/*
 * Copyright 2012, 2013 Red Hat, Inc.
 *
 * This file is part of Thermostat.
 *
 * Thermostat 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.
 *
 * Thermostat 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 Thermostat; see the file COPYING.  If not see
 * <http://www.gnu.org/licenses/>.
 *
 * Linking this code with other modules is making a combined work
 * based on this code.  Thus, the terms and conditions of the GNU
 * General Public License cover the whole combination.
 *
 * As a special exception, the copyright holders of this code give
 * you permission to link this code with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also
 * meet, for each linked independent module, the terms and conditions
 * of the license of that module.  An independent module is a module
 * which is not derived from or based on this code.  If you modify
 * this code, you may extend this exception to your version of the
 * library, but you are not obligated to do so.  If you do not wish
 * to do so, delete this exception statement from your version.
 */

package com.redhat.thermostat.client.swing.internal;

import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.osgi.framework.BundleContext;
import org.osgi.framework.InvalidSyntaxException;

import com.redhat.thermostat.client.core.Filter;
import com.redhat.thermostat.client.core.InformationService;
import com.redhat.thermostat.client.core.NameMatchingRefFilter;
import com.redhat.thermostat.client.core.views.AgentInformationDisplayView;
import com.redhat.thermostat.client.core.views.AgentInformationViewProvider;
import com.redhat.thermostat.client.core.views.ClientConfigViewProvider;
import com.redhat.thermostat.client.core.views.ClientConfigurationView;
import com.redhat.thermostat.client.core.views.HostInformationViewProvider;
import com.redhat.thermostat.client.core.views.SummaryViewProvider;
import com.redhat.thermostat.client.core.views.VmInformationViewProvider;
import com.redhat.thermostat.client.osgi.service.ContextAction;
import com.redhat.thermostat.client.osgi.service.DecoratorProvider;
import com.redhat.thermostat.client.osgi.service.HostContextAction;
import com.redhat.thermostat.client.osgi.service.MenuAction;
import com.redhat.thermostat.client.osgi.service.VMContextAction;
import com.redhat.thermostat.client.swing.internal.MainView.Action;
import com.redhat.thermostat.client.swing.internal.osgi.HostContextActionServiceTracker;
import com.redhat.thermostat.client.swing.internal.osgi.InformationServiceTracker;
import com.redhat.thermostat.client.swing.internal.osgi.VMContextActionServiceTracker;
import com.redhat.thermostat.client.ui.AgentInformationDisplayController;
import com.redhat.thermostat.client.ui.AgentInformationDisplayModel;
import com.redhat.thermostat.client.ui.ClientConfigurationController;
import com.redhat.thermostat.client.ui.HostInformationController;
import com.redhat.thermostat.client.ui.MainWindowController;
import com.redhat.thermostat.client.ui.SummaryController;
import com.redhat.thermostat.client.ui.VmInformationController;
import com.redhat.thermostat.common.ActionEvent;
import com.redhat.thermostat.common.ActionListener;
import com.redhat.thermostat.common.ApplicationInfo;
import com.redhat.thermostat.common.ApplicationService;
import com.redhat.thermostat.common.MultipleServiceTracker;
import com.redhat.thermostat.common.ThermostatExtensionRegistry;
import com.redhat.thermostat.common.Timer;
import com.redhat.thermostat.common.Timer.SchedulingType;
import com.redhat.thermostat.common.config.ClientPreferences;
import com.redhat.thermostat.common.utils.LoggingUtils;
import com.redhat.thermostat.common.utils.OSGIUtils;
import com.redhat.thermostat.storage.core.DefaultHostsVMsLoader;
import com.redhat.thermostat.storage.core.HostRef;
import com.redhat.thermostat.storage.core.HostsVMsLoader;
import com.redhat.thermostat.storage.core.Ref;
import com.redhat.thermostat.storage.core.VmRef;
import com.redhat.thermostat.storage.dao.HostInfoDAO;
import com.redhat.thermostat.storage.dao.VmInfoDAO;
import com.redhat.thermostat.utils.keyring.Keyring;

public class MainWindowControllerImpl implements MainWindowController {

    private static final Logger logger = LoggingUtils.getLogger(MainWindowControllerImpl.class);

    private final CopyOnWriteArrayList<Filter<HostRef>> hostFilters = new CopyOnWriteArrayList<>();
    private final CopyOnWriteArrayList<Filter<VmRef>> vmFilters = new CopyOnWriteArrayList<>();

    private final CopyOnWriteArrayList<DecoratorProvider<HostRef>> hostTreeDecorators = new CopyOnWriteArrayList<>();
    private final CopyOnWriteArrayList<DecoratorProvider<VmRef>> vmTreeDecorators = new CopyOnWriteArrayList<>();

    private ApplicationService appSvc;
    private Timer backgroundUpdater;

    private MainView view;

    private HostInfoDAO hostInfoDAO;
    private VmInfoDAO vmInfoDAO;

    private SummaryViewProvider summaryViewProvider;
    private HostInformationViewProvider hostInfoViewProvider;
    private VmInformationViewProvider vmInfoViewProvider;
    
    private ApplicationInfo appInfo;

    private InformationServiceTracker infoServiceTracker;
    private HostContextActionServiceTracker hostContextActionTracker;
    private VMContextActionServiceTracker vmContextActionTracker;
    private MultipleServiceTracker depTracker;
    
    private CountDownLatch shutdown;

    private MenuRegistry menuRegistry;
    private ActionListener<ThermostatExtensionRegistry.Action> menuListener =
            new ActionListener<ThermostatExtensionRegistry.Action>()
    {
        @Override
        public void actionPerformed(
            ActionEvent<ThermostatExtensionRegistry.Action> actionEvent) {
            MenuAction action = (MenuAction) actionEvent.getPayload();

            switch (actionEvent.getActionId()) {
            case SERVICE_ADDED:
                view.addMenu(action);
                break;

            case SERVICE_REMOVED:
                view.removeMenu(action);
                break;

            default:
                logger.log(Level.WARNING, "received unknown event from MenuRegistry: " +
                                           actionEvent.getActionId());
                break;
            }
        }
    };

    private NameMatchingRefFilter<HostRef> hostFilter;
    private NameMatchingRefFilter<VmRef> vmFilter;
    private VmFilterRegistry vmFilterRegistry;
    private HostFilterRegistry hostFilterRegistry;

    private ActionListener<ThermostatExtensionRegistry.Action> hostFilterListener = new FilterExtensionListener<HostRef>(hostFilters);
    private ActionListener<ThermostatExtensionRegistry.Action> vmFilterListener = new FilterExtensionListener<VmRef>(vmFilters);

    private HostTreeDecoratorRegistry hostDecoratorRegistry;
    private VMTreeDecoratorRegistry vmDecoratorRegistry;

    private ActionListener<ThermostatExtensionRegistry.Action> hostDecoratorListener = new DecoratorProviderExtensionListener<HostRef>(hostTreeDecorators);
    private ActionListener<ThermostatExtensionRegistry.Action> vmDecoratorListener = new DecoratorProviderExtensionListener<VmRef>(vmTreeDecorators);

    private VMInformationRegistry vmInfoRegistry;
    private ActionListener<ThermostatExtensionRegistry.Action> vmInfoRegistryListener =
            new ActionListener<ThermostatExtensionRegistry.Action> ()
    {
        public void actionPerformed(com.redhat.thermostat.common.ActionEvent<ThermostatExtensionRegistry.Action>
                                    actionEvent)
        {
            updateView();
        };
    };
            
    private boolean showHistory;

    private VmInformationControllerProvider vmInfoControllerProvider;
    
    public MainWindowControllerImpl(BundleContext context, ApplicationService appSvc,
            CountDownLatch shutdown) {
        this(context, appSvc, new MainWindow(), new RegistryFactory(context), shutdown);
    }

    MainWindowControllerImpl(BundleContext context, ApplicationService appSvc,
            final MainView view,
            RegistryFactory registryFactory,
            final CountDownLatch shutdown) {
        this.appSvc = appSvc;
        try {
            vmFilterRegistry = registryFactory.createVmFilterRegistry();
            hostFilterRegistry = registryFactory.createHostFilterRegistry();
            hostDecoratorRegistry = registryFactory.createHostTreeDecoratorRegistry();
            vmDecoratorRegistry = registryFactory.createVMTreeDecoratorRegistry();
            menuRegistry = registryFactory.createMenuRegistry();
            vmInfoRegistry = registryFactory.createVMInformationRegistry();
            
        } catch (InvalidSyntaxException e) {
            throw new RuntimeException(e);
        }

        hostFilter = new NameMatchingRefFilter<>();
        vmFilter = new NameMatchingRefFilter<>();
        
        hostFilters.add(hostFilter);
        vmFilters.add(vmFilter);
        
        this.infoServiceTracker = new InformationServiceTracker(context);
        this.infoServiceTracker.open();
        
        this.hostContextActionTracker = new HostContextActionServiceTracker(context);
        this.hostContextActionTracker.open();

        this.vmContextActionTracker = new VMContextActionServiceTracker(context);
        this.vmContextActionTracker.open();
        
        this.shutdown = shutdown;

        Class<?>[] deps = new Class<?>[] {
                HostInfoDAO.class,
                VmInfoDAO.class,
                SummaryViewProvider.class,
                HostInformationViewProvider.class,
                VmInformationViewProvider.class
        };
        depTracker = new MultipleServiceTracker(context, deps, new MultipleServiceTracker.Action() {
            
            @Override
            public void dependenciesAvailable(Map<String, Object> services) {
                hostInfoDAO = (HostInfoDAO) services.get(HostInfoDAO.class.getName());
                Objects.requireNonNull(hostInfoDAO);
                vmInfoDAO = (VmInfoDAO) services.get(VmInfoDAO.class.getName());
                Objects.requireNonNull(vmInfoDAO);
                summaryViewProvider = (SummaryViewProvider) services.get(SummaryViewProvider.class.getName());
                Objects.requireNonNull(summaryViewProvider);
                hostInfoViewProvider = (HostInformationViewProvider) services.get(HostInformationViewProvider.class.getName());
                Objects.requireNonNull(hostInfoViewProvider);
                vmInfoViewProvider = (VmInformationViewProvider) services.get(VmInformationViewProvider.class.getName());
                Objects.requireNonNull(vmInfoViewProvider);
                
                initView(view);

                vmInfoControllerProvider = new VmInformationControllerProvider();

                appInfo = new ApplicationInfo();
                view.setWindowTitle(appInfo.getName());
                initializeTimer();

                updateView();

                installListenersAndStartRegistries();
            }

            @Override
            public void dependenciesUnavailable() {
                if (shutdown.getCount() > 0) {
                    // In the rare case we lose one of our deps, gracefully shutdown
                    logger.severe("Dependency unexpectedly became unavailable");
                    shutdown.countDown();
                }
            }
        });
        depTracker.open();
    }

    /*
     * This method is for testing purposes only
     */
    Filter<HostRef> getHostFilter() {
        return hostFilter;
    }
    /*
     * This also is for testing purposes.
     */
    Filter<VmRef> getVmFilter() {
        return vmFilter;
    }
    
    /**
     * This method is for testing purposes only
     */ 
    List<DecoratorProvider<VmRef>> getVmTreeDecorators() {
        return vmTreeDecorators;
    }
    
    /**
     * This method is for testing purposes only
     */
    ActionListener<ThermostatExtensionRegistry.Action> getMenuListener() {
        return menuListener;
    }
    
    private void initializeTimer() {
        backgroundUpdater = appSvc.getTimerFactory().createTimer();
        backgroundUpdater.setAction(new Runnable() {
            @Override
            public void run() {
                doUpdateTreeAsync();
            }
        });
        backgroundUpdater.setInitialDelay(0);
        backgroundUpdater.setDelay(3);
        backgroundUpdater.setTimeUnit(TimeUnit.SECONDS);
        backgroundUpdater.setSchedulingType(SchedulingType.FIXED_RATE);
    }

    private void startBackgroundUpdates() {
        backgroundUpdater.start();
    }

    public void stopBackgroundUpdates() {
        backgroundUpdater.stop();
    }

    @Override
    public void setHostVmTreeFilter(String filter) {
        this.hostFilter.setPattern(filter);
        this.vmFilter.setPattern(filter);
        doUpdateTreeAsync();
    }

    public void doUpdateTreeAsync() {
        HostsVMsLoader loader = new DefaultHostsVMsLoader(hostInfoDAO, vmInfoDAO, !showHistory);
        view.updateTree(hostFilters, vmFilters, hostTreeDecorators, vmTreeDecorators, loader);
    }

    private void initView(MainView mainView) {
        this.view = mainView;
        mainView.addActionListener(new ActionListener<MainView.Action>() {

            @Override
            public void actionPerformed(ActionEvent<MainView.Action> evt) {
                MainView.Action action = evt.getActionId();
                switch (action) {
                case VISIBLE:
                    startBackgroundUpdates();
                    break;
                case HIDDEN:
                    stopBackgroundUpdates();
                    break;
                case HOST_VM_SELECTION_CHANGED:
                    updateView();
                    break;
                case HOST_VM_TREE_FILTER:
                    String filter = view.getHostVmTreeFilterText();
                    setHostVmTreeFilter(filter);
                    break;
                case SHOW_AGENT_CONFIG:
                    showAgentConfiguration();
                    break;
                case SHOW_CLIENT_CONFIG:
                    showConfigureClientPreferences();
                    break;
                case SWITCH_HISTORY_MODE:
                    switchHistoryMode();
                    break;
                case SHOW_ABOUT_DIALOG:
                    showAboutDialog();
                    break;
                case SHOW_HOST_VM_CONTEXT_MENU:
                    showContextMenu(evt);
                    break;
                case HOST_VM_CONTEXT_ACTION:
                    handleVMHooks(evt);
                    break;
                case SHUTDOWN:
                    // Main will call shutdownApplication
                    shutdown.countDown();
                    break;
                default:
                    throw new IllegalStateException("unhandled action");
                }
            }

        });
    }

    /*
     * Called by Main to cleanup when shutting down
     */
    void shutdownApplication() {
        uninstallListenersAndStopRegistries();

        view.hideMainWindow();
        appSvc.getTimerFactory().shutdown();
        
        depTracker.close();
        infoServiceTracker.close();
        hostContextActionTracker.close();
        vmContextActionTracker.close();
    }

    private void installListenersAndStartRegistries() {
        menuRegistry.addActionListener(menuListener);
        menuRegistry.start();

        hostFilterRegistry.addActionListener(hostFilterListener);
        hostFilterRegistry.start();

        vmFilterRegistry.addActionListener(vmFilterListener);
        vmFilterRegistry.start();

        hostDecoratorRegistry.addActionListener(hostDecoratorListener);
        hostDecoratorRegistry.start();

        vmDecoratorRegistry.addActionListener(vmDecoratorListener);
        vmDecoratorRegistry.start();

        vmInfoRegistry.addActionListener(vmInfoRegistryListener);
        vmInfoRegistry.start();
    }

    private void uninstallListenersAndStopRegistries() {
        menuRegistry.removeActionListener(menuListener);
        menuListener = null;
        menuRegistry.stop();

        hostFilterRegistry.removeActionListener(hostFilterListener);
        hostFilterListener = null;
        hostFilterRegistry.stop();

        vmFilterRegistry.removeActionListener(vmFilterListener);
        vmFilterListener = null;
        vmFilterRegistry.stop();

        hostDecoratorRegistry.removeActionListener(hostDecoratorListener);
        hostDecoratorListener = null;
        hostDecoratorRegistry.stop();

        vmDecoratorRegistry.removeActionListener(vmDecoratorListener);
        vmDecoratorListener = null;
        vmDecoratorRegistry.stop();

        vmInfoRegistry.removeActionListener(vmInfoRegistryListener);
        vmInfoRegistryListener = null;
        vmInfoRegistry.stop();
    }

    private void showContextMenu(ActionEvent<Action> evt) {
        List<ContextAction> toShow = new ArrayList<>();

        Ref ref = view.getSelectedHostOrVm();
        if (ref instanceof HostRef) {
            HostRef vm = (HostRef) ref;

            logger.log(Level.INFO, "registering applicable HostContextActions actions to show");

            for (HostContextAction action : hostContextActionTracker.getHostContextActions()) {
                if (action.getFilter().matches(vm)) {
                    toShow.add(action);
                }
            }
        } else if (ref instanceof VmRef) {
            VmRef vm = (VmRef) ref;

            logger.log(Level.INFO, "registering applicable VMContextActions actions to show");

            for (VMContextAction action : vmContextActionTracker.getVmContextActions()) {
                if (action.getFilter().matches(vm)) {
                    toShow.add(action);
                }
            }
        }

        view.showContextActions(toShow, (MouseEvent) evt.getPayload());
    }

    private void handleVMHooks(ActionEvent<MainView.Action> event) {
        Object payload = event.getPayload();
        try {
            if (payload instanceof HostContextAction) {
                HostContextAction action = (HostContextAction) payload;
                action.execute((HostRef) view.getSelectedHostOrVm());
            } else if (payload instanceof VMContextAction) {
                VMContextAction action = (VMContextAction) payload;
                action.execute((VmRef) view.getSelectedHostOrVm());
            }
        } catch (Throwable error) {
            logger.log(Level.SEVERE, "error invocating context action", error);
        }
    }

    @Override
    public void showMainMainWindow() {
        view.showMainWindow();
    }

    private void showAboutDialog() {
        AboutDialog aboutDialog = new AboutDialog(appInfo);
        aboutDialog.setModal(true);
        aboutDialog.pack();
        aboutDialog.setLocationRelativeTo(view.getTopFrame());
        aboutDialog.setVisible(true);
    }

    private void showAgentConfiguration() {
        AgentInformationDisplayModel model = new AgentInformationDisplayModel();
        AgentInformationViewProvider viewProvider = OSGIUtils.getInstance().getService(AgentInformationViewProvider.class);
        AgentInformationDisplayView view = viewProvider.createView();
        AgentInformationDisplayController controller = new AgentInformationDisplayController(model, view);
        controller.showView();
    }

    private void showConfigureClientPreferences() {
        ClientPreferences prefs = new ClientPreferences(OSGIUtils.getInstance().getService(Keyring.class));
        ClientConfigViewProvider viewProvider = OSGIUtils.getInstance().getService(ClientConfigViewProvider.class);
        ClientConfigurationView view = viewProvider.createView();
        ClientConfigurationController controller = new ClientConfigurationController(prefs, view);
        controller.showDialog();
    }

    private void switchHistoryMode() {
        showHistory = !showHistory;
        doUpdateTreeAsync();
    }

    private void updateView() {
        // this is quite an ugly method. there must be a cleaner way to do this
        Ref ref = view.getSelectedHostOrVm();

        if (ref == null) {
            SummaryController controller = createSummaryController();
            view.setSubView(controller.getView());
        } else if (ref instanceof HostRef) {
            HostRef hostRef = (HostRef) ref;
            HostInformationController hostController = createHostInformationController(hostRef);
            view.setSubView(hostController.getView());
            view.setStatusBarPrimaryStatus("host: " + hostRef.getHostName() + ", id: " + hostRef.getAgentId());
        } else if (ref instanceof VmRef) {
            VmRef vmRef = (VmRef) ref;
            VmInformationController vmInformation =
                    vmInfoControllerProvider.getVmInfoController(vmRef);
            view.setSubView(vmInformation.getView());
            view.setStatusBarPrimaryStatus("vm: " + vmRef.getName() + ", pid: " + vmRef.getStringID() +
                                           ", host: " + vmRef.getAgent().getHostName());
        } else {
            throw new IllegalArgumentException("unknown type of ref");
        }
    }

    private class FilterExtensionListener<T> implements ActionListener<ThermostatExtensionRegistry.Action> {

        private final CopyOnWriteArrayList<Filter<T>> extensionList;

        public FilterExtensionListener(CopyOnWriteArrayList<Filter<T>> addRemoveExtensionsFrom) {
            this.extensionList = addRemoveExtensionsFrom;
        }

        @SuppressWarnings("unchecked")
        @Override
        public void actionPerformed(ActionEvent<ThermostatExtensionRegistry.Action> actionEvent) {

            Object payload = actionEvent.getPayload();
            Filter<T> filter = null;

            try {
                filter = (Filter<T>) payload;
            } catch (ClassCastException cce) {
                throw new IllegalArgumentException("unexpected payload type. " +
                            payload.getClass().getName() + " not allowed here.", cce);
            }
        

            switch (actionEvent.getActionId()) {
            case SERVICE_ADDED:
                extensionList.add(filter);
                doUpdateTreeAsync();
                break;

            case SERVICE_REMOVED:
                extensionList.remove(filter);
                doUpdateTreeAsync();
                break;

            default:
                logger.log(Level.WARNING, "received unknown event from ExtensionRegistry: " +
                                           actionEvent.getActionId());
                break;
            }
        }
    }

    private class DecoratorProviderExtensionListener<T extends Ref> implements ActionListener<ThermostatExtensionRegistry.Action> {

        private final CopyOnWriteArrayList<DecoratorProvider<T>> extensionList;

        public DecoratorProviderExtensionListener(CopyOnWriteArrayList<DecoratorProvider<T>> addRemoveExtensionsFrom) {
            this.extensionList = addRemoveExtensionsFrom;
        }

        @SuppressWarnings("unchecked")
        @Override
        public void actionPerformed(ActionEvent<com.redhat.thermostat.common.ThermostatExtensionRegistry.Action> actionEvent) {

            Object payload = actionEvent.getPayload();
            DecoratorProvider<T> decorator = null;

            try {
                decorator = (DecoratorProvider<T>) payload;
            } catch (ClassCastException cce) {
                throw new IllegalArgumentException("unexpected payload type. " + payload.getClass().getName() + "not allowed here.", cce);
            }
        

            switch (actionEvent.getActionId()) {
            case SERVICE_ADDED:
                extensionList.add(decorator);
                doUpdateTreeAsync();
                break;

            case SERVICE_REMOVED:
                extensionList.remove(decorator);
                doUpdateTreeAsync();
                break;

            default:
                logger.log(Level.WARNING, "received unknown event from ExtensionRegistry: " +
                                           actionEvent.getActionId());
                break;
            }
        }
    }

    private class VmInformationControllerProvider {
        private VmInformationController lastSelectedVM;
        private Map<VmRef, Integer> selectedForVM = new ConcurrentHashMap<>();
        
        VmInformationController getVmInfoController(VmRef vmRef) {
            int id = 0;
            if (lastSelectedVM != null) {
                id = lastSelectedVM.getSelectedChildID();
            }
            
            lastSelectedVM = createVmController(vmRef);
            if (!lastSelectedVM.selectChildID(id)) {
                Integer _id = selectedForVM.get(vmRef);
                id = _id != null? _id : 0;
                lastSelectedVM.selectChildID(id);
            }

            selectedForVM.put(vmRef, id);
            
            return lastSelectedVM;
        }
    }
    
    private SummaryController createSummaryController() {
        return new SummaryController(appSvc, hostInfoDAO, vmInfoDAO, summaryViewProvider);
    }

    private HostInformationController createHostInformationController(HostRef ref) {
        List<InformationService<HostRef>> hostInfoServices = infoServiceTracker.getHostInformationServices();
        return new HostInformationController(hostInfoServices, ref, hostInfoViewProvider);
    }

    private VmInformationController createVmController(VmRef ref) {
        List<InformationService<VmRef>> vmInfoServices = infoServiceTracker.getVmInformationServices();
        return new VmInformationController(vmInfoServices, ref, vmInfoViewProvider);
    }

}