/*******************************************************************************
 * Copyright (c) 2000, 2012 QNX Software Systems and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.cdt.internal.ui.preferences;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.cdt.internal.ui.preferences.OverlayPreferenceStore.OverlayKey;
import org.eclipse.cdt.internal.ui.text.folding.CFoldingStructureProviderDescriptor;
import org.eclipse.cdt.internal.ui.text.folding.CFoldingStructureProviderRegistry;
import org.eclipse.cdt.ui.CUIPlugin;
import org.eclipse.cdt.ui.PreferenceConstants;
import org.eclipse.cdt.ui.text.folding.ICFoldingPreferenceBlock;
import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.jface.layout.PixelConverter;
import org.eclipse.jface.viewers.ComboViewer;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.IStructuredContentProvider;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StackLayout;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;

/**
 * Configures C Editor folding preferences.
 *
 * @since 3.0
 */
class FoldingConfigurationBlock implements IPreferenceConfigurationBlock {

	private static class ErrorPreferences implements ICFoldingPreferenceBlock {
		private final String fMessage;

		protected ErrorPreferences(String message) {
			fMessage = message;
		}

		@Override
		public Control createControl(Composite composite) {
			Composite inner = new Composite(composite, SWT.NONE);
			inner.setLayout(new FillLayout(SWT.VERTICAL));

			Label label = new Label(inner, SWT.CENTER);
			label.setText(fMessage);

			return inner;
		}

		@Override
		public void initialize() {
		}

		@Override
		public void performOk() {
		}

		@Override
		public void performDefaults() {
		}

		@Override
		public void dispose() {
		}
	}

	/** The overlay preference store. */
	protected final OverlayPreferenceStore fStore;

	/* The controls */
	private Combo fProviderCombo;
	protected Button fFoldingCheckbox;
	private ComboViewer fProviderViewer;
	protected Map<String, CFoldingStructureProviderDescriptor> fProviderDescriptors;
	private Composite fGroup;
	private final Map<String, ICFoldingPreferenceBlock> fProviderPreferences;
	private final Map<String, Control> fProviderControls;
	private StackLayout fStackLayout;

	public FoldingConfigurationBlock(OverlayPreferenceStore store) {
		Assert.isNotNull(store);
		fStore = store;
		fStore.addKeys(createOverlayStoreKeys());
		fProviderDescriptors = createListModel();
		fProviderPreferences = new HashMap<>();
		fProviderControls = new HashMap<>();
	}

	private Map<String, CFoldingStructureProviderDescriptor> createListModel() {
		CFoldingStructureProviderRegistry reg = CUIPlugin.getDefault().getFoldingStructureProviderRegistry();
		reg.reloadExtensions();
		CFoldingStructureProviderDescriptor[] descs = reg.getFoldingProviderDescriptors();
		Map<String, CFoldingStructureProviderDescriptor> map = new HashMap<>();
		for (int i = 0; i < descs.length; i++) {
			map.put(descs[i].getId(), descs[i]);
		}
		return map;
	}

	private OverlayPreferenceStore.OverlayKey[] createOverlayStoreKeys() {

		ArrayList<OverlayKey> overlayKeys = new ArrayList<>();

		overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.BOOLEAN,
				PreferenceConstants.EDITOR_FOLDING_ENABLED));
		overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.STRING,
				PreferenceConstants.EDITOR_FOLDING_PROVIDER));

		OverlayPreferenceStore.OverlayKey[] keys = new OverlayPreferenceStore.OverlayKey[overlayKeys.size()];
		overlayKeys.toArray(keys);
		return keys;
	}

	@Override
	public Control createControl(Composite parent) {

		Composite composite = new Composite(parent, SWT.NULL);
		// assume parent page uses griddata
		GridData gd = new GridData(GridData.HORIZONTAL_ALIGN_CENTER | GridData.VERTICAL_ALIGN_FILL);
		composite.setLayoutData(gd);
		GridLayout layout = new GridLayout();
		layout.numColumns = 2;
		PixelConverter pc = new PixelConverter(composite);
		layout.verticalSpacing = pc.convertHeightInCharsToPixels(1) / 2;
		composite.setLayout(layout);

		/* check box for new editors */
		fFoldingCheckbox = new Button(composite, SWT.CHECK);
		fFoldingCheckbox.setText(PreferencesMessages.FoldingConfigurationBlock_enable);
		gd = new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING | GridData.VERTICAL_ALIGN_BEGINNING);
		fFoldingCheckbox.setLayoutData(gd);
		fFoldingCheckbox.addSelectionListener(new SelectionListener() {
			@Override
			public void widgetSelected(SelectionEvent e) {
				boolean enabled = fFoldingCheckbox.getSelection();
				fStore.setValue(PreferenceConstants.EDITOR_FOLDING_ENABLED, enabled);
				updateCheckboxDependencies();
			}

			@Override
			public void widgetDefaultSelected(SelectionEvent e) {
			}
		});

		Label label = new Label(composite, SWT.CENTER);
		gd = new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_BEGINNING);
		label.setLayoutData(gd);

		/* list */
		Composite comboComp = new Composite(composite, SWT.NONE);
		gd = new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_BEGINNING);
		GridLayout gridLayout = new GridLayout(2, false);
		gridLayout.marginWidth = 0;
		comboComp.setLayout(gridLayout);

		Label comboLabel = new Label(comboComp, SWT.CENTER);
		gd = new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING | GridData.VERTICAL_ALIGN_CENTER);
		comboLabel.setLayoutData(gd);
		comboLabel.setText(PreferencesMessages.FoldingConfigurationBlock_combo_caption);

		label = new Label(composite, SWT.CENTER);
		gd = new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_BEGINNING);
		label.setLayoutData(gd);

		fProviderCombo = new Combo(comboComp, SWT.READ_ONLY | SWT.DROP_DOWN);
		gd = new GridData(GridData.HORIZONTAL_ALIGN_END | GridData.VERTICAL_ALIGN_CENTER);
		fProviderCombo.setLayoutData(gd);

		/* list viewer */
		fProviderViewer = new ComboViewer(fProviderCombo);
		fProviderViewer.setContentProvider(new IStructuredContentProvider() {
			@Override
			public void dispose() {
			}

			@Override
			public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
			}

			@Override
			public Object[] getElements(Object inputElement) {
				return fProviderDescriptors.values().toArray();
			}
		});
		fProviderViewer.setLabelProvider(new LabelProvider() {
			@Override
			public Image getImage(Object element) {
				return null;
			}

			@Override
			public String getText(Object element) {
				return ((CFoldingStructureProviderDescriptor) element).getName();
			}
		});
		fProviderViewer.addSelectionChangedListener(new ISelectionChangedListener() {
			@Override
			public void selectionChanged(SelectionChangedEvent event) {
				IStructuredSelection sel = (IStructuredSelection) event.getSelection();
				if (!sel.isEmpty()) {
					fStore.setValue(PreferenceConstants.EDITOR_FOLDING_PROVIDER,
							((CFoldingStructureProviderDescriptor) sel.getFirstElement()).getId());
					updateListDependencies();
				}
			}
		});
		fProviderViewer.setInput(fProviderDescriptors);
		fProviderViewer.refresh();

		Composite groupComp = new Composite(composite, SWT.NONE);
		gd = new GridData(GridData.FILL_BOTH);
		gd.horizontalSpan = 2;
		groupComp.setLayoutData(gd);
		gridLayout = new GridLayout(1, false);
		gridLayout.marginWidth = 0;
		groupComp.setLayout(gridLayout);

		/* contributed provider preferences. */
		fGroup = new Composite(groupComp, SWT.NONE);
		gd = new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING | GridData.VERTICAL_ALIGN_BEGINNING);
		fGroup.setLayoutData(gd);
		fStackLayout = new StackLayout();
		fGroup.setLayout(fStackLayout);

		return composite;
	}

	protected void updateCheckboxDependencies() {
	}

	void updateListDependencies() {
		String id = fStore.getString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
		CFoldingStructureProviderDescriptor desc = fProviderDescriptors.get(id);
		ICFoldingPreferenceBlock prefs;

		if (desc == null) {
			// safety in case there is no such descriptor
			String message = PreferencesMessages.FoldingConfigurationBlock_error_not_exist;
			CUIPlugin.log(new Status(IStatus.WARNING, CUIPlugin.getPluginId(), IStatus.OK, message, null));
			prefs = new ErrorPreferences(message);
		} else {
			prefs = fProviderPreferences.get(id);
			if (prefs == null) {
				try {
					prefs = desc.createPreferences();
					fProviderPreferences.put(id, prefs);
				} catch (CoreException e) {
					CUIPlugin.log(e);
					prefs = new ErrorPreferences(e.getLocalizedMessage());
				}
			}
		}

		Control control = fProviderControls.get(id);
		if (control == null) {
			control = prefs.createControl(fGroup);
			if (control == null) {
				String message = PreferencesMessages.FoldingConfigurationBlock_info_no_preferences;
				control = new ErrorPreferences(message).createControl(fGroup);
			} else {
				fProviderControls.put(id, control);
			}
		}
		fStackLayout.topControl = control;
		control.pack();
		fGroup.layout();
		fGroup.getParent().layout();

		prefs.initialize();
	}

	@Override
	public void initialize() {
		restoreFromPreferences();
	}

	@Override
	public void performOk() {
		for (ICFoldingPreferenceBlock prefs : fProviderPreferences.values()) {
			prefs.performOk();
		}
	}

	@Override
	public void performDefaults() {
		restoreFromPreferences();
		for (ICFoldingPreferenceBlock prefs : fProviderPreferences.values()) {
			prefs.performDefaults();
		}
	}

	@Override
	public void dispose() {
		for (ICFoldingPreferenceBlock prefs : fProviderPreferences.values()) {
			prefs.dispose();
		}
	}

	private void restoreFromPreferences() {
		boolean enabled = fStore.getBoolean(PreferenceConstants.EDITOR_FOLDING_ENABLED);
		fFoldingCheckbox.setSelection(enabled);
		updateCheckboxDependencies();

		String id = fStore.getString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
		Object provider = fProviderDescriptors.get(id);
		if (provider != null) {
			fProviderViewer.setSelection(new StructuredSelection(provider), true);
			updateListDependencies();
		}
	}
}
