/*
 * Copyright (C) 2009, Christian Halstrick <christian.halstrick@sap.com>
 * Copyright (C) 2009, Johannes E. Schindelin
 * Copyright (C) 2009, Johannes Schindelin <johannes.schindelin@gmx.de>
 * and other copyright owners as documented in the project's IP log.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
 * available at http://www.eclipse.org/org/documents/edl-v10.php
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * - Neither the name of the Eclipse Foundation, Inc. nor the
 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.eclipse.jgit.pgm;

import static org.eclipse.jgit.lib.Constants.HEAD;
import static org.eclipse.jgit.lib.Constants.OBJECT_ID_STRING_LENGTH;

import java.io.BufferedOutputStream;
import java.io.PrintWriter;
import java.text.MessageFormat;
import java.util.List;
import java.util.concurrent.TimeUnit;

import org.eclipse.jgit.diff.DiffAlgorithm;
import org.eclipse.jgit.diff.DiffAlgorithm.SupportedAlgorithm;
import org.eclipse.jgit.diff.DiffEntry;
import org.eclipse.jgit.diff.DiffFormatter;
import org.eclipse.jgit.diff.RawTextComparator;
import org.eclipse.jgit.diff.RenameDetector;
import org.eclipse.jgit.dircache.DirCacheIterator;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.TextProgressMonitor;
import org.eclipse.jgit.pgm.opt.PathTreeFilterHandler;
import org.eclipse.jgit.treewalk.AbstractTreeIterator;
import org.eclipse.jgit.treewalk.CanonicalTreeParser;
import org.eclipse.jgit.treewalk.FileTreeIterator;
import org.eclipse.jgit.treewalk.filter.TreeFilter;
import org.kohsuke.args4j.Argument;
import org.kohsuke.args4j.Option;

@Command(common = true, usage = "usage_ShowDiffs")
class Diff extends TextBuiltin {
	private final DiffFormatter diffFmt = new DiffFormatter( //
			new BufferedOutputStream(System.out));

	@Argument(index = 0, metaVar = "metaVar_treeish")
	private AbstractTreeIterator oldTree;

	@Argument(index = 1, metaVar = "metaVar_treeish")
	private AbstractTreeIterator newTree;

	@Option(name = "--cached", usage = "usage_cached")
	private boolean cached;

	@Option(name = "--", metaVar = "metaVar_paths", multiValued = true, handler = PathTreeFilterHandler.class)
	private TreeFilter pathFilter = TreeFilter.ALL;

	// BEGIN -- Options shared with Log
	@Option(name = "-p", usage = "usage_showPatch")
	boolean showPatch;

	@Option(name = "-M", usage = "usage_detectRenames")
	private Boolean detectRenames;

	@Option(name = "--no-renames", usage = "usage_noRenames")
	void noRenames(@SuppressWarnings("unused") boolean on) {
		detectRenames = Boolean.FALSE;
	}

	@Option(name = "--algorithm", metaVar = "metaVar_diffAlg", usage = "usage_diffAlgorithm")
	void setAlgorithm(SupportedAlgorithm s) {
		diffFmt.setDiffAlgorithm(DiffAlgorithm.getAlgorithm(s));
	}

	@Option(name = "-l", usage = "usage_renameLimit")
	private Integer renameLimit;

	@Option(name = "--name-status", usage = "usage_nameStatus")
	private boolean showNameAndStatusOnly;

	@Option(name = "--ignore-space-at-eol")
	void ignoreSpaceAtEol(@SuppressWarnings("unused") boolean on) {
		diffFmt.setDiffComparator(RawTextComparator.WS_IGNORE_TRAILING);
	}

	@Option(name = "--ignore-leading-space")
	void ignoreLeadingSpace(@SuppressWarnings("unused") boolean on) {
		diffFmt.setDiffComparator(RawTextComparator.WS_IGNORE_LEADING);
	}

	@Option(name = "-b", aliases = { "--ignore-space-change" })
	void ignoreSpaceChange(@SuppressWarnings("unused") boolean on) {
		diffFmt.setDiffComparator(RawTextComparator.WS_IGNORE_CHANGE);
	}

	@Option(name = "-w", aliases = { "--ignore-all-space" })
	void ignoreAllSpace(@SuppressWarnings("unused") boolean on) {
		diffFmt.setDiffComparator(RawTextComparator.WS_IGNORE_ALL);
	}

	@Option(name = "-U", aliases = { "--unified" }, metaVar = "metaVar_linesOfContext")
	void unified(int lines) {
		diffFmt.setContext(lines);
	}

	@Option(name = "--abbrev", metaVar = "metaVar_n")
	void abbrev(int lines) {
		diffFmt.setAbbreviationLength(lines);
	}

	@Option(name = "--full-index")
	void abbrev(@SuppressWarnings("unused") boolean on) {
		diffFmt.setAbbreviationLength(OBJECT_ID_STRING_LENGTH);
	}

	@Option(name = "--src-prefix", usage = "usage_srcPrefix")
	void sourcePrefix(String path) {
		diffFmt.setOldPrefix(path);
	}

	@Option(name = "--dst-prefix", usage = "usage_dstPrefix")
	void dstPrefix(String path) {
		diffFmt.setNewPrefix(path);
	}

	@Option(name = "--no-prefix", usage = "usage_noPrefix")
	void noPrefix(@SuppressWarnings("unused") boolean on) {
		diffFmt.setOldPrefix("");
		diffFmt.setNewPrefix("");
	}

	// END -- Options shared with Log

	@Override
	protected void run() throws Exception {
		diffFmt.setRepository(db);
		try {
			if (cached) {
				if (oldTree == null) {
					ObjectId head = db.resolve(HEAD + "^{tree}");
					if (head == null)
						die(MessageFormat.format(CLIText.get().notATree, HEAD));
					CanonicalTreeParser p = new CanonicalTreeParser();
					ObjectReader reader = db.newObjectReader();
					try {
						p.reset(reader, head);
					} finally {
						reader.release();
					}
					oldTree = p;
				}
				newTree = new DirCacheIterator(db.readDirCache());
			} else if (oldTree == null) {
				oldTree = new DirCacheIterator(db.readDirCache());
				newTree = new FileTreeIterator(db);
			} else if (newTree == null)
				newTree = new FileTreeIterator(db);

			TextProgressMonitor pm = new TextProgressMonitor();
			pm.setDelayStart(2, TimeUnit.SECONDS);
			diffFmt.setProgressMonitor(pm);
			diffFmt.setPathFilter(pathFilter);
			if (detectRenames != null)
				diffFmt.setDetectRenames(detectRenames.booleanValue());
			if (renameLimit != null && diffFmt.isDetectRenames()) {
				RenameDetector rd = diffFmt.getRenameDetector();
				rd.setRenameLimit(renameLimit.intValue());
			}

			if (showNameAndStatusOnly) {
				nameStatus(out, diffFmt.scan(oldTree, newTree));
				out.flush();

			} else {
				diffFmt.format(oldTree, newTree);
				diffFmt.flush();
			}
		} finally {
			diffFmt.release();
		}
	}

	static void nameStatus(PrintWriter out, List<DiffEntry> files) {
		for (DiffEntry ent : files) {
			switch (ent.getChangeType()) {
			case ADD:
				out.println("A\t" + ent.getNewPath());
				break;
			case DELETE:
				out.println("D\t" + ent.getOldPath());
				break;
			case MODIFY:
				out.println("M\t" + ent.getNewPath());
				break;
			case COPY:
				out.format("C%1$03d\t%2$s\t%3$s", ent.getScore(), //
						ent.getOldPath(), ent.getNewPath());
				out.println();
				break;
			case RENAME:
				out.format("R%1$03d\t%2$s\t%3$s", ent.getScore(), //
						ent.getOldPath(), ent.getNewPath());
				out.println();
				break;
			}
		}
	}
}