/*

 * Copyright 2000-2001 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package com.sun.imageio.plugins.png;

import java.awt.image.ColorModel;

import java.awt.image.IndexColorModel;

import java.awt.image.SampleModel;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.StringTokenizer;

import javax.imageio.ImageTypeSpecifier;

import javax.imageio.metadata.IIOInvalidTreeException;

import javax.imageio.metadata.IIOMetadata;

import javax.imageio.metadata.IIOMetadataFormat;

import javax.imageio.metadata.IIOMetadataFormatImpl;

import javax.imageio.metadata.IIOMetadataNode;

import org.w3c.dom.Node;

public class PNGMetadata extends IIOMetadata implements Cloneable {

    // package scope

    public static final String

        nativeMetadataFormatName = "javax_imageio_png_1.0";

    protected static final String nativeMetadataFormatClassName

        = "com.sun.imageio.plugins.png.PNGMetadataFormat";

    // Color types for IHDR chunk

    public static final String[] IHDR_colorTypeNames = {

        "Grayscale", null, "RGB", "Palette",

        "GrayAlpha", null, "RGBAlpha"

    };

    public static final int[] IHDR_numChannels = {

        1, 0, 3, 3, 2, 0, 4

    };

    // Bit depths for IHDR chunk

    public static final String[] IHDR_bitDepths = {

        "1", "2", "4", "8", "16"

    };

    // Compression methods for IHDR chunk

    public static final String[] IHDR_compressionMethodNames = {

        "deflate"

    };

    // Filter methods for IHDR chunk

    public static final String[] IHDR_filterMethodNames = {

        "adaptive"

    };

    // Interlace methods for IHDR chunk

    public static final String[] IHDR_interlaceMethodNames = {

        "none", "adam7"

    };

    // Compression methods for iCCP chunk

    public static final String[] iCCP_compressionMethodNames = {

        "deflate"

    };

    // Compression methods for zTXt chunk

    public static final String[] zTXt_compressionMethodNames = {

        "deflate"

    };

    // "Unknown" unit for pHYs chunk

    public static final int PHYS_UNIT_UNKNOWN = 0;

    // "Meter" unit for pHYs chunk

    public static final int PHYS_UNIT_METER = 1;

    // Unit specifiers for pHYs chunk

    public static final String[] unitSpecifierNames = {

        "unknown", "meter"

    };

    // Rendering intents for sRGB chunk

    public static final String[] renderingIntentNames = {

        "Perceptual", // 0

        "Relative colorimetric", // 1

        "Saturation", // 2

        "Absolute colorimetric" // 3

    };

    // Color space types for Chroma->ColorSpaceType node

    public static final String[] colorSpaceTypeNames = {

        "GRAY", null, "RGB", "RGB",

        "GRAY", null, "RGB"

    };

    // IHDR chunk

    public boolean IHDR_present;

    public int IHDR_width;

    public int IHDR_height;

    public int IHDR_bitDepth;

    public int IHDR_colorType;

    public int IHDR_compressionMethod;

    public int IHDR_filterMethod;

    public int IHDR_interlaceMethod; // 0 == none, 1 == adam7

    // PLTE chunk

    public boolean PLTE_present;

    public byte[] PLTE_red;

    public byte[] PLTE_green;

    public byte[] PLTE_blue;

    // If non-null, used to reorder palette entries during encoding in

    // order to minimize the size of the tRNS chunk.  Thus an index of

    // 'i' in the source should be encoded as index 'PLTE_order[i]'.

    // PLTE_order will be null unless 'initialize' is called with an

    // IndexColorModel image type.

    public int[] PLTE_order = null;

    // bKGD chunk

    // If external (non-PNG sourced) data has red = green = blue,

    // always store it as gray and promote when writing

    public boolean bKGD_present;

    public int bKGD_colorType; // PNG_COLOR_GRAY, _RGB, or _PALETTE

    public int bKGD_index;

    public int bKGD_gray;

    public int bKGD_red;

    public int bKGD_green;

    public int bKGD_blue;

    // cHRM chunk

    public boolean cHRM_present;

    public int cHRM_whitePointX;

    public int cHRM_whitePointY;

    public int cHRM_redX;

    public int cHRM_redY;

    public int cHRM_greenX;

    public int cHRM_greenY;

    public int cHRM_blueX;

    public int cHRM_blueY;

    // gAMA chunk

    public boolean gAMA_present;

    public int gAMA_gamma;

    // hIST chunk

    public boolean hIST_present;

    public char[] hIST_histogram;

    // iCCP chunk

    public boolean iCCP_present;

    public String iCCP_profileName;

    public int iCCP_compressionMethod;

    public byte[] iCCP_compressedProfile;

    // iTXt chunk

    public ArrayList iTXt_keyword = new ArrayList(); // Strings

    public ArrayList iTXt_compressionFlag = new ArrayList(); // Integers

    public ArrayList iTXt_compressionMethod = new ArrayList(); // Integers

    public ArrayList iTXt_languageTag = new ArrayList(); // Strings

    public ArrayList iTXt_translatedKeyword = new ArrayList(); // Strings

    public ArrayList iTXt_text = new ArrayList(); // Strings

    // pHYs chunk

    public boolean pHYs_present;

    public int pHYs_pixelsPerUnitXAxis;

    public int pHYs_pixelsPerUnitYAxis;

    public int pHYs_unitSpecifier; // 0 == unknown, 1 == meter

    // sBIT chunk

    public boolean sBIT_present;

    public int sBIT_colorType; // PNG_COLOR_GRAY, _GRAY_ALPHA, _RGB, _RGB_ALPHA

    public int sBIT_grayBits;

    public int sBIT_redBits;

    public int sBIT_greenBits;

    public int sBIT_blueBits;

    public int sBIT_alphaBits;

    // sPLT chunk

    public boolean sPLT_present;

    public String sPLT_paletteName; // 1-79 characters

    public int sPLT_sampleDepth; // 8 or 16

    public int[] sPLT_red;

    public int[] sPLT_green;

    public int[] sPLT_blue;

    public int[] sPLT_alpha;

    public int[] sPLT_frequency;

    // sRGB chunk

    public boolean sRGB_present;

    public int sRGB_renderingIntent;

    // tEXt chunk

    public ArrayList tEXt_keyword = new ArrayList(); // 1-79 char Strings

    public ArrayList tEXt_text = new ArrayList(); // Strings

    // tIME chunk

    public boolean tIME_present;

    public int tIME_year;

    public int tIME_month;

    public int tIME_day;

    public int tIME_hour;

    public int tIME_minute;

    public int tIME_second;

    // tRNS chunk

    // If external (non-PNG sourced) data has red = green = blue,

    // always store it as gray and promote when writing

    public boolean tRNS_present;

    public int tRNS_colorType; // PNG_COLOR_GRAY, _RGB, or _PALETTE

    public byte[] tRNS_alpha; // May have fewer entries than PLTE_red, etc.

    public int tRNS_gray;

    public int tRNS_red;

    public int tRNS_green;

    public int tRNS_blue;

    // zTXt chunk

    public ArrayList zTXt_keyword = new ArrayList(); // Strings

    public ArrayList zTXt_compressionMethod = new ArrayList(); // Integers

    public ArrayList zTXt_text = new ArrayList(); // Strings

    // Unknown chunks

    public ArrayList unknownChunkType = new ArrayList(); // Strings

    public ArrayList unknownChunkData = new ArrayList(); // byte arrays

    public PNGMetadata() {

        super(true,

              nativeMetadataFormatName,

              nativeMetadataFormatClassName,

              null, null);

    }

    public PNGMetadata(IIOMetadata metadata) {

        // TODO -- implement

    }

    /**

     * Sets the IHDR_bitDepth and IHDR_colorType variables.

     * The <code>numBands</code> parameter is necessary since

     * we may only be writing a subset of the image bands.

     */

    public void initialize(ImageTypeSpecifier imageType, int numBands) {

        ColorModel colorModel = imageType.getColorModel();

        SampleModel sampleModel = imageType.getSampleModel();

        // Initialize IHDR_bitDepth

        int[] sampleSize = sampleModel.getSampleSize();

        int bitDepth = sampleSize[0];

        // Choose max bit depth over all channels

        // Fixes bug 4413109

        for (int i = 1; i < sampleSize.length; i++) {

            if (sampleSize[i] > bitDepth) {

                bitDepth = sampleSize[i];

            }

        }

        // Multi-channel images must have a bit depth of 8 or 16

        if (sampleSize.length > 1 && bitDepth < 8) {

            bitDepth = 8;

        }

        // Round bit depth up to a power of 2

        if (bitDepth > 2 && bitDepth < 4) {

            bitDepth = 4;

        } else if (bitDepth > 4 && bitDepth < 8) {

            bitDepth = 8;

        } else if (bitDepth > 8 && bitDepth < 16) {

            bitDepth = 16;

        } else if (bitDepth > 16) {

            throw new RuntimeException("bitDepth > 16!");

        }

        IHDR_bitDepth = bitDepth;

        // Initialize IHDR_colorType

        if (colorModel instanceof IndexColorModel) {

            IndexColorModel icm = (IndexColorModel)colorModel;

            int size = icm.getMapSize();

            byte[] reds = new byte[size];

            icm.getReds(reds);

            byte[] greens = new byte[size];

            icm.getGreens(greens);

            byte[] blues = new byte[size];

            icm.getBlues(blues);

            // Determine whether the color tables are actually a gray ramp

            // if the color type has not been set previously

            boolean isGray = false;

            if (!IHDR_present ||

                (IHDR_colorType != PNGImageReader.PNG_COLOR_PALETTE)) {

                isGray = true;

                int scale = 255/((1 << IHDR_bitDepth) - 1);

                for (int i = 0; i < size; i++) {

                    byte red = reds[i];

                    if ((red != (byte)(i*scale)) ||

                        (red != greens[i]) ||

                        (red != blues[i])) {

                        isGray = false;

                        break;

                    }

                }

            }

            // Determine whether transparency exists

            boolean hasAlpha = colorModel.hasAlpha();

            byte[] alpha = null;

            if (hasAlpha) {

                alpha = new byte[size];

                icm.getAlphas(alpha);

            }

            /*

             * NB: PNG_COLOR_GRAY_ALPHA color type may be not optimal for images

             * contained more than 1024 pixels (or even than 768 pixels in case of

             * single transparent pixel in palette).

             * For such images alpha samples in raster will occupy more space than

             * it is required to store palette so it could be reasonable to

             * use PNG_COLOR_PALETTE color type for large images.

             */

            if (isGray && hasAlpha && (bitDepth == 8 || bitDepth == 16)) {

                IHDR_colorType = PNGImageReader.PNG_COLOR_GRAY_ALPHA;

            } else if (isGray && !hasAlpha) {

                IHDR_colorType = PNGImageReader.PNG_COLOR_GRAY;

            } else {

                IHDR_colorType = PNGImageReader.PNG_COLOR_PALETTE;

                PLTE_present = true;

                PLTE_order = null;

                PLTE_red = (byte[])reds.clone();

                PLTE_green = (byte[])greens.clone();

                PLTE_blue = (byte[])blues.clone();

                if (hasAlpha) {

                    tRNS_present = true;

                    tRNS_colorType = PNGImageReader.PNG_COLOR_PALETTE;

                    PLTE_order = new int[alpha.length];

                    // Reorder the palette so that non-opaque entries

                    // come first.  Since the tRNS chunk does not have

                    // to store trailing 255's, this can save a

                    // considerable amount of space when encoding

                    // images with only one transparent pixel value,

                    // e.g., images from GIF sources.

                    byte[] newAlpha = new byte[alpha.length];

                    // Scan for non-opaque entries and assign them

                    // positions starting at 0.

                    int newIndex = 0;

                    for (int i = 0; i < alpha.length; i++) {

                        if (alpha[i] != (byte)255) {

                            PLTE_order[i] = newIndex;

                            newAlpha[newIndex] = alpha[i];

                            ++newIndex;

                        }

                    }

                    int numTransparent = newIndex;

                    // Scan for opaque entries and assign them

                    // positions following the non-opaque entries.

                    for (int i = 0; i < alpha.length; i++) {

                        if (alpha[i] == (byte)255) {

                            PLTE_order[i] = newIndex++;

                        }

                    }

                    // Reorder the palettes

                    byte[] oldRed = PLTE_red;

                    byte[] oldGreen = PLTE_green;

                    byte[] oldBlue = PLTE_blue;

                    int len = oldRed.length; // All have the same length

                    PLTE_red = new byte[len];

                    PLTE_green = new byte[len];

                    PLTE_blue = new byte[len];

                    for (int i = 0; i < len; i++) {

                        PLTE_red[PLTE_order[i]] = oldRed[i];

                        PLTE_green[PLTE_order[i]] = oldGreen[i];

                        PLTE_blue[PLTE_order[i]] = oldBlue[i];

                    }

                    // Copy only the transparent entries into tRNS_alpha

                    tRNS_alpha = new byte[numTransparent];

                    System.arraycopy(newAlpha, 0,

                                     tRNS_alpha, 0, numTransparent);

                }

            }

        } else {

            if (numBands == 1) {

                IHDR_colorType = PNGImageReader.PNG_COLOR_GRAY;

            } else if (numBands == 2) {

                IHDR_colorType = PNGImageReader.PNG_COLOR_GRAY_ALPHA;

            } else if (numBands == 3) {

                IHDR_colorType = PNGImageReader.PNG_COLOR_RGB;

            } else if (numBands == 4) {

                IHDR_colorType = PNGImageReader.PNG_COLOR_RGB_ALPHA;

            } else {

                throw new RuntimeException("Number of bands not 1-4!");

            }

        }

        IHDR_present = true;

    }

    public boolean isReadOnly() {

        return false;

    }

    private ArrayList cloneBytesArrayList(ArrayList in) {

        if (in == null) {

            return null;

        } else {

            ArrayList list = new ArrayList(in.size());

            Iterator iter = in.iterator();

            while (iter.hasNext()) {

                Object o = iter.next();

                if (o == null) {

                    list.add(null);

                } else {

                    list.add(((byte[])o).clone());

                }

            }

            return list;

        }

    }

    // Deep clone

    public Object clone() {

        PNGMetadata metadata;

        try {

            metadata = (PNGMetadata)super.clone();

        } catch (CloneNotSupportedException e) {

            return null;

        }

        // unknownChunkData needs deep clone

        metadata.unknownChunkData =

            cloneBytesArrayList(this.unknownChunkData);

        return metadata;

    }

    public Node getAsTree(String formatName) {

        if (formatName.equals(nativeMetadataFormatName)) {

            return getNativeTree();

        } else if (formatName.equals

                   (IIOMetadataFormatImpl.standardMetadataFormatName)) {

            return getStandardTree();

        } else {

            throw new IllegalArgumentException("Not a recognized format!");

        }

    }

    private Node getNativeTree() {

        IIOMetadataNode node = null; // scratch node

        IIOMetadataNode root = new IIOMetadataNode(nativeMetadataFormatName);

        // IHDR

        if (IHDR_present) {

            IIOMetadataNode IHDR_node = new IIOMetadataNode("IHDR");

            IHDR_node.setAttribute("width", Integer.toString(IHDR_width));

            IHDR_node.setAttribute("height", Integer.toString(IHDR_height));

            IHDR_node.setAttribute("bitDepth",

                                   Integer.toString(IHDR_bitDepth));

            IHDR_node.setAttribute("colorType",

                                   IHDR_colorTypeNames[IHDR_colorType]);

            // IHDR_compressionMethod must be 0 in PNG 1.1

            IHDR_node.setAttribute("compressionMethod",

                          IHDR_compressionMethodNames[IHDR_compressionMethod]);

            // IHDR_filterMethod must be 0 in PNG 1.1

            IHDR_node.setAttribute("filterMethod",

                                    IHDR_filterMethodNames[IHDR_filterMethod]);

            IHDR_node.setAttribute("interlaceMethod",

                              IHDR_interlaceMethodNames[IHDR_interlaceMethod]);

            root.appendChild(IHDR_node);

        }

        // PLTE

        if (PLTE_present) {

            IIOMetadataNode PLTE_node = new IIOMetadataNode("PLTE");

            int numEntries = PLTE_red.length;

            for (int i = 0; i < numEntries; i++) {

                IIOMetadataNode entry = new IIOMetadataNode("PLTEEntry");

                entry.setAttribute("index", Integer.toString(i));

                entry.setAttribute("red",

                                   Integer.toString(PLTE_red[i] & 0xff));

                entry.setAttribute("green",

                                   Integer.toString(PLTE_green[i] & 0xff));

                entry.setAttribute("blue",

                                   Integer.toString(PLTE_blue[i] & 0xff));

                PLTE_node.appendChild(entry);

            }

            root.appendChild(PLTE_node);

        }

        // bKGD

        if (bKGD_present) {

            IIOMetadataNode bKGD_node = new IIOMetadataNode("bKGD");

            if (bKGD_colorType == PNGImageReader.PNG_COLOR_PALETTE) {

                node = new IIOMetadataNode("bKGD_Palette");

                node.setAttribute("index", Integer.toString(bKGD_index));

            } else if (bKGD_colorType == PNGImageReader.PNG_COLOR_GRAY) {

                node = new IIOMetadataNode("bKGD_Grayscale");

                node.setAttribute("gray", Integer.toString(bKGD_gray));

            } else if (bKGD_colorType == PNGImageReader.PNG_COLOR_RGB) {

                node = new IIOMetadataNode("bKGD_RGB");