/*******************************************************************************
 * Copyright (C) 2011, Mathias Kinzler <mathias.kinzler@sap.com>
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *******************************************************************************/
package org.eclipse.egit.ui.internal.fetch;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.eclipse.egit.ui.Activator;
import org.eclipse.egit.ui.UIUtils;
import org.eclipse.egit.ui.internal.UIText;
import org.eclipse.jface.dialogs.IMessageProvider;
import org.eclipse.jface.layout.GridDataFactory;
import org.eclipse.jface.wizard.WizardPage;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.transport.RemoteConfig;
import org.eclipse.osgi.util.NLS;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.ModifyEvent;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Text;

/**
 * Obtain the Fetch Source, i.e. the {@link Ref} on the remote
 * {@link Repository}
 */
public class FetchDestinationPage extends WizardPage {
	private final Repository repository;

	private final RemoteConfig config;

	private Text sourceText;

	private Text destinationText;

	private Button force;

	private List<Ref> trackingBranches;

	/**
	 * Default constructor
	 *
	 * @param repository
	 * @param config
	 */
	public FetchDestinationPage(Repository repository, RemoteConfig config) {
		super(FetchDestinationPage.class.getName());
		this.repository = repository;
		this.config = config;
		setTitle(UIText.FetchDestinationPage_PageTitle);
	}

	@Override
	public void createControl(Composite parent) {
		Composite main = new Composite(parent, SWT.NONE);
		main.setLayout(new GridLayout(2, false));
		GridDataFactory.fillDefaults().grab(true, true).applyTo(main);

		Label repositoryLabel = new Label(main, SWT.NONE);
		repositoryLabel.setText(UIText.FetchDestinationPage_RepositoryLabel);
		Text repositoryText = new Text(main, SWT.READ_ONLY | SWT.BORDER);
		repositoryText.setText(Activator.getDefault().getRepositoryUtil()
				.getRepositoryName(repository));
		GridDataFactory.fillDefaults().grab(true, false)
				.applyTo(repositoryText);

		Label sourceLabel = new Label(main, SWT.NONE);
		sourceLabel.setText(UIText.FetchDestinationPage_SourceLabel);

		sourceText = new Text(main, SWT.READ_ONLY | SWT.BORDER);
		GridDataFactory.fillDefaults().grab(true, false).applyTo(sourceText);

		Label destinationLabel = new Label(main, SWT.NONE);
		destinationLabel.setText(UIText.FetchDestinationPage_DestinationLabel);
		destinationText = new Text(main, SWT.BORDER);
		destinationText.addModifyListener(new ModifyListener() {
			@Override
			public void modifyText(ModifyEvent e) {
				checkPage();
			}
		});
		GridDataFactory.fillDefaults().grab(true, false).applyTo(
				destinationText);
		UIUtils.addRefContentProposalToText(sourceText, repository,
				() -> getRemoteRefs());

		force = new Button(main, SWT.CHECK);
		force.setText(UIText.FetchDestinationPage_ForceCheckbox);
		GridDataFactory.fillDefaults().grab(true, false).span(2, 1).applyTo(
				force);

		checkPage();
		destinationText.setFocus();
		setControl(main);
	}

	@Override
	public void setVisible(boolean visible) {
		super.setVisible(visible);
		if (visible) {
			FetchSourcePage fsp = (FetchSourcePage) getWizard()
					.getPreviousPage(this);
			String sourceString = fsp.getSource();
			sourceText.setText(sourceString);
			if (sourceString.length() > 0) {
				destinationText.setText(Constants.R_REMOTES + config.getName()
						+ '/' + Repository.shortenRefName(sourceString));
			}
			destinationText.setFocus();
		}
	}

	/**
	 * @return the source
	 */
	public String getDestination() {
		return destinationText.getText();
	}

	/**
	 * @return if force is checked
	 */
	public boolean isForce() {
		return force.getSelection();
	}

	private List<Ref> getRemoteRefs() {
		if (this.trackingBranches == null) {
			List<Ref> proposals = new ArrayList<>();
			try {
				for (Ref ref : repository.getRefDatabase().getRefs(
						Constants.R_REMOTES).values()) {
					proposals.add(ref);
				}
				this.trackingBranches = proposals;
			} catch (IOException e) {
				setErrorMessage(UIText.FetchDestinationPage_CouldNotGetBranchesMessage);
			}
		}
		return this.trackingBranches;
	}

	private void checkPage() {
		setMessage(null, IMessageProvider.WARNING);
		setErrorMessage(null);
		setMessage(UIText.FetchDestinationPage_PageMessage);
		if (destinationText.getText().length() == 0) {
			setPageComplete(false);
			return;
		}
		boolean found = false;
		for (Ref ref : getRemoteRefs()) {
			if (ref.getName().equals(destinationText.getText()))
				found = true;
		}
		if (!found)
			setMessage(NLS.bind(
					UIText.FetchDestinationPage_TrackingBranchNotFoundMessage,
					destinationText.getText()), IMessageProvider.WARNING);
		setPageComplete(true);
	}
}