/*
 * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
 * Copyright (C) 2016 Furrtek
 * Copyright (C) 2024 u-foka
 * Copyleft (ɔ) 2024 zxkmm under GPL license
 *
 * This file is part of PortaPack.
 *
 * 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, 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include "ui_navigation.hpp"

// #include "modules.h"

#include "bmp_modal_warning.hpp"
#include "bmp_splash.hpp"
#include "event_m0.hpp"
#include "portapack_persistent_memory.hpp"
#include "portapack_shared_memory.hpp"
#include "portapack.hpp"

#include "ui_about_simple.hpp"
#include "ui_adsb_rx.hpp"
#include "ui_adsb_tx.hpp"
#include "ui_aprs_rx.hpp"
#include "ui_aprs_tx.hpp"
#include "ui_bht_tx.hpp"
#include "ui_btle_rx.hpp"
// #include "ui_coasterp.hpp" //moved to ext
#include "ui_debug.hpp"
#include "ui_encoders.hpp"
#include "ui_fileman.hpp"
#include "ui_flash_utility.hpp"
#include "ui_font_fixed_8x16.hpp"
#include "ui_freqman.hpp"
#include "ui_fsk_rx.hpp"
#include "ui_iq_trim.hpp"
// #include "ui_jammer.hpp" //moved to ext
//  #include "ui_keyfob.hpp" //moved to ext
//  #include "ui_lcr.hpp"
#include "ui_level.hpp"
#include "ui_looking_glass_app.hpp"
#include "ui_mictx.hpp"
#include "ui_morse.hpp"
// #include "ui_nrf_rx.hpp" //moved to ext
// #include "ui_numbers.hpp"
// #include "ui_nuoptix.hpp"
// #include "ui_playdead.hpp"
#include "ui_playlist.hpp"
#include "ui_pocsag_tx.hpp"
#include "ui_rds.hpp"
#include "ui_recon.hpp"
#include "ui_remote.hpp"
#include "ui_scanner.hpp"
#include "ui_sd_over_usb.hpp"
#include "ui_sd_wipe.hpp"
#include "ui_search.hpp"
#include "ui_settings.hpp"
#include "ui_siggen.hpp"
#include "ui_sonde.hpp"
// #include "ui_spectrum_painter.hpp" //moved to ext app
#include "ui_ss_viewer.hpp"
#include "ui_sstvtx.hpp"
#include "ui_styles.hpp"
// #include "ui_test.hpp"
#include "ui_text_editor.hpp"
#include "ui_tone_search.hpp"
#include "ui_touchtunes.hpp"
#include "ui_view_wav.hpp"
#include "ui_weatherstation.hpp"
#include "ui_subghzd.hpp"
#include "ui_whipcalc.hpp"
#include "ui_external_items_menu_loader.hpp"

// #include "acars_app.hpp"
#include "ais_app.hpp"
#include "analog_audio_app.hpp"
// #include "analog_tv_app.hpp" //moved to ext
#include "ble_comm_app.hpp"
#include "ble_rx_app.hpp"
#include "ble_tx_app.hpp"
#include "capture_app.hpp"
#include "ert_app.hpp"
// #include "gps_sim_app.hpp" //moved to ext
// #include "lge_app.hpp" //moved to ext
#include "pocsag_app.hpp"
#include "replay_app.hpp"
#include "soundboard_app.hpp"
#include "tpms_app.hpp"

#include "core_control.hpp"
#include "file.hpp"
#include "file_reader.hpp"
#include "png_writer.hpp"

using portapack::receiver_model;
using portapack::transmitter_model;
namespace pmem = portapack::persistent_memory;

namespace ui {

bool CstrCmp::operator()(const char* a, const char* b) const {
    return strcmp(a, b) < 0;
}

static NavigationView::AppMap generate_app_map(const NavigationView::AppList& appList) {
    NavigationView::AppMap out;

    for (auto& app : appList) {
        if (app.id == nullptr) {
            // Skip items with no id
            continue;
        }

        auto res = out.emplace(app.id, app);
        if (!res.second) {
            chDbgPanic("Application cannot be added, ID not unique!");
        }
    }

    return out;
}

// TODO(u-foka): Check consistency of command names (where we add rx/tx postfix)
const NavigationView::AppList NavigationView::appList = {
    /* HOME ******************************************************************/
    //{"playdead", "Play dead", HOME, Color::red(), &bitmap_icon_playdead, new ViewFactory<PlayDeadView>()},
    {nullptr, "Receive", HOME, Color::cyan(), &bitmap_icon_receivers, new ViewFactory<ReceiversMenuView>()},
    {nullptr, "Transmit", HOME, Color::cyan(), &bitmap_icon_transmit, new ViewFactory<TransmittersMenuView>()},
    {"capture", "Capture", HOME, Color::red(), &bitmap_icon_capture, new ViewFactory<CaptureAppView>()},
    {"replay", "Replay", HOME, Color::green(), &bitmap_icon_replay, new ViewFactory<PlaylistView>()},
    {"remote", "Remote", HOME, ui::Color::green(), &bitmap_icon_remote, new ViewFactory<RemoteView>()},
    {"scanner", "Scanner", HOME, Color::green(), &bitmap_icon_scanner, new ViewFactory<ScannerView>()},
    {"microphone", "Microphone", HOME, Color::green(), &bitmap_icon_microphone, new ViewFactory<MicTXView>()},
    {"lookingglass", "Looking Glass", HOME, Color::green(), &bitmap_icon_looking, new ViewFactory<GlassView>()},
    {nullptr, "Utilities", HOME, Color::cyan(), &bitmap_icon_utilities, new ViewFactory<UtilitiesMenuView>()},
    {nullptr, "Settings", HOME, Color::cyan(), &bitmap_icon_setup, new ViewFactory<SettingsMenuView>()},
    {nullptr, "Debug", HOME, Color::light_grey(), &bitmap_icon_debug, new ViewFactory<DebugMenuView>()},
    //{"about", "About", HOME, Color::cyan(), nullptr, new ViewFactory<AboutView>()},
    /* RX ********************************************************************/
    //{"acars", "ACARS", RX, Color::yellow(), &bitmap_icon_adsb, new ViewFactory<ACARSAppView>()},
    {"adsbrx", "ADS-B", RX, Color::green(), &bitmap_icon_adsb, new ViewFactory<ADSBRxView>()},
    {"ais", "AIS Boats", RX, Color::green(), &bitmap_icon_ais, new ViewFactory<AISAppView>()},
    {"aprsrx", "APRS", RX, Color::green(), &bitmap_icon_aprs, new ViewFactory<APRSRXView>()},
    {"audio", "Audio", RX, Color::green(), &bitmap_icon_speaker, new ViewFactory<AnalogAudioView>()},
    //{"btle", "BTLE", RX, Color::yellow(), &bitmap_icon_btle, new ViewFactory<BTLERxView>()},
    //{"blecomm", "BLE Comm", RX, ui::Color::orange(), &bitmap_icon_btle, new ViewFactory<BLECommView>()},
    {"blerx", "BLE Rx", RX, Color::green(), &bitmap_icon_btle, new ViewFactory<BLERxView>()},
    {"ert", "ERT Meter", RX, Color::green(), &bitmap_icon_ert, new ViewFactory<ERTAppView>()},
    {"level", "Level", RX, Color::green(), &bitmap_icon_options_radio, new ViewFactory<LevelView>()},
    {"pocsag", "POCSAG", RX, Color::green(), &bitmap_icon_pocsag, new ViewFactory<POCSAGAppView>()},
    {"radiosonde", "Radiosnde", RX, Color::green(), &bitmap_icon_sonde, new ViewFactory<SondeView>()},
    {"recon", "Recon", RX, Color::green(), &bitmap_icon_scanner, new ViewFactory<ReconView>()},
    {"search", "Search", RX, Color::yellow(), &bitmap_icon_search, new ViewFactory<SearchView>()},
    {"tmps", "TPMS Cars", RX, Color::green(), &bitmap_icon_tpms, new ViewFactory<TPMSAppView>()},
    {"weather", "Weather", RX, Color::green(), &bitmap_icon_thermometer, new ViewFactory<WeatherView>()},
    {"subghzd", "SubGhzD", RX, Color::yellow(), &bitmap_icon_remote, new ViewFactory<SubGhzDView>()},
    //{"fskrx", "FSK RX", RX, Color::yellow(), &bitmap_icon_remote, new ViewFactory<FskxRxMainView>()},
    //{"dmr", "DMR", RX, Color::dark_grey(), &bitmap_icon_dmr, new ViewFactory<NotImplementedView>()},
    //{"sigfox", "SIGFOX", RX, Color::dark_grey(), &bitmap_icon_fox, new ViewFactory<NotImplementedView>()},
    //{"lora", "LoRa", RX, Color::dark_grey(), &bitmap_icon_lora, new ViewFactory<NotImplementedView>()},
    //{"sstv", "SSTV", RX, Color::dark_grey(), &bitmap_icon_sstv, new ViewFactory<NotImplementedView>()},
    //{"tetra", "TETRA", RX, Color::dark_grey(), &bitmap_icon_tetra, new ViewFactory<NotImplementedView>()},
    /* TX ********************************************************************/
    {"adsbtx", "ADS-B TX", TX, ui::Color::green(), &bitmap_icon_adsb, new ViewFactory<ADSBTxView>()},
    {"aprstx", "APRS TX", TX, ui::Color::green(), &bitmap_icon_aprs, new ViewFactory<APRSTXView>()},
    {"bht", "BHT Xy/EP", TX, ui::Color::green(), &bitmap_icon_bht, new ViewFactory<BHTView>()},
    {"bletx", "BLE Tx", TX, ui::Color::green(), &bitmap_icon_btle, new ViewFactory<BLETxView>()},
    {"morse", "Morse", TX, ui::Color::green(), &bitmap_icon_morse, new ViewFactory<MorseView>()},
    //{"nuoptixdtmf", "Nuoptix DTMF", TX, ui::Color::green(), &bitmap_icon_nuoptix, new ViewFactory<NuoptixView>()},
    {"ooktx", "OOK", TX, ui::Color::yellow(), &bitmap_icon_remote, new ViewFactory<EncodersView>()},
    {"pocsagtx", "POCSAG TX", TX, ui::Color::green(), &bitmap_icon_pocsag, new ViewFactory<POCSAGTXView>()},
    {"rdstx", "RDS", TX, ui::Color::green(), &bitmap_icon_rds, new ViewFactory<RDSView>()},
    {"soundbrd", "Soundbrd", TX, ui::Color::green(), &bitmap_icon_soundboard, new ViewFactory<SoundBoardView>()},
    {"sstvtx", "SSTV", TX, ui::Color::green(), &bitmap_icon_sstv, new ViewFactory<SSTVTXView>()},
    {"touchtune", "TouchTune", TX, ui::Color::green(), &bitmap_icon_touchtunes, new ViewFactory<TouchTunesView>()},
    /* UTILITIES *************************************************************/
    {"antennalength", "Antenna Length", UTILITIES, Color::green(), &bitmap_icon_tools_antenna, new ViewFactory<WhipCalcView>()},
    {"filemanager", "File Manager", UTILITIES, Color::green(), &bitmap_icon_dir, new ViewFactory<FileManagerView>()},
    {"freqman", "Freq. Manager", UTILITIES, Color::green(), &bitmap_icon_freqman, new ViewFactory<FrequencyManagerView>()},
    {"notepad", "Notepad", UTILITIES, Color::dark_cyan(), &bitmap_icon_notepad, new ViewFactory<TextEditorView>()},
    {"iqtrim", "IQ Trim", UTILITIES, Color::orange(), &bitmap_icon_trim, new ViewFactory<IQTrimView>()},
    {nullptr, "SD Over USB", UTILITIES, Color::yellow(), &bitmap_icon_hackrf, new ViewFactory<SdOverUsbView>()},
    {"signalgen", "Signal Gen", UTILITIES, Color::green(), &bitmap_icon_cwgen, new ViewFactory<SigGenView>()},
    //{"testapp", "Test App", UTILITIES, Color::dark_grey(), nullptr, new ViewFactory<TestView>()},
    //{"tonesearch", "Tone Search", UTILITIES, Color::dark_grey(), nullptr, new ViewFactory<ToneSearchView>()},
    {"wavview", "Wav View", UTILITIES, Color::yellow(), &bitmap_icon_soundboard, new ViewFactory<ViewWavView>()},
    // Dangerous apps.
    {nullptr, "Flash Utility", UTILITIES, Color::red(), &bitmap_icon_temperature, new ViewFactory<FlashUtilityView>()},
    {nullptr, "Wipe SD card", UTILITIES, Color::red(), &bitmap_icon_tools_wipesd, new ViewFactory<WipeSDView>()},
};

const NavigationView::AppMap NavigationView::appMap = generate_app_map(NavigationView::appList);

bool NavigationView::StartAppByName(const char* name) {
    home(false);

    auto it = appMap.find(name);
    if (it != appMap.end()) {
        push_view(std::unique_ptr<View>(it->second.viewFactory->produce(*this)));
        return true;
    }

    return false;
}

/* StatusTray ************************************************************/

StatusTray::StatusTray(Point pos)
    : View{{pos, {0, height}}},
      pos_(pos) {
    set_focusable(false);
}

void StatusTray::add(Widget* child) {
    width_ += child->parent_rect().width();
    add_child(child);
}

void StatusTray::update_layout() {
    // Widen the tray's parent rect.
    auto rect = parent_rect();
    set_parent_rect({{rect.left() - width_, rect.top()}, {rect.right() + width_, height}});

    // Update the children.
    auto x = 0;
    for (auto child : children()) {
        auto size = child->parent_rect().size();
        child->set_parent_rect({{x, 0}, size});
        x += size.width();
    }
    set_dirty();
}

void StatusTray::clear() {
    // More efficient than 'remove_children'.
    for (auto child : children())
        child->set_parent(nullptr);
    children_.clear();
    width_ = 0;
    set_parent_rect({pos_, {width_, height}});
    set_dirty();
}

void StatusTray::paint(Painter&) {
}

/* SystemStatusView ******************************************************/

SystemStatusView::SystemStatusView(
    NavigationView& nav)
    : nav_(nav) {
    add_children({
        &backdrop,
        &button_back,
        &title,
        &button_title,
        &status_icons,
    });

    rtc_battery_workaround();

    ui::load_blacklist();

    if (pmem::should_use_sdcard_for_pmem()) {
        pmem::load_persistent_settings_from_file();
    }

    // configure CLKOUT per pmem setting
    portapack::clock_manager.enable_clock_output(pmem::clkout_enabled());

    // force apply of selected sdcard speed override at UI startup
    pmem::set_config_sdcard_high_speed_io(pmem::config_sdcard_high_speed_io(), false);

    button_back.id = -1;  // Special ID used by FocusManager
    title.set_style(&Styles::bg_dark_grey);

    button_back.on_select = [this](ImageButton&) {
        if (pmem::should_use_sdcard_for_pmem()) {
            pmem::save_persistent_settings_to_file();
        }
        if (this->on_back)
            this->on_back();
    };

    button_title.on_select = [this](ImageButton&) {
        this->on_title();
    };

    button_converter.on_select = [this](ImageButton&) {
        this->on_converter();
    };

    toggle_speaker.on_change = [this](bool v) {
        pmem::set_config_speaker_disable(v);
        audio::output::update_audio_mute();
        refresh();
    };

    toggle_mute.on_change = [this](bool v) {
        pmem::set_config_audio_mute(v);
        audio::output::update_audio_mute();
        refresh();
    };

    toggle_stealth.on_change = [this, &nav](bool v) {
        pmem::set_stealth_mode(v);
        if (nav.is_valid() && v) {
            nav.display_modal(
                "Stealth",
                "You just enabled stealth mode.\n"
                "When you transmit,\n"
                "screen will turn off;\n");
        }
        refresh();
    };

    toggle_fake_brightness.on_change = [this, &nav](bool v) {
        set_dirty();
        pmem::set_apply_fake_brightness(v);
        refresh();
        if (nullptr != parent()) {
            parent()->set_dirty();  // The parent of NavigationView shal be the SystemView
        }
    };

    button_bias_tee.on_select = [this](ImageButton&) {
        this->on_bias_tee();
    };

    button_camera.on_select = [this](ImageButton&) {
        this->on_camera();
    };

    button_sleep.on_select = [this](ImageButton&) {
        DisplaySleepMessage message;
        EventDispatcher::send_message(message);
    };

    button_clock_status.on_select = [this](ImageButton&) {
        this->on_clk();
    };

    // Initialize toggle buttons
    toggle_speaker.set_value(pmem::config_speaker_disable());
    toggle_mute.set_value(pmem::config_audio_mute());
    toggle_stealth.set_value(pmem::stealth_mode());
    toggle_fake_brightness.set_value(pmem::apply_fake_brightness());

    audio::output::stop();
    audio::output::update_audio_mute();
    refresh();
}

void SystemStatusView::refresh() {
    // NB: Order of insertion is the display order Left->Right.
    // TODO: Might be better to support hide and only add once.
    status_icons.clear();
    if (!pmem::ui_hide_camera()) status_icons.add(&button_camera);
    if (!pmem::ui_hide_sleep()) status_icons.add(&button_sleep);
    if (!pmem::ui_hide_stealth()) status_icons.add(&toggle_stealth);
    if (!pmem::ui_hide_converter()) status_icons.add(&button_converter);
    if (!pmem::ui_hide_bias_tee()) status_icons.add(&button_bias_tee);
    if (!pmem::ui_hide_clock()) status_icons.add(&button_clock_status);
    if (!pmem::ui_hide_mute()) status_icons.add(&toggle_mute);

    // Display "Disable speaker" icon only if AK4951 Codec which has separate speaker/headphone control
    if (audio::speaker_disable_supported() && !pmem::ui_hide_speaker()) status_icons.add(&toggle_speaker);

    if (!pmem::ui_hide_fake_brightness()) status_icons.add(&toggle_fake_brightness);

    if (!pmem::ui_hide_sd_card()) status_icons.add(&sd_card_status_view);
    status_icons.update_layout();

    // Clock status
    bool external_clk = portapack::clock_manager.get_reference().source == ClockManager::ReferenceSource::External;
    button_clock_status.set_bitmap(external_clk ? &bitmap_icon_clk_ext : &bitmap_icon_clk_int);
    button_clock_status.set_foreground(pmem::clkout_enabled() ? Color::green() : Color::light_grey());

    // Antenna DC Bias
    if (portapack::get_antenna_bias()) {
        button_bias_tee.set_bitmap(&bitmap_icon_biast_on);
        button_bias_tee.set_foreground(Color::yellow());
    } else {
        button_bias_tee.set_bitmap(&bitmap_icon_biast_off);
        button_bias_tee.set_foreground(Color::light_grey());
    }

    // Converter
    button_converter.set_bitmap(pmem::config_updown_converter() ? &bitmap_icon_downconvert : &bitmap_icon_upconvert);
    button_converter.set_foreground(pmem::config_converter() ? Color::red() : Color::light_grey());

    // Brightness
    toggle_fake_brightness.set_value(pmem::apply_fake_brightness());

    set_dirty();
}

void SystemStatusView::set_back_enabled(bool new_value) {
    if (new_value) {
        add_child(&button_back);
    } else {
        remove_child(&button_back);
    }
}

void SystemStatusView::set_title_image_enabled(bool new_value) {
    if (new_value) {
        add_child(&button_title);
    } else {
        remove_child(&button_title);
    }
}

void SystemStatusView::set_title(const std::string new_value) {
    if (new_value.empty()) {
        title.set(default_title);
    } else {
        // Limit length of title string to prevent partial characters if too many StatusView icons
        size_t max_len = (status_icons.parent_rect().left() - title.parent_rect().left()) / 8;
        title.set(truncate(new_value, max_len));
    }
}

void SystemStatusView::on_converter() {
    pmem::set_config_converter(!pmem::config_converter());

    // Poke to update tuning
    // NOTE: Code assumes here that a TX app isn't active, since RX & TX have diff tuning offsets
    // (and there's only one tuner in the radio so can't update tuner for both).
    // TODO: Maybe expose the 'enabled_' flag on models.
    receiver_model.set_target_frequency(receiver_model.target_frequency());
    refresh();
}

void SystemStatusView::on_bias_tee() {
    if (!portapack::get_antenna_bias()) {
        nav_.display_modal(
            "Bias voltage",
            "Enable DC voltage on\nantenna connector?",
            YESNO,
            [this](bool v) {
                if (v) {
                    portapack::set_antenna_bias(true);
                    receiver_model.set_antenna_bias();
                    transmitter_model.set_antenna_bias();
                    refresh();
                }
            });
    } else {
        portapack::set_antenna_bias(false);
        receiver_model.set_antenna_bias();
        transmitter_model.set_antenna_bias();

        // Ensure this is disabled. The models don't actually
        // update the radio unless they are 'enabled_'.
        radio::set_antenna_bias(false);
        refresh();
    }
}

void SystemStatusView::on_camera() {
    ensure_directory("SCREENSHOTS");
    auto path = next_filename_matching_pattern(u"SCREENSHOTS/SCR_????.PNG");

    if (path.empty())
        return;

    PNGWriter png;
    auto error = png.create(path);
    if (error)
        return;

    for (int i = 0; i < screen_height; i++) {
        std::array<ColorRGB888, screen_width> row;
        portapack::display.read_pixels({0, i, screen_width, 1}, row);
        png.write_scanline(row);
    }
}

void SystemStatusView::on_clk() {
    pmem::set_clkout_enabled(!pmem::clkout_enabled());
    portapack::clock_manager.enable_clock_output(pmem::clkout_enabled());
    refresh();
}

void SystemStatusView::on_title() {
    if (nav_.is_top())
        nav_.push<AboutView>();
    else
        nav_.pop();
}

void SystemStatusView::rtc_battery_workaround() {
    if (sd_card::status() != sd_card::Status::Mounted)
        return;

    uint16_t year;
    uint8_t month;
    uint8_t day;
    FATTimestamp timestamp;
    rtc::RTC datetime;

    rtcGetTime(&RTCD1, &datetime);

    // if year is 0000, assume RTC battery is dead
    if (datetime.year() == 0) {
        // if timestamp file is present, use it's date and add 1 day
        if (std::filesystem::file_exists(DATE_FILEFLAG)) {
            timestamp = file_created_date(DATE_FILEFLAG);

            year = (timestamp.FAT_date >> 9) + 1980;
            month = (timestamp.FAT_date >> 5) & 0xF;
            day = timestamp.FAT_date & 0x1F;

            // bump to next month
            if (++day > rtc_time::days_per_month(year, month)) {
                day = 1;
                if (++month > 12) {
                    month = 1;
                    ++year;
                }
            }
        } else {
            ensure_directory(SETTINGS_DIR);
            make_new_file(DATE_FILEFLAG);

            year = 1980;
            month = 1;
            day = 1;
        }

        // update RTC (keeps ticking while powered on regardless of RTC battery condition)
        rtc::RTC new_datetime{year, month, day, datetime.hour(), datetime.minute(), datetime.second()};
        rtcSetTime(&RTCD1, &new_datetime);

        // update file date
        timestamp.FAT_date = ((year - 1980) << 9) | ((uint16_t)month << 5) | day;
        timestamp.FAT_time = 0;
        file_update_date(DATE_FILEFLAG, timestamp);
    }
}

/* Information View *****************************************************/

InformationView::InformationView(
    NavigationView& nav)
    : nav_(nav) {
    static constexpr Style style_infobar{
        .font = font::fixed_8x16,
        .background = {33, 33, 33},
        .foreground = Color::white(),
    };

    add_children({&backdrop,
                  &version,
                  &ltime});

#if GCC_VERSION_MISMATCH
    version.set_style(&Styles::yellow);
#else
    version.set_style(&style_infobar);
#endif

    if (firmware_checksum_error()) {
        version.set("FLASH ERR");
        version.set_style(&Styles::red);
    }

    ltime.set_style(&style_infobar);
    refresh();
    set_dirty();
}

void InformationView::refresh() {
    ltime.set_hide_clock(pmem::hide_clock());
    ltime.set_seconds_enabled(true);
    ltime.set_date_enabled(pmem::clock_with_date());
}

bool InformationView::firmware_checksum_error() {
    static bool fw_checksum_checked{false};
    static bool fw_checksum_error{false};

    // only checking firmware checksum once per boot
    if (!fw_checksum_checked) {
        fw_checksum_error = (simple_checksum(FLASH_STARTING_ADDRESS, FLASH_ROM_SIZE) != FLASH_EXPECTED_CHECKSUM);
    }
    return fw_checksum_error;
}

/* Navigation ************************************************************/

bool NavigationView::is_top() const {
    return view_stack.size() == 1;
}

bool NavigationView::is_valid() const {
    return view_stack.size() != 0;  // work around to check if nav is valid, not elegant i know. so TODO
}

View* NavigationView::push_view(std::unique_ptr<View> new_view) {
    free_view();

    const auto p = new_view.get();
    view_stack.emplace_back(ViewState{std::move(new_view), {}});

    update_view();

    return p;
}

void NavigationView::pop(bool trigger_update) {
    // Don't pop off the NavView.
    if (view_stack.size() <= 1)
        return;

    auto on_pop = view_stack.back().on_pop;

    free_view();
    view_stack.pop_back();

    // NB: These are executed _after_ the view has been
    // destroyed. The old view MUST NOT be referenced in
    // these callbacks or it will cause crashes.
    if (trigger_update) update_view();
    if (on_pop) on_pop();
}

void NavigationView::home(bool trigger_update) {
    while (view_stack.size() > 1) {
        pop(false);
    }

    if (trigger_update) update_view();
}

void NavigationView::display_modal(
    const std::string& title,
    const std::string& message) {
    display_modal(title, message, INFO, nullptr);
}

void NavigationView::display_modal(
    const std::string& title,
    const std::string& message,
    modal_t type,
    std::function<void(bool)> on_choice) {
    push<ModalMessageView>(title, message, type, on_choice);
}

void NavigationView::free_view() {
    // The focus_manager holds a raw pointer to the currently focused Widget.
    // It then tries to call blur() on that instance when the focus is changed.
    // This causes crashes if focused_widget has been deleted (as is the case
    // when a view is popped). Calling blur() here resets the focus_manager's
    // focus_widget pointer so focus can be called safely.
    this->blur();
    remove_child(view());
}

void NavigationView::update_view() {
    const auto& top = view_stack.back();
    auto top_view = top.view.get();

    add_child(top_view);
    top_view->set_parent_rect({{0, 0}, size()});

    focus();
    set_dirty();

    if (on_view_changed)
        on_view_changed(*top_view);
}

Widget* NavigationView::view() const {
    return children_.empty() ? nullptr : children_[0];
}

void NavigationView::focus() {
    if (view())
        view()->focus();
}

bool NavigationView::set_on_pop(std::function<void()> on_pop) {
    if (view_stack.size() <= 1)
        return false;

    auto& top = view_stack.back();
    if (top.on_pop)
        return false;

    top.on_pop = on_pop;
    return true;
}

/* Helpers  **************************************************************/

static void add_apps(NavigationView& nav, BtnGridView& grid, app_location_t loc) {
    for (auto& app : NavigationView::appList) {
        if (app.menuLocation == loc) {
            grid.add_item({app.displayName, app.iconColor, app.icon,
                           [&nav, &app]() { nav.push_view(std::unique_ptr<View>(app.viewFactory->produce(nav))); }});
        }
    };
}

void addExternalItems(NavigationView& nav, app_location_t location, BtnGridView& grid) {
    auto externalItems = ExternalItemsMenuLoader::load_external_items(location, nav);
    if (externalItems.empty()) {
        grid.add_item({"Notice",
                       Color::red(),
                       &bitmap_icon_debug,
                       [&nav]() {
                           nav.display_modal(
                               "Notice",
                               "External app directory empty;\n"
                               "see Mayhem wiki and copy apps\n"
                               "to APPS folder of SD card.");
                       }});
    } else {
        for (auto const& gridItem : externalItems) {
            grid.add_item(gridItem);
        }
    }
}

/* ReceiversMenuView *****************************************************/

ReceiversMenuView::ReceiversMenuView(NavigationView& nav) {
    if (pmem::show_gui_return_icon()) {
        add_item({"..", Color::light_grey(), &bitmap_icon_previous, [&nav]() { nav.pop(); }});
    }

    add_apps(nav, *this, RX);

    addExternalItems(nav, app_location_t::RX, *this);
}

/* TransmittersMenuView **************************************************/

TransmittersMenuView::TransmittersMenuView(NavigationView& nav) {
    if (pmem::show_gui_return_icon()) {
        add_items({{"..", Color::light_grey(), &bitmap_icon_previous, [&nav]() { nav.pop(); }}});
    }

    add_apps(nav, *this, TX);

    addExternalItems(nav, app_location_t::TX, *this);
}

/* UtilitiesMenuView *****************************************************/

UtilitiesMenuView::UtilitiesMenuView(NavigationView& nav) {
    if (pmem::show_gui_return_icon()) {
        add_items({{"..", Color::light_grey(), &bitmap_icon_previous, [&nav]() { nav.pop(); }}});
    }

    add_apps(nav, *this, UTILITIES);

    addExternalItems(nav, app_location_t::UTILITIES, *this);

    set_max_rows(2);  // allow wider buttons
}

/* SystemMenuView ********************************************************/

void SystemMenuView::hackrf_mode(NavigationView& nav) {
    nav.push<ModalMessageView>(
        "HackRF mode",
        " This mode enables HackRF\n functionality. To return,\n  press the reset button.\n\n  Switch to HackRF mode?",
        YESNO,
        [this](bool choice) {
            if (choice) {
                EventDispatcher::request_stop();
            }
        });
}

SystemMenuView::SystemMenuView(NavigationView& nav) {
    add_apps(nav, *this, HOME);

    add_item({"HackRF", Color::cyan(), &bitmap_icon_hackrf, [this, &nav]() { hackrf_mode(nav); }});

    set_max_rows(2);  // allow wider buttons
    set_arrow_enabled(false);
}

/* SystemView ************************************************************/

SystemView::SystemView(
    Context& context,
    const Rect parent_rect)
    : View{parent_rect},
      context_(context) {
    set_style(&Styles::white);

    constexpr Dim status_view_height = 16;
    constexpr Dim info_view_height = 16;

    add_child(&status_view);
    status_view.set_parent_rect(
        {{0, 0},
         {parent_rect.width(), status_view_height}});
    status_view.on_back = [this]() {
        this->navigation_view.pop();
    };

    add_child(&navigation_view);
    navigation_view.set_parent_rect(
        {{0, status_view_height},
         {parent_rect.width(), static_cast<Dim>(parent_rect.height() - status_view_height)}});

    add_child(&info_view);
    info_view.set_parent_rect(
        {{0, 19 * 16},
         {parent_rect.width(), info_view_height}});

    navigation_view.on_view_changed = [this](const View& new_view) {
        if (!this->navigation_view.is_top()) {
            remove_child(&info_view);
        } else {
            add_child(&info_view);
            info_view.refresh();
        }

        this->status_view.set_back_enabled(!this->navigation_view.is_top());
        this->status_view.set_title_image_enabled(this->navigation_view.is_top());
        this->status_view.set_title(new_view.title());
        this->status_view.set_dirty();
    };

    navigation_view.push<SystemMenuView>();

    if (pmem::config_splash()) {
        navigation_view.push<BMPView>();
    }
    status_view.set_back_enabled(false);
    status_view.set_title_image_enabled(true);
    status_view.set_dirty();
}

Context& SystemView::context() const {
    return context_;
}
NavigationView* SystemView::get_navigation_view() {
    return &navigation_view;
}

void SystemView::toggle_overlay() {
    switch (++overlay_active) {
        case 1:
            this->add_child(&this->overlay);
            this->set_dirty();
            shared_memory.request_m4_performance_counter = 1;
            shared_memory.m4_performance_counter = 0;
            shared_memory.m4_heap_usage = 0;
            shared_memory.m4_stack_usage = 0;
            break;
        case 2:
            this->remove_child(&this->overlay);
            this->add_child(&this->overlay2);
            this->set_dirty();
            shared_memory.request_m4_performance_counter = 2;
            break;
        case 3:
            this->remove_child(&this->overlay2);
            this->set_dirty();
            shared_memory.request_m4_performance_counter = 0;
            overlay_active = 0;
            break;
    }
}

void SystemView::paint_overlay() {
    static bool last_paint_state = false;
    if (overlay_active) {
        // paint background only every other second
        if ((((chTimeNow() >> 10) & 0x01) == 0x01) == last_paint_state)
            return;

        last_paint_state = !last_paint_state;
        if (overlay_active == 1)
            this->overlay.set_dirty();
        else
            this->overlay2.set_dirty();
    }
}

/* ***********************************************************************/

void BMPView::focus() {
    button_done.focus();
}

BMPView::BMPView(NavigationView& nav) {
    add_children({&button_done});

    button_done.on_select = [this, &nav](Button&) {
        nav.pop();
    };
}

void BMPView::paint(Painter&) {
    if (!portapack::display.drawBMP2({0, 0}, splash_dot_bmp))
        portapack::display.drawBMP({(240 - 230) / 2, (320 - 50) / 2 - 10}, splash_bmp, false);
}

/* NotImplementedView ****************************************************/

/*NotImplementedView::NotImplementedView(NavigationView& nav) {
        button_done.on_select = [&nav](Button&){
                nav.pop();
        };

        add_children({
                &text_title,
                &button_done,
        });
}

void NotImplementedView::focus() {
        button_done.focus();
}*/

/* ModalMessageView ******************************************************/

ModalMessageView::ModalMessageView(
    NavigationView& nav,
    const std::string& title,
    const std::string& message,
    modal_t type,
    std::function<void(bool)> on_choice)
    : title_{title},
      message_{message},
      type_{type},
      on_choice_{on_choice} {
    if (type == INFO) {
        add_child(&button_ok);
        button_ok.on_select = [this, &nav](Button&) {
            if (on_choice_) on_choice_(true);
            nav.pop();
        };

    } else if (type == YESNO) {
        add_children({&button_yes,
                      &button_no});

        button_yes.on_select = [this, &nav](Button&) {
            if (on_choice_) on_choice_(true);
            nav.pop();
        };
        button_no.on_select = [this, &nav](Button&) {
            if (on_choice_) on_choice_(false);
            nav.pop();
        };

    } else {  // ABORT
        add_child(&button_ok);

        button_ok.on_select = [this, &nav](Button&) {
            if (on_choice_) on_choice_(true);
            nav.pop(false);  // Pop the modal.
            nav.pop();       // Pop the underlying view.
        };
    }
}

void ModalMessageView::paint(Painter& painter) {
    portapack::display.drawBMP({100, 48}, modal_warning_bmp, false);

    // Break lines.
    auto lines = split_string(message_, '\n');
    for (size_t i = 0; i < lines.size(); ++i) {
        painter.draw_string(
            {1 * 8, (Coord)(120 + (i * 16))},
            style(),
            lines[i]);
    }
}

void ModalMessageView::focus() {
    if ((type_ == YESNO)) {
        button_yes.focus();
    } else {
        button_ok.focus();
    }
}

} /* namespace ui */