/*******************************************************************************
 * Copyright (c) 2000, 2018 IBM Corporation 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.ui.internal.editors.text;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.BusyIndicator;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;

import org.eclipse.core.runtime.CoreException;

import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;

import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.layout.GridLayoutFactory;
import org.eclipse.jface.viewers.ITreeContentProvider;

import org.eclipse.ui.dialogs.TypeFilteringDialog;
import org.eclipse.ui.model.WorkbenchContentProvider;
import org.eclipse.ui.model.WorkbenchLabelProvider;


/**
 * Dialog for selecting resources.
 *
 * @since 3.1
 */
class SelectResourcesDialog extends Dialog {

	interface IFilter {
		boolean accept(IResource resource);
	}

	private SelectResourcesBlock fResourceGroup;
	private List<Object> fAcceptedFileTypes = new ArrayList<>();
	private IResource[] fInput;
	private String fTitle;
	private String fInstruction;
	private Label fCountIndication;
	private IFilter fAcceptableLocationsFilter;


	public SelectResourcesDialog(Shell parentShell, String title, String instruction, IFilter acceptableLocationsFilter) {
		super(parentShell);
		fTitle= title;
		fInstruction= instruction;
		fAcceptableLocationsFilter= acceptableLocationsFilter;
	}

	@Override
	protected boolean isResizable() {
		return true;
	}

	public void setInput(IResource[] input) {
		fInput= input;
	}

	public void refresh() {
		fResourceGroup.refresh();
		setSelection(fInput, fAcceptableLocationsFilter);
	}
	
	public IResource[] getSelectedResources() {
		List<Object> items= fResourceGroup.getAllCheckedListItems();
		return items.toArray(new IResource[items.size()]);
	}

	@Override
	protected void configureShell(Shell newShell) {
		super.configureShell(newShell);

		if (fTitle != null)
			newShell.setText(fTitle);
	}

	@Override
	protected Control createDialogArea(Composite parent) {
		Composite composite= (Composite) super.createDialogArea(parent);
		Label label= new Label(composite, SWT.LEFT);
		label.setText(fInstruction);
		label.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));

		fResourceGroup= new SelectResourcesBlock(composite, ResourcesPlugin.getWorkspace().getRoot(), getResourceProvider(IResource.FOLDER | IResource.PROJECT), WorkbenchLabelProvider.getDecoratingWorkbenchLabelProvider(), getResourceProvider(IResource.FILE), WorkbenchLabelProvider.getDecoratingWorkbenchLabelProvider(), SWT.NONE, useHeightHint(parent));
		fResourceGroup.addCheckStateListener(event -> updateSelectionCount());

		fCountIndication= new Label(composite, SWT.LEFT);
		fCountIndication.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));

		createSelectionButtonGroup(composite);

		setInitialSelection();
		return composite;
	}

	private boolean useHeightHint(Composite parent) {
		int fontHeight= (parent.getFont().getFontData())[0].getHeight();
		int displayHeight= parent.getDisplay().getClientArea().height;
		return (displayHeight / fontHeight) > 50;
	}

	private ITreeContentProvider getResourceProvider(final int resourceType) {
		return new WorkbenchContentProvider() {
			@Override
			public Object[] getChildren(Object o) {
				if (o instanceof IWorkspaceRoot) {
					HashSet<IResource> projects= new HashSet<>();
					for (int i= 0; i < fInput.length; i++) {
						IResource project= fInput[i].getProject();
						if ((project.getType() & resourceType) > 0)
							projects.add(project);
					}
					return projects.toArray();
				}

				if (o instanceof IContainer) {
					IResource[] members = null;
					try {
						members = ((IContainer) o).members();
					} catch (CoreException e) {
						//just return an empty set of children
						return new Object[0];
					}

					//filter out the desired resource types
					ArrayList<IResource> results = new ArrayList<>();
					for (int i = 0; i < members.length; i++) {
						//And the test bits with the resource types to see if they are what we want
						if ((members[i].getType() & resourceType) > 0 && (resourceType != IResource.FILE || fAcceptableLocationsFilter == null || fAcceptableLocationsFilter.accept(members[i]))) {
							results.add(members[i]);
						}
					}
					return results.toArray();
				}

				//input element case
				if (o instanceof ArrayList)
					return ((ArrayList<?>) o).toArray();

				return new Object[0];
			}
		};
	}

	protected Composite createSelectionButtonGroup(Composite parent) {

		Font font= parent.getFont();

		// top level group
		Composite buttonComposite= new Composite(parent, SWT.NONE);
		buttonComposite.setFont(parent.getFont());

		buttonComposite.setLayout(GridLayoutFactory.fillDefaults().numColumns(0).equalWidth(true).create());

		Button selectButton= createButton(buttonComposite, IDialogConstants.SELECT_ALL_ID, TextEditorMessages.SelectResourcesDialog_selectAll, false);

		SelectionListener listener= new SelectionAdapter() {
			@Override
			public void widgetSelected(SelectionEvent e) {
				fResourceGroup.setAllSelections(true);
				updateSelectionCount();
			}
		};
		selectButton.addSelectionListener(listener);
		selectButton.setFont(font);
		setButtonLayoutData(selectButton);

		Button deselectButton= createButton(buttonComposite, IDialogConstants.DESELECT_ALL_ID, TextEditorMessages.SelectResourcesDialog_deselectAll, false);

		listener= new SelectionAdapter() {
			@Override
			public void widgetSelected(SelectionEvent e) {
				fResourceGroup.setAllSelections(false);
				updateSelectionCount();
			}
		};
		deselectButton.addSelectionListener(listener);
		deselectButton.setFont(font);
		setButtonLayoutData(deselectButton);

		// types edit button
		Button selectTypesButton= createButton(buttonComposite, IDialogConstants.SELECT_TYPES_ID, TextEditorMessages.SelectResourcesDialog_filterSelection, false);

		listener= new SelectionAdapter() {
			@Override
			public void widgetSelected(SelectionEvent e) {
				handleSelectFileTypes();
			}
		};
		selectTypesButton.addSelectionListener(listener);
		selectTypesButton.setFont(font);
		setButtonLayoutData(selectTypesButton);
		
		return buttonComposite;
	}

	protected void handleSelectFileTypes() {
		Object[] acceptedFileTypes= queryFileTypes();
		if (acceptedFileTypes != null) {
			fAcceptedFileTypes= Arrays.asList(acceptedFileTypes);
			filterSelection();
		}
	}

	protected Object[] queryFileTypes() {
		TypeFilteringDialog dialog= new TypeFilteringDialog(getShell(), fAcceptedFileTypes);
		dialog.open();
		return dialog.getResult();
	}

	private void filterSelection() {

		final IFilter filter= resource -> hasAcceptedFileType(resource);

		List<Object> list= fResourceGroup.getAllWhiteCheckedItems();
		final IResource[] resources= list.toArray(new IResource[list.size()]);

		Runnable runnable= () -> setSelection(resources, filter);

		BusyIndicator.showWhile(getShell().getDisplay(), runnable);
	}

	protected boolean hasAcceptedFileType(IResource resource) {
		if (fAcceptedFileTypes == null)
			return true;

		String resourceName= resource.getName();
		int separatorIndex= resourceName.lastIndexOf("."); //$NON-NLS-1$
		if (separatorIndex == -1)
			return false;

		String extension= resourceName.substring(separatorIndex + 1);

		Iterator<Object> e= fAcceptedFileTypes.iterator();
		while (e.hasNext()) {
			if (extension.equalsIgnoreCase((String) e.next()))
				return true;
		}

		return false;
	}

	protected void setInitialSelection() {
		setSelection(fInput, fAcceptableLocationsFilter);
		selectAndReveal(fInput[0]);
	}

	protected void setSelection(IResource[] input, IFilter filter) {
		Map<IContainer, List<Object>> selectionMap= new Hashtable<>();
		for (int i= 0; i < input.length; i++) {
			IResource resource= input[i];
			if ((resource.getType() & IResource.FILE) > 0) {
				if (filter.accept(resource)) {
					List<Object> files= null;
					IContainer parent= resource.getParent();
					if (selectionMap.containsKey(parent))
						files= selectionMap.get(parent);
					else
						files= new ArrayList<>();

					files.add(resource);
					selectionMap.put(parent, files);
				}
			} else
				setSelection(selectionMap, (IContainer) resource, filter);
		}
		fResourceGroup.updateSelections(selectionMap);
		updateSelectionCount();
	}

	private void setSelection(Map<IContainer, List<Object>> selectionMap, IContainer parent, IFilter filter) {
		try {

			IResource[] resources= parent.members();
			List<Object> selections= new ArrayList<>();

			for (int i= 0; i < resources.length; i++) {
				IResource resource= resources[i];
				if ((resource.getType() & IResource.FILE) > 0) {
					if (filter.accept(resource))
						selections.add(resource);
				} else {
					setSelection(selectionMap, (IContainer) resource, filter);
				}
			}

			if (!selections.isEmpty())
				selectionMap.put(parent, selections);

		} catch (CoreException x) {
			//Just return if we can't get any info
			return;
		}
	}

	private void selectAndReveal(IResource resource) {
		IContainer container= null;
		if ((IResource.FILE & resource.getType()) > 0)
			container= resource.getParent();
		else
			container= (IContainer) resource;
		fResourceGroup.selectAndReveal(container);
	}

	private void updateSelectionCount() {
		List<Object> listItems= fResourceGroup.getAllCheckedListItems();
		int checkedFiles= listItems.size();
		StringBuilder buffer= new StringBuilder();
		switch (checkedFiles) {
			case 0:
				buffer.append(TextEditorMessages.SelectResourcesDialog_noFilesSelected);
				break;
			case 1:
				buffer.append(TextEditorMessages.SelectResourcesDialog_oneFileSelected);
				break;
			default:
				buffer.append(NLSUtility.format(TextEditorMessages.SelectResourcesDialog_nFilesSelected, Integer.valueOf(checkedFiles)));
		}
		fCountIndication.setText(buffer.toString());

		Button okButton= getButton(IDialogConstants.OK_ID);
		if (okButton != null)
			okButton.setEnabled(checkedFiles > 0);
	}
}