/*
    * Copyright (c) 2020 bahlef.
    * All rights reserved. This program and the accompanying materials
    * are made available under the terms of the Eclipse Public License v2.0
    * which accompanies this distribution, and is available at
    * http://www.eclipse.org/legal/epl-v20.html
    * Contributors:
    * bahlef - initial API and implementation and/or initial documentation
    */
  package de.funfried.netbeans.plugins.external.formatter.java.spring;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Objects;
  import java.util.SortedSet;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import org.apache.commons.collections4.CollectionUtils;
  import org.apache.commons.lang3.tuple.Pair;
  import org.eclipse.jdt.core.formatter.CodeFormatter;
  import org.eclipse.jface.text.Document;
  import org.eclipse.jface.text.IDocument;
  import org.eclipse.jface.text.IRegion;
  import org.eclipse.jface.text.Region;
  import org.eclipse.text.edits.TextEdit;
  import org.netbeans.api.annotations.common.CheckForNull;
  import org.netbeans.api.annotations.common.NonNull;
  
  import de.funfried.netbeans.plugins.external.formatter.exceptions.FormattingFailedException;
  import io.spring.javaformat.formatter.Formatter;
  
  /**
   * Delegation class to the Spring formatter implementation.
   *
   * @author bahlef
   */
  public final class SpringJavaFormatterWrapper {
  	/** Use to specify the kind of the code snippet to format. */
  	private static final int FORMATTER_OPTS = CodeFormatter.K_COMPILATION_UNIT | CodeFormatter.F_INCLUDE_COMMENTS /* + CodeFormatter.K_CLASS_BODY_DECLARATIONS + CodeFormatter.K_STATEMENTS */;
  
  	/** The Spring {@link Formatter}. */
  	private final Formatter formatter = new Formatter();
  
  	/**
  	 * Package private Constructor for creating a new instance of {@link SpringJavaFormatterWrapper}.
  	 */
  	SpringJavaFormatterWrapper() {
  	}
  
  	/**
  	 * Formats the given {@code code} with the given configurations and returns
  	 * the formatted code.
  	 *
  	 * @param code the unformatted code
  	 * @param lineFeed the line feed to use for formatting
  	 * @param changedElements a {@link SortedSet} containing ranges as {@link Pair}
  	 *        objects defining the offsets which should be formatted
  	 *
  	 * @return the formatted code
  	 *
  	 * @throws FormattingFailedException if the external formatter failed to format the given code
  	 */
  	@CheckForNull
  	public String format(String code, String lineFeed, SortedSet<Pair<Integer, Integer>> changedElements) throws FormattingFailedException {
  		if (code == null) {
  			return null;
  		}
  
  		int codeLength = code.length();
  
  		List<IRegion> regions = new ArrayList<>();
  		if (changedElements == null) {
  			regions.add(new Region(0, codeLength));
  		} else if (!CollectionUtils.isEmpty(changedElements)) {
  			for (Pair<Integer, Integer> changedElement : changedElements) {
  				int length = (changedElement.getRight() - changedElement.getLeft()) + 1;
  				if (length > codeLength) {
  					length = codeLength;
  				}
  
  				regions.add(new Region(changedElement.getLeft(), length));
  			}
  		} else {
  			// empty changed elements means nothing's left which can be formatted due to guarded sections
  			return code;
  		}
  
  		return format(code, regions.toArray(new IRegion[regions.size()]), lineFeed);
  	}
  
  	/**
  	 * Formats the given {@code code} with the given configurations and returns
  	 * the formatted code.
  	 *
  	 * @param formatter the {@link CodeFormatter}
  	 * @param code the unformatted code
  	 * @param lineFeed the line feed to use for formatting
  	 * @param regions an array containing {@link IRegion} objects defining the offsets which should be formatted
 	 *
 	 * @return the formatted code
 	 *
 	 * @throws FormattingFailedException if the external formatter failed to format the given code
 	 */
 	@CheckForNull
 	private String format(@NonNull String code, @NonNull IRegion[] regions, String lineFeed) throws FormattingFailedException {
 		String formattedCode = null;
 
 		try {
 			TextEdit te = formatter.format(FORMATTER_OPTS, code, regions, 0, lineFeed);
 			//TextEdit te = formatter.format(code, regions, lineFeed);
 			if (te != null && te.getChildrenSize() > 0) {
 				IDocument dc = new Document(code);
 				te.apply(dc);
 
 				formattedCode = dc.get();
 
 				if (Objects.equals(code, formattedCode)) {
 					return null;
 				}
 			}
 		} catch (FormattingFailedException | IllegalArgumentException ex) {
 			throw ex;
 		} catch (Exception ex) {
 			Logger.getLogger(SpringJavaFormatterWrapper.class.getName()).log(Level.SEVERE, "Formatting ran into", ex);
 
 			throw new FormattingFailedException(ex);
 		}
 
 		return formattedCode;
 	}
 }