/*
 * Copyright  2003-2005 The Apache Software Foundation
 *
 *  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.apache.tools.ant.util;

import org.apache.tools.ant.Project;
import org.apache.tools.ant.ProjectComponent;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.ResourceFactory;
import org.apache.tools.ant.types.selectors.SelectorUtils;

import java.io.File;
import java.util.Vector;

/**
 * This class provides utility methods to process Resources.
 *
 * @since Ant 1.5.2
 */
public class ResourceUtils {

    /** Utilities used for file operations */
    private static final FileUtils FILE_UTILS = FileUtils.getFileUtils();

    /**
     * Tells which source files should be reprocessed based on the
     * last modification date of target files.
     * @param logTo where to send (more or less) interesting output.
     * @param source array of resources bearing relative path and last
     * modification date.
     * @param mapper filename mapper indicating how to find the target
     * files.
     * @param targets object able to map as a resource a relative path
     * at <b>destination</b>.
     * @return array containing the source files which need to be
     * copied or processed, because the targets are out of date or do
     * not exist.
     */
    public static Resource[] selectOutOfDateSources(ProjectComponent logTo,
                                                    Resource[] source,
                                                    FileNameMapper mapper,
                                                    ResourceFactory targets) {
        return selectOutOfDateSources(logTo, source, mapper, targets,
                                      FILE_UTILS.getFileTimestampGranularity());
    }

    /**
     * Tells which source files should be reprocessed based on the
     * last modification date of target files.
     * @param logTo where to send (more or less) interesting output.
     * @param source array of resources bearing relative path and last
     * modification date.
     * @param mapper filename mapper indicating how to find the target
     * files.
     * @param targets object able to map as a resource a relative path
     * at <b>destination</b>.
     * @param granularity The number of milliseconds leeway to give
     * before deciding a target is out of date.
     * @return array containing the source files which need to be
     * copied or processed, because the targets are out of date or do
     * not exist.
     * @since Ant 1.6.2
     */
    public static Resource[] selectOutOfDateSources(ProjectComponent logTo,
                                                    Resource[] source,
                                                    FileNameMapper mapper,
                                                    ResourceFactory targets,
                                                    long granularity) {
        long now = (new java.util.Date()).getTime() + granularity;

        Vector vresult = new Vector();
        for (int counter = 0; counter < source.length; counter++) {
            if (source[counter].getLastModified() > now) {
                logTo.log("Warning: " + source[counter].getName()
                         + " modified in the future.",
                         Project.MSG_WARN);
            }
            String[] targetnames =
                mapper.mapFileName(source[counter].getName()
                                   .replace('/', File.separatorChar));
            if (targetnames != null) {
                boolean added = false;
                StringBuffer targetList = new StringBuffer();
                for (int ctarget = 0; !added && ctarget < targetnames.length;
                     ctarget++) {
                    Resource atarget =
                        targets.getResource(targetnames[ctarget]
                                            .replace(File.separatorChar, '/'));
                    // if the target does not exist, or exists and
                    // is older than the source, then we want to
                    // add the resource to what needs to be copied
                    if (!atarget.isExists()) {
                        logTo.log(source[counter].getName() + " added as "
                                  + atarget.getName()
                                  + " doesn\'t exist.", Project.MSG_VERBOSE);
                        vresult.addElement(source[counter]);
                        added = true;
                    } else if (!atarget.isDirectory()
                               && SelectorUtils.isOutOfDate(source[counter],
                                                         atarget,
                                                         (int) granularity)) {
                        logTo.log(source[counter].getName() + " added as "
                                  + atarget.getName()
                                  + " is outdated.", Project.MSG_VERBOSE);
                        vresult.addElement(source[counter]);
                        added = true;
                    } else {
                        if (targetList.length() > 0) {
                            targetList.append(", ");
                        }
                        targetList.append(atarget.getName());
                    }
                }
                if (!added) {
                    logTo.log(source[counter].getName()
                              + " omitted as " + targetList.toString()
                              + (targetnames.length == 1 ? " is" : " are ")
                              + " up to date.", Project.MSG_VERBOSE);
                }
            } else {
                logTo.log(source[counter].getName()
                          + " skipped - don\'t know how to handle it",
                          Project.MSG_VERBOSE);
            }
        }
        Resource[] result = new Resource[vresult.size()];
        vresult.copyInto(result);
        return result;
    }
}
