/*
    * Copyright (C) 2009, Christian Halstrick <christian.halstrick@sap.com>
    * Copyright (C) 2014, André de Oliveira <andre.oliveira@liferay.com> and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
   */
  
  package org.eclipse.jgit.merge;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.nio.charset.Charset;
  import java.util.List;
  
  import org.eclipse.jgit.diff.RawText;
  import org.eclipse.jgit.merge.MergeChunk.ConflictState;
  
  class MergeFormatterPass {
  
  	private final EolAwareOutputStream out;
  
  	private final MergeResult<RawText> res;
  
  	private final List<String> seqName;
  
  	private final Charset charset;
  
  	private final boolean threeWayMerge;
  
  	private String lastConflictingName; // is set to non-null whenever we are in
  										// a conflict
  
  	/**
  	 * @param out
  	 *            the {@link java.io.OutputStream} where to write the textual
  	 *            presentation
  	 * @param res
  	 *            the merge result which should be presented
  	 * @param seqName
  	 *            When a conflict is reported each conflicting range will get a
  	 *            name. This name is following the "&lt;&lt;&lt;&lt;&lt;&lt;&lt;
  	 *            " or "&gt;&gt;&gt;&gt;&gt;&gt;&gt; " conflict markers. The
  	 *            names for the sequences are given in this list
  	 * @param charset
  	 *            the character set used when writing conflict metadata
  	 */
  	MergeFormatterPass(OutputStream out, MergeResult<RawText> res,
  			List<String> seqName, Charset charset) {
  		this.out = new EolAwareOutputStream(out);
  		this.res = res;
  		this.seqName = seqName;
  		this.charset = charset;
  		this.threeWayMerge = (res.getSequences().size() == 3);
  	}
  
  	void formatMerge() throws IOException {
  		boolean missingNewlineAtEnd = false;
  		for (MergeChunk chunk : res) {
  			RawText seq = res.getSequences().get(chunk.getSequenceIndex());
  			writeConflictMetadata(chunk);
  			// the lines with conflict-metadata are written. Now write the chunk
  			for (int i = chunk.getBegin(); i < chunk.getEnd(); i++)
  				writeLine(seq, i);
  			missingNewlineAtEnd = seq.isMissingNewlineAtEnd();
  		}
  		// one possible leftover: if the merge result ended with a conflict we
  		// have to close the last conflict here
  		if (lastConflictingName != null)
  			writeConflictEnd();
  		if (!missingNewlineAtEnd)
  			out.beginln();
  	}
  
  	private void writeConflictMetadata(MergeChunk chunk) throws IOException {
  		if (lastConflictingName != null
  				&& chunk.getConflictState() != ConflictState.NEXT_CONFLICTING_RANGE) {
  			// found the end of an conflict
  			writeConflictEnd();
  		}
  		if (chunk.getConflictState() == ConflictState.FIRST_CONFLICTING_RANGE) {
  			// found the start of an conflict
  			writeConflictStart(chunk);
  		} else if (chunk.getConflictState() == ConflictState.NEXT_CONFLICTING_RANGE) {
  			// found another conflicting chunk
  			writeConflictChange(chunk);
  		}
  	}
  
  	private void writeConflictEnd() throws IOException {
  		writeln(">>>>>>> " + lastConflictingName); //$NON-NLS-1$
  		lastConflictingName = null;
  	}
  
  	private void writeConflictStart(MergeChunk chunk) throws IOException {
  		lastConflictingName = seqName.get(chunk.getSequenceIndex());
 		writeln("<<<<<<< " + lastConflictingName); //$NON-NLS-1$
 	}
 
 	private void writeConflictChange(MergeChunk chunk) throws IOException {
 		/*
 		 * In case of a non-three-way merge I'll add the name of the conflicting
 		 * chunk behind the equal signs. I also append the name of the last
 		 * conflicting chunk after the ending greater-than signs. If somebody
 		 * knows a better notation to present non-three-way merges - feel free
 		 * to correct here.
 		 */
 		lastConflictingName = seqName.get(chunk.getSequenceIndex());
 		writeln(threeWayMerge ? "=======" : "======= " //$NON-NLS-1$ //$NON-NLS-2$
 				+ lastConflictingName);
 	}
 
 	private void writeln(String s) throws IOException {
 		out.beginln();
 		out.write((s + "\n").getBytes(charset)); //$NON-NLS-1$
 	}
 
 	private void writeLine(RawText seq, int i) throws IOException {
 		out.beginln();
 		seq.writeLine(out, i);
 		// still BOL? It was a blank line. But writeLine won't lf, so we do.
 		if (out.isBeginln())
 			out.write('\n');
 	}
 }