/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.fastlz;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.net.URLDecoder;
import java.nio.ByteBuffer;

import org.simantics.compressions.impl.Buffers;
import org.simantics.fastlz.impl.FastLZConfig;
import org.simantics.fastlz.impl.FastLZInputStream;
import org.simantics.fastlz.impl.FastLZOutputStream;
import org.simantics.fastlz.impl.OS;
import org.simantics.fastlz.java.FastLZJavaInputStream;
import org.simantics.fastlz.java.FastLZJavaOutputStream;

/**
 * @author Tuukka Lehtonen
 */
@SuppressWarnings("resource")
public class FastLZ {

    private static boolean nativeInitialized = false;

    public static boolean isNativeInitialized() {
        return nativeInitialized;
    }

    private static boolean isNativeDisabled() {
        return "false".equalsIgnoreCase(System.getProperty("fastlz.native", "true"));
    }

    public synchronized static void initialize(File path) {
        if (nativeInitialized || isNativeDisabled())
            return;

//        System.out.println("INITIALIZE FASTLZ: " + path);

        String osName = System.getProperty("os.name");
        String osArch = System.getProperty("os.arch");
        String lib = "fastlz";

        try {
            if (path == null) {
                lib += OS.formOsArchSuffix();
                System.loadLibrary(lib);
            } else {
                if (path.isDirectory()) {
                    lib = System.mapLibraryName(lib + OS.formOsArchSuffix());
                    lib = new File(path, lib).toString();
                } else if (path.isFile()) {
                    lib = path.toString();
                } else {
                    throw new IllegalArgumentException("Invalid path for FastLZ library: " + path);
                }
                try {
                    System.load(lib);
                } catch (UnsatisfiedLinkError e) {
                    String fallback = "fastlz";
                    fallback += OS.formOsArchSuffix();
                    System.loadLibrary(fallback);
                }
            }
            nativeInitialized = true;
        } catch (UnsatisfiedLinkError e) {
            System.err.println("Couldn't load library '" + lib + "' for os '" + osName + "' and architecture '" + osArch + "'");
            e.printStackTrace();
        }
    }

    static {
        if (!isNativeDisabled() && FastLZConfig.attemptStaticInitialization) {
            String osName = System.getProperty("os.name");
            String osArch = System.getProperty("os.arch");
            String libName = OS.resolveLibName();
            URL libURL = FastLZ.class.getResource("/" + libName);
//            System.out.println("FastLZ libURL: " + libURL);
//            System.out.println(".: " + FastLZ.class.getResource("."));
//            System.out.println("..: " + FastLZ.class.getResource("../../../" + resolveLibName()));
//            System.out.println("libname: " + FastLZ.class.getResource(resolveLibName()));
//            System.out.println("/libname: " + FastLZ.class.getResource("/" + resolveLibName()));
//            System.out.println("libname stream: " + FastLZ.class.getResourceAsStream(resolveLibName()));
//            System.out.println("/libname stream: " + FastLZ.class.getResourceAsStream("/" + resolveLibName()));
            if (libURL != null) {
                if ("file".equals(libURL.getProtocol())) {
                    try {
                        File path = new File(URLDecoder.decode(libURL.getPath(), "UTF-8"));
                        initialize(path);
                    } catch (UnsupportedEncodingException e) {
                        e.printStackTrace();
                    }
                } else if ("jar".equals(libURL.getProtocol())) {
                    try {
                        File libFile = OS.extractLib(libURL, libName);
                        initialize(libFile);
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                } else {
                    System.err.println("Unsupported URL protocol '" + libURL + "' for FastLZ native library file '" + libName + "' for os '" + osName + "' and architecture '" + osArch + "'");
                }
            } else {
                initialize(null); // Final fallback. (Needed when running DB tests by ant script).
            }
        }
    }

    /**
     * The output buffer must be at least 5% larger than the input buffer and
     * can not be smaller than 66 bytes.
     * 
     * @param inputSize size of uncompressed input data in bytes
     * @return maximum amount of bytes needed for the compressed data
     */
    public static int compressBound(int inputSize) {
        return Math.max(66, inputSize + inputSize/20+1);
    }

    /**
     * Compress a block of data in the input buffer and returns the size of
     * compressed block. The size of input buffer is specified by length. The
     * minimum input buffer size is 16.
     * 
     * <p>
     * The output buffer must be at least 5% larger than the input buffer and
     * can not be smaller than 66 bytes.
     * 
     * <p>
     * If the input is not compressible, the return value might be larger than
     * length (input buffer size).
     * 
     * <p>
     * The input buffer and the output buffer can not overlap.
     * 
     * <p>
     * The input and output buffers are assumed to be direct byte buffers.
     */
    static native int compress(ByteBuffer input, int inputOffset, int length,
            ByteBuffer output, int outputOffset);

    /**
     * Decompress a block of compressed data and returns the size of the
     * decompressed block. If error occurs, e.g. the compressed data is
     * corrupted or the output buffer is not large enough, then 0 (zero) will be
     * returned instead.
     * 
     * <p>
     * The input buffer and the output buffer can not overlap.
     * 
     * <p>
     * Decompression is memory safe and guaranteed not to write the output
     * buffer more than what is specified in maxout.
     * 
     * <p>
     * The input and output buffers are assumed to be direct byte buffers.
     */
    static native int decompress(ByteBuffer input, int inputOffset, int length,
            ByteBuffer output, int outputOffset, int maxout);

    /**
     * Compress a block of data in the input buffer and returns the size of
     * compressed block. The size of input buffer is specified by length. The
     * minimum input buffer size is 16.
     * 
     * <p>
     * The output buffer must be at least 5% larger than the input buffer and
     * can not be smaller than 66 bytes.
     * 
     * <p>
     * If the input is not compressible, the return value might be larger than
     * length (input buffer size).
     * 
     * <p>
     * The input buffer and the output buffer can not overlap.
     * 
     * <p>
     * It is recommended to have both input buffers as direct or heap buffers,
     * not mixed. Mixing different types of buffers will hurt performance a lot.
     * If both buffers are direct byte buffers and native decompression is
     * available, it will be employed.
     */
    public static int compressBuffer(ByteBuffer input, int inputOffset, int length,
            ByteBuffer output, int outputOffset) {
        if (output.isReadOnly())
            throw new IllegalArgumentException("read-only output buffer");

        if (isNativeInitialized()) {
            if (input.isDirect() && output.isDirect())
                return compress(input, inputOffset, length, output, outputOffset);
        }

        byte[] inarr = Buffers.getInputArray(input);
        byte[] outarr = Buffers.getOutputArray(output);
        int result = FastLZJava.compress(inarr, inputOffset, length, outarr, outputOffset);
        Buffers.writeOutput(output, outarr);
        return result;
    }

    /**
     * Decompress a block of compressed data and returns the size of the
     * decompressed block. If error occurs, e.g. the compressed data is
     * corrupted or the output buffer is not large enough, then 0 (zero) will be
     * returned instead.
     * 
     * <p>
     * The input buffer and the output buffer can not overlap.
     * 
     * <p>
     * Decompression is memory safe and guaranteed not to write the output
     * buffer more than what is specified in maxout.
     * 
     * <p>
     * It is recommended to have both input buffers as direct or heap buffers,
     * not mixed. Mixing different types of buffers will hurt performance a lot.
     * If both buffers are direct byte buffers and native decompression is
     * available, it will be employed.
     */
    public static int decompressBuffer(ByteBuffer input, int inputOffset, int length,
            ByteBuffer output, int outputOffset, int maxout) {
        if (output.isReadOnly())
            throw new IllegalArgumentException("read-only output buffer");

        if (isNativeInitialized()) {
            if (input.isDirect() && output.isDirect())
                return decompress(input, inputOffset, length, output, outputOffset, maxout);
        }

        byte[] inarr = Buffers.getInputArray(input);
        byte[] outarr = Buffers.getOutputArray(output);
        int result = FastLZJava.decompress(inarr, inputOffset, length, outarr, outputOffset, maxout);
        Buffers.writeOutput(output, outarr);
        return result;
    }

    /**
     * @param file the FastLZ-compressed file to read
     * @return input stream that decompresses its output using the FastLZ
     *         algorithm. Caller is responsible of closing the returned stream.
     * @throws FileNotFoundException see
     *         {@link FileOutputStream#FileOutputStream(File)} for when this is
     *         thrown
     */
    public static InputStream read(File file) throws FileNotFoundException {
        return nativeInitialized ? new FastLZInputStream(file)
                : new FastLZJavaInputStream(file);
    }

    /**
     * @param input
     * @return
     * @param input
     *            the input stream to decompress
     * @return a stream that decompresses the specified FastLZ compressed input
     *         stream
     */
    public static InputStream read(InputStream input) {
        return nativeInitialized ? new FastLZInputStream(input)
                : new FastLZJavaInputStream(input);
    }

    /**
     * @param file the FastLZ-compressed file to write
     * @return output stream that compresses its input using the FastLZ
     *         algorithm. Caller is responsible of closing the returned stream.
     * @throws FileNotFoundException see
     *         {@link FileOutputStream#FileOutputStream(File)} for when this is
     *         thrown
     */
    public static OutputStream write(File file) throws FileNotFoundException {
        return nativeInitialized ? new FastLZOutputStream(file)
                : new FastLZJavaOutputStream(file);
    }

    /**
     * @param output
     *            the stream to write compressed output into
     * @return a stream that compresses into the specified output stream with
     *         FastLZ
     */
    public static OutputStream write(OutputStream output) {
        return nativeInitialized ? new FastLZOutputStream(output)
                : new FastLZJavaOutputStream(output);
    }

    /**
     * Warning: custom utility for performance reasons. Only used by
     * org.simantics.db.procore. Do not use elsewhere.
     * 
     * @param deflated
     * @param deflatedSize
     * @param inflatedSize
     * @param arrays
     * @return
     */
    public static synchronized native int decompressCluster(ByteBuffer deflated, int deflatedSize, int inflatedSize, Object[] arrays);

}