/*=============================================================================#
 # Copyright (c) 2008, 2019 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.ltk.ui;

import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.ui.part.ShowInContext;

import org.eclipse.statet.ltk.ast.core.util.AstSelection;
import org.eclipse.statet.ltk.core.LTKUtils;
import org.eclipse.statet.ltk.model.core.IModelManager;
import org.eclipse.statet.ltk.model.core.elements.IModelElement;
import org.eclipse.statet.ltk.model.core.elements.ISourceStructElement;
import org.eclipse.statet.ltk.model.core.elements.ISourceUnit;
import org.eclipse.statet.ltk.model.core.elements.ISourceUnitModelInfo;


/**
 * Data/state of LTK based input of a view/editor.
 * 
 * E.g. used for {@link ISelectionWithElementInfoListener} or {@link ShowInContext}
 */
public class LTKInputData implements ISelection {
	
	
	protected ISourceUnit inputElement;
	protected ISourceUnitModelInfo inputInfo;
	
	protected ISelectionProvider selectionProvider;
	protected ISelection selection;
	protected AstSelection astSelection;
	protected ISourceStructElement modelSelection;
	
	
	public LTKInputData(final ISourceUnit inputElement, final ISelection selection) {
		this.inputElement= inputElement;
		this.selection= selection;
	}
	
	public LTKInputData(final ISourceUnit inputElement, final ISelectionProvider selectionProvider) {
		this.inputElement= inputElement;
		this.selectionProvider= selectionProvider;
		this.selection= selectionProvider.getSelection();
	}
	
	
	public boolean update() {
		if (this.selectionProvider != null) {
			final ISelection selection= this.selectionProvider.getSelection();
			if (!selection.equals(this.selection)) {
				this.astSelection= null;
				this.modelSelection= null;
			}
			return true;
		}
		return false;
	}
	
	public IModelElement getInputElement() {
		return this.inputElement;
	}
	
	public ISourceUnitModelInfo getInputInfo() {
		if (this.inputInfo == null) {
			this.inputInfo= this.inputElement.getModelInfo(null, IModelManager.NONE, new NullProgressMonitor());
		}
		return this.inputInfo;
	}
	
	
	@Override
	public boolean isEmpty() {
		return this.selection.isEmpty();
	}
	
	public ISelection getSelection() {
		return this.selection;
	}
	
	public AstSelection getAstSelection() {
		if (this.astSelection == null) {
			if (this.selection instanceof ITextSelection && getInputInfo() != null) {
				final ITextSelection textSelection= (ITextSelection) this.selection;
				this.astSelection= AstSelection.search(getInputInfo().getAst().getRoot(),
						textSelection.getOffset(), textSelection.getOffset()+textSelection.getLength(),
						AstSelection.MODE_COVERING_SAME_LAST );
			}
		}
		return this.astSelection;
	}
	
	public ISourceStructElement getModelSelection() {
		if (this.modelSelection == null) {
			if (this.selection instanceof ITextSelection && getInputInfo() != null) {
				final ITextSelection textSelection= (ITextSelection) this.selection;
				this.modelSelection= LTKUtils.getCoveringSourceElement(getInputInfo().getSourceElement(), textSelection.getOffset(), textSelection.getOffset()+textSelection.getLength());
			}
		}
		return this.modelSelection;
	}
	
	
	public boolean isStillValid() {
		return true;
	}
	
}