/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * 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
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.jdt.internal.ui.preferences;

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

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;

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;

import org.eclipse.jface.dialogs.Dialog;
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.jface.text.Assert;

import org.eclipse.jdt.internal.corext.util.Messages;

import org.eclipse.jdt.ui.PreferenceConstants;
import org.eclipse.jdt.ui.text.folding.IJavaFoldingPreferenceBlock;

import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.text.folding.JavaFoldingStructureProviderDescriptor;
import org.eclipse.jdt.internal.ui.text.folding.JavaFoldingStructureProviderRegistry;
import org.eclipse.jdt.internal.ui.util.PixelConverter;

/**
 * Configures Java Editor folding preferences.
 * 
 * @since 3.0
 */
class FoldingConfigurationBlock implements IPreferenceConfigurationBlock {
	
	private static class ErrorPreferences implements IJavaFoldingPreferenceBlock {
		private String fMessage;
		
		protected ErrorPreferences(String message) {
			fMessage= message;
		}
		
		/*
		 * @see org.eclipse.jdt.internal.ui.text.folding.IJavaFoldingPreferences#createControl(org.eclipse.swt.widgets.Group)
		 */
		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;
		}

		public void initialize() {
		}

		public void performOk() {
		}

		public void performDefaults() {
		}

		public void dispose() {
		}
		
	}

	/** The overlay preference store. */
	private final OverlayPreferenceStore fStore;
	
	/* The controls */
	private Combo fProviderCombo;
	private Button fFoldingCheckbox;
	private ComboViewer fProviderViewer;
	private Composite fGroup;
	private StackLayout fStackLayout;
	
	/* the model */
	private final Map fProviderDescriptors;
	private final Map fProviderPreferences;
	private final Map fProviderControls;
	

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

	private Map createListModel() {
		JavaFoldingStructureProviderRegistry reg= JavaPlugin.getDefault().getFoldingStructureProviderRegistry();
		reg.reloadExtensions();
		JavaFoldingStructureProviderDescriptor[] descs= reg.getFoldingProviderDescriptors();
		Map 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 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;
	}

	/**
	 * Creates page for folding preferences.
	 * 
	 * @param parent the parent composite
	 * @return the control for the preference page
	 */
	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() {
			public void widgetSelected(SelectionEvent e) {
				boolean enabled= fFoldingCheckbox.getSelection(); 
				fStore.setValue(PreferenceConstants.EDITOR_FOLDING_ENABLED, enabled);
				updateCheckboxDependencies();
			}

			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);

		if (fProviderDescriptors.size() > 1) {
			/* 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);

			fProviderViewer= createProviderViewer();
		}
		
		Composite groupComp= new Composite(composite, SWT.NONE);
		gd= new GridData(GridData.FILL_BOTH);
		gd.horizontalSpan= 2;
		groupComp.setLayoutData(gd);
		GridLayout 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;
	}

	private ComboViewer createProviderViewer() {
		/* list viewer */
		ComboViewer viewer= new ComboViewer(fProviderCombo);
		viewer.setContentProvider(new IStructuredContentProvider() {

			/*
			 * @see org.eclipse.jface.viewers.IContentProvider#dispose()
			 */
			public void dispose() {
			}

			/*
			 * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
			 */
			public void inputChanged(Viewer v, Object oldInput, Object newInput) {
			}

			/*
			 * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object)
			 */
			public Object[] getElements(Object inputElement) {
				return fProviderDescriptors.values().toArray();
			}
		});
		viewer.setLabelProvider(new LabelProvider() {
			/*
			 * @see org.eclipse.jface.viewers.LabelProvider#getImage(java.lang.Object)
			 */
			public Image getImage(Object element) {
				return null;
			}
			
			/*
			 * @see org.eclipse.jface.viewers.LabelProvider#getText(java.lang.Object)
			 */
			public String getText(Object element) {
				return ((JavaFoldingStructureProviderDescriptor) element).getName();
			}
		});
		viewer.addSelectionChangedListener(new ISelectionChangedListener() {

			public void selectionChanged(SelectionChangedEvent event) {
				IStructuredSelection sel= (IStructuredSelection) event.getSelection();
				if (!sel.isEmpty()) {
					fStore.setValue(PreferenceConstants.EDITOR_FOLDING_PROVIDER, ((JavaFoldingStructureProviderDescriptor) sel.getFirstElement()).getId());
					updateListDependencies();
				}
			}
		});
		viewer.setInput(fProviderDescriptors);
		viewer.refresh();
		
		return viewer;
	}

	private void updateCheckboxDependencies() {
	}

	void updateListDependencies() {
		String id= fStore.getString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
		JavaFoldingStructureProviderDescriptor desc= (JavaFoldingStructureProviderDescriptor) fProviderDescriptors.get(id);
		IJavaFoldingPreferenceBlock prefs;
		
		if (desc == null) {
			// safety in case there is no such descriptor
			String message= Messages.format(PreferencesMessages.FoldingConfigurationBlock_error_not_exist, id);
			JavaPlugin.log(new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, message, null));
			prefs= new ErrorPreferences(message);
		} else {
			prefs= (IJavaFoldingPreferenceBlock) fProviderPreferences.get(id);
			if (prefs == null) {
				try {
					prefs= desc.createPreferences();
					fProviderPreferences.put(id, prefs);
				} catch (CoreException e) {
					JavaPlugin.log(e);
					prefs= new ErrorPreferences(e.getLocalizedMessage());
				}
			}
		}
		
		Control 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);
			}
		}
		Dialog.applyDialogFont(control);
		fStackLayout.topControl= control;
		control.pack();
		fGroup.layout();
		fGroup.getParent().layout();
		
		prefs.initialize();
	}

	public void initialize() {
		restoreFromPreferences();
	}

	public void performOk() {
		for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
			IJavaFoldingPreferenceBlock prefs= (IJavaFoldingPreferenceBlock) it.next();
			prefs.performOk();
		}
	}
	
	public void performDefaults() {
		restoreFromPreferences();
		for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
			IJavaFoldingPreferenceBlock prefs= (IJavaFoldingPreferenceBlock) it.next();
			prefs.performDefaults();
		}
	}
	
	public void dispose() {
		for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
			IJavaFoldingPreferenceBlock prefs= (IJavaFoldingPreferenceBlock) it.next();
			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);
		
		// Fallback to default
		if (provider == null) {
			String message= Messages.format(PreferencesMessages.FoldingConfigurationBlock_warning_providerNotFound_resetToDefault, id);
			JavaPlugin.log(new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, message, null));
			
			id= JavaPlugin.getDefault().getPreferenceStore().getDefaultString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
			
			provider= fProviderDescriptors.get(id);
			/*
			 * In 3.2.1 we don't want to risk anything, hence don't
			 * Assert.isNotNull(provider);
			 */
			if (provider == null)
				return;
			
			fStore.setToDefault(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
		}
		
		if (fProviderViewer == null)
			updateListDependencies();
		else
			fProviderViewer.setSelection(new StructuredSelection(provider), true);
	}
}