/*
 *  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.tools.ant.taskdefs;


import java.io.File;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.ResourceCollection;
import org.apache.tools.ant.types.resources.FileProvider;
import org.apache.tools.ant.types.resources.FileResource;

/**
 * Abstract Base class for unpack tasks.
 *
 * @since Ant 1.5
 */

public abstract class Unpack extends Task {
    // CheckStyle:VisibilityModifier OFF - bc
    protected File source;
    protected File dest;
    protected Resource srcResource;
    // CheckStyle:VisibilityModifier ON

    /**
     * @deprecated since 1.5.x.
     *             setSrc(String) is deprecated and is replaced with
     *             setSrc(File) to make Ant's Introspection
     *             mechanism do the work and also to encapsulate operations on
     *             the type in its own class.
     * @ant.attribute ignore="true"
     * @param src a <code>String</code> value
     */
    public void setSrc(String src) {
        log("DEPRECATED - The setSrc(String) method has been deprecated."
            + " Use setSrc(File) instead.");
        setSrc(getProject().resolveFile(src));
    }

    /**
     * @deprecated since 1.5.x.
     *             setDest(String) is deprecated and is replaced with
     *             setDest(File) to make Ant's Introspection
     *             mechanism do the work and also to encapsulate operations on
     *             the type in its own class.
     * @ant.attribute ignore="true"
     * @param dest a <code>String</code> value
     */
    public void setDest(String dest) {
        log("DEPRECATED - The setDest(String) method has been deprecated."
            + " Use setDest(File) instead.");
        setDest(getProject().resolveFile(dest));
    }

    /**
     * The file to expand; required.
     * @param src file to expand
     */
    public void setSrc(File src) {
        setSrcResource(new FileResource(src));
    }

    /**
     * The resource to expand; required.
     * @param src resource to expand
     */
    public void setSrcResource(Resource src) {
        if (!src.isExists()) {
            throw new BuildException(
                "the archive " + src.getName() + " doesn't exist");
        }
        if (src.isDirectory()) {
            throw new BuildException(
                "the archive " + src.getName() + " can't be a directory");
        }
        FileProvider fp = src.as(FileProvider.class);
        if (fp != null) {
            source = fp.getFile();
        } else if (!supportsNonFileResources()) {
            throw new BuildException(
                "The source " + src.getName()
                + " is not a FileSystem "
                + "Only FileSystem resources are"
                + " supported.");
        }
        srcResource = src;
    }

    /**
     * Set the source Archive resource.
     * @param a the archive as a single element Resource collection.
     */
    public void addConfigured(ResourceCollection a) {
        if (a.size() != 1) {
            throw new BuildException("only single argument resource collections"
                                     + " are supported as archives");
        }
        setSrcResource(a.iterator().next());
    }

    /**
     * The destination file or directory; optional.
     * @param dest destination file or directory
     */
    public void setDest(File dest) {
        this.dest = dest;
    }

    private void validate() throws BuildException {
        if (srcResource == null) {
            throw new BuildException("No Src specified", getLocation());
        }

        if (dest == null) {
            if (source == null) {
                throw new BuildException("dest is required when using a non-filesystem source",
                                         getLocation());
            }
            dest = new File(source.getParent());
        }

        if (dest.isDirectory()) {
            String defaultExtension = getDefaultExtension();
            createDestFile(defaultExtension);
        }
    }

    private void createDestFile(String defaultExtension) {
        String sourceName = source == null
            ? getLastNamePart(srcResource) : source.getName();
        int len = sourceName.length();
        if (defaultExtension != null
            && len > defaultExtension.length()
            && defaultExtension.equalsIgnoreCase(
                sourceName.substring(len - defaultExtension.length()))) {
            dest = new File(dest, sourceName.substring(0,
                                                       len - defaultExtension.length()));
        } else {
            dest = new File(dest, sourceName);
        }
    }

    /**
     * Execute the task.
     * @throws BuildException on error
     */
    public void execute() throws BuildException {
        File savedDest = dest; // may be altered in validate
        try {
            validate();
            extract();
        } finally {
            dest = savedDest;
        }
    }

    /**
     * Get the extension.
     * This is to be overridden by subclasses.
     * @return the default extension.
     */
    protected abstract String getDefaultExtension();

    /**
     * Do the uncompressing.
     * This is to be overridden by subclasses.
     */
    protected abstract void extract();

    /**
     * Whether this task can deal with non-file resources.
     *
     * <p>This implementation returns false.</p>
     * @return false for this task.
     * @since Ant 1.7
     */
    protected boolean supportsNonFileResources() {
        return false;
    }

    private String getLastNamePart(Resource r) {
        String n = r.getName();
        int idx = n.lastIndexOf("/");
        return idx < 0 ? n : n.substring(idx + 1);
    }
}
