/*
    Copyright © 2014-2015 by The qTox Project Contributors

    This file is part of qTox, a Qt-based graphical interface for Tox.

    qTox is libre 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 3 of the License, or
    (at your option) any later version.

    qTox 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 qTox.  If not, see <http://www.gnu.org/licenses/>.
*/


#include "nexus.h"
#include "persistence/settings.h"
#include "src/core/core.h"
#include "src/core/coreav.h"
#include "src/persistence/profile.h"
#include "src/widget/widget.h"
#include "video/camerasource.h"
#include "widget/gui.h"
#include "widget/loginscreen.h"
#include <QApplication>
#include <QDebug>
#include <QDesktopWidget>
#include <QFile>
#include <QImageReader>
#include <QThread>
#include <cassert>
#include <vpx/vpx_image.h>

#ifdef Q_OS_MAC
#include <QActionGroup>
#include <QMenuBar>
#include <QSignalMapper>
#include <QWindow>
#endif

/**
 * @class Nexus
 *
 * This class is in charge of connecting various systems together
 * and forwarding signals appropriately to the right objects,
 * it is in charge of starting the GUI and the Core.
 */

Q_DECLARE_OPAQUE_POINTER(ToxAV*)

static Nexus* nexus{nullptr};

Nexus::Nexus(QObject* parent)
    : QObject(parent)
    , profile{nullptr}
    , widget{nullptr}
    , loginScreen{nullptr}
    , running{true}
    , quitOnLastWindowClosed{true}
{
}

Nexus::~Nexus()
{
    delete widget;
    widget = nullptr;
    delete loginScreen;
    loginScreen = nullptr;
    delete profile;
    profile = nullptr;
    Settings::getInstance().saveGlobal();
#ifdef Q_OS_MAC
    delete globalMenuBar;
#endif
}

/**
 * @brief Sets up invariants and calls showLogin
 *
 * Hides the login screen and shows the GUI for the given profile.
 * Will delete the current GUI, if it exists.
 */
void Nexus::start()
{
    qDebug() << "Starting up";

    // Setup the environment
    qRegisterMetaType<Status>("Status");
    qRegisterMetaType<vpx_image>("vpx_image");
    qRegisterMetaType<uint8_t>("uint8_t");
    qRegisterMetaType<uint16_t>("uint16_t");
    qRegisterMetaType<uint32_t>("uint32_t");
    qRegisterMetaType<const int16_t*>("const int16_t*");
    qRegisterMetaType<int32_t>("int32_t");
    qRegisterMetaType<int64_t>("int64_t");
    qRegisterMetaType<QPixmap>("QPixmap");
    qRegisterMetaType<Profile*>("Profile*");
    qRegisterMetaType<ToxAV*>("ToxAV*");
    qRegisterMetaType<ToxFile>("ToxFile");
    qRegisterMetaType<ToxFile::FileDirection>("ToxFile::FileDirection");
    qRegisterMetaType<std::shared_ptr<VideoFrame>>("std::shared_ptr<VideoFrame>");
    qRegisterMetaType<ToxPk>("ToxPk");
    qRegisterMetaType<ToxId>("ToxId");

    loginScreen = new LoginScreen();

    // We need this LastWindowClosed dance because the LoginScreen may be shown
    // and closed in a processEvents() loop before the start of the real
    // exec() event loop, meaning we wouldn't receive the onLastWindowClosed,
    // and so we wouldn't have a chance to tell the processEvents() loop to quit.
    qApp->setQuitOnLastWindowClosed(false);
    connect(qApp, &QApplication::lastWindowClosed, this, &Nexus::onLastWindowClosed);
    connect(loginScreen, &LoginScreen::closed, this, &Nexus::onLastWindowClosed);

#ifdef Q_OS_MAC
    globalMenuBar = new QMenuBar(0);
    dockMenu = new QMenu(globalMenuBar);

    viewMenu = globalMenuBar->addMenu(QString());

    windowMenu = globalMenuBar->addMenu(QString());
    globalMenuBar->addAction(windowMenu->menuAction());

    fullscreenAction = viewMenu->addAction(QString());
    fullscreenAction->setShortcut(QKeySequence::FullScreen);
    connect(fullscreenAction, &QAction::triggered, this, &Nexus::toggleFullscreen);

    minimizeAction = windowMenu->addAction(QString());
    minimizeAction->setShortcut(Qt::CTRL + Qt::Key_M);
    connect(minimizeAction, &QAction::triggered, [this]() {
        minimizeAction->setEnabled(false);
        QApplication::focusWindow()->showMinimized();
    });

    windowMenu->addSeparator();
    frontAction = windowMenu->addAction(QString());
    connect(frontAction, &QAction::triggered, this, &Nexus::bringAllToFront);

    QAction* quitAction = new QAction(globalMenuBar);
    quitAction->setMenuRole(QAction::QuitRole);
    connect(quitAction, &QAction::triggered, qApp, &QApplication::quit);

    windowMapper = new QSignalMapper(this);
    connect(windowMapper, SIGNAL(mapped(QObject*)), this, SLOT(onOpenWindow(QObject*)));

    connect(loginScreen, &LoginScreen::windowStateChanged, this, &Nexus::onWindowStateChanged);

    retranslateUi();
#endif

    if (profile)
        showMainGUI();
    else
        showLogin();
}

/**
 * @brief Hides the main GUI, delete the profile, and shows the login screen
 */
void Nexus::showLogin()
{
    delete widget;
    widget = nullptr;

    delete profile;
    profile = nullptr;

    loginScreen->reset();
    loginScreen->move(QApplication::desktop()->screen()->rect().center()
                      - loginScreen->rect().center());
    loginScreen->show();
    quitOnLastWindowClosed = true;
}

void Nexus::showMainGUI()
{
    assert(profile);

    quitOnLastWindowClosed = false;
    loginScreen->close();

    // Create GUI
    widget = Widget::getInstance();

    // Start GUI
    widget->init();
    GUI::getInstance();

    // Zetok protection
    // There are small instants on startup during which no
    // profile is loaded but the GUI could still receive events,
    // e.g. between two modal windows. Disable the GUI to prevent that.
    GUI::setEnabled(false);

    // Connections
    Core* core = profile->getCore();
    connect(core, &Core::connected, widget, &Widget::onConnected);
    connect(core, &Core::disconnected, widget, &Widget::onDisconnected);
    connect(core, &Core::failedToStart, widget, &Widget::onFailedToStartCore,
            Qt::BlockingQueuedConnection);
    connect(core, &Core::badProxy, widget, &Widget::onBadProxyCore, Qt::BlockingQueuedConnection);
    connect(core, &Core::statusSet, widget, &Widget::onStatusSet);
    connect(core, &Core::usernameSet, widget, &Widget::setUsername);
    connect(core, &Core::statusMessageSet, widget, &Widget::setStatusMessage);
    connect(core, &Core::selfAvatarChanged, widget, &Widget::onSelfAvatarLoaded);
    connect(core, &Core::friendAdded, widget, &Widget::addFriend);
    connect(core, &Core::friendshipChanged, widget, &Widget::onFriendshipChanged);
    connect(core, &Core::failedToAddFriend, widget, &Widget::addFriendFailed);
    connect(core, &Core::friendUsernameChanged, widget, &Widget::onFriendUsernameChanged);
    connect(core, &Core::friendStatusChanged, widget, &Widget::onFriendStatusChanged);
    connect(core, &Core::friendStatusMessageChanged, widget, &Widget::onFriendStatusMessageChanged);
    connect(core, &Core::friendRequestReceived, widget, &Widget::onFriendRequestReceived);
    connect(core, &Core::friendMessageReceived, widget, &Widget::onFriendMessageReceived);
    connect(core, &Core::receiptRecieved, widget, &Widget::onReceiptRecieved);
    connect(core, &Core::groupInviteReceived, widget, &Widget::onGroupInviteReceived);
    connect(core, &Core::groupMessageReceived, widget, &Widget::onGroupMessageReceived);
    connect(core, &Core::groupNamelistChanged, widget, &Widget::onGroupNamelistChanged);
    connect(core, &Core::groupTitleChanged, widget, &Widget::onGroupTitleChanged);
    connect(core, &Core::groupPeerAudioPlaying, widget, &Widget::onGroupPeerAudioPlaying);
    connect(core, &Core::emptyGroupCreated, widget, &Widget::onEmptyGroupCreated);
    connect(core, &Core::friendTypingChanged, widget, &Widget::onFriendTypingChanged);
    connect(core, &Core::messageSentResult, widget, &Widget::onMessageSendResult);
    connect(core, &Core::groupSentResult, widget, &Widget::onGroupSendResult);

    connect(widget, &Widget::statusSet, core, &Core::setStatus);
    connect(widget, &Widget::friendRequested, core, &Core::requestFriendship);
    connect(widget, &Widget::friendRequestAccepted, core, &Core::acceptFriendRequest);

    profile->startCore();
}

/**
 * @brief Calls QApplication::quit(), and causes Nexus::isRunning() to return false
 */
void Nexus::quit()
{
    running = false;
    qApp->quit();
}

/**
 * @brief Returns true until Nexus::quit is called.
 *
 * Any blocking processEvents() loop should check this as a return condition,
 * since the application can not quit until control is returned to the event loop.
 */
bool Nexus::isRunning()
{
    return running;
}

/**
 * @brief Returns the singleton instance.
 */
Nexus& Nexus::getInstance()
{
    if (!nexus)
        nexus = new Nexus;

    return *nexus;
}

void Nexus::destroyInstance()
{
    delete nexus;
    nexus = nullptr;
}

/**
 * @brief Get core instance.
 * @return nullptr if not started, core instance otherwise.
 */
Core* Nexus::getCore()
{
    Nexus& nexus = getInstance();
    if (!nexus.profile)
        return nullptr;

    return nexus.profile->getCore();
}

/**
 * @brief Get current user profile.
 * @return nullptr if not started, profile otherwise.
 */
Profile* Nexus::getProfile()
{
    return getInstance().profile;
}

/**
 * @brief Unload the current profile, if any, and replaces it.
 * @param profile Profile to set.
 */
void Nexus::setProfile(Profile* profile)
{
    getInstance().profile = profile;
    if (profile)
        Settings::getInstance().loadPersonal(profile);
}

/**
 * @brief Get desktop GUI widget.
 * @return nullptr if not started, desktop widget otherwise.
 */
Widget* Nexus::getDesktopGUI()
{
    return getInstance().widget;
}

QString Nexus::getSupportedImageFilter()
{
    QString res;
    for (auto type : QImageReader::supportedImageFormats())
        res += QString("*.%1 ").arg(QString(type));

    return tr("Images (%1)", "filetype filter").arg(res.left(res.size() - 1));
}

/**
 * @brief Dangerous way to find out if a path is writable.
 * @param filepath Path to file which should be deleted.
 * @return True, if file writeable, false otherwise.
 */
bool Nexus::tryRemoveFile(const QString& filepath)
{
    QFile tmp(filepath);
    bool writable = tmp.open(QIODevice::WriteOnly);
    tmp.remove();
    return writable;
}

/**
 * @brief Calls showLogin asynchronously, so we can safely logout from within the main GUI
 */
void Nexus::showLoginLater()
{
    GUI::setEnabled(false);
    QMetaObject::invokeMethod(&getInstance(), "showLogin", Qt::QueuedConnection);
}

void Nexus::onLastWindowClosed()
{
    if (quitOnLastWindowClosed)
        quit();
}

#ifdef Q_OS_MAC
void Nexus::retranslateUi()
{
    viewMenu->menuAction()->setText(tr("View", "OS X Menu bar"));
    windowMenu->menuAction()->setText(tr("Window", "OS X Menu bar"));
    minimizeAction->setText(tr("Minimize", "OS X Menu bar"));
    frontAction->setText((tr("Bring All to Front", "OS X Menu bar")));
}

void Nexus::onWindowStateChanged(Qt::WindowStates state)
{
    minimizeAction->setEnabled(QApplication::activeWindow() != nullptr);

    if (QApplication::activeWindow() != nullptr && sender() == QApplication::activeWindow()) {
        if (state & Qt::WindowFullScreen)
            minimizeAction->setEnabled(false);

        if (state & Qt::WindowFullScreen)
            fullscreenAction->setText(tr("Exit Fullscreen"));
        else
            fullscreenAction->setText(tr("Enter Fullscreen"));

        updateWindows();
    }

    updateWindowsStates();
}

void Nexus::updateWindows()
{
    updateWindowsArg(nullptr);
}

void Nexus::updateWindowsArg(QWindow* closedWindow)
{
    QWindowList windowList = QApplication::topLevelWindows();
    delete windowActions;
    windowActions = new QActionGroup(this);

    windowMenu->addSeparator();

    QAction* dockLast;
    if (!dockMenu->actions().isEmpty())
        dockLast = dockMenu->actions().first();
    else
        dockLast = nullptr;

    QWindow* activeWindow;

    if (QApplication::activeWindow())
        activeWindow = QApplication::activeWindow()->windowHandle();
    else
        activeWindow = nullptr;

    for (int i = 0; i < windowList.size(); ++i) {
        if (closedWindow == windowList[i])
            continue;

        QAction* action = windowActions->addAction(windowList[i]->title());
        action->setCheckable(true);
        action->setChecked(windowList[i] == activeWindow);
        connect(action, SIGNAL(triggered()), windowMapper, SLOT(map()));
        windowMapper->setMapping(action, windowList[i]);
        windowMenu->addAction(action);
        dockMenu->insertAction(dockLast, action);
    }

    if (dockLast && !dockLast->isSeparator())
        dockMenu->insertSeparator(dockLast);
}

void Nexus::updateWindowsClosed()
{
    updateWindowsArg(static_cast<QWidget*>(sender())->windowHandle());
}

void Nexus::updateWindowsStates()
{
    bool exists = false;
    QWindowList windowList = QApplication::topLevelWindows();

    for (QWindow* window : windowList) {
        if (!(window->windowState() & Qt::WindowMinimized)) {
            exists = true;
            break;
        }
    }

    frontAction->setEnabled(exists);
}

void Nexus::onOpenWindow(QObject* object)
{
    QWindow* window = static_cast<QWindow*>(object);

    if (window->windowState() & QWindow::Minimized)
        window->showNormal();

    window->raise();
    window->requestActivate();
}

void Nexus::toggleFullscreen()
{
    QWidget* window = QApplication::activeWindow();

    if (window->isFullScreen())
        window->showNormal();
    else
        window->showFullScreen();
}

void Nexus::bringAllToFront()
{
    QWindowList windowList = QApplication::topLevelWindows();
    QWindow* focused = QApplication::focusWindow();

    for (QWindow* window : windowList)
        window->raise();

    focused->raise();
}
#endif