/*
 * 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.
 */

/* $Id$ */

package org.apache.fop.pdf;

// Java...
import java.util.List;

import org.apache.fop.render.shading.Function;
import org.apache.fop.render.shading.Shading;
import org.apache.fop.render.shading.ShadingPattern;

/**
 * class representing a PDF Smooth Shading object.
 *
 * PDF Functions represent parameterized mathematical formulas and sampled representations with
 * arbitrary resolution. Functions are used in two areas: device-dependent
 * rasterization information for halftoning and transfer
 * functions, and color specification for smooth shading (a PDF 1.3 feature).
 *
 * All PDF Functions have a shadingType (0,2,3, or 4), a Domain, and a Range.
 */
public class PDFShading extends PDFObject implements Shading {
    // Guts common to all function types

    /**
     * The name of the Shading e.g. "Shading1"
     */
    protected String shadingName = null;

    /**
     * Required: The Type of shading (1,2,3,4,5,6,7)
     */
    protected int shadingType = 3;    // Default

    /**
     * A ColorSpace representing the colorspace. "DeviceRGB" is an example.
     */
    protected PDFDeviceColorSpace colorSpace = null;

    /**
     * The background color. Since shading is opaque,
     * this is very rarely used.
     */
    protected List background = null;

    /**
     * Optional: A List specifying the clipping rectangle
     */
    protected List bBox = null;

    /**
     * Optional: A flag whether or not to filter the shading function
     * to prevent aliasing artifacts. Default is false.
     */
    protected boolean antiAlias = false;

    /**
     * Optional for Type 1: Array of four numbers, xmin, xmax, ymin, ymax.
     *                      Default is [0 1 0 1]
     * Optional for Type 2: An array of two numbers between which the blend
     *                      varies between start and end points. Default is 0, 1.
     * Optional for Type 3: An array of two numbers between which the blend
     *                      varies between start and end points. Default is 0, 1.
     */
    protected List domain = null;

    /**
     * Optional for Type 1: A transformation matrix
     */
    protected List matrix = null;

    /**
     * Required for Type 1, 2, and 3:
     * The object of the color mapping function (usually type 2 or 3).
     * Optional for Type 4,5,6, and 7: When it's nearly the same thing.
     */
    protected PDFFunction function = null;

    /**
     * Required for Type 2: An Array of four numbers specifying
     *                      the starting and ending coordinate pairs
     * Required for Type 3: An Array of six numbers [x0,y0,r0,x1,y1,r1]
     *                      specifying the centers and radii of
     *                      the starting and ending circles.
     */
    protected List coords = null;

    /**
     * Required for Type 2+3: An Array of two boolean values specifying
     * whether to extend the start and end colors past the start
     * and end points, respectively.
     * Default is false, false.
     */
    protected List extend = null;

    /**
     * Required for Type 4,5,6, and 7: Specifies the number of bits used
     * to represent each vertex coordinate.
     * Allowed to be 1,2,4,8,12,16,24, or 32.
     */
    protected int bitsPerCoordinate = 0;

    /**
     * Required for Type 4,5,6, and 7: Specifies the number of bits used
     * to represent the edge flag for each vertex.
     * Allowed to be 2,4,or 8, while the Edge flag itself is allowed to
     * be 0,1 or 2.
     */
    protected int bitsPerFlag = 0;

    /**
     * Required for Type 4,5,6, and 7: Array of Doubles which specifies
     * how to decode coordinate and color component values.
     * Each type has a differing number of decode array members, so check
     * the spec.
     * Page 303 in PDF Spec 1.3
     */
    protected List decode = null;

    /**
     * Required for Type 4,5,6, and 7: Specifies the number of bits used
     * to represent each color coordinate.
     * Allowed to be 1,2,4,8,12, or 16
     */
    protected int bitsPerComponent = 0;

    /**
     * Required for Type 5:The number of vertices in each "row" of
     * the lattice; it must be greater than or equal to 2.
     */
    protected int verticesPerRow = 0;

    /**
     * Constructor for type function based shading
     *
     * @param theShadingType The type of shading object, which should be 1 for function
     * based shading.
     * @param theColorSpace The colorspace is 'DeviceRGB' or something similar.
     * @param theBackground An array of color components appropriate to the
     * colorspace key specifying a single color value.
     * This key is used by the f operator buy ignored by the sh operator.
     * @param theBBox List of double's representing a rectangle
     * in the coordinate space that is current at the
     * time of shading is imaged. Temporary clipping
     * boundary.
     * @param theAntiAlias Whether or not to anti-alias.
     * @param theDomain Optional vector of Doubles specifying the domain.
     * @param theMatrix List of Doubles specifying the matrix.
     * If it's a pattern, then the matrix maps it to pattern space.
     * If it's a shading, then it maps it to current user space.
     * It's optional, the default is the identity matrix
     * @param theFunction The PDF Function that maps an (x,y) location to a color
     */
    public PDFShading(int theShadingType, PDFDeviceColorSpace theColorSpace,
            List theBackground, List theBBox,
            boolean theAntiAlias, List theDomain,
            List theMatrix, PDFFunction theFunction) {
        super();
        this.shadingType = theShadingType;    // 1
        this.colorSpace = theColorSpace;
        this.background = theBackground;
        this.bBox = theBBox;
        this.antiAlias = theAntiAlias;

        this.domain = theDomain;
        this.matrix = theMatrix;
        this.function = theFunction;

    }

    /**
     * Constructor for Type 2 and 3
     *
     * @param theShadingType 2 or 3 for axial or radial shading
     * @param theColorSpace "DeviceRGB" or similar.
     * @param theBackground theBackground An array of color components appropriate to the
     * colorspace key specifying a single color value.
     * This key is used by the f operator buy ignored by the sh operator.
     * @param theBBox List of double's representing a rectangle
     * in the coordinate space that is current at the
     * time of shading is imaged. Temporary clipping
     * boundary.
     * @param theAntiAlias Default is false
     * @param theCoords List of four (type 2) or 6 (type 3) Double
     * @param theDomain List of Doubles specifying the domain
     * @param theFunction the Stitching (PDFfunction type 3) function,
     *                    even if it's stitching a single function
     * @param theExtend List of Booleans of whether to extend the start
     *                  and end colors past the start and end points
     * The default is [false, false]
     */
    public PDFShading(int theShadingType, PDFDeviceColorSpace theColorSpace,
            List theBackground, List theBBox,
            boolean theAntiAlias, List theCoords,
            List theDomain, Function theFunction,
            List theExtend) {
        super();
        this.shadingType = theShadingType;    // 2 or 3
        this.colorSpace = theColorSpace;
        this.background = theBackground;
        this.bBox = theBBox;
        this.antiAlias = theAntiAlias;

        this.coords = theCoords;
        this.domain = theDomain;
        assert theFunction instanceof PDFFunction;
        this.function = (PDFFunction)theFunction;
        this.extend = theExtend;

    }

    /**
     * Constructor for Type 4,6, or 7
     *
     * @param theShadingType 4, 6, or 7 depending on whether it's
     * Free-form gouraud-shaded triangle meshes, coons patch meshes,
     * or tensor product patch meshes, respectively.
     * @param theColorSpace "DeviceRGB" or similar.
     * @param theBackground theBackground An array of color components appropriate to the
     * colorspace key specifying a single color value.
     * This key is used by the f operator buy ignored by the sh operator.
     * @param theBBox List of double's representing a rectangle
     * in the coordinate space that is current at the
     * time of shading is imaged. Temporary clipping
     * boundary.
     * @param theAntiAlias Default is false
     * @param theBitsPerCoordinate 1,2,4,8,12,16,24 or 32.
     * @param theBitsPerComponent 1,2,4,8,12, and 16
     * @param theBitsPerFlag 2,4,8.
     * @param theDecode List of Doubles see PDF 1.3 spec pages 303 to 312.
     * @param theFunction the PDFFunction
     */
    public PDFShading(int theShadingType, PDFDeviceColorSpace theColorSpace,
            List theBackground, List theBBox,
            boolean theAntiAlias, int theBitsPerCoordinate,
            int theBitsPerComponent, int theBitsPerFlag,
            List theDecode, PDFFunction theFunction) {
        super();

        this.shadingType = theShadingType;    // 4,6 or 7
        this.colorSpace = theColorSpace;
        this.background = theBackground;
        this.bBox = theBBox;
        this.antiAlias = theAntiAlias;

        this.bitsPerCoordinate = theBitsPerCoordinate;
        this.bitsPerComponent = theBitsPerComponent;
        this.bitsPerFlag = theBitsPerFlag;
        this.decode = theDecode;
        this.function = theFunction;
    }

    /**
     * Constructor for type 5
     *
     * @param theShadingType 5 for lattice-Form Gouraud shaded-triangle mesh
     * @param theColorSpace "DeviceRGB" or similar.
     * @param theBackground theBackground An array of color components appropriate to the
     * colorspace key specifying a single color value.
     * This key is used by the f operator buy ignored by the sh operator.
     * @param theBBox List of double's representing a rectangle
     * in the coordinate space that is current at the
     * time of shading is imaged. Temporary clipping
     * boundary.
     * @param theAntiAlias Default is false
     * @param theBitsPerCoordinate 1,2,4,8,12,16, 24, or 32
     * @param theBitsPerComponent 1,2,4,8,12,24,32
     * @param theDecode List of Doubles. See page 305 in PDF 1.3 spec.
     * @param theVerticesPerRow number of vertices in each "row" of the lattice.
     * @param theFunction The PDFFunction that's mapped on to this shape
     */
    public PDFShading(int theShadingType, PDFDeviceColorSpace theColorSpace,
            List theBackground, List theBBox,
            boolean theAntiAlias, int theBitsPerCoordinate,
            int theBitsPerComponent, List theDecode,
            int theVerticesPerRow, PDFFunction theFunction) {
        super();
        this.shadingType = theShadingType;    // 5
        this.colorSpace = theColorSpace;
        this.background = theBackground;
        this.bBox = theBBox;
        this.antiAlias = theAntiAlias;

        this.bitsPerCoordinate = theBitsPerCoordinate;
        this.bitsPerComponent = theBitsPerComponent;
        this.decode = theDecode;
        this.verticesPerRow = theVerticesPerRow;
        this.function = theFunction;

    }

    /**
     * Get the name of this shading.
     *
     * @return the name of the shading
     */
    public String getName() {
        return (this.shadingName);
    }

    /**
     * Sets the name of the shading
     * @param name the name of the shading pattern. Can be anything
     * without spaces. "Shading1" or "Sh1" are good examples.
     */
    public void setName(String name) {
        if (name.indexOf(" ") >= 0) {
            throw new IllegalArgumentException(
                    "Shading name must not contain any spaces");
        }
        this.shadingName = name;
    }

    /**
     * represent as PDF. Whatever the shadingType is, the correct
     * representation spits out. The sets of required and optional
     * attributes are different for each type, but if a required
     * attribute's object was constructed as null, then no error
     * is raised. Instead, the malformed PDF that was requested
     * by the construction is dutifully output.
     * This policy should be reviewed.
     *
     * @return the PDF string.
     */
    public String toPDFString() {
        ShadingPattern pattern = new ShadingPattern(this);
        return pattern.toString(colorSpace, shadingType, background, bBox, antiAlias);
    }

    /** {@inheritDoc} */
    protected boolean contentEquals(PDFObject obj) {
        if (obj == null) {
            return false;
        }
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof PDFShading)) {
            return false;
        }
        PDFShading shad = (PDFShading)obj;
        if (shadingType != shad.shadingType) {
            return false;
        }
        if (antiAlias != shad.antiAlias) {
            return false;
        }
        if (bitsPerCoordinate != shad.bitsPerCoordinate) {
            return false;
        }
        if (bitsPerFlag != shad.bitsPerFlag) {
            return false;
        }
        if (bitsPerComponent != shad.bitsPerComponent) {
            return false;
        }
        if (verticesPerRow != shad.verticesPerRow) {
            return false;
        }
        if (colorSpace != null) {
            if (!colorSpace.equals(shad.colorSpace)) {
                return false;
            }
        } else if (shad.colorSpace != null) {
            return false;
        }
        if (background != null) {
            if (!background.equals(shad.background)) {
                return false;
            }
        } else if (shad.background != null) {
            return false;
        }
        if (bBox != null) {
            if (!bBox.equals(shad.bBox)) {
                return false;
            }
        } else if (shad.bBox != null) {
            return false;
        }
        if (domain != null) {
            if (!domain.equals(shad.domain)) {
                return false;
            }
        } else if (shad.domain != null) {
            return false;
        }
        if (matrix != null) {
            if (!matrix.equals(shad.matrix)) {
                return false;
            }
        } else if (shad.matrix != null) {
            return false;
        }
        if (coords != null) {
            if (!coords.equals(shad.coords)) {
                return false;
            }
        } else if (shad.coords != null) {
            return false;
        }
        if (extend != null) {
            if (!extend.equals(shad.extend)) {
                return false;
            }
        } else if (shad.extend != null) {
            return false;
        }
        if (decode != null) {
            if (!decode.equals(shad.decode)) {
                return false;
            }
        } else if (shad.decode != null) {
            return false;
        }
        if (function != null) {
            if (!function.equals(shad.function)) {
                return false;
            }
        } else if (shad.function != null) {
            return false;
        }
        return true;
    }

    /**
     * A method to write a type 1 shading object
     * @param p The StringBuffer to write the shading object
     * @return Returns the StringBuffer to which the shading object was written
     */
    public StringBuffer handleShadingType1(StringBuffer p) {
        if (this.domain != null) {
            p.append("/Domain [ ");
            for (int domainIndex = 0; domainIndex < domain.size(); domainIndex++) {
                p.append(PDFNumber.doubleOut((Double)this.domain.get(domainIndex))
                         + " ");
            }
            p.append("] \n");
        } else {
            p.append("/Domain [ 0 1 ] \n");
        }

        if (this.matrix != null) {
            p.append("/Matrix [ ");
            for (int matrixIndex = 0; matrixIndex < matrix.size(); matrixIndex++) {
                p.append(PDFNumber.doubleOut((Double)this.matrix.get(matrixIndex))
                         + " ");
            }
            p.append("] \n");
        }

        if (this.function != null) {
            p.append("/Function ");
            p.append(this.function.referencePDF() + " \n");
        }
        return p;
    }

    /**
     * A method to write a type 2 or 3 shading object
     * @param p The StringBuffer to write the shading object
     * @return Returns the StringBuffer to which the shading object was written
     */
    public StringBuffer handleShadingType2or3(StringBuffer p) {
        // 3 is radial shading (circular gradient)
        if (this.coords != null) {
            p.append("/Coords [ ");
            for (int coordIndex = 0; coordIndex < coords.size(); coordIndex++) {
                p.append(PDFNumber.doubleOut((Double)this.coords.get(coordIndex))
                         + " ");
            }
            p.append("] \n");
        }

        // DOMAIN
        if (this.domain != null) {
            p.append("/Domain [ ");
            for (int domainIndex = 0; domainIndex < domain.size(); domainIndex++) {
                p.append(PDFNumber.doubleOut((Double)this.domain.get(domainIndex))
                         + " ");
            }
            p.append("] \n");
        } else {
            p.append("/Domain [ 0 1 ] \n");
        }

        if (this.extend != null) {
            p.append("/Extend [ ");
            for (int extendIndex = 0; extendIndex < extend.size(); extendIndex++) {
                p.append((this.extend.get(extendIndex)) + " ");
            }

            p.append("] \n");
        } else {
            p.append("/Extend [ true true ] \n");
        }


        if (this.function != null) {
            p.append("/Function ");
            p.append(this.function.referencePDF() + " \n");
        }

        return p;
    }

    /**
     * A method to write a type 4, 6 or 7 shading object
     * @param p The StringBuffer to write the shading object
     * @return Returns the StringBuffer to which the shading object was written
     */
    public StringBuffer handleShadingType4or6or7(StringBuffer p) {
        // 6:coons patch meshes
        // 7://tensor product patch meshes (which no one ever uses)
        if (this.bitsPerCoordinate > 0) {
            p.append("/BitsPerCoordinate " + this.bitsPerCoordinate
                     + " \n");
        } else {
            p.append("/BitsPerCoordinate 1 \n");
        }

        if (this.bitsPerComponent > 0) {
            p.append("/BitsPerComponent " + this.bitsPerComponent
                     + " \n");
        } else {
            p.append("/BitsPerComponent 1 \n");
        }

        if (this.bitsPerFlag > 0) {
            p.append("/BitsPerFlag " + this.bitsPerFlag + " \n");
        } else {
            p.append("/BitsPerFlag 2 \n");
        }

        if (this.decode != null) {
            p.append("/Decode [ ");
            for (int decodeIndex = 0; decodeIndex < decode.size(); decodeIndex++) {
                p.append((this.decode.get(decodeIndex)) + " ");
            }

            p.append("] \n");
        }

        if (this.function != null) {
            p.append("/Function ");
            p.append(this.function.referencePDF() + " \n");
        }

        return p;
    }

    /**
     * A method to write a type 5 shading object
     * @param p The StringBuffer to write the shading object
     * @return Returns the StringBuffer to which the shading object was written
     */
    public StringBuffer handleShadingType5(StringBuffer p) {
        if (this.bitsPerCoordinate > 0) {
            p.append("/BitsPerCoordinate " + this.bitsPerCoordinate
                     + " \n");
        } else {
            p.append("/BitsPerCoordinate 1 \n");
        }

        if (this.bitsPerComponent > 0) {
            p.append("/BitsPerComponent " + this.bitsPerComponent
                     + " \n");
        } else {
            p.append("/BitsPerComponent 1 \n");
        }

        if (this.decode != null) {
            p.append("/Decode [ ");
            for (int decodeIndex = 0; decodeIndex < decode.size(); decodeIndex++) {
                p.append((this.decode.get(decodeIndex)) + " ");
            }

            p.append("] \n");
        }

        if (this.function != null) {
            p.append("/Function ");
            p.append(this.function.referencePDF() + " \n");
        }

        if (this.verticesPerRow > 0) {
            p.append("/VerticesPerRow " + this.verticesPerRow + " \n");
        } else {
            p.append("/VerticesPerRow 2 \n");
        }

        return p;
    }
}