/*
 * libsyncml - A syncml protocol implementation
 * Copyright (C) 2005  Armin Bauer <armin.bauer@opensync.org>
 * Copyright (C) 2009  Michael Bell <michael.bell@opensync.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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 GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
 *
 */

#include <config.h>
 
#include "sml_queue_internals.h"

#include "sml_support.h"
#include "sml_error_internals.h"

#ifndef DOXYGEN_SHOULD_SKIP_THIS

static gboolean
_queue_prepare (GSource *source,
                gint *timeout_)
{
	smlTrace(TRACE_INTERNAL, "%s(%p, %p)", __func__, source, timeout_);
	*timeout_ = 1;
	return FALSE;
}

/* TODO only use me for debugging */
void
smlQueueAssert (SmlQueue *queue)
{
	if (queue->tail) {
		smlAssert(queue->head);
	}
	if (queue->prio) {
		smlAssert(queue->head);
	}
	if (queue->head) {
		smlAssert(queue->tail);
	}
	
	if (g_list_length(queue->head) == 1) {
		smlAssert(queue->tail == queue->head);
	}
	
	smlAssert(g_list_last(queue->head) == queue->tail);
}

static gboolean
_queue_check (GSource *source)
{
	SmlQueue *queue = *((SmlQueue **)(source + 1));
	return smlQueueCheck(queue);
}

static gboolean
_queue_dispatch (GSource *source,
                 GSourceFunc callback,
                 gpointer user_data)
{
	smlTrace(TRACE_INTERNAL, "%s(%p, %p, %p)", __func__, source, callback, user_data);
	SmlQueue *queue = user_data;
	smlAssert(queue->handler);
	
	while (smlQueueCheck(queue))
		smlQueueDispatch(queue);
	
	return TRUE;
}
#endif /* DOXYGEN_SHOULD_SKIP_THIS */

/*! @brief Creates a new asynchronous queue
 * 
 * This function return the pointer to a newly created SmlQueue
 * 
 */
SmlQueue*
smlQueueNew (GError **error)
{
	CHECK_ERROR_REF
	SmlQueue *queue = smlTryMalloc0(sizeof(SmlQueue), error);
	if (!queue)
		return NULL;
	
	if (!g_thread_supported ()) g_thread_init (NULL);
	
	queue->mutex = g_mutex_new();
	
	return queue;
}

void
smlQueueFree (SmlQueue *queue)
{
	if (queue->source)
		smlQueueDetach(queue);
	
	if (queue->head)
		g_list_free(queue->head);
	
	g_mutex_free(queue->mutex);
	
	smlSafeFree((gpointer *)&queue);
}

void
smlQueueFlush (SmlQueue *queue)
{
	g_mutex_lock(queue->mutex);
	
	smlQueueAssert(queue);
	
	queue->tail = NULL;
	g_list_free(queue->head);
	queue->head = NULL;
	queue->prio = NULL;
	
	smlQueueAssert(queue);
	
	g_mutex_unlock(queue->mutex);
}

gboolean
smlQueueCheckPrio (SmlQueue *queue)
{
	g_mutex_lock(queue->mutex);
	gboolean ret = (queue->prio == NULL) ? FALSE : TRUE;
	g_mutex_unlock(queue->mutex);
	
	return ret;
}

gboolean
smlQueueCheck (SmlQueue *queue)
{
	g_mutex_lock(queue->mutex);
	gboolean ret = (queue->head == NULL) ? FALSE : TRUE;
	g_mutex_unlock(queue->mutex);
	
	return ret;
}

gsize
smlQueueLength (SmlQueue *queue)
{
	g_mutex_lock(queue->mutex);
	unsigned int ret = g_list_length(queue->head);
	g_mutex_unlock(queue->mutex);
	
	return ret;
}

gsize
smlQueueLengthPrio (SmlQueue *queue)
{
	g_mutex_lock(queue->mutex);
	unsigned int ret = g_list_length(queue->prio);
	g_mutex_unlock(queue->mutex);
	
	return ret;
}

void*
smlQueueTryPop (SmlQueue *queue)
{
	smlAssert(queue);
	void *message = NULL;
	
	g_mutex_lock(queue->mutex);
	
	smlQueueAssert(queue);
	
	if (queue->head) {
		message = queue->head->data;
		if (queue->head == queue->tail)
			queue->tail = NULL;
		if (queue->prio && message == queue->prio->data)
			queue->prio = g_list_delete_link(queue->prio, queue->prio);
		queue->head = g_list_delete_link(queue->head, queue->head);
	}
	
	smlQueueAssert(queue);
	
	g_mutex_unlock(queue->mutex);
	
	return message;
}

void*
smlQueueTryPopPrio (SmlQueue *queue)
{
	smlAssert(queue);
	void *message = NULL;
	
	g_mutex_lock(queue->mutex);
	
	smlQueueAssert(queue);
	
	message = queue->prio ? queue->prio->data : NULL;
	queue->prio = g_list_delete_link(queue->prio, queue->prio);
	
	if (message) {
		queue->head = g_list_remove(queue->head, message);
		queue->tail = g_list_last(queue->head);
	}
	
	smlQueueAssert(queue);
	
	g_mutex_unlock(queue->mutex);
	
	return message;
}

void
smlQueueLock (SmlQueue *queue)
{
	smlAssert(queue);
	g_mutex_lock(queue->mutex);
}

void
smlQueueUnlock (SmlQueue *queue)
{
	smlAssert(queue);
	g_mutex_unlock(queue->mutex);
}

void*
smlQueuePeek (SmlQueue *queue)
{
	smlAssert(queue);
	return queue->head ? queue->head->data : NULL;
}

void*
smlQueuePeekPrio (SmlQueue *queue)
{
	smlAssert(queue);
	void *message = NULL;
	
	g_mutex_lock(queue->mutex);
	
	message = queue->prio ? queue->prio->data : NULL;
	
	smlQueueAssert(queue);
	
	g_mutex_unlock(queue->mutex);
	
	return message;
}

void
smlQueuePrint (SmlQueue *queue)
{
	smlAssert(queue);
	
	g_mutex_lock(queue->mutex);
	
	GString *info = g_string_new("Contents of queue ");
	g_string_append_printf(info, "%p:", queue);
	
	GList *m = NULL;
	for (m = queue->head; m; m = m->next) {
		g_string_append_printf(info, ", %p (list %p)", m->data, m);
	}
	smlTrace(TRACE_INTERNAL, "%s: %s", __func__, VA_STRING(info->str));
	g_string_free(info, TRUE);
	
	info = g_string_new("Contents of prio queue:");
	for (m = queue->prio; m; m = m->next) {
		g_string_append_printf(info, ", %p (list %p)", m->data, m);
	}
	smlTrace(TRACE_INTERNAL, "%s: %s", __func__, VA_STRING(info->str));
	g_string_free(info, TRUE);
	smlTrace(TRACE_INTERNAL, "%s: Tail of queue: %p (list %p)", __func__, queue->tail ? queue->tail->data : NULL, queue->tail);
	
	g_mutex_unlock(queue->mutex);
}

GList*
smlQueuePeekNext (SmlQueue *queue,
                  GList *prev)
{
	smlAssert(queue);
	
	if (!prev)
		return queue->head;
	else
		return prev->next;
}

void
smlQueuePushHeadPrio (SmlQueue *queue,
                      void *data)
{
	smlAssert(queue);
	smlAssert(data);
	
	g_mutex_lock(queue->mutex);
	
	smlQueueAssert(queue);
	
	queue->head = g_list_prepend(queue->head, data);
	if (!queue->tail)
		queue->tail = queue->head;
	queue->prio = g_list_prepend(queue->prio, data);
	
	smlQueueAssert(queue);
	
	g_mutex_unlock(queue->mutex);
}

void
smlQueuePushHead (SmlQueue *queue,
                  void *data)
{
	smlAssert(queue);
	smlAssert(data);
	
	g_mutex_lock(queue->mutex);
	
	smlQueueAssert(queue);
	
	queue->head = g_list_prepend(queue->head, data);
	if (!queue->tail)
		queue->tail = queue->head;
	
	smlQueueAssert(queue);
	
	g_mutex_unlock(queue->mutex);
}

/*! @brief Sends a message down a queue
 * 
 * @param queue The queue to send the message to
 * @param message The message to send
 * 
 */
void
smlQueueSendPrio (SmlQueue *queue,
                  void *data)
{
	smlAssert(queue);
	smlAssert(data);
	
	g_mutex_lock(queue->mutex);
	
	smlQueueAssert(queue);
	
	if (queue->tail) {
		queue->tail = g_list_append(queue->tail, data);
		queue->tail = queue->tail->next;
	} else {
		queue->head = g_list_append(queue->head, data);
		queue->tail = queue->head;
	}
	queue->prio = g_list_append(queue->prio, data);
	
	smlQueueAssert(queue);
	
	g_mutex_unlock(queue->mutex);
}


/*! @brief Sends a message down a queue
 * 
 * @param queue The queue to send the message to
 * @param message The message to send
 * 
 */
void
smlQueueSend (SmlQueue *queue,
              void *data)
{
	smlAssert(queue);
	smlAssert(data);
	
	g_mutex_lock(queue->mutex);
	
	smlQueueAssert(queue);
	
	if (queue->tail) {
		queue->tail = g_list_append(queue->tail, data);
		queue->tail = queue->tail->next;
	} else {
		queue->head = g_list_append(queue->head, data);
		queue->tail = queue->head;
	}
	
	smlQueueAssert(queue);
	
	g_mutex_unlock(queue->mutex);
}

/*! @brief Sets the message handler for a queue
 * 
 * Sets the function that will receive all messages, except the methodcall replies
 * 
 * @param queue The queue to set the handler on
 * @param handler The message handler function
 * @param user_data The userdata that the message handler should receive
 * 
 */
void
smlQueueSetHandler (SmlQueue *queue,
                    SmlQueueHandler handler,
                    void *userdata)
{
	queue->handler = handler;
	queue->userdata = userdata;
}

/*! @brief Sets the queue to use the gmainloop with the given context
 * 
 * This function will attach the SmlQueue as a source to the given context.
 * The queue will then be check for new messages and the messages will be
 * handled.
 * 
 * @param queue The queue to set up
 * @param context The context to use. NULL for default loop
 * 
 */
void
smlQueueAttach (SmlQueue *queue,
                GMainContext *context)
{
	smlTrace(TRACE_ENTRY, "%s(%p, %p)", __func__, queue, context);
	
	smlAssert(queue);
	smlAssert(queue->source == NULL);
	
	GSourceFuncs *functions = g_malloc0(sizeof(GSourceFuncs));
	functions->prepare = _queue_prepare;
	functions->check = _queue_check;
	functions->dispatch = _queue_dispatch;
	functions->finalize = NULL;

	GSource *source = g_source_new(functions, sizeof(GSource) + sizeof(SmlQueue *));
	SmlQueue **queueptr = (SmlQueue **)(source + 1);
	*queueptr = queue;
	g_source_set_callback(source, NULL, queue, NULL);
	queue->source = source;
	queue->functions = functions;
	g_source_attach(source, context);
	queue->context = context;
	if (context)
		g_main_context_ref(context);
	
	smlTrace(TRACE_EXIT, "%s", __func__);
}

void
smlQueueDetach (SmlQueue *queue)
{
	smlTrace(TRACE_ENTRY, "%s(%p)", __func__, queue);
	
	smlAssert(queue);
	smlAssert(queue->source);
	
	g_source_destroy(queue->source);
	g_source_unref(queue->source);
	
	smlSafeFree((gpointer *)&(queue->functions));
	
	queue->source = NULL;
	
	if (queue->context) {
		g_main_context_unref(queue->context);
		queue->context = NULL;
	}
	
	smlTrace(TRACE_EXIT, "%s", __func__);
}

gboolean
smlQueueIsAttached (SmlQueue *queue)
{
	return queue->source ? TRUE : FALSE;
}

void
smlQueueDispatch (SmlQueue *queue)
{
	void *message = smlQueueTryPop(queue);
	if (message)
		queue->handler(message, queue->userdata);
}

void
smlQueueDispatchPrio (SmlQueue *queue)
{
	
	void *message = smlQueueTryPopPrio(queue);
	if (message)
		queue->handler(message, queue->userdata);
}

/*@}*/