/*
 * Copyright 2005 the original author or authors.
 * 
 * Licensed 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.wamblee.test;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;

import junit.framework.Assert;

/**
 * @author Erik Test support utility.
 */
public final class TestSupport {
    
    /**
     * Disabled constructor.
     *
     */
    private TestSupport() { 
        // Empty
    }

    /**
     * Obtain root directory of JUnit tests.
     * 
     * @return Directory name.
     */
    public static File getTestRootDir() {
        return new File("testdata");
    }

    /**
     * Returns a temporary directory.
     * 
     * @return Temporary directory.
     */
    public static File getTmpDir() {
        return new File(getTestRootDir(), "tmpdir");
    }

    /**
     * Recursively remove a directory.
     * 
     * @param aSrc
     *            Directoryto remove.
     */
    public static void removeDir(File aSrc) {
        if (!aSrc.exists()) {
            return;
        }
        Assert.assertTrue(aSrc.getPath(), aSrc.isDirectory());
        File[] files = aSrc.listFiles();
        for (int i = 0; i < files.length; i++) {
            File file = files[i];
            if (file.isDirectory()) {
                removeDir(file);
            } else {
                Assert.assertTrue(file.getPath(), file.delete());
            }
        }
        Assert.assertTrue(aSrc.getPath(), aSrc.delete());
    }

    /**
     * Recursively copy a directory.
     * 
     * @param aSrc
     *            Source directory
     * @param aTarget
     *            Target directory.
     */
    public static void copyDir(File aSrc, File aTarget) {
        Assert.assertTrue(aSrc.isDirectory());
        Assert.assertTrue(!aTarget.exists());

        aTarget.mkdirs();

        File[] files = aSrc.listFiles();
        for (int i = 0; i < files.length; i++) {
            File file = files[i];
            if (file.isDirectory()) {
                if (!file.getName().equals(".svn")) {
                    copyDir(new File(aSrc, file.getName()), new File(aTarget,
                            file.getName()));
                }
            } else {
                copyFile(file, new File(aTarget, file.getName()));
            }
        }
    }

    /**
     * Copy a file. If copying fails then the testcase will fail.
     * 
     * @param aSrc
     *            Source file.
     * @param aTarget
     *            Target file.
     */
    public static void copyFile(File aSrc, File aTarget) {

        try {
            FileInputStream fis = new FileInputStream(aSrc);
            FileOutputStream fos = new FileOutputStream(aTarget);
            FileChannel fcin = fis.getChannel();
            FileChannel fcout = fos.getChannel();

            // map input file

            MappedByteBuffer mbb = fcin.map(FileChannel.MapMode.READ_ONLY, 0,
                    fcin.size());

            // do the file copy
            fcout.write(mbb);

            // finish up

            fcin.close();
            fcout.close();
            fis.close();
            fos.close();
        } catch (IOException e) {
            Assert.assertTrue("Copying file " + aSrc.getPath() + " to "
                    + aTarget.getPath() + " failed.", false);
        }
    }

    /**
     * Remove a file or directory. The test case will fail if this does not
     * succeed.
     * 
     * @param aFile
     *            entry to remove.
     */
    public static void delete(File aFile) {
        Assert
                .assertTrue("Could not delete " + aFile.getPath(), aFile
                        .delete());
    }

    /**
     * Remove all files within a given directory including the directory itself.
     * This only attempts to remove regular files and not directories within the
     * directory. If the directory contains a nested directory, the deletion
     * will fail. The test case will fail if this fails.
     * 
     * @param aDir
     *            Directory to remove.
     */
    public static void deleteDir(File aDir) {
        cleanDir(aDir);
        delete(aDir);
    }

    /**
     * Remove all regular files within a given directory.
     * 
     * @param outputDirName
     */
    public static void cleanDir(File aDir) {
        if (!aDir.exists()) {
            return; // nothing to do.
        }
        File[] entries = aDir.listFiles();
        for (int i = 0; i < entries.length; i++) {
            File file = entries[i];
            if (file.isFile()) {
                Assert.assertTrue("Could not delete " + entries[i].getPath(),
                        entries[i].delete());
            }
        }
    }

    /**
     * Creates directory if it does not already exist. The test case will fail
     * if the directory cannot be created.
     * 
     * @param aDir
     *            Directory to create.
     */
    public static void createDir(File aDir) {
        if (aDir.isDirectory()) {
            return; // nothing to do.
        }
        Assert.assertTrue("Could not create directory " + aDir.getPath(), aDir
                .mkdirs());
    }
}