/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.scm.provider.git.gitexe.command.diff;

import java.io.File;

import org.apache.commons.lang3.StringUtils;
import org.apache.maven.scm.ScmException;
import org.apache.maven.scm.ScmFileSet;
import org.apache.maven.scm.ScmVersion;
import org.apache.maven.scm.command.diff.AbstractDiffCommand;
import org.apache.maven.scm.command.diff.DiffScmResult;
import org.apache.maven.scm.provider.ScmProviderRepository;
import org.apache.maven.scm.provider.git.command.GitCommand;
import org.apache.maven.scm.provider.git.command.diff.GitDiffConsumer;
import org.apache.maven.scm.provider.git.gitexe.command.GitCommandLineUtils;
import org.codehaus.plexus.util.cli.CommandLineUtils;
import org.codehaus.plexus.util.cli.Commandline;

/**
 * @author <a href="mailto:struberg@yahoo.de">Mark Struberg</a>
 */
public class GitDiffCommand extends AbstractDiffCommand implements GitCommand {
    /**
     * {@inheritDoc}
     */
    protected DiffScmResult executeDiffCommand(
            ScmProviderRepository repo, ScmFileSet fileSet, ScmVersion startVersion, ScmVersion endVersion)
            throws ScmException {
        GitDiffConsumer consumer = new GitDiffConsumer(fileSet.getBasedir());
        CommandLineUtils.StringStreamConsumer stderr = new CommandLineUtils.StringStreamConsumer();
        int exitCode;

        Commandline clDiff2Index = createCommandLine(fileSet.getBasedir(), startVersion, endVersion, false);

        exitCode = GitCommandLineUtils.execute(clDiff2Index, consumer, stderr);
        if (exitCode != 0) {
            return new DiffScmResult(
                    clDiff2Index.toString(), "The git-diff command failed.", stderr.getOutput(), false);
        }

        Commandline clDiff2Head = createCommandLine(fileSet.getBasedir(), startVersion, endVersion, true);

        exitCode = GitCommandLineUtils.execute(clDiff2Head, consumer, stderr);
        if (exitCode != 0) {
            return new DiffScmResult(clDiff2Head.toString(), "The git-diff command failed.", stderr.getOutput(), false);
        }

        return new DiffScmResult(
                clDiff2Index.toString(), consumer.getChangedFiles(), consumer.getDifferences(), consumer.getPatch());
    }

    // ----------------------------------------------------------------------
    //
    // ----------------------------------------------------------------------

    /**
     * @param cached if <code>true</code> diff the index to the head, else diff the tree to the index
     */
    public static Commandline createCommandLine(
            File workingDirectory, ScmVersion startVersion, ScmVersion endVersion, boolean cached) {
        Commandline cl = GitCommandLineUtils.getBaseGitCommandLine(workingDirectory, "diff");

        if (cached) {
            cl.createArg().setValue("--cached");
        }

        if (startVersion != null && StringUtils.isNotEmpty(startVersion.getName())) {
            cl.createArg().setValue(startVersion.getName());
        }
        if (endVersion != null && StringUtils.isNotEmpty(endVersion.getName())) {
            cl.createArg().setValue(endVersion.getName());
        }

        return cl;
    }

    /**
     * Create a CommandLine for executing a git diff --raw command.
     * This will output all affected files affected since the given commit and
     * the current version.
     *
     * @param workingDirectory
     */
    public static Commandline createDiffRawCommandLine(File workingDirectory, String sha1) {
        Commandline cl = GitCommandLineUtils.getBaseGitCommandLine(workingDirectory, "diff");

        cl.createArg().setValue("--raw");
        cl.createArg().setValue(sha1);

        return cl;
    }
}
