/*
 * 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.imaging.bytesource;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Path;
import java.util.Objects;

import org.apache.commons.imaging.common.BinaryFunctions;
import org.apache.commons.io.IOUtils;
import org.apache.commons.io.build.AbstractOrigin;
import org.apache.commons.io.build.AbstractOrigin.ByteArrayOrigin;
import org.apache.commons.io.build.AbstractOrigin.FileOrigin;
import org.apache.commons.io.build.AbstractOrigin.PathOrigin;

public class ByteSource {

    public static ByteSource array(final byte[] array) {
        return new ByteSource(new ByteArrayOrigin(array), null);
    }

    public static ByteSource array(final byte[] array, final String name) {
        return new ByteSource(new ByteArrayOrigin(array), name);
    }

    public static ByteSource file(final File file) {
        return new ByteSource(new FileOrigin(file), file.getName());
    }

    public static final InputStream getInputStream(final ByteSource byteSource, final long skip) throws IOException {
        InputStream is = null;
        boolean succeeded = false;
        try {
            is = byteSource.getInputStream();
            BinaryFunctions.skipBytes(is, skip);
            succeeded = true;
        } finally {
            if (!succeeded) {
                IOUtils.close(is);
            }
        }
        return is;
    }

    public static ByteSource inputStream(final InputStream is, final String name) throws IOException {
        return new InputStreamByteSource(is, name);
    }

    public static ByteSource path(final Path file) {
        return new ByteSource(new PathOrigin(file), Objects.toString(file.getFileName(), null));
    }

    private final String fileName;
    private final AbstractOrigin<?, ?> origin;

    ByteSource(final AbstractOrigin<?, ?> origin, final String fileName) {
        this.origin = Objects.requireNonNull(origin, "origin");
        this.fileName = fileName; // may be null
    }

    public byte[] getByteArray(final long position, final int length) throws IOException {
        return origin.getByteArray(position, length);
    }

    public final String getFileName() {
        return fileName;
    }

    public InputStream getInputStream() throws IOException {
        return origin.getInputStream();
    }

    /**
     * This operation can be VERY expensive; for InputStream byte sources, the entire stream must be drained to determine its length.
     *
     * @return the byte source length
     * @throws IOException if it fails to read the byte source data
     */
    public long size() throws IOException {
        return origin.size();
    }

    @Override
    public String toString() {
        return getClass().getSimpleName() + "[" + getFileName() + "]";
    }

}
