/*
 * Copyright (C) 2010 Robert Ancell.
 * Author: Robert Ancell <robert.ancell@canonical.com>
 * 
 * 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 3 of the License, or (at your option) any
 * later version. See http://www.gnu.org/copyleft/lgpl.html the full text of the
 * license.
 */

#include <string.h>
#include <gio/gdesktopappinfo.h>

#include "lightdm/session.h"

enum {
    PROP_0,
    PROP_KEY,
    PROP_NAME,
    PROP_COMMENT
};

typedef struct
{
    gchar *key;
    gchar *name;
    gchar *comment;
} LightDMSessionPrivate;

G_DEFINE_TYPE (LightDMSession, lightdm_session, G_TYPE_OBJECT);

#define GET_PRIVATE(obj) G_TYPE_INSTANCE_GET_PRIVATE ((obj), LIGHTDM_TYPE_SESSION, LightDMSessionPrivate)

static gboolean have_sessions = FALSE;
static GList *sessions = NULL;

static gint 
compare_session (gconstpointer a, gconstpointer b)
{
    LightDMSessionPrivate *priv_a = GET_PRIVATE (a);
    LightDMSessionPrivate *priv_b = GET_PRIVATE (b);
    return strcmp (priv_a->name, priv_b->name);
}

static LightDMSession *
load_session (GKeyFile *key_file, const gchar *key)
{
    gchar *domain, *name;
    LightDMSession *session;
    LightDMSessionPrivate *priv;
    gchar *try_exec;
  
    if (g_key_file_get_boolean (key_file, G_KEY_FILE_DESKTOP_GROUP, G_KEY_FILE_DESKTOP_KEY_NO_DISPLAY, NULL) ||
        g_key_file_get_boolean (key_file, G_KEY_FILE_DESKTOP_GROUP, G_KEY_FILE_DESKTOP_KEY_HIDDEN, NULL))
        return NULL;

#ifdef G_KEY_FILE_DESKTOP_KEY_GETTEXT_DOMAIN
    domain = g_key_file_get_string (key_file, G_KEY_FILE_DESKTOP_GROUP, G_KEY_FILE_DESKTOP_KEY_GETTEXT_DOMAIN, NULL);
#else
    domain = g_key_file_get_string (key_file, G_KEY_FILE_DESKTOP_GROUP, "X-GNOME-Gettext-Domain", NULL);
#endif
    name = g_key_file_get_locale_string (key_file, G_KEY_FILE_DESKTOP_GROUP, G_KEY_FILE_DESKTOP_KEY_NAME, domain, NULL);
    if (!name)
    {
        g_warning ("Ignoring session without name");
        g_free (domain);
        return NULL;
    }

    try_exec = g_key_file_get_locale_string (key_file, G_KEY_FILE_DESKTOP_GROUP, G_KEY_FILE_DESKTOP_KEY_TRY_EXEC, domain, NULL);
    if (try_exec)
    {
        gchar *full_path;

        full_path = g_find_program_in_path (try_exec);
        g_free (try_exec);

        if (!full_path)
        {
            g_free (name);
            g_free (domain);
            return NULL;
        }
        g_free (full_path);
    }

    session = g_object_new (LIGHTDM_TYPE_SESSION, NULL);
    priv = GET_PRIVATE (session);

    g_free (priv->key);
    priv->key = g_strdup (key);

    g_free (priv->name);
    priv->name = name;

    g_free (priv->comment);
    priv->comment = g_key_file_get_locale_string (key_file, G_KEY_FILE_DESKTOP_GROUP, G_KEY_FILE_DESKTOP_KEY_COMMENT, domain, NULL);
    if (!priv->comment)
        priv->comment = g_strdup ("");

    sessions = g_list_insert_sorted (sessions, session, compare_session);

    g_free (domain);

    return session;
}

static void
update_sessions (void)
{
    GDir *directory;
    gboolean result;
    GError *error = NULL;

    GKeyFile *config_key_file = NULL;
    gchar *config_path = NULL;
    gchar *xsessions_dir = g_strdup (XSESSIONS_DIR);

    if (have_sessions)
        return;

    config_path = g_build_filename (CONFIG_DIR, "lightdm.conf", NULL);
    config_key_file = g_key_file_new ();
    result = g_key_file_load_from_file (config_key_file, config_path, G_KEY_FILE_NONE, &error);
    if (error)
        g_warning ("Failed to open configuration file: %s", error->message);
    g_clear_error (&error);
    if (result)
    {
        gchar *xd_value = g_key_file_get_string (config_key_file, "LightDM", "xsessions-directory", NULL);
        if (xd_value)
        {
            g_free (xsessions_dir);
            xsessions_dir = xd_value;
        }
    }
    g_key_file_free (config_key_file);
    g_free (config_path);
    
    directory = g_dir_open (xsessions_dir, 0, &error);
    if (error)
        g_warning ("Failed to open sessions directory: %s", error->message);
    g_clear_error (&error);
    if (!directory)
    {
        g_free (xsessions_dir);
        return;
    }

    while (TRUE)
    {
        const gchar *filename;
        gchar *path;
        GKeyFile *key_file;
        gboolean result;

        filename = g_dir_read_name (directory);
        if (filename == NULL)
            break;

        if (!g_str_has_suffix (filename, ".desktop"))
            continue;

        path = g_build_filename (xsessions_dir, filename, NULL);

        key_file = g_key_file_new ();
        result = g_key_file_load_from_file (key_file, path, G_KEY_FILE_NONE, &error);
        if (error)
            g_warning ("Failed to load session file %s: %s:", path, error->message);
        g_clear_error (&error);

        if (result)
        {
            gchar *key;
            LightDMSession *session;

            key = g_strndup (filename, strlen (filename) - strlen (".desktop"));
            session = load_session (key_file, key);
            if (session)
                g_debug ("Loaded session %s (%s, %s)", path, GET_PRIVATE (session)->name, GET_PRIVATE (session)->comment);
            else
                g_debug ("Ignoring session %s", path);
            g_free (key);
        }

        g_free (path);
        g_key_file_free (key_file);
    }

    g_dir_close (directory);
    g_free (xsessions_dir);

    have_sessions = TRUE;
}

/**
 * lightdm_get_sessions:
 *
 * Get the available sessions.
 *
 * Return value: (element-type LightDMSession) (transfer none): A list of #LightDMSession
 **/
GList *
lightdm_get_sessions (void)
{
    update_sessions ();
    return sessions;
}

/**
 * lightdm_session_get_key:
 * @session: A #LightDMSession
 * 
 * Get the key for a session
 * 
 * Return value: The session key
 **/
const gchar *
lightdm_session_get_key (LightDMSession *session)
{
    g_return_val_if_fail (LIGHTDM_IS_SESSION (session), NULL);
    return GET_PRIVATE (session)->key;
}

/**
 * lightdm_session_get_name:
 * @session: A #LightDMSession
 * 
 * Get the name for a session
 * 
 * Return value: The session name
 **/
const gchar *
lightdm_session_get_name (LightDMSession *session)
{
    g_return_val_if_fail (LIGHTDM_IS_SESSION (session), NULL);
    return GET_PRIVATE (session)->name;
}

/**
 * lightdm_session_get_comment:
 * @session: A #LightDMSession
 * 
 * Get the comment for a session
 * 
 * Return value: The session comment
 **/
const gchar *
lightdm_session_get_comment (LightDMSession *session)
{
    g_return_val_if_fail (LIGHTDM_IS_SESSION (session), NULL);
    return GET_PRIVATE (session)->comment;
}

static void
lightdm_session_init (LightDMSession *session)
{
}

static void
lightdm_session_set_property (GObject      *object,
                          guint         prop_id,
                          const GValue *value,
                          GParamSpec   *pspec)
{
    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
}

static void
lightdm_session_get_property (GObject    *object,
                          guint       prop_id,
                          GValue     *value,
                          GParamSpec *pspec)
{
    LightDMSession *self;

    self = LIGHTDM_SESSION (object);

    switch (prop_id) {
    case PROP_KEY:
        g_value_set_string (value, lightdm_session_get_key (self));
        break;
    case PROP_NAME:
        g_value_set_string (value, lightdm_session_get_name (self));
        break;
    case PROP_COMMENT:
        g_value_set_string (value, lightdm_session_get_comment (self));
        break;
    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
        break;
    }
}

static void
lightdm_session_finalize (GObject *object)
{
    LightDMSession *self = LIGHTDM_SESSION (object);
    LightDMSessionPrivate *priv = GET_PRIVATE (self);

    g_free (priv->key);
    g_free (priv->name);
    g_free (priv->comment);
}

static void
lightdm_session_class_init (LightDMSessionClass *klass)
{
    GObjectClass *object_class = G_OBJECT_CLASS (klass);
  
    g_type_class_add_private (klass, sizeof (LightDMSessionPrivate));

    object_class->set_property = lightdm_session_set_property;
    object_class->get_property = lightdm_session_get_property;
    object_class->finalize = lightdm_session_finalize;

    g_object_class_install_property (object_class,
                                     PROP_KEY,
                                     g_param_spec_string ("key",
                                                          "key",
                                                          "Session key",
                                                          NULL,
                                                          G_PARAM_READABLE));
    g_object_class_install_property (object_class,
                                     PROP_NAME,
                                     g_param_spec_string ("name",
                                                          "name",
                                                          "Session name",
                                                          NULL,
                                                          G_PARAM_READABLE));
    g_object_class_install_property (object_class,
                                     PROP_COMMENT,
                                     g_param_spec_string ("comment",
                                                          "comment",
                                                          "Session comment",
                                                          NULL,
                                                          G_PARAM_READABLE));
}