/*
 * 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.wicket.util.file;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.Serializable;
import java.net.URI;
import java.time.Instant;
import org.apache.wicket.util.io.Streams;
import org.apache.wicket.util.watch.IModifiable;


/**
 * Simple extension of File that adds an implementation of IModifiable for files. This allows the
 * ModificationWatcher class to watch files for modification. The IModifiable.lastModifiedTime()
 * method also returns a Time object with a more convenient API than either Date or a value in
 * milliseconds.
 * 
 * @author Jonathan Locke
 */
public class File extends java.io.File implements IModifiable
{
        private static final long serialVersionUID = 1L;

        /**
         * Constructor.
         * 
         * @param parent
         *            parent
         * @param child
         *            child
         */
        public File(final File parent, final String child)
        {
                super(parent, child);
        }

        /**
         * Construct.
         * 
         * @param parent
         *            parent
         * @param child
         *            child
         */
        public File(final java.io.File parent, final String child)
        {
                super(parent, child);
        }

        /**
         * Construct.
         * 
         * @param file
         *            File from java.io package
         */
        public File(final java.io.File file)
        {
                super(file.getAbsolutePath());
        }

        /**
         * Constructor.
         * 
         * @param pathname
         *            path name
         */
        public File(final String pathname)
        {
                super(pathname);
        }

        /**
         * Constructor.
         * 
         * @param parent
         *            parent
         * @param child
         *            child
         */
        public File(final String parent, final String child)
        {
                super(parent, child);
        }

        /**
         * Constructor.
         * 
         * @param uri
         *            file uri
         */
        public File(final URI uri)
        {
                super(uri);
        }

        /**
         * @param name
         *            Name of child file
         * @return Child file object
         */
        public File file(final String name)
        {
                return new File(this, name);
        }

        /**
         * @return File extension (whatever is after the last '.' in the file name)
         */
        public String getExtension()
        {
                final int lastDot = getName().lastIndexOf('.');
                if (lastDot >= 0)
                {
                        return getName().substring(lastDot + 1);
                }
                return null;
        }

        /**
         * @return Parent folder
         */
        public Folder getParentFolder()
        {
                return new Folder(getParent());
        }

        /**
         * @return Input stream that reads this file
         * @throws FileNotFoundException
         *             Thrown if the file cannot be found
         */
        public InputStream inputStream() throws FileNotFoundException
        {
                return new BufferedInputStream(new FileInputStream(this));
        }

        /**
         * Returns a Time object representing the most recent time this file was modified.
         *
         * @return This file's lastModified() value as a Time object or <code>null</code> if
         * that information is not available
         */
        @Override
        public Instant lastModifiedTime()
        {
                final long time = lastModified();
                
                if(time == 0)
                {
                        return null;
                }
                return Instant.ofEpochMilli(time);
        }

        /**
         * Creates a buffered output stream that writes to this file. If the parent folder does not yet
         * exist, creates all necessary folders in the path.
         * 
         * @return Output stream that writes to this file
         * @throws FileNotFoundException
         *             Thrown if the file cannot be found
         */
        public OutputStream outputStream() throws FileNotFoundException
        {
                final Folder parent = getParentFolder();
                if (!parent.exists())
                {
                        if (!parent.mkdirs())
                        {
                                throw new FileNotFoundException("Couldn't create path " + parent);
                        }
                }
                return new BufferedOutputStream(new FileOutputStream(this));
        }

        /**
         * @return String read from this file
         * @throws IOException
         */
        public String readString() throws IOException
        {
                final InputStream in = new FileInputStream(this);
                try
                {
                        return Streams.readString(in);
                }
                finally
                {
                        in.close();
                }
        }

        /**
         * @return Object read from serialization file
         * @throws IOException
         * @throws ClassNotFoundException
         */
        public Object readObject() throws IOException, ClassNotFoundException
        {
                return new ObjectInputStream(inputStream()).readObject();
        }

        /**
         * @param object
         *            Object to write to this file
         * @throws IOException
         */
        public void writeObject(final Serializable object) throws IOException
        {
                new ObjectOutputStream(outputStream()).writeObject(object);
        }

        /**
         * @return True if the file was removed
         * @see java.io.File#delete()
         */
        public boolean remove()
        {
                return Files.remove(this);
        }

        /**
         * Force contents of file to physical storage
         * 
         * @throws IOException
         */
        public void sync() throws IOException
        {
                final FileInputStream in = new FileInputStream(this);
                try
                {
                        in.getFD().sync();
                }
                finally
                {
                        in.close();
                }
        }

        /**
         * @return This file in double quotes (useful for passing to commands and tools that have issues
         *         with spaces in filenames)
         */
        public String toQuotedString()
        {
                return "\"" + toString() + "\"";
        }

        /**
         * Writes the given file to this one
         * 
         * @param file
         *            The file to copy
         * @return number of bytes written
         * @throws IOException
         */
        public int write(final File file) throws IOException
        {
                final InputStream in = new BufferedInputStream(new FileInputStream(file));
                try
                {
                        return write(in);
                }
                finally
                {
                        in.close();
                }
        }

        /**
         * Writes the given input stream to this file
         * 
         * @param input
         *            The input
         * @return Number of bytes written
         * @throws IOException
         */
        public int write(final InputStream input) throws IOException
        {
                return Files.writeTo(this, input);
        }

        /**
         * Write the given string to this file
         * 
         * @param string
         *            The string to write
         * @throws IOException
         */
        public void write(final String string) throws IOException
        {
                final FileWriter out = new FileWriter(this);
                try
                {
                        out.write(string);
                }
                finally
                {
                        out.close();
                }
        }
}