/*******************************************************************************
 * Copyright (c) 2000, 2011 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.jdt.internal.ui.preferences;

import java.util.Iterator;

import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.RGB;

import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.preference.PreferenceConverter;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.DefaultInformationControl;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextHover;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.contentassist.ContentAssistant;
import org.eclipse.jface.text.contentassist.IContentAssistant;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.jface.text.templates.TemplateContextType;
import org.eclipse.jface.text.templates.TemplateVariableResolver;

import org.eclipse.ui.texteditor.ITextEditor;

import org.eclipse.jdt.ui.PreferenceConstants;
import org.eclipse.jdt.ui.text.IColorManager;
import org.eclipse.jdt.ui.text.IJavaPartitions;
import org.eclipse.jdt.ui.text.JavaTextTools;

import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.text.JavaWordFinder;
import org.eclipse.jdt.internal.ui.text.SimpleJavaSourceViewerConfiguration;
import org.eclipse.jdt.internal.ui.text.template.preferences.TemplateVariableProcessor;


public class CodeTemplateSourceViewerConfiguration extends SimpleJavaSourceViewerConfiguration {

	private static class TemplateVariableTextHover implements ITextHover {

		private TemplateVariableProcessor fProcessor;

		/**
		 * @param processor the template variable processor
		 */
		public TemplateVariableTextHover(TemplateVariableProcessor processor) {
			fProcessor= processor;
		}

		@Override
		public String getHoverInfo(ITextViewer textViewer, IRegion subject) {
			try {
				IDocument doc= textViewer.getDocument();
				int offset= subject.getOffset();
				if (offset >= 2 && "${".equals(doc.get(offset-2, 2))) { //$NON-NLS-1$
					String varName= doc.get(offset, subject.getLength());
					TemplateContextType contextType= fProcessor.getContextType();
					if (contextType != null) {
						Iterator<TemplateVariableResolver> iter= contextType.resolvers();
						while (iter.hasNext()) {
							TemplateVariableResolver var= iter.next();
							if (varName.equals(var.getType())) {
								return var.getDescription();
							}
						}
					}
				}
			} catch (BadLocationException e) {
			}
			return null;
		}

		@Override
		public IRegion getHoverRegion(ITextViewer textViewer, int offset) {
			if (textViewer != null) {
				return JavaWordFinder.findWord(textViewer.getDocument(), offset);
			}
			return null;
		}

	}

	private final TemplateVariableProcessor fProcessor;

	public CodeTemplateSourceViewerConfiguration(IColorManager colorManager, IPreferenceStore store, ITextEditor editor, TemplateVariableProcessor processor) {
		super(colorManager, store, editor, IJavaPartitions.JAVA_PARTITIONING, false);
		fProcessor= processor;
	}

	/*
	 * @see SourceViewerConfiguration#getContentAssistant(ISourceViewer)
	 */
	@Override
	public IContentAssistant getContentAssistant(ISourceViewer sourceViewer) {

		IPreferenceStore store= JavaPlugin.getDefault().getPreferenceStore();
		JavaTextTools textTools= JavaPlugin.getDefault().getJavaTextTools();
		IColorManager manager= textTools.getColorManager();


		ContentAssistant assistant= new ContentAssistant();
		assistant.setContentAssistProcessor(fProcessor, IDocument.DEFAULT_CONTENT_TYPE);
			// Register the same processor for strings and single line comments to get code completion at the start of those partitions.
		assistant.setContentAssistProcessor(fProcessor, IJavaPartitions.JAVA_STRING);
		assistant.setContentAssistProcessor(fProcessor, IJavaPartitions.JAVA_CHARACTER);
		assistant.setContentAssistProcessor(fProcessor, IJavaPartitions.JAVA_SINGLE_LINE_COMMENT);
		assistant.setContentAssistProcessor(fProcessor, IJavaPartitions.JAVA_MULTI_LINE_COMMENT);
		assistant.setContentAssistProcessor(fProcessor, IJavaPartitions.JAVA_DOC);

		assistant.enableAutoInsert(store.getBoolean(PreferenceConstants.CODEASSIST_AUTOINSERT));
		assistant.enableAutoActivation(store.getBoolean(PreferenceConstants.CODEASSIST_AUTOACTIVATION));
		assistant.setAutoActivationDelay(store.getInt(PreferenceConstants.CODEASSIST_AUTOACTIVATION_DELAY));
		assistant.setProposalPopupOrientation(IContentAssistant.PROPOSAL_OVERLAY);
		assistant.setContextInformationPopupOrientation(IContentAssistant.CONTEXT_INFO_ABOVE);
		assistant.setInformationControlCreator(parent -> new DefaultInformationControl(parent, JavaPlugin.getAdditionalInfoAffordanceString()));

		Color background= getColor(store, PreferenceConstants.CODEASSIST_PARAMETERS_BACKGROUND, manager);
		assistant.setContextInformationPopupBackground(background);
		assistant.setContextSelectorBackground(background);

		Color foreground= getColor(store, PreferenceConstants.CODEASSIST_PARAMETERS_FOREGROUND, manager);
		assistant.setContextInformationPopupForeground(foreground);
		assistant.setContextSelectorForeground(foreground);

		return assistant;
	}

	private Color getColor(IPreferenceStore store, String key, IColorManager manager) {
		RGB rgb= PreferenceConverter.getColor(store, key);
		return manager.getColor(rgb);
	}

	/*
	 * @see SourceViewerConfiguration#getTextHover(ISourceViewer, String, int)
	 * @since 2.1
	 */
	@Override
	public ITextHover getTextHover(ISourceViewer sourceViewer, String contentType, int stateMask) {
		return new TemplateVariableTextHover(fProcessor);
	}

}
