package com.minres.scviewer.e4.application.handlers;

import java.lang.reflect.InvocationTargetException;
import java.net.URI;
import java.net.URISyntaxException;

import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.SubMonitor;
import org.eclipse.core.runtime.jobs.IJobChangeEvent;
import org.eclipse.core.runtime.jobs.JobChangeAdapter;
import org.eclipse.e4.core.di.annotations.Execute;
import org.eclipse.e4.ui.di.UISynchronize;
import org.eclipse.e4.ui.workbench.IWorkbench;
import org.eclipse.equinox.p2.core.IProvisioningAgent;
import org.eclipse.equinox.p2.operations.ProvisioningJob;
import org.eclipse.equinox.p2.operations.ProvisioningSession;
import org.eclipse.equinox.p2.operations.UpdateOperation;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.dialogs.ProgressMonitorDialog;
import org.eclipse.jface.operation.IRunnableWithProgress;

public class UpdateHandler {

	boolean cancelled = false;

	@Execute
	public void execute(IProvisioningAgent agent, UISynchronize sync, IWorkbench workbench) {
		// update using a progress monitor
		IRunnableWithProgress runnable = new IRunnableWithProgress() {
			@Override
			public void run(IProgressMonitor monitor) throws InvocationTargetException, InterruptedException {
				update(agent, monitor, sync, workbench);
			}
		};
		try {
			new ProgressMonitorDialog(null).run(true, true, runnable);
		} catch (InvocationTargetException | InterruptedException e) {
			e.printStackTrace();
		}
	}

	private IStatus update(IProvisioningAgent agent, IProgressMonitor monitor, UISynchronize sync,
			IWorkbench workbench) {
		ProvisioningSession session = new ProvisioningSession(agent);
		// update the whole running profile, otherwise specify IUs
		UpdateOperation operation = new UpdateOperation(session);
		try {
			operation.getProvisioningContext().setArtifactRepositories(new URI("http://https://minres.github.io/SCViewer/repository"));
			operation.getProvisioningContext().setMetadataRepositories(new URI("http://https://minres.github.io/SCViewer/repository"));
		} catch (URISyntaxException e) {}
		SubMonitor sub = SubMonitor.convert(monitor, "Checking for application updates...", 200);
		// check if updates are available
		IStatus status = operation.resolveModal(sub.newChild(100));
		if (status.getCode() == UpdateOperation.STATUS_NOTHING_TO_UPDATE) {
			showMessage(sync, "Nothing to update");
			return Status.CANCEL_STATUS;
		} else {
			ProvisioningJob provisioningJob = operation.getProvisioningJob(sub.newChild(100));
			if (provisioningJob != null) {
				sync.syncExec(new Runnable() {
					@Override
					public void run() {
						boolean performUpdate = MessageDialog.openQuestion(null, "Updates available",
								"There are updates available. Do you want to install them now?");
						if (performUpdate) {
							provisioningJob.addJobChangeListener(new JobChangeAdapter() {
								@Override
								public void done(IJobChangeEvent event) {
									if (event.getResult().isOK()) {
										sync.syncExec(new Runnable() {

											@Override
											public void run() {
												boolean restart = MessageDialog.openQuestion(null,
														"Updates installed, restart?",
														"Updates have been installed successfully, do you want to restart?");
												if (restart) {
													workbench.restart();
												}
											}
										});
									} else {
										showError(sync, event.getResult().getMessage());
										cancelled = true;
									}
								}
							});
							// since we switched to the UI thread for interacting with the user
							// we need to schedule the provisioning thread, otherwise it would
							// be executed also in the UI thread and not in a background thread
							provisioningJob.schedule();
						} else {
							cancelled = true;
						}
					}
				});
			} else {
				if (operation.hasResolved()) {
					showError(sync, "Couldn't get provisioning job: " + operation.getResolutionResult());
				} else {
					showError(sync, "Couldn't resolve provisioning job");
				}
				cancelled = true;
			}
		}
		if (cancelled) {
			// reset cancelled flag
			cancelled = false;
			return Status.CANCEL_STATUS;
		}
		return Status.OK_STATUS;
	}

	private void showMessage(UISynchronize sync, final String message) {
		// as the provision needs to be executed in a background thread
		// we need to ensure that the message dialog is executed in
		// the UI thread
		sync.syncExec(new Runnable() {

			@Override
			public void run() {
				MessageDialog.openInformation(null, "Information", message);
			}
		});
	}

	private void showError(UISynchronize sync, final String message) {
		// as the provision needs to be executed in a background thread
		// we need to ensure that the message dialog is executed in
		// the UI thread
		sync.syncExec(new Runnable() {
			@Override
			public void run() {
				MessageDialog.openError(null, "Error", message);
			}
		});
	}
}