/*
 * Copyright (C) 2007 Novell, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"

#include <string.h>
#include <glib/gi18n.h>

#include "eggsmclient.h"
#include "eggsmclient-private.h"

static void egg_sm_client_debug_handler (const char *log_domain,
        GLogLevelFlags log_level,
        const char *message,
        gpointer user_data);

enum
{
    SAVE_STATE,
    QUIT_REQUESTED,
    QUIT_CANCELLED,
    QUIT,
    LAST_SIGNAL
};

static guint signals[LAST_SIGNAL];

struct _EggSMClientPrivate
{
    GKeyFile *state_file;
};

#define EGG_SM_CLIENT_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), EGG_TYPE_SM_CLIENT, EggSMClientPrivate))

G_DEFINE_TYPE (EggSMClient, egg_sm_client, G_TYPE_OBJECT)

static EggSMClient *global_client;
static EggSMClientMode global_client_mode = EGG_SM_CLIENT_MODE_NORMAL;

static void
egg_sm_client_init (EggSMClient *client)
{
    ;
}

static void
egg_sm_client_class_init (EggSMClientClass *klass)
{
    GObjectClass *object_class = G_OBJECT_CLASS (klass);

    g_type_class_add_private (klass, sizeof (EggSMClientPrivate));

    /**
     * EggSMClient::save_state:
     * @client: the client
     * @state_file: a #GKeyFile to save state information into
     *
     * Emitted when the session manager has requested that the
     * application save information about its current state. The
     * application should save its state into @state_file, and then the
     * session manager may then restart the application in a future
     * session and tell it to initialize itself from that state.
     *
     * You should not save any data into @state_file's "start group"
     * (ie, the %NULL group). Instead, applications should save their
     * data into groups with names that start with the application name,
     * and libraries that connect to this signal should save their data
     * into groups with names that start with the library name.
     *
     * Alternatively, rather than (or in addition to) using @state_file,
     * the application can save its state by calling
     * egg_sm_client_set_restart_command() during the processing of this
     * signal (eg, to include a list of files to open).
     **/
    signals[SAVE_STATE] =
        g_signal_new ("save_state",
                      G_OBJECT_CLASS_TYPE (object_class),
                      G_SIGNAL_RUN_LAST,
                      G_STRUCT_OFFSET (EggSMClientClass, save_state),
                      NULL, NULL,
                      g_cclosure_marshal_VOID__POINTER,
                      G_TYPE_NONE,
                      1, G_TYPE_POINTER);

    /**
     * EggSMClient::quit_requested:
     * @client: the client
     *
     * Emitted when the session manager requests that the application
     * exit (generally because the user is logging out). The application
     * should decide whether or not it is willing to quit (perhaps after
     * asking the user what to do with documents that have unsaved
     * changes) and then call egg_sm_client_will_quit(), passing %TRUE
     * or %FALSE to give its answer to the session manager. (It does not
     * need to give an answer before returning from the signal handler;
     * it can interact with the user asynchronously and then give its
     * answer later on.) If the application does not connect to this
     * signal, then #EggSMClient will automatically return %TRUE on its
     * behalf.
     *
     * The application should not save its session state as part of
     * handling this signal; if the user has requested that the session
     * be saved when logging out, then ::save_state will be emitted
     * separately.
     *
     * If the application agrees to quit, it should then wait for either
     * the ::quit_cancelled or ::quit signals to be emitted.
     **/
    signals[QUIT_REQUESTED] =
        g_signal_new ("quit_requested",
                      G_OBJECT_CLASS_TYPE (object_class),
                      G_SIGNAL_RUN_LAST,
                      G_STRUCT_OFFSET (EggSMClientClass, quit_requested),
                      NULL, NULL,
                      g_cclosure_marshal_VOID__VOID,
                      G_TYPE_NONE,
                      0);

    /**
     * EggSMClient::quit_cancelled:
     * @client: the client
     *
     * Emitted when the session manager decides to cancel a logout after
     * the application has already agreed to quit. After receiving this
     * signal, the application can go back to what it was doing before
     * receiving the ::quit_requested signal.
     **/
    signals[QUIT_CANCELLED] =
        g_signal_new ("quit_cancelled",
                      G_OBJECT_CLASS_TYPE (object_class),
                      G_SIGNAL_RUN_LAST,
                      G_STRUCT_OFFSET (EggSMClientClass, quit_cancelled),
                      NULL, NULL,
                      g_cclosure_marshal_VOID__VOID,
                      G_TYPE_NONE,
                      0);

    /**
     * EggSMClient::quit:
     * @client: the client
     *
     * Emitted when the session manager wants the application to quit
     * (generally because the user is logging out). The application
     * should exit as soon as possible after receiving this signal; if
     * it does not, the session manager may choose to forcibly kill it.
     *
     * Normally a GUI application would only be sent a ::quit if it
     * agreed to quit in response to a ::quit_requested signal. However,
     * this is not guaranteed; in some situations the session manager
     * may decide to end the session without giving applications a
     * chance to object.
     **/
    signals[QUIT] =
        g_signal_new ("quit",
                      G_OBJECT_CLASS_TYPE (object_class),
                      G_SIGNAL_RUN_LAST,
                      G_STRUCT_OFFSET (EggSMClientClass, quit),
                      NULL, NULL,
                      g_cclosure_marshal_VOID__VOID,
                      G_TYPE_NONE,
                      0);
}

static gboolean sm_client_disable = FALSE;
static char *sm_client_state_file = NULL;
static char *sm_client_id = NULL;
static char *sm_config_prefix = NULL;

static gboolean
sm_client_post_parse_func (GOptionContext  *context,
                           GOptionGroup    *group,
                           gpointer         data,
                           GError         **error)
{
    EggSMClient *client = egg_sm_client_get ();

    if (sm_client_id == NULL)
    {
        const gchar *desktop_autostart_id;

        desktop_autostart_id = g_getenv ("DESKTOP_AUTOSTART_ID");

        if (desktop_autostart_id != NULL)
            sm_client_id = g_strdup (desktop_autostart_id);
    }

    /* Unset DESKTOP_AUTOSTART_ID in order to avoid child processes to
     * use the same client id. */
    g_unsetenv ("DESKTOP_AUTOSTART_ID");

    if (EGG_SM_CLIENT_GET_CLASS (client)->startup)
        EGG_SM_CLIENT_GET_CLASS (client)->startup (client, sm_client_id);
    return TRUE;
}

/**
 * egg_sm_client_get_option_group:
 *
 * Creates a %GOptionGroup containing the session-management-related
 * options. You should add this group to the application's
 * %GOptionContext if you want to use #EggSMClient.
 *
 * Return value: the %GOptionGroup
 **/
GOptionGroup *
egg_sm_client_get_option_group (void)
{
    const GOptionEntry entries[] =
    {
        {
            "sm-client-disable", 0, 0,
            G_OPTION_ARG_NONE, &sm_client_disable,
            N_("Disable connection to session manager"), NULL
        },
        {
            "sm-client-state-file", 0, 0,
            G_OPTION_ARG_FILENAME, &sm_client_state_file,
            N_("Specify file containing saved configuration"), N_("FILE")
        },
        {
            "sm-client-id", 0, 0,
            G_OPTION_ARG_STRING, &sm_client_id,
            N_("Specify session management ID"), N_("ID")
        },
        /* MateClient compatibility option */
        {
            "sm-disable", 0, G_OPTION_FLAG_HIDDEN,
            G_OPTION_ARG_NONE, &sm_client_disable,
            NULL, NULL
        },
        /* MateClient compatibility option. This is a dummy option that only
         * exists so that sessions saved by apps with MateClient can be restored
         * later when they've switched to EggSMClient. See bug #575308.
         */
        {
            "sm-config-prefix", 0, G_OPTION_FLAG_HIDDEN,
            G_OPTION_ARG_STRING, &sm_config_prefix,
            NULL, NULL
        },
        { NULL }
    };
    GOptionGroup *group;

    /* Use our own debug handler for the "EggSMClient" domain. */
    g_log_set_handler (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,
                       egg_sm_client_debug_handler, NULL);

    group = g_option_group_new ("sm-client",
                                _("Session management options:"),
                                _("Show session management options"),
                                NULL, NULL);
    g_option_group_add_entries (group, entries);
    g_option_group_set_parse_hooks (group, NULL, sm_client_post_parse_func);

    return group;
}

/**
 * egg_sm_client_set_mode:
 * @mode: an #EggSMClient mode
 *
 * Sets the "mode" of #EggSMClient as follows:
 *
 *    %EGG_SM_CLIENT_MODE_DISABLED: Session management is completely
 *    disabled. The application will not even connect to the session
 *    manager. (egg_sm_client_get() will still return an #EggSMClient,
 *    but it will just be a dummy object.)
 *
 *    %EGG_SM_CLIENT_MODE_NO_RESTART: The application will connect to
 *    the session manager (and thus will receive notification when the
 *    user is logging out, etc), but will request to not be
 *    automatically restarted with saved state in future sessions.
 *
 *    %EGG_SM_CLIENT_MODE_NORMAL: The default. #EggSMCLient will
 *    function normally.
 *
 * This must be called before the application's main loop begins.
 **/
void
egg_sm_client_set_mode (EggSMClientMode mode)
{
    global_client_mode = mode;
}

/**
 * egg_sm_client_get_mode:
 *
 * Gets the global #EggSMClientMode. See egg_sm_client_set_mode()
 * for details.
 *
 * Return value: the global #EggSMClientMode
 **/
EggSMClientMode
egg_sm_client_get_mode (void)
{
    return global_client_mode;
}

/**
 * egg_sm_client_get:
 *
 * Returns the master #EggSMClient for the application.
 *
 * On platforms that support saved sessions (ie, POSIX/X11), the
 * application will only request to be restarted by the session
 * manager if you call egg_set_desktop_file() to set an application
 * desktop file. In particular, if the desktop file contains the key
 * "X
 *
 * Return value: the master #EggSMClient.
 **/
EggSMClient *
egg_sm_client_get (void)
{
    if (!global_client)
    {
        if (global_client_mode != EGG_SM_CLIENT_MODE_DISABLED &&
                !sm_client_disable)
        {
#if defined (GDK_WINDOWING_WIN32)
            global_client = egg_sm_client_win32_new ();
#elif defined (GDK_WINDOWING_QUARTZ)
            global_client = egg_sm_client_osx_new ();
#else
            /* If both D-Bus and XSMP are compiled in, try XSMP first
             * (since it supports state saving) and fall back to D-Bus
             * if XSMP isn't available.
             */
# ifdef EGG_SM_CLIENT_BACKEND_XSMP
            global_client = egg_sm_client_xsmp_new ();
# endif
# ifdef EGG_SM_CLIENT_BACKEND_DBUS
            if (!global_client)
                global_client = egg_sm_client_dbus_new ();
# endif
#endif
        }

        /* Fallback: create a dummy client, so that callers don't have
         * to worry about a %NULL return value.
         */
        if (!global_client)
            global_client = g_object_new (EGG_TYPE_SM_CLIENT, NULL);
    }

    return global_client;
}

/**
 * egg_sm_client_is_resumed:
 * @client: the client
 *
 * Checks whether or not the current session has been resumed from
 * a previous saved session. If so, the application should call
 * egg_sm_client_get_state_file() and restore its state from the
 * returned #GKeyFile.
 *
 * Return value: %TRUE if the session has been resumed
 **/
gboolean
egg_sm_client_is_resumed (EggSMClient *client)
{
    g_return_val_if_fail (client == global_client, FALSE);

    return sm_client_state_file != NULL;
}

/**
 * egg_sm_client_get_state_file:
 * @client: the client
 *
 * If the application was resumed by the session manager, this will
 * return the #GKeyFile containing its state from the previous
 * session.
 *
 * Note that other libraries and #EggSMClient itself may also store
 * state in the key file, so if you call egg_sm_client_get_groups(),
 * on it, the return value will likely include groups that you did not
 * put there yourself. (It is also not guaranteed that the first
 * group created by the application will still be the "start group"
 * when it is resumed.)
 *
 * Return value: the #GKeyFile containing the application's earlier
 * state, or %NULL on error. You should not free this key file; it
 * is owned by @client.
 **/
GKeyFile *
egg_sm_client_get_state_file (EggSMClient *client)
{
    EggSMClientPrivate *priv = EGG_SM_CLIENT_GET_PRIVATE (client);
    char *state_file_path;
    GError *err = NULL;

    g_return_val_if_fail (client == global_client, NULL);

    if (!sm_client_state_file)
        return NULL;
    if (priv->state_file)
        return priv->state_file;

    if (!strncmp (sm_client_state_file, "file://", 7))
        state_file_path = g_filename_from_uri (sm_client_state_file, NULL, NULL);
    else
        state_file_path = g_strdup (sm_client_state_file);

    priv->state_file = g_key_file_new ();
    if (!g_key_file_load_from_file (priv->state_file, state_file_path, 0, &err))
    {
        g_warning ("Could not load SM state file '%s': %s",
                   sm_client_state_file, err->message);
        g_clear_error (&err);
        g_key_file_free (priv->state_file);
        priv->state_file = NULL;
    }

    g_free (state_file_path);
    return priv->state_file;
}

/**
 * egg_sm_client_set_restart_command:
 * @client: the client
 * @argc: the length of @argv
 * @argv: argument vector
 *
 * Sets the command used to restart @client if it does not have a
 * .desktop file that can be used to find its restart command.
 *
 * This can also be used when handling the ::save_state signal, to
 * save the current state via an updated command line. (Eg, providing
 * a list of filenames to open when the application is resumed.)
 **/
void
egg_sm_client_set_restart_command (EggSMClient  *client,
                                   int           argc,
                                   const char  **argv)
{
    g_return_if_fail (EGG_IS_SM_CLIENT (client));

    if (EGG_SM_CLIENT_GET_CLASS (client)->set_restart_command)
        EGG_SM_CLIENT_GET_CLASS (client)->set_restart_command (client, argc, argv);
}

/**
 * egg_sm_client_will_quit:
 * @client: the client
 * @will_quit: whether or not the application is willing to quit
 *
 * This MUST be called in response to the ::quit_requested signal, to
 * indicate whether or not the application is willing to quit. The
 * application may call it either directly from the signal handler, or
 * at some later point (eg, after asynchronously interacting with the
 * user).
 *
 * If the application does not connect to ::quit_requested,
 * #EggSMClient will call this method on its behalf (passing %TRUE
 * for @will_quit).
 *
 * After calling this method, the application should wait to receive
 * either ::quit_cancelled or ::quit.
 **/
void
egg_sm_client_will_quit (EggSMClient *client,
                         gboolean     will_quit)
{
    g_return_if_fail (EGG_IS_SM_CLIENT (client));

    if (EGG_SM_CLIENT_GET_CLASS (client)->will_quit)
        EGG_SM_CLIENT_GET_CLASS (client)->will_quit (client, will_quit);
}

/**
 * egg_sm_client_end_session:
 * @style: a hint at how to end the session
 * @request_confirmation: whether or not the user should get a chance
 * to confirm the action
 *
 * Requests that the session manager end the current session. @style
 * indicates how the session should be ended, and
 * @request_confirmation indicates whether or not the user should be
 * given a chance to confirm the logout/reboot/shutdown. Both of these
 * flags are merely hints though; the session manager may choose to
 * ignore them.
 *
 * Return value: %TRUE if the request was sent; %FALSE if it could not
 * be (eg, because it could not connect to the session manager).
 **/
gboolean
egg_sm_client_end_session (EggSMClientEndStyle  style,
                           gboolean             request_confirmation)
{
    EggSMClient *client = egg_sm_client_get ();

    g_return_val_if_fail (EGG_IS_SM_CLIENT (client), FALSE);

    if (EGG_SM_CLIENT_GET_CLASS (client)->end_session)
    {
        return EGG_SM_CLIENT_GET_CLASS (client)->end_session (client, style,
                request_confirmation);
    }
    else
        return FALSE;
}

/* Signal-emitting callbacks from platform-specific code */

GKeyFile *
egg_sm_client_save_state (EggSMClient *client)
{
    GKeyFile *state_file;
    char *group;

    g_return_val_if_fail (client == global_client, NULL);

    state_file = g_key_file_new ();

    g_debug ("Emitting save_state");
    g_signal_emit (client, signals[SAVE_STATE], 0, state_file);
    g_debug ("Done emitting save_state");

    group = g_key_file_get_start_group (state_file);
    if (group)
    {
        g_free (group);
        return state_file;
    }
    else
    {
        g_key_file_free (state_file);
        return NULL;
    }
}

void
egg_sm_client_quit_requested (EggSMClient *client)
{
    g_return_if_fail (client == global_client);

    if (!g_signal_has_handler_pending (client, signals[QUIT_REQUESTED], 0, FALSE))
    {
        g_debug ("Not emitting quit_requested because no one is listening");
        egg_sm_client_will_quit (client, TRUE);
        return;
    }

    g_debug ("Emitting quit_requested");
    g_signal_emit (client, signals[QUIT_REQUESTED], 0);
    g_debug ("Done emitting quit_requested");
}

void
egg_sm_client_quit_cancelled (EggSMClient *client)
{
    g_return_if_fail (client == global_client);

    g_debug ("Emitting quit_cancelled");
    g_signal_emit (client, signals[QUIT_CANCELLED], 0);
    g_debug ("Done emitting quit_cancelled");
}

void
egg_sm_client_quit (EggSMClient *client)
{
    g_return_if_fail (client == global_client);

    g_debug ("Emitting quit");
    g_signal_emit (client, signals[QUIT], 0);
    g_debug ("Done emitting quit");

    /* FIXME: should we just call gtk_main_quit() here? */
}

static void
egg_sm_client_debug_handler (const char *log_domain,
                             GLogLevelFlags log_level,
                             const char *message,
                             gpointer user_data)
{
    static int debug = -1;

    if (debug < 0)
        debug = (g_getenv ("EGG_SM_CLIENT_DEBUG") != NULL);

    if (debug)
        g_log_default_handler (log_domain, log_level, message, NULL);
}
