rockbox/apps/root_menu.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2007 Jonathan Gordon
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include "string-extra.h"
#include "config.h"
#include "appevents.h"
#include "menu.h"
#include "root_menu.h"
#include "lang.h"
#include "settings.h"
#include "screens.h"
#include "kernel.h"
#include "debug.h"
#include "misc.h"
#include "rolo.h"
#include "powermgmt.h"
#include "power.h"
#include "talk.h"
#include "audio.h"
#include "shortcuts.h"

#ifdef HAVE_HOTSWAP
#include "storage.h"
#include "dir.h"
#endif
/* gui api */
#include "list.h"
#include "splash.h"
#include "action.h"
#include "yesno.h"
#include "viewport.h"

#include "tree.h"
#if CONFIG_TUNER
#include "radio.h"
#endif
#ifdef HAVE_RECORDING
#include "recording.h"
#endif
#include "wps.h"
#include "bookmark.h"
#include "playlist.h"
#include "playlist_viewer.h"
#include "playlist_catalog.h"
#include "menus/exported_menus.h"
#ifdef HAVE_RTC_ALARM
#include "rtc.h"
#endif
#ifdef HAVE_TAGCACHE
#include "tagcache.h"
#endif
#include "language.h"
#include "plugin.h"
#include "disk.h"

struct root_items {
    int (*function)(void* param);
    void* param;
    const struct menu_item_ex *context_menu;
};
static int next_screen = GO_TO_ROOT; /* holding info about the upcoming screen
                                        * which is the current screen for the
                                        * rest of the code after load_screen
                                        * is called */
static int last_screen = GO_TO_ROOT; /* unfortunatly needed so we can resume
                                        or goto current track based on previous
                                        screen */


static char current_track_path[MAX_PATH];
static void rootmenu_track_changed_callback(void* param)
{
    struct mp3entry *id3 = ((struct track_event *)param)->id3;
    strlcpy(current_track_path, id3->path, MAX_PATH);
}
static int browser(void* param)
{
    int ret_val;
#ifdef HAVE_TAGCACHE
    struct tree_context* tc = tree_get_context();
#endif
    struct browse_context browse;
    int filter = SHOW_SUPPORTED;
    char folder[MAX_PATH] = "/";
    /* stuff needed to remember position in file browser */
    static char last_folder[MAX_PATH] = "/";
    /* and stuff for the database browser */
#ifdef HAVE_TAGCACHE
    static int last_db_dirlevel = 0, last_db_selection = 0;
#endif

    switch ((intptr_t)param)
    {
        case GO_TO_FILEBROWSER:
            filter = global_settings.dirfilter;
            if (global_settings.browse_current &&
                    last_screen == GO_TO_WPS &&
                    current_track_path[0])
            {
                strcpy(folder, current_track_path);
            }
            else if (!strcmp(last_folder, "/"))
            {
                strcpy(folder, global_settings.start_directory);
            }
            else
            {
#ifdef HAVE_HOTSWAP
                bool in_hotswap = false;
                /* handle entering an ejected drive */
                int i;
                for (i = 0; i < NUM_VOLUMES; i++)
                {
                    char vol_string[VOL_ENUM_POS + 8];
                    if (!volume_removable(i))
                        continue;
                    /* VOL_NAMES contains a %d */
                    snprintf(vol_string, sizeof(vol_string), "/"VOL_NAMES, i);
                    /* test whether we would browse the external card */
                    if (!volume_present(i) &&
                            (strstr(last_folder, vol_string)
#ifdef HAVE_HOTSWAP_STORAGE_AS_MAIN
                                                                || (i == 0)
#endif
                                                                ))
                    {   /* leave folder as "/" to avoid crash when trying
                         * to access an ejected drive */
                        strcpy(folder, "/");
                        in_hotswap = true;
                        break;
                    }
                }
                if (!in_hotswap)
#endif
                    strcpy(folder, last_folder);
            }
            push_current_activity(ACTIVITY_FILEBROWSER);
        break;
#ifdef HAVE_TAGCACHE
        case GO_TO_DBBROWSER:
            if (!tagcache_is_usable())
            {
                bool reinit_attempted = false;

                /* Now display progress until it's ready or the user exits */
                while(!tagcache_is_usable())
                {
                    struct tagcache_stat *stat = tagcache_get_stat();

                    /* Allow user to exit */
                    if (action_userabort(HZ/2))
                        break;

                    /* Maybe just needs to reboot due to delayed commit */
                    if (stat->commit_delayed)
                    {
                        splash(HZ*2, ID2P(LANG_PLEASE_REBOOT));
                        break;
                    }

                    /* Check if ready status is known */
                    if (!stat->readyvalid)
                    {
                        splash(0, str(LANG_TAGCACHE_BUSY));
                        continue;
                    }

                    /* Re-init if required */
                    if (!reinit_attempted && !stat->ready &&
                        stat->processed_entries == 0 && stat->commit_step == 0)
                    {
                        /* Prompt the user */
                        reinit_attempted = true;
                        static const char *lines[]={
                            ID2P(LANG_TAGCACHE_BUSY), ID2P(LANG_TAGCACHE_FORCE_UPDATE)};
                        static const struct text_message message={lines, 2};
                        if(gui_syncyesno_run(&message, NULL, NULL) == YESNO_NO)
                            break;
                        FOR_NB_SCREENS(i)
                            screens[i].clear_display();

                        /* Start initialisation */
                        tagcache_rebuild();
                    }

                    /* Display building progress */
                    static long talked_tick = 0;
                    if(global_settings.talk_menu &&
                       (talked_tick == 0
                        || TIME_AFTER(current_tick, talked_tick+7*HZ)))
                    {
                        talked_tick = current_tick;
                        if (stat->commit_step > 0)
                        {
                            talk_id(LANG_TAGCACHE_INIT, false);
                            talk_number(stat->commit_step, true);
                            talk_id(VOICE_OF, true);
                            talk_number(tagcache_get_max_commit_step(), true);
                        } else if(stat->processed_entries)
                        {
                            talk_number(stat->processed_entries, false);
                            talk_id(LANG_BUILDING_DATABASE, true);
                        }
                    }
                    if (stat->commit_step > 0)
                    {
                        if (lang_is_rtl())
                        {
                            splashf(0, "[%d/%d] %s", stat->commit_step,
                                tagcache_get_max_commit_step(),
                                str(LANG_TAGCACHE_INIT));
                        }
                        else
                        {
                            splashf(0, "%s [%d/%d]", str(LANG_TAGCACHE_INIT),
                                stat->commit_step,
                                tagcache_get_max_commit_step());
                        }
                    }
                    else
                    {
                        splashf(0, str(LANG_BUILDING_DATABASE),
                                   stat->processed_entries);
                    }
                }
            }
            if (!tagcache_is_usable())
                return GO_TO_PREVIOUS;
            filter = SHOW_ID3DB;
            tc->dirlevel = last_db_dirlevel;
            tc->selected_item = last_db_selection;
            push_current_activity(ACTIVITY_DATABASEBROWSER);
        break;
#endif
    }

    browse_context_init(&browse, filter, 0, NULL, NOICON, folder, NULL);
    ret_val = rockbox_browse(&browse);
    pop_current_activity();
    switch ((intptr_t)param)
    {
        case GO_TO_FILEBROWSER:
            if (!get_current_file(last_folder, MAX_PATH) ||
                (!strchr(&last_folder[1], '/') &&
                 global_settings.start_directory[1] != '\0'))
            {
                last_folder[0] = '/';
                last_folder[1] = '\0';
            }
        break;
#ifdef HAVE_TAGCACHE
        case GO_TO_DBBROWSER:
            last_db_dirlevel = tc->dirlevel;
            last_db_selection = tc->selected_item;
        break;
#endif
    }
    return ret_val;
}

#ifdef HAVE_RECORDING
static int recscrn(void* param)
{
    (void)param;
    recording_screen(false);
    return GO_TO_ROOT;
}
#endif
static int wpsscrn(void* param)
{
    int ret_val = GO_TO_PREVIOUS;
    (void)param;
    push_current_activity(ACTIVITY_WPS);
    if (audio_status())
    {
        talk_shutup();
        ret_val = gui_wps_show();
    }
    else if ( global_status.resume_index != -1 )
    {
        DEBUGF("Resume index %X crc32 %lX offset %lX\n",
               global_status.resume_index,
               (unsigned long)global_status.resume_crc32,
               (unsigned long)global_status.resume_offset);
        if (playlist_resume() != -1)
        {
            playlist_resume_track(global_status.resume_index,
                global_status.resume_crc32,
                global_status.resume_offset);
            ret_val = gui_wps_show();
        }
    }
    else
    {
        splash(HZ*2, ID2P(LANG_NOTHING_TO_RESUME));
    }
    pop_current_activity();
    return ret_val;
}
#if CONFIG_TUNER
static int radio(void* param)
{
    (void)param;
    radio_screen();
    return GO_TO_ROOT;
}
#endif

static int miscscrn(void * param)
{
    const struct menu_item_ex *menu = (const struct menu_item_ex*)param;
    int result = do_menu(menu, NULL, NULL, false);
    switch (result)
    {
        case GO_TO_PLAYLIST_VIEWER:
        case GO_TO_WPS:
            return result;
        default:
            return GO_TO_ROOT;
    }
}


static int playlist_view_catalog(void * param)
{
    /* kludge untill catalog_view_playlists() returns something useful */
    int old_playstatus = audio_status();
    (void)param;
    push_current_activity(ACTIVITY_PLAYLISTBROWSER);
    catalog_view_playlists();
    pop_current_activity();
    if (!old_playstatus && audio_status())
        return GO_TO_WPS;
    return GO_TO_PREVIOUS;
}

static int playlist_view(void * param)
{
    (void)param;
    int val;

    push_current_activity(ACTIVITY_PLAYLISTVIEWER);
    val = playlist_viewer();
    pop_current_activity();
    switch (val)
    {
        case PLAYLIST_VIEWER_MAINMENU:
        case PLAYLIST_VIEWER_USB:
            return GO_TO_ROOT;
        case PLAYLIST_VIEWER_OK:
            return GO_TO_PREVIOUS;
    }
    return GO_TO_PREVIOUS;
}

static int load_bmarks(void* param)
{
    (void)param;
    if(bookmark_mrb_load())
        return GO_TO_WPS;
    return GO_TO_PREVIOUS;
}

/* These are all static const'd from apps/menus/ *.c
   so little hack so we can use them */
extern struct menu_item_ex
        file_menu,
#ifdef HAVE_TAGCACHE
        tagcache_menu,
#endif
        main_menu_,
        manage_settings,
        plugin_menu,
        playlist_options,
        info_menu,
        system_menu;
static const struct root_items items[] = {
    [GO_TO_FILEBROWSER] =   { browser, (void*)GO_TO_FILEBROWSER, &file_menu},
#ifdef HAVE_TAGCACHE
    [GO_TO_DBBROWSER] =     { browser, (void*)GO_TO_DBBROWSER, &tagcache_menu },
#endif
    [GO_TO_WPS] =           { wpsscrn, NULL, &playback_settings },
    [GO_TO_MAINMENU] =      { miscscrn, (struct menu_item_ex*)&main_menu_,
                                                            &manage_settings },

#ifdef HAVE_RECORDING
    [GO_TO_RECSCREEN] =     {  recscrn, NULL, &recording_settings_menu },
#endif

#if CONFIG_TUNER
    [GO_TO_FM] =            { radio, NULL, &radio_settings_menu },
#endif

    [GO_TO_RECENTBMARKS] =  { load_bmarks, NULL, &bookmark_settings_menu },
    [GO_TO_BROWSEPLUGINS] = { miscscrn, &plugin_menu, NULL },
    [GO_TO_PLAYLISTS_SCREEN] = { playlist_view_catalog, NULL,
                                                        &playlist_options },
    [GO_TO_PLAYLIST_VIEWER] = { playlist_view, NULL, &playlist_options },
    [GO_TO_SYSTEM_SCREEN] = { miscscrn, &info_menu, &system_menu },
    [GO_TO_SHORTCUTMENU] = { do_shortcut_menu, NULL, NULL },

};
static const int nb_items = sizeof(items)/sizeof(*items);

static int item_callback(int action, const struct menu_item_ex *this_item) ;

MENUITEM_RETURNVALUE(shortcut_menu, ID2P(LANG_SHORTCUTS), GO_TO_SHORTCUTMENU,
                        NULL, Icon_Bookmark);

MENUITEM_RETURNVALUE(file_browser, ID2P(LANG_DIR_BROWSER), GO_TO_FILEBROWSER,
                        NULL, Icon_file_view_menu);
#ifdef HAVE_TAGCACHE
MENUITEM_RETURNVALUE(db_browser, ID2P(LANG_TAGCACHE), GO_TO_DBBROWSER,
                        NULL, Icon_Audio);
#endif
MENUITEM_RETURNVALUE(rocks_browser, ID2P(LANG_PLUGINS), GO_TO_BROWSEPLUGINS,
                        NULL, Icon_Plugin);

MENUITEM_RETURNVALUE(playlist_browser, ID2P(LANG_CATALOG), GO_TO_PLAYLIST_VIEWER,
                        NULL, Icon_Playlist);

static char *get_wps_item_name(int selected_item, void * data, char *buffer)
{
    (void)selected_item; (void)data; (void)buffer;
    if (audio_status())
        return ID2P(LANG_NOW_PLAYING);
    return ID2P(LANG_RESUME_PLAYBACK);
}
MENUITEM_RETURNVALUE_DYNTEXT(wps_item, GO_TO_WPS, NULL, get_wps_item_name,
                                NULL, NULL, Icon_Playback_menu);
#ifdef HAVE_RECORDING
MENUITEM_RETURNVALUE(rec, ID2P(LANG_RECORDING), GO_TO_RECSCREEN,
                        NULL, Icon_Recording);
#endif
#if CONFIG_TUNER
MENUITEM_RETURNVALUE(fm, ID2P(LANG_FM_RADIO), GO_TO_FM,
                        item_callback, Icon_Radio_screen);
#endif
MENUITEM_RETURNVALUE(menu_, ID2P(LANG_SETTINGS), GO_TO_MAINMENU,
                        NULL, Icon_Submenu_Entered);
MENUITEM_RETURNVALUE(bookmarks, ID2P(LANG_BOOKMARK_MENU_RECENT_BOOKMARKS),
                        GO_TO_RECENTBMARKS,  item_callback,
                        Icon_Bookmark);
MENUITEM_RETURNVALUE(playlists, ID2P(LANG_CATALOG), GO_TO_PLAYLISTS_SCREEN,
                     NULL, Icon_Playlist);
MENUITEM_RETURNVALUE(system_menu_, ID2P(LANG_SYSTEM), GO_TO_SYSTEM_SCREEN,
                     NULL, Icon_System_menu);

#if CONFIG_KEYPAD == PLAYER_PAD
static int do_shutdown(void)
{
#if CONFIG_CHARGING
    if (charger_inserted())
        charging_splash();
    else
#endif
        sys_poweroff();
    return 0;
}
MENUITEM_FUNCTION(do_shutdown_item, 0, ID2P(LANG_SHUTDOWN),
                  do_shutdown, NULL, NULL, Icon_NOICON);
#endif

struct menu_item_ex root_menu_;
static struct menu_callback_with_desc root_menu_desc = {
        item_callback, ID2P(LANG_ROCKBOX_TITLE), Icon_Rockbox };
struct menu_table {
    char *string;
    const struct menu_item_ex *item;
};
static struct menu_table menu_table[] = {
    /* Order here represents the default ordering */
    { "bookmarks", &bookmarks },
    { "files", &file_browser },
#ifdef HAVE_TAGCACHE
    { "database", &db_browser },
#endif
    { "wps", &wps_item },
    { "settings", &menu_ },
#ifdef HAVE_RECORDING
    { "recording", &rec },
#endif
#if CONFIG_TUNER
    { "radio", &fm },
#endif
    { "playlists", &playlists },
    { "plugins", &rocks_browser },
    { "system_menu", &system_menu_ },
#if CONFIG_KEYPAD == PLAYER_PAD
    { "shutdown", &do_shutdown_item },
#endif
    { "shortcuts", &shortcut_menu },
};
#define MAX_MENU_ITEMS (sizeof(menu_table) / sizeof(struct menu_table))
static struct menu_item_ex *root_menu__[MAX_MENU_ITEMS];

void root_menu_load_from_cfg(void* setting, char *value)
{
    char *next = value, *start, *end;
    unsigned int menu_item_count = 0, i;
    bool main_menu_added = false;

    if (*value == '-')
    {
        root_menu_set_default(setting, NULL);
        return;
    }
    root_menu_.flags = MENU_HAS_DESC | MT_MENU;
    root_menu_.submenus = (const struct menu_item_ex **)&root_menu__;
    root_menu_.callback_and_desc = &root_menu_desc;

    while (next && menu_item_count < MAX_MENU_ITEMS)
    {
        start = next;
        next = strchr(next, ',');
        if (next)
        {
            *next = '\0';
            next++;
        }
        start = skip_whitespace(start);
        if ((end = strchr(start, ' ')))
            *end = '\0';
        for (i=0; i<MAX_MENU_ITEMS; i++)
        {
            if (*start && !strcmp(start, menu_table[i].string))
            {
                root_menu__[menu_item_count++] = (struct menu_item_ex *)menu_table[i].item;
                if (menu_table[i].item == &menu_)
                    main_menu_added = true;
                break;
            }
        }
    }
    if (!main_menu_added)
        root_menu__[menu_item_count++] = (struct menu_item_ex *)&menu_;
    root_menu_.flags |= MENU_ITEM_COUNT(menu_item_count);
    *(bool*)setting = true;
}

char* root_menu_write_to_cfg(void* setting, char*buf, int buf_len)
{
    (void)setting;
    unsigned i, written, j;
    for (i = 0; i < MENU_GET_COUNT(root_menu_.flags); i++)
    {
        for (j=0; j<MAX_MENU_ITEMS; j++)
        {
            if (menu_table[j].item == root_menu__[i])
            {
                written = snprintf(buf, buf_len, "%s, ", menu_table[j].string);
                buf_len -= written;
                buf += written;
                break;
            }
        }
    }
    return buf;
}

void root_menu_set_default(void* setting, void* defaultval)
{
    unsigned i;
    (void)defaultval;

    root_menu_.flags = MENU_HAS_DESC | MT_MENU;
    root_menu_.submenus = (const struct menu_item_ex **)&root_menu__;
    root_menu_.callback_and_desc = &root_menu_desc;

    for (i=0; i<MAX_MENU_ITEMS; i++)
    {
        root_menu__[i] = (struct menu_item_ex *)menu_table[i].item;
    }
    root_menu_.flags |= MENU_ITEM_COUNT(MAX_MENU_ITEMS);
    *(bool*)setting = false;
}

bool root_menu_is_changed(void* setting, void* defaultval)
{
    (void)defaultval;
    return *(bool*)setting;
}

static int item_callback(int action, const struct menu_item_ex *this_item)
{
    switch (action)
    {
        case ACTION_TREE_STOP:
            return ACTION_REDRAW;
        case ACTION_REQUEST_MENUITEM:
#if CONFIG_TUNER
            if (this_item == &fm)
            {
                if (radio_hardware_present() == 0)
                    return ACTION_EXIT_MENUITEM;
            }
            else
#endif
                if (this_item == &bookmarks)
            {
                if (global_settings.usemrb == 0)
                    return ACTION_EXIT_MENUITEM;
            }
        break;
    }
    return action;
}
static int get_selection(int last_screen)
{
    int i;
    int len = ARRAYLEN(root_menu__);
    for(i=0; i < len; i++)
    {
        if (((root_menu__[i]->flags&MENU_TYPE_MASK) == MT_RETURN_VALUE) &&
            (root_menu__[i]->value == last_screen))
        {
            return i;
        }
    }
    return 0;
}

static inline int load_screen(int screen)
{
    /* set the global_status.last_screen before entering,
        if we dont we will always return to the wrong screen on boot */
    int old_previous = last_screen;
    int ret_val;
    enum current_activity activity = ACTIVITY_UNKNOWN;
    if (screen <= GO_TO_ROOT)
        return screen;
    if (screen == old_previous)
        old_previous = GO_TO_ROOT;
    global_status.last_screen = (char)screen;
    status_save();

    if (screen == GO_TO_BROWSEPLUGINS)
        activity = ACTIVITY_PLUGINBROWSER;
    else if (screen == GO_TO_MAINMENU)
        activity = ACTIVITY_SETTINGS;
    else if (screen == GO_TO_SYSTEM_SCREEN)
        activity =  ACTIVITY_SYSTEMSCREEN;

    if (activity != ACTIVITY_UNKNOWN)
        push_current_activity(activity);

    ret_val = items[screen].function(items[screen].param);

    if (activity != ACTIVITY_UNKNOWN)
        pop_current_activity();

    last_screen = screen;
    if (ret_val == GO_TO_PREVIOUS)
        last_screen = old_previous;
    return ret_val;
}
static int load_context_screen(int selection)
{
    const struct menu_item_ex *context_menu = NULL;
    int retval = GO_TO_PREVIOUS;
    push_current_activity(ACTIVITY_CONTEXTMENU);
    if ((root_menu__[selection]->flags&MENU_TYPE_MASK) == MT_RETURN_VALUE)
    {
        int item = root_menu__[selection]->value;
        context_menu = items[item].context_menu;
    }
    /* special cases */
    else if (root_menu__[selection] == &info_menu)
    {
        context_menu = &system_menu;
    }

    if (context_menu)
        retval = do_menu(context_menu, NULL, NULL, false);
    pop_current_activity();
    return retval;
}

#ifdef HAVE_PICTUREFLOW_INTEGRATION
static int load_plugin_screen(char *plug_path)
{
    int ret_val;
    int old_previous = last_screen;
    last_screen = next_screen;
    global_status.last_screen = (char)next_screen;
    status_save();

    switch (plugin_load(plug_path, NULL))
    {
    case PLUGIN_GOTO_WPS:
        ret_val = GO_TO_WPS;
        break;
    case PLUGIN_OK:
        ret_val = audio_status() ? GO_TO_PREVIOUS : GO_TO_ROOT;
        break;
    default:
        ret_val = GO_TO_PREVIOUS;
        break;
    }

    if (ret_val == GO_TO_PREVIOUS)
        last_screen = (old_previous == next_screen) ? GO_TO_ROOT : old_previous;
    return ret_val;
}
#endif

static int previous_music = GO_TO_WPS;

void previous_music_is_wps(void)
{
    previous_music = GO_TO_WPS;
}

void root_menu(void)
{
    int previous_browser = GO_TO_FILEBROWSER;
    int selected = 0;

    push_current_activity(ACTIVITY_MAINMENU);

    if (global_settings.start_in_screen == 0)
        next_screen = (int)global_status.last_screen;
    else next_screen = global_settings.start_in_screen - 2;
    add_event(PLAYBACK_EVENT_TRACK_CHANGE, false, rootmenu_track_changed_callback);
#ifdef HAVE_RTC_ALARM
    if ( rtc_check_alarm_started(true) )
    {
        rtc_enable_alarm(false);
        next_screen = GO_TO_WPS;
#if CONFIG_TUNER
        if (global_settings.alarm_wake_up_screen == ALARM_START_FM)
            next_screen = GO_TO_FM;
#endif
#ifdef HAVE_RECORDING
        if (global_settings.alarm_wake_up_screen == ALARM_START_REC)
        {
            recording_start_automatic = true;
            next_screen = GO_TO_RECSCREEN;
        }
#endif
    }
#endif /* HAVE_RTC_ALARM */

#ifdef HAVE_HEADPHONE_DETECTION
    if (next_screen == GO_TO_WPS &&
        (global_settings.unplug_autoresume && !headphones_inserted() ))
            next_screen = GO_TO_ROOT;
#endif

    while (true)
    {
        switch (next_screen)
        {
            case MENU_ATTACHED_USB:
            case MENU_SELECTED_EXIT:
                /* fall through */
            case GO_TO_ROOT:
                if (last_screen != GO_TO_ROOT)
                    selected = get_selection(last_screen);
#if (CONFIG_PLATFORM&PLATFORM_ANDROID)
                /* When we are in the main menu we want the hardware BACK
                 * button to be handled by Android instead of rockbox */
                android_ignore_back_button(true);
#endif
                next_screen = do_menu(&root_menu_, &selected, NULL, false);
#if (CONFIG_PLATFORM&PLATFORM_ANDROID)
                android_ignore_back_button(false);
#endif
                if (next_screen != GO_TO_PREVIOUS)
                    last_screen = GO_TO_ROOT;
                break;

            case GO_TO_PREVIOUS:
                next_screen = last_screen;
                break;

            case GO_TO_PREVIOUS_BROWSER:
                next_screen = previous_browser;
                break;

            case GO_TO_PREVIOUS_MUSIC:
                next_screen = previous_music;
                break;
            case GO_TO_ROOTITEM_CONTEXT:
                next_screen = load_context_screen(selected);
                break;
#ifdef HAVE_PICTUREFLOW_INTEGRATION
            case GO_TO_PICTUREFLOW:
                while ( !tagcache_is_usable() )
                {
                    splash(0, str(LANG_TAGCACHE_BUSY));
                    if ( action_userabort(HZ/5) )
                        break;
                }
                {
                    char pf_path[MAX_PATH];
                    snprintf(pf_path, sizeof(pf_path),
                            "%s/pictureflow.rock",
                            PLUGIN_DEMOS_DIR);
                    next_screen = load_plugin_screen(pf_path);
                }
                previous_browser = GO_TO_PICTUREFLOW;
                break;
#endif
            default:
                if (next_screen == GO_TO_FILEBROWSER
#ifdef HAVE_TAGCACHE
                    || next_screen == GO_TO_DBBROWSER
#endif
                   )
                    previous_browser = next_screen;
                if (next_screen == GO_TO_WPS
#if CONFIG_TUNER
                    || next_screen == GO_TO_FM
#endif
                   )
                    previous_music = next_screen;
                next_screen = load_screen(next_screen);
                break;
        } /* switch() */
    }
}