/*
 * 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.pdfbox.pdmodel.graphics.image;

import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import javax.imageio.stream.MemoryCacheImageOutputStream;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.filter.Filter;
import org.apache.pdfbox.filter.FilterFactory;
import org.apache.pdfbox.io.RandomAccessReadBuffer;
import org.apache.pdfbox.io.RandomAccessReadBufferedFile;
import org.apache.pdfbox.io.RandomAccessRead;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.graphics.color.PDColorSpace;
import org.apache.pdfbox.pdmodel.graphics.color.PDDeviceGray;

/**
 * Factory for creating a PDImageXObject containing a CCITT Fax compressed TIFF image.
 * 
 * @author Ben Litchfield
 * @author Paul King
 */
public final class CCITTFactory
{
    private CCITTFactory()
    {
    }
    
    /**
     * Creates a new CCITT group 4 (T6) compressed image XObject from a b/w BufferedImage. This
     * compression technique usually results in smaller images than those produced by {@link LosslessFactory#createFromImage(PDDocument, BufferedImage)
     * }.
     *
     * @param document the document to create the image as part of.
     * @param image the image.
     * @return a new image XObject.
     * @throws IOException if there is an error creating the image.
     * @throws IllegalArgumentException if the BufferedImage is not a b/w image.
     */
    public static PDImageXObject createFromImage(PDDocument document, BufferedImage image)
            throws IOException
    {
        if (image.getType() != BufferedImage.TYPE_BYTE_BINARY && image.getColorModel().getPixelSize() != 1)
        {
            throw new IllegalArgumentException("Only 1-bit b/w images supported");
        }
        
        int height = image.getHeight();
        int width = image.getWidth();

        ByteArrayOutputStream bos = new ByteArrayOutputStream(Math.max(32, (width + 1) * height));
        try (MemoryCacheImageOutputStream mcios = new MemoryCacheImageOutputStream(bos))
        {
            for (int y = 0; y < height; ++y)
            {
                for (int x = 0; x < width; ++x)
                {
                    // flip bit to avoid having to set /BlackIs1
                    mcios.writeBits(~(image.getRGB(x, y) & 1), 1);
                }
                int bitOffset = mcios.getBitOffset();
                if (bitOffset != 0)
                {
                    mcios.writeBits(0, 8 - bitOffset);
                }
            }
            mcios.flush();
        }

        return prepareImageXObject(document, bos.toByteArray(), width, height, PDDeviceGray.INSTANCE);
    }

    /**
     * Creates a new CCITT Fax compressed image XObject from a specific image of a TIFF file stored
     * in a byte array. Only single-strip CCITT T4 or T6 compressed TIFF files are supported. If
     * you're not sure what TIFF files you have, use
     * {@link LosslessFactory#createFromImage(PDDocument, BufferedImage) }
     * or {@link CCITTFactory#createFromImage(PDDocument, BufferedImage) }
     * instead.
     *
     * @param document the document to create the image as part of.
     * @param byteArray the TIFF file in a byte array which contains a suitable CCITT compressed
     * image
     * @return a new Image XObject
     * @throws IOException if there is an error reading the TIFF data.
     */
    public static PDImageXObject createFromByteArray(PDDocument document, byte[] byteArray)
            throws IOException
    {
        return createFromByteArray(document, byteArray, 0);
    }

    /**
     * Creates a new CCITT Fax compressed image XObject from a specific image of a TIFF file stored
     * in a byte array. Only single-strip CCITT T4 or T6 compressed TIFF files are supported. If
     * you're not sure what TIFF files you have, use
     * {@link LosslessFactory#createFromImage(PDDocument, BufferedImage) }
     * or {@link CCITTFactory#createFromImage(PDDocument, BufferedImage) }
     * instead.
     *
     * @param document the document to create the image as part of.
     * @param byteArray the TIFF file in a byte array which contains a suitable CCITT compressed
     * image
     * @param number TIFF image number, starting from 0
     * @return a new Image XObject
     * @throws IOException if there is an error reading the TIFF data.
     */
    public static PDImageXObject createFromByteArray(PDDocument document, byte[] byteArray, int number)
            throws IOException
    {
        try (RandomAccessRead raf = new RandomAccessReadBuffer(byteArray))
        {
            return createFromRandomAccessImpl(document, raf, number);
        }
    }

    private static PDImageXObject prepareImageXObject(PDDocument document,
            byte[] byteArray, int width, int height,
            PDColorSpace initColorSpace) throws IOException
    {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        Filter filter = FilterFactory.INSTANCE.getFilter(COSName.CCITTFAX_DECODE);
        COSDictionary dict = new COSDictionary();
        dict.setInt(COSName.COLUMNS, width);
        dict.setInt(COSName.ROWS, height);
        filter.encode(new ByteArrayInputStream(byteArray), baos, dict, 0);

        ByteArrayInputStream encodedByteStream = new ByteArrayInputStream(baos.toByteArray());
        PDImageXObject image = new PDImageXObject(document, encodedByteStream, COSName.CCITTFAX_DECODE,
                width, height, 1, initColorSpace);
        dict.setInt(COSName.K, -1);
        image.getCOSObject().setItem(COSName.DECODE_PARMS, dict);
        return image;
    }

    /**
     * Creates a new CCITT Fax compressed image XObject from the first image of a TIFF file. Only
     * single-strip CCITT T4 or T6 compressed TIFF files are supported. If you're not sure what TIFF
     * files you have, use
     * {@link LosslessFactory#createFromImage(org.apache.pdfbox.pdmodel.PDDocument, java.awt.image.BufferedImage)}
     * or {@link CCITTFactory#createFromImage(PDDocument, BufferedImage) }
     * instead.
     *
     * @param document the document to create the image as part of.
     * @param file the  TIFF file which contains a suitable CCITT compressed image
     * @return a new Image XObject
     * @throws IOException if there is an error reading the TIFF data.
     */
    public static PDImageXObject createFromFile(PDDocument document, File file)
            throws IOException
    {
        return createFromFile(document, file, 0);
    }

    /**
     * Creates a new CCITT Fax compressed image XObject from a specific image of a TIFF file. Only
     * single-strip CCITT T4 or T6 compressed TIFF files are supported. If you're not sure what TIFF
     * files you have, use
     * {@link LosslessFactory#createFromImage(PDDocument, BufferedImage) }
     * or {@link CCITTFactory#createFromImage(PDDocument, BufferedImage) }
     * instead.
     *
     * @param document the document to create the image as part of.
     * @param file the TIFF file which contains a suitable CCITT compressed image
     * @param number TIFF image number, starting from 0
     * @return a new Image XObject
     * @throws IOException if there is an error reading the TIFF data.
     */
    public static PDImageXObject createFromFile(PDDocument document, File file, int number)
            throws IOException
    {
        try (RandomAccessRead raf = new RandomAccessReadBufferedFile(file))
        {
            return createFromRandomAccessImpl(document, raf, number);
        }
    }
    
    /**
     * Creates a new CCITT Fax compressed image XObject from a TIFF file.
     * 
     * @param document the document to create the image as part of.
     * @param reader the random access TIFF file which contains a suitable CCITT
     * compressed image
     * @param number TIFF image number, starting from 0
     * @return a new Image XObject, or null if no such page
     * @throws IOException if there is an error reading the TIFF data.
     */
    private static PDImageXObject createFromRandomAccessImpl(PDDocument document,
            RandomAccessRead reader,
                                                             int number) throws IOException
    {
        COSDictionary decodeParms = new COSDictionary();
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        extractFromTiff(reader, bos, decodeParms, number);
        if (bos.size() == 0)
        {
            return null;
        }
        ByteArrayInputStream encodedByteStream = new ByteArrayInputStream(bos.toByteArray());
        PDImageXObject pdImage = new PDImageXObject(document, 
                encodedByteStream, 
                COSName.CCITTFAX_DECODE, 
                decodeParms.getInt(COSName.COLUMNS), 
                decodeParms.getInt(COSName.ROWS),
                1,
                PDDeviceGray.INSTANCE);
        
        COSDictionary dict = pdImage.getCOSObject();
        dict.setItem(COSName.DECODE_PARMS, decodeParms);
        return pdImage;
    }

    // extracts the CCITT stream from the TIFF file
    private static void extractFromTiff(RandomAccessRead reader,
            OutputStream os,
            COSDictionary params, int number) throws IOException
    {
        try (os)
        {
            // First check the basic tiff header
            reader.seek(0);
            char endianess = (char) reader.read();
            if ((char) reader.read() != endianess)
            {
                throw new IOException("Not a valid tiff file");
            }
            // ensure that endianess is either M or I
            if (endianess != 'M' && endianess != 'I')
            {
                throw new IOException("Not a valid tiff file");
            }
            int magicNumber = readshort(endianess, reader);
            if (magicNumber != 42)
            {
                throw new IOException("Not a valid tiff file");
            }

            // Relocate to the first set of tags
            long address = readlong(endianess, reader);
            reader.seek(address);
    
            // If some higher page number is required, skip this page's tags, 
            // then read the next page's address
            for (int i = 0; i < number; i++)
            {
                int numtags = readshort(endianess, reader);
                if (numtags > 50)
                {
                    throw new IOException("Not a valid tiff file");
                }
                reader.seek(address + 2 + numtags * 12L);
                address = readlong(endianess, reader);
                if (address == 0)
                {
                    return;
                }
                reader.seek(address);
            }

            int numtags = readshort(endianess, reader);

            // The number 50 is somewhat arbitrary, it just stops us load up junk from somewhere
            // and tramping on
            if (numtags > 50)
            {
                throw new IOException("Not a valid tiff file");
            }

            // Loop through the tags, some will convert to items in the params dictionary
            // Other point us to where to find the data stream.
            // The only param which might change as a result of other TIFF tags is K, so
            // we'll deal with that differently.
            
            // Default value to detect error
            int k = -1000;
            
            int dataoffset = 0;
            int datalength = 0;

            for (int i = 0; i < numtags; i++)
            {
                int tag = readshort(endianess, reader);
                int type = readshort(endianess, reader);
                int count = readlong(endianess, reader);
                int val;
                // Note that when the type is shorter than 4 bytes, the rest can be garbage
                // and must be ignored. E.g. short (2 bytes) from "01 00 38 32" (little endian)
                // is 1, not 842530817 (seen in a real-life TIFF image).
                switch (type)
                {
                    case 1: // byte value
                        val = reader.read();
                        reader.read();
                        reader.read();
                        reader.read();
                        break;
                    case 3: // short value
                        val = readshort(endianess, reader);
                        reader.read();
                        reader.read();
                        break;
                    default: // long and other types
                        val = readlong(endianess, reader);
                        break;
                }
                switch (tag)
                {
                    case 256:
                    {
                        params.setInt(COSName.COLUMNS, val);
                        break;
                    }
                    case 257:
                    {
                        params.setInt(COSName.ROWS, val);
                        break;
                    }
                    case 259:
                    {
                        if (val == 4)
                        {
                            k = -1;
                        }
                        if (val == 3)
                        {
                            k = 0;
                        }
                        break; // T6/T4 Compression
                    }
                    case 262:
                    {
                        if (val == 1)
                        {
                            params.setBoolean(COSName.BLACK_IS_1, true);
                        }
                        break;
                    }
                    case 266:
                    {
                        if (val != 1)
                        {
                            throw new IOException("FillOrder " + val + " is not supported");
                        }
                        break;
                    }
                    case 273:
                    {
                        if (count == 1)
                        {
                            dataoffset = val;
                        }
                        break;
                    }
                    case 274:
                    {
                        // http://www.awaresystems.be/imaging/tiff/tifftags/orientation.html
                        if (val != 1)
                        {
                            throw new IOException("Orientation " + val + " is not supported");
                        }
                        break;
                    }
                    case 279:
                    {
                        if (count == 1)
                        {
                            datalength = val;
                        }
                        break;
                    }
                    case 292:
                    {
                        if ((val & 1) != 0)
                        {
                            // T4 2D - arbitrary positive K value
                            k = 50;
                        }
                        // http://www.awaresystems.be/imaging/tiff/tifftags/t4options.html
                        if ((val & 4) != 0)
                        {
                            throw new IOException("CCITT Group 3 'uncompressed mode' is not supported");
                        }
                        if ((val & 2) != 0)
                        {
                            throw new IOException("CCITT Group 3 'fill bits before EOL' is not supported");
                        }
                        break;
                    }
                    case 324:
                    {
                        if (count == 1)
                        {
                            dataoffset = val;
                        }
                        break;
                    }
                    case 325:
                    {
                        if (count == 1)
                        {
                            datalength = val;
                        }
                        break;
                    }
                    default:
                    {
                        // do nothing
                    }
                }
            }

            if (k == -1000)
            {
                throw new IOException("First image in tiff is not CCITT T4 or T6 compressed");
            }
            if (dataoffset == 0)
            {
                throw new IOException("First image in tiff is not a single tile/strip");
            }

            params.setInt(COSName.K, k);

            reader.seek(dataoffset);

            byte[] buf = new byte[8192];
            int amountRead;
            while ((amountRead = reader.read(buf, 0, Math.min(8192, datalength))) > 0)
            {
                datalength -= amountRead;
                os.write(buf, 0, amountRead);
            }

        }
    }

    private static int readshort(char endianess, RandomAccessRead raf) throws IOException
    {
        if (endianess == 'I')
        {
            return raf.read() | (raf.read() << 8);
        }
        return (raf.read() << 8) | raf.read();
    }

    private static int readlong(char endianess, RandomAccessRead raf) throws IOException
    {
        if (endianess == 'I')
        {
            return raf.read() | (raf.read() << 8) | (raf.read() << 16) | (raf.read() << 24);
        }
        return (raf.read() << 24) | (raf.read() << 16) | (raf.read() << 8) | raf.read();
    }
}
