d o t c o m>
 *
 * Version: MPL 1.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 *
 * The Initial Developer of the Original Code is
 * Damjan Jovanovic <d a m j a n d o t j o v a t g m a i l d o t c o m>
 * Portions created by the Initial Developer are Copyright (C)
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 * 
 * Damjan Jovanovic <d a m j a n d o t j o v a t g m a i l d o t c o m>
 *
 *
 * mod_java.c -- Java Module
 *
 */

#include <switch.h>
#include <jni.h>


static switch_memory_pool_t *memoryPool = NULL;
static switch_dso_lib_t javaVMHandle = NULL;

JavaVM *javaVM = NULL;
jclass launcherClass = NULL;

SWITCH_MODULE_LOAD_FUNCTION(mod_java_load);
SWITCH_MODULE_SHUTDOWN_FUNCTION(mod_java_shutdown);
SWITCH_MODULE_DEFINITION(mod_java, mod_java_load, mod_java_shutdown, NULL);

struct user_method {
	const char * class;
	const char * method;
	const char * arg;
};

typedef struct user_method user_method_t;

struct vm_control {
	struct user_method startup;
	struct user_method shutdown;
};

typedef struct vm_control vm_control_t;
static vm_control_t  vmControl;

static void launch_java(switch_core_session_t *session, const char *data, JNIEnv *env)
{
    jmethodID launch = NULL;
    jstring uuid = NULL;
    jstring args = NULL;

    if (launcherClass == NULL)
    {
        goto done;
    }

    launch = (*env)->GetStaticMethodID(env, launcherClass, "launch", "(Ljava/lang/String;Ljava/lang/String;)V");
    if (launch == NULL)
    {
        (*env)->ExceptionDescribe(env);
        goto done;
    }

    uuid = (*env)->NewStringUTF(env, switch_core_session_get_uuid(session));
    if (uuid == NULL)
    {
        (*env)->ExceptionDescribe(env);
        goto done;
    }

    args = (*env)->NewStringUTF(env, data);
    if (args == NULL)
    {
        (*env)->ExceptionDescribe(env);
        goto done;
    }

    (*env)->CallStaticVoidMethod(env, launcherClass, launch, uuid, args);
    if ((*env)->ExceptionOccurred(env))
        (*env)->ExceptionDescribe(env);

done:
    if (args != NULL)
        (*env)->DeleteLocalRef(env, args);
    if (uuid != NULL)
        (*env)->DeleteLocalRef(env, uuid);
}

static switch_status_t exec_user_method(user_method_t * userMethod) {
    switch_status_t status = SWITCH_STATUS_SUCCESS;
    jclass  class = NULL;
    jmethodID method = NULL;
    jstring arg = NULL;
    JNIEnv *env;
    jint res;

    if (javaVM == NULL || userMethod->class == NULL) {
        return status;
    }

    res = (*javaVM)->AttachCurrentThread(javaVM, (void*) &env, NULL);

    if (res != JNI_OK) {
        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Error attaching thread to Java VM!\n");
        (*env)->ExceptionDescribe(env);
        status =  SWITCH_STATUS_FALSE;
		goto done;
    }

    class = (*env)->FindClass(env, userMethod->class);

    if (class == NULL) {
        (*env)->ExceptionDescribe(env);
        status =  SWITCH_STATUS_FALSE;
        goto done;
    }

    method = (*env)->GetStaticMethodID(env, class, userMethod->method, "(Ljava/lang/String;)V");

    if (method == NULL) {
        (*env)->ExceptionDescribe(env);
        status =  SWITCH_STATUS_FALSE;
        goto done;
    }

    if (userMethod->arg != NULL) {
        arg = (*env)->NewStringUTF(env, userMethod->arg);

        if (arg == NULL) {
            (*env)->ExceptionDescribe(env);
            status =  SWITCH_STATUS_FALSE;
            goto done;
        }
    }

    (*env)->CallStaticVoidMethod(env, class, method, arg);

    if ((*env)->ExceptionOccurred(env)){
        (*env)->ExceptionDescribe(env);
        status =  SWITCH_STATUS_FALSE;
    }

done:
    if (arg != NULL)
        (*env)->DeleteLocalRef(env, arg);
    if (class != NULL)
        (*env)->DeleteLocalRef(env, class);
 	(*javaVM)->DetachCurrentThread(javaVM);
    return status;
}

SWITCH_STANDARD_APP(java_function)
{
    JNIEnv *env;
    jint res;

    if (javaVM == NULL)
        return;

    res = (*javaVM)->AttachCurrentThread(javaVM, (void*) &env, NULL);
    if (res == JNI_OK)
    {
        launch_java(session, data, env);
        (*javaVM)->DetachCurrentThread(javaVM);
    }
    else
        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Error attaching thread to Java VM!\n");
}

static switch_status_t load_config(JavaVMOption **javaOptions, int *optionCount, vm_control_t * vmControl)
{
    switch_xml_t cfg, xml;
    switch_status_t status;
	char *derr = NULL;

    xml = switch_xml_open_cfg("java.conf", &cfg, NULL);
    if (xml)
    {
        switch_xml_t javavm;
        switch_xml_t options;
        switch_xml_t startup;
        switch_xml_t shutdown;

        javavm = switch_xml_child(cfg, "javavm");
        if (javavm != NULL)
        {
            const char *path = switch_xml_attr_soft(javavm, "path");
            if (path != NULL)
            {
				javaVMHandle = switch_dso_open(path, 0, &derr);
				if (derr || !javaVMHandle) {
                    switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Error loading %s\n", path);
				}
            }
            else
            {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "No Java VM path specified in java.conf.xml\n");
                status = SWITCH_STATUS_FALSE;
            }
        }
        else
        {
            switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "No Java VM specified in java.conf.xml\n");
            status = SWITCH_STATUS_FALSE;
            goto close;
        }

        options = switch_xml_child(cfg, "options");
        if (options != NULL)
        {
            switch_xml_t option;
            int i = 0;
            *optionCount = 0;
            for (option = switch_xml_child(options, "option"); option; option = option->next)
            {
                const char *value = switch_xml_attr_soft(option, "value");
                if (value != NULL)
                    ++*optionCount;
            }
            *optionCount += 1;
            *javaOptions = switch_core_alloc(memoryPool, (switch_size_t)(*optionCount * sizeof(JavaVMOption)));
            if (*javaOptions == NULL)
            {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Out of memory!\n");
                status = SWITCH_STATUS_FALSE;
                goto close;
            }
            for (option = switch_xml_child(options, "option"); option; option = option->next)
            {
                const char *value = switch_xml_attr_soft(option, "value");
                if (value == NULL)
                    continue;
                (*javaOptions)[i].optionString = switch_core_strdup(memoryPool, value);
                if ((*javaOptions)[i].optionString == NULL)
                {
                    switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Out of memory!\n");
                    status = SWITCH_STATUS_FALSE;
                    goto close;
                }
                ++i;
            }
            (*javaOptions)[i].optionString = "-Djava.library.path=" SWITCH_PREFIX_DIR SWITCH_PATH_SEPARATOR "mod";
        }

	/*
	<startup class="net/cog/fs/system/Control" method="startup" arg="start up arg"/>
	<shutdown class="net/cog/fs/system/Control" method="shutdown" arg="shutdown arg"/>
	*/

        memset(vmControl, 0, sizeof(struct vm_control));
        startup = switch_xml_child(cfg, "startup");
        if (startup != NULL) {
            vmControl->startup.class = switch_xml_attr_soft(startup, "class");
            vmControl->startup.method = switch_xml_attr_soft(startup, "method");
            vmControl->startup.arg = switch_xml_attr_soft(startup, "arg");
        }
        shutdown = switch_xml_child(cfg, "shutdown");
        if (shutdown != NULL) {
            vmControl->shutdown.class = switch_xml_attr_soft(shutdown, "class");
            vmControl->shutdown.method = switch_xml_attr_soft(shutdown, "method");
            vmControl->shutdown.arg = switch_xml_attr_soft(shutdown, "arg");
        }

    close:
        switch_xml_free(xml);
    }
    else
    {
        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Error opening java.conf.xml\n");
        status = SWITCH_STATUS_FALSE;
    }
    return status;
}

static switch_status_t create_java_vm(JavaVMOption *options, int optionCount, vm_control_t * vmControl)
{
    jint (JNICALL *pJNI_CreateJavaVM)(JavaVM**,void**,void*);
    switch_status_t status;
	char *derr = NULL;

	pJNI_CreateJavaVM = (jint (*)(JavaVM **, void **, void *))switch_dso_func_sym(javaVMHandle, "JNI_CreateJavaVM", &derr);
		
    if (!derr)
    {
        JNIEnv *env;
        JavaVMInitArgs initArgs;
        jint res;

        memset(&initArgs, 0, sizeof(initArgs));
        initArgs.version = JNI_VERSION_1_4;
        initArgs.nOptions = optionCount;
        initArgs.options = options;
        initArgs.ignoreUnrecognized = JNI_TRUE;

        res = pJNI_CreateJavaVM(&javaVM, (void*) &env, &initArgs);
        if (res == JNI_OK)
        {
        	// call FindClass here already so that the Java VM executes the static
        	// initializer (@see org.freeswitch.Launcher) which loads the jni library
        	// so we can use jni functions right away (for example in the startup method)
        	launcherClass = (*env)->FindClass(env, "org/freeswitch/Launcher");
        	if ( launcherClass == NULL )
        	{
        		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Unable to find 'org.freeswitch.Launcher' class!\n");
        		(*env)->ExceptionDescribe(env);
        		status = SWITCH_STATUS_FALSE;
        	}

        	// store a global reference for use in the launch_java() function
            launcherClass = (*env)->NewGlobalRef(env, launcherClass);
        	if ( launcherClass == NULL )
        	{
        		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Out of memory!\n");
        		(*env)->ExceptionDescribe(env);
        		status = SWITCH_STATUS_FALSE;
        	}
        	else
        	{
        		status = SWITCH_STATUS_SUCCESS;
        	}

            (*javaVM)->DetachCurrentThread(javaVM);
        }
        else
        {
            switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Error creating Java VM!\n");
            status = SWITCH_STATUS_FALSE;
        }
    }
    else
    {
        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Specified Java VM doesn't have JNI_CreateJavaVM\n");
        status = SWITCH_STATUS_FALSE;
    }
    return status;
}

SWITCH_MODULE_LOAD_FUNCTION(mod_java_load)
{
    switch_status_t status;
    JavaVMOption *options = NULL;

    int optionCount = 0;
	switch_application_interface_t *app_interface;

	*module_interface = switch_loadable_module_create_module_interface(pool, modname);
	SWITCH_ADD_APP(app_interface, "java", NULL, NULL, java_function, NULL, SAF_SUPPORT_NOMEDIA);

    switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_NOTICE, "Java Framework Loading...\n");

    if (javaVM != NULL)
        return SWITCH_STATUS_SUCCESS;

    status = switch_core_new_memory_pool(&memoryPool);
    if (status == SWITCH_STATUS_SUCCESS)
    {
        status = load_config(&options, &optionCount, &vmControl);

        if (status == SWITCH_STATUS_SUCCESS) {

            status = create_java_vm(options, optionCount, &vmControl);

            if (status == SWITCH_STATUS_SUCCESS) {
				status = exec_user_method(&vmControl.startup);
                if (status == SWITCH_STATUS_SUCCESS){
                    return SWITCH_STATUS_SUCCESS;
                }
			}

			if (javaVMHandle) {
				switch_dso_destroy(&javaVMHandle);
			}
        }
        switch_core_destroy_memory_pool(&memoryPool);
    }
    else
        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Error creating memory pool\n");

    return status == SWITCH_STATUS_SUCCESS ? SWITCH_STATUS_NOUNLOAD : status;
}

SWITCH_MODULE_SHUTDOWN_FUNCTION(mod_java_shutdown)
{
    if (javaVM == NULL)
        return SWITCH_STATUS_FALSE;

    exec_user_method(&vmControl.shutdown);
    (*javaVM)->DestroyJavaVM(javaVM);
    javaVM = NULL;
	if (javaVMHandle) {
		switch_dso_destroy(&javaVMHandle);
	}
    switch_core_destroy_memory_pool(&memoryPool);
    return SWITCH_STATUS_SUCCESS;
}


