package org.openslx.dozmod.gui.wizard;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.ArrayList;
import java.util.List;

import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSeparator;
import javax.swing.SwingConstants;

import org.openslx.dozmod.gui.Gui;
import org.openslx.dozmod.gui.control.QLabel;
import org.openslx.dozmod.gui.helper.GridManager;
import org.openslx.dozmod.util.ResourceLoader;

@SuppressWarnings("serial")
public abstract class Wizard extends JDialog {

	private final QLabel titleLabel;
	private final QLabel messageLabel;
	private final List<WizardPage> pages = new ArrayList<>();
	private WizardPage postFinishPage = null;
	private boolean isPostFinish = false;
	private final JPanel contentPanel;
	private int currentPage = -1;
	private boolean needsLayout = true;
	private boolean isCancelled = false;

	private final JButton btnPrev;
	private final JButton btnNext;
	private final JButton btnCancel;
	private final JButton btnFinish;

	public Wizard(Window parent) {
		super(parent, ModalityType.APPLICATION_MODAL);
		setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
		setLayout(new BorderLayout());
		JPanel header = new JPanel();
		header.setMinimumSize(Gui.getScaledDimension(0, 100));
		header.setOpaque(true);
		header.setBackground(Color.WHITE);
		header.setLayout(new BoxLayout(header, BoxLayout.PAGE_AXIS));
		header.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
		// Labels in header
		titleLabel = new QLabel("<title>");
		messageLabel = new QLabel("<message>");
		titleLabel.setFont(titleLabel.getFont().deriveFont(Font.BOLD));
		titleLabel.setForeground(Color.BLACK);
		messageLabel.setForeground(Color.BLACK);
		messageLabel.setHorizontalTextPosition(SwingConstants.RIGHT);
		header.add(titleLabel);
		header.add(messageLabel);
		// Add header
		JPanel headerWrapper = new JPanel();
		GridManager grid = new GridManager(headerWrapper, 1, false);
		grid.add(header).expand(true, false).fill(true, false);
		grid.add(new JSeparator()).expand(true, false).fill(true, false);
		grid.finish(false);
		getContentPane().add(headerWrapper, BorderLayout.PAGE_START);
		// Buttons in footer
		JPanel footer = new JPanel();
		footer.setLayout(new BoxLayout(footer, BoxLayout.LINE_AXIS));
		footer.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
		footer.add(Box.createHorizontalGlue());
		btnPrev = new JButton("< Zurück");
		btnNext = new JButton("Weiter >");
		btnCancel = new JButton("Abbrechen");
		btnFinish = new JButton("Fertigstellen");
		footer.add(btnPrev);
		footer.add(btnNext);
		footer.add(Box.createRigidArea(new Dimension(10, 10)));
		footer.add(btnCancel);
		footer.add(Box.createRigidArea(new Dimension(5, 5)));
		footer.add(btnFinish);
		add(footer, BorderLayout.PAGE_END);
		// Add content panel
		contentPanel = new JPanel();
		contentPanel.setLayout(new BoxLayout(contentPanel, BoxLayout.PAGE_AXIS));
		contentPanel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
		add(contentPanel, BorderLayout.CENTER);

		// Scale window with font size
		setPreferredSize(Gui.getScaledDimension(550, 420));
		setResizable(false);
		pack();
		Gui.centerShellOverShell(parent, this);

		// Window events
		addWindowListener(new WindowAdapter() {
			@Override
			public void windowClosing(WindowEvent we) {
				doCancel();
			}
		});
		// Äkschns
		btnNext.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				doNext();
			}
		});
		btnPrev.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				doPrevious();
			}
		});
		btnCancel.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				doCancel();
			}
		});
		btnFinish.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				doFinish();
			}
		});
	}

	@SuppressWarnings("deprecation")
	@Override
	public void show() {
		if (needsLayout) {
			needsLayout = false;
			pack();
			if (!pages.isEmpty()) {
				showPage(0);
			}
		}
		super.show();
	}

	private void showPage(int index) {
		if (currentPage != -1) {
			WizardPage old = getPage(currentPage);
			old.onPageLeave();
			old.setVisible(false);
		}
		WizardPage page = getPage(index);
		page.onPageEnter();
		page.setVisible(true);
		currentPage = index;
		updateHeader(page);
		updateButtons(page);
		validate();
	}

	void updateHeader(WizardPage page) {
		if (!isPostFinish && (currentPage == -1 || getPage(currentPage) != page))
			return;
		String pageTitle = page.getTitle();
		String pageDesc = page.getMessage();
		if (pageTitle == null)
			pageTitle = "Step " + currentPage;
		if (pageDesc == null)
			pageDesc = "";
		titleLabel.setText(pageTitle);
		messageLabel.setText(pageDesc);
		messageLabel.setIcon(ResourceLoader.getScaledIcon(page.getMessageIcon(), messageLabel.getHeight(), messageLabel));
		messageLabel.setForeground(page.getMessageColor());
		messageLabel.validate();
		setTitle(getWindowTitle() + " - " + pageTitle);
	}

	public abstract String getWindowTitle();

	protected final void addPage(WizardPage page) {
		contentPanel.add(page);
		if (!pages.isEmpty()) {
			page.setVisible(false);
		}
		pages.add(page);
	}

	protected void addSummaryPage(WizardPage page) {
		postFinishPage = page;
	}

	void updateButtons(WizardPage page) {
		if (isPostFinish) {
			btnFinish.setEnabled(postFinishPage.isComplete());
			return;
		}
		// State of finish button
		boolean canFinish = true;
		for (WizardPage p : pages) {
			if (!p.isComplete()) {
				canFinish = false;
				break;
			}
		}
		btnFinish.setEnabled(canFinish);
		// State of next button
		if (currentPage != -1 && getPage(currentPage) == page) {
			btnNext.setEnabled(currentPage + 1 < pages.size() && page.isComplete());
			btnPrev.setEnabled(currentPage > 0 && getPage(currentPage - 1).canComeBack);
		}
	}

	/**
	 * Returns whether the page currently shown is the summary page.
	 * 
	 * @return whether the page currently shown is the summary page.
	 */
	protected final boolean isSummaryPage() {
		return isPostFinish;
	}

	/**
	 * Returns true if the wizard was cancelled. Mostly useful in onPageLeave to
	 * distinguish what's happening.
	 * 
	 * @return true if the wizard was cancelled.
	 */
	public final boolean isCancelled() {
		return isCancelled;
	}

	public final void doNext() {
		if (isPostFinish || !btnNext.isEnabled())
			return;
		if (currentPage + 1 < pages.size()) {
			if (!getPage(currentPage).wantNextOrFinish())
				return; // Page canceled the operation
			showPage(currentPage + 1);
		}
	}

	protected final void doPrevious() {
		if (isPostFinish || !btnPrev.isEnabled())
			return;
		if (currentPage > 0) {
			showPage(currentPage - 1);
		}
	}

	protected final void doCancel() {
		if (onCancelRequest()) {
			isCancelled = true;
			if (currentPage != -1) {
				getPage(currentPage).onPageLeave();
			}
			if (isPostFinish) {
				postFinishPage.onPageLeave();
			}
			dispose();
		}
	}

	protected final void doFinish() {
		if (isPostFinish) {
			postFinishPage.onPageLeave();
			dispose();
			return;
		}
		if (!btnFinish.isEnabled())
			return;
		if (currentPage != -1) {
			if (!getPage(currentPage).wantNextOrFinish())
				return;
		}
		if (wantFinish()) {
			if (currentPage != -1) {
				getPage(currentPage).onPageLeave();
			}
			postFinishPage = performFinish();
			if (postFinishPage == null) {
				dispose();
			} else {
				isPostFinish = true;
				btnPrev.setVisible(false);
				btnNext.setVisible(false);
				btnFinish.setText("Schließen");
				postFinishPage.setVisible(false);
				contentPanel.add(postFinishPage);
				showPage(-1);
			}
		}
	}

	private WizardPage getPage(int index) {
		if (isPostFinish && index == -1)
			return postFinishPage;
		return pages.get(index);
	}

	/*
	 * Callback to wizard implementation
	 */

	/**
	 * User clicked cancel or (X) - when returning false,
	 * wizard will stay open
	 * 
	 * @return
	 */
	protected boolean onCancelRequest() {
		return true;
	}

	/**
	 * Called when user clicks finish. Override to do final checks and take
	 * appropriate actions.
	 * 
	 * @return <code>true</code> if finish is allowed, <code>false</code>
	 *         otherwise
	 */
	protected boolean wantFinish() {
		return true;
	}

	/**
	 * Called so the wizard can perform finishing steps. This is called after
	 * wantFinish() returned true and onPageLeave was called on the currently
	 * visible wizard step.
	 * If a wizard page is returned, it will serve as a summary page shown to
	 * the user within the wizard frame. The prev and next buttons will
	 * disappear, and the finish button will change to a close button.
	 * 
	 * @return A wizard page that serves as a summary page, or null if the
	 *         wizard should just close
	 */
	protected WizardPage performFinish() {
		return null;
	}

}