/*
 * 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.commons.vfs2.tasks;

import org.apache.commons.logging.Log;
import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystemException;
import org.apache.commons.vfs2.impl.StandardFileSystemManager;
import org.apache.tools.ant.BuildEvent;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.SubBuildListener;
import org.apache.tools.ant.Task;

/**
 * Base class for the VFS Ant tasks. Takes care of creating a FileSystemManager, and for cleaning it up at the end of
 * the build. Also provides some utility methods.
 */
public class VfsTask extends Task {

    /**
     * A commons-logging wrapper for Ant logging.
     */
    private final class AntLogger implements Log {
        @Override
        public void debug(final Object o) {
            log(String.valueOf(o), Project.MSG_DEBUG);
        }

        @Override
        public void debug(final Object o, final Throwable throwable) {
            debug(o);
        }

        @Override
        public void error(final Object o) {
            log(String.valueOf(o), Project.MSG_ERR);
        }

        @Override
        public void error(final Object o, final Throwable throwable) {
            error(o);
        }

        @Override
        public void fatal(final Object o) {
            log(String.valueOf(o), Project.MSG_ERR);
        }

        @Override
        public void fatal(final Object o, final Throwable throwable) {
            fatal(o);
        }

        @Override
        public void info(final Object o) {
            log(String.valueOf(o), Project.MSG_INFO);
        }

        @Override
        public void info(final Object o, final Throwable throwable) {
            info(o);
        }

        @Override
        public boolean isDebugEnabled() {
            return true;
        }

        @Override
        public boolean isErrorEnabled() {
            return true;
        }

        @Override
        public boolean isFatalEnabled() {
            return true;
        }

        @Override
        public boolean isInfoEnabled() {
            return true;
        }

        @Override
        public boolean isTraceEnabled() {
            return false;
        }

        @Override
        public boolean isWarnEnabled() {
            return true;
        }

        @Override
        public void trace(final Object o) {
            // no-op
        }

        @Override
        public void trace(final Object o, final Throwable throwable) {
            // no-op
        }

        @Override
        public void warn(final Object o) {
            log(String.valueOf(o), Project.MSG_WARN);
        }

        @Override
        public void warn(final Object o, final Throwable throwable) {
            warn(o);
        }
    }

    /**
     * Closes the VFS manager when the project finishes.
     */
    private final class CloseListener implements SubBuildListener {
        @Override
        public void buildFinished(final BuildEvent event) {
            closeManager();
        }

        @Override
        public void buildStarted(final BuildEvent event) {
            // no-op
        }

        @Override
        public void messageLogged(final BuildEvent event) {
            // no-op
        }

        @Override
        public void subBuildFinished(final BuildEvent buildEvent) {
            closeManager();
        }

        @Override
        public void subBuildStarted(final BuildEvent buildEvent) {
            // no-op
        }

        @Override
        public void targetFinished(final BuildEvent event) {
            // no-op
        }

        @Override
        public void targetStarted(final BuildEvent event) {
            // no-op
        }

        @Override
        public void taskFinished(final BuildEvent event) {
            // no-op
        }

        @Override
        public void taskStarted(final BuildEvent event) {
            // no-op
        }
    }

    private static StandardFileSystemManager manager;

    /**
     * Constructs a new instance.
     */
    public VfsTask() {
        // empty
    }

    /**
     * Close the manager
     */
    protected void closeManager() {
        if (manager != null) {
            manager.close();
            manager = null;
        }
    }

    /**
     * Resolves a URI to a file, relative to the project's base directory.
     *
     * @param uri The URI to resolve.
     * @return resolved file object.
     * @throws FileSystemException If an error occurred.
     */
    protected FileObject resolveFile(final String uri) throws FileSystemException {
        if (manager == null) {
            final StandardFileSystemManager mngr = new StandardFileSystemManager();
            mngr.setLogger(new AntLogger());
            mngr.init();
            manager = mngr;
            getProject().addBuildListener(new CloseListener());
        }
        return manager.resolveFile(getProject().getBaseDir(), uri);
    }
}