/*
 * 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.catalina.storeconfig;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.sql.Timestamp;

import org.apache.catalina.Globals;
import org.apache.tomcat.util.res.StringManager;

/**
 * Move server.xml or context.xml as backup
 */
public class StoreFileMover {

    /**
     * The string manager for this package.
     */
    protected static final StringManager sm = StringManager.getManager(Constants.Package);

    private String filename = "conf/server.xml";

    private String encoding = "UTF-8";

    private String basename = System.getProperty(Globals.CATALINA_BASE_PROP);

    private File configOld;

    private File configNew;

    private File configSave;

    /**
     * Returns the File object representing the new configuration file.
     *
     * @return the new configuration file
     */
    public File getConfigNew() {
        return configNew;
    }

    /**
     * Returns the File object representing the old configuration file.
     *
     * @return the old configuration file
     */
    public File getConfigOld() {
        return configOld;
    }

    /**
     * Returns the File object representing the saved backup configuration file.
     *
     * @return the backup configuration file
     */
    public File getConfigSave() {
        return configSave;
    }

    /**
     * Returns the base directory path for configuration files.
     *
     * @return the base directory path
     */
    public String getBasename() {
        return basename;
    }

    /**
     * Sets the base directory path for configuration files.
     *
     * @param basename the base directory path
     */
    public void setBasename(String basename) {
        this.basename = basename;
    }

    /**
     * Returns the configuration file name.
     *
     * @return the configuration file name
     */
    public String getFilename() {
        return filename;
    }

    /**
     * Sets the configuration file name.
     *
     * @param string the configuration file name
     */
    public void setFilename(String string) {
        filename = string;
    }

    /**
     * Returns the character encoding used for configuration files.
     *
     * @return the character encoding
     */
    public String getEncoding() {
        return encoding;
    }

    /**
     * Sets the character encoding used for configuration files.
     *
     * @param string the character encoding
     */
    public void setEncoding(String string) {
        encoding = string;
    }

    /**
     * Calculate file objects for the old and new configuration files.
     *
     * @param basename The base path
     * @param encoding The encoding of the file
     * @param filename The file name
     */
    public StoreFileMover(String basename, String filename, String encoding) {
        setBasename(basename);
        setEncoding(encoding);
        setFilename(filename);
        init();
    }

    /**
     * Generate the Filename to new with TimeStamp.
     */
    public void init() {
        if (getBasename() == null || getFilename() == null || getEncoding() == null) {
            throw new IllegalArgumentException(sm.getString("storeFileMover.null"));
        }
        String configFile = getFilename();
        configOld = new File(configFile);
        if (!configOld.isAbsolute()) {
            configOld = new File(getBasename(), configFile);
        }
        configNew = new File(configFile + ".new");
        if (!configNew.isAbsolute()) {
            configNew = new File(getBasename(), configFile + ".new");
        }
        if (!configNew.getParentFile().exists()) {
            if (!configNew.getParentFile().mkdirs()) {
                throw new IllegalStateException(sm.getString("storeFileMover.directoryCreationError", configNew));
            }
        }
        String sb = getTimeTag();
        int i = 0;
        do {
            configSave = new File(configFile + sb + "-" + String.valueOf(i));
            if (!configSave.isAbsolute()) {
                configSave = new File(getBasename(), configFile + sb + "-" + String.valueOf(i));
            }
            i++;
        } while (configSave.exists());
    }

    /**
     * Shuffle old-&gt;save and new-&gt;old.
     *
     * @throws IOException a file operation error occurred
     */
    public void move() throws IOException {
        if (configOld.renameTo(configSave)) {
            if (!configNew.renameTo(configOld)) {
                if (!configSave.renameTo(configOld)) {
                    throw new IOException(sm.getString("storeFileMover.restoreError", configNew.getAbsolutePath(),
                            configOld.getAbsolutePath()));
                }
                throw new IOException(sm.getString("storeFileMover.renameError", configNew.getAbsolutePath(),
                        configOld.getAbsolutePath()));
            }
        } else {
            if (!configOld.exists()) {
                if (!configNew.renameTo(configOld)) {
                    throw new IOException(sm.getString("storeFileMover.renameError", configNew.getAbsolutePath(),
                            configOld.getAbsolutePath()));
                }
            } else {
                throw new IOException(sm.getString("storeFileMover.renameError", configOld.getAbsolutePath(),
                        configSave.getAbsolutePath()));
            }
        }
    }

    /**
     * Open an output writer for the new configuration file.
     *
     * @return The writer
     *
     * @throws IOException Failed opening a writer to the new file
     */
    public PrintWriter getWriter() throws IOException {
        return new PrintWriter(new OutputStreamWriter(new FileOutputStream(configNew), getEncoding()));
    }

    /**
     * Time value for backup yyyy-mm-dd.hh-mm-ss.
     *
     * @return The time
     */
    protected String getTimeTag() {
        String ts = (new Timestamp(System.currentTimeMillis())).toString();
        // yyyy-mm-dd hh:mm:ss
        // 0123456789012345678
        StringBuilder sb = new StringBuilder(".");
        sb.append(ts, 0, 10);
        sb.append('.');
        sb.append(ts, 11, 13);
        sb.append('-');
        sb.append(ts, 14, 16);
        sb.append('-');
        sb.append(ts, 17, 19);
        return sb.toString();
    }

}
