/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * Copyright (C) 2003 Imendio AB
 *
 * This program 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 of the
 * License, or (at your option) any later version.
 *
 * This program 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 program; if not, see <https://www.gnu.org/licenses>
 */

/**
 * SECTION:lm-message-handler
 * @Title: LmMessageHandler
 * @Short_description: A handler for incoming messages.
 *
 *  A handler can be registered to listen to incoming messages with lm_connection_register_message_handler(). When a message is recieved the handlers of the correct type will be called.
 */

#include <config.h>

#include "lm-internals.h"
#include "lm-message-handler.h"

struct LmMessageHandler {
    gboolean                valid;
    gint                    ref_count;
    LmHandleMessageFunction function;
    gpointer                user_data;
    GDestroyNotify          notify;
};

LmHandlerResult
_lm_message_handler_handle_message (LmMessageHandler *handler,
                                    LmConnection     *connection,
                                    LmMessage        *message)
{
    g_return_val_if_fail (handler != NULL,
                          LM_HANDLER_RESULT_ALLOW_MORE_HANDLERS);

    if (!handler->valid) {
        return LM_HANDLER_RESULT_ALLOW_MORE_HANDLERS;
    }

    if (handler->function) {
        return (* handler->function) (handler, connection,
                                      message, handler->user_data);
    }

    return LM_HANDLER_RESULT_ALLOW_MORE_HANDLERS;
}

/**
 * lm_message_handler_new:
 * @function: a callback
 * @user_data: user data passed to function
 * @notify: function called when the message handler is freed
 *
 * Creates a new message handler. This can be set to handle incoming messages
 * and when a message of the type the handler is registered to handle is
 * received @function will be called and @user_data will be passed to it.
 * @notify is called when the message handler is freed, that way any memory
 * allocated by @user_data can be freed.
 *
 * Return value: a newly created message handler
 **/
LmMessageHandler *
lm_message_handler_new (LmHandleMessageFunction function,
                        gpointer                user_data,
                        GDestroyNotify          notify)
{
    LmMessageHandler *handler;

    g_return_val_if_fail (function != NULL, NULL);

    handler = g_new0 (LmMessageHandler, 1);

    if (handler == NULL) {
        return NULL;
    }

    handler->valid     = TRUE;
    handler->ref_count = 1;
    handler->function  = function;
    handler->user_data = user_data;
    handler->notify    = notify;

    return handler;
}

/**
 * lm_message_handler_invalidate
 * @handler: an #LmMessageHandler
 *
 * Invalidates the handler. Useful if you need to cancel a reply
 **/
void
lm_message_handler_invalidate (LmMessageHandler *handler)
{
    handler->valid = FALSE;
}

/**
 * lm_message_handler_is_valid
 * @handler: an #LmMessageHandler
 *
 * Fetches whether the handler is valid or not.
 *
 * Return value: #TRUE if @handler is valid, otherwise #FALSE
 **/
gboolean
lm_message_handler_is_valid (LmMessageHandler *handler)
{
    g_return_val_if_fail (handler != NULL, FALSE);

    return handler->valid;
}

/**
 * lm_message_handler_ref:
 * @handler: an #LmMessageHandler
 *
 * Adds a reference to @handler.
 *
 * Return value: the message handler
 **/
LmMessageHandler *
lm_message_handler_ref (LmMessageHandler *handler)
{
    g_return_val_if_fail (handler != NULL, NULL);

    handler->ref_count++;

    return handler;
}

/**
 * lm_message_handler_unref:
 * @handler: an #LmMessageHandler
 *
 * Removes a reference from @handler. When no more references are present the
 * handler is freed.
 **/
void
lm_message_handler_unref (LmMessageHandler *handler)
{
    g_return_if_fail (handler != NULL);

    handler->ref_count --;

    if (handler->ref_count == 0) {
        if (handler->notify) {
            (* handler->notify) (handler->user_data);
        }
        g_free (handler);
    }
}