/*
 * 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.fop.render.gradient;

import java.util.Arrays;
import java.util.List;

import org.apache.fop.pdf.PDFDeviceColorSpace;
import org.apache.fop.render.gradient.GradientMaker.DoubleFormatter;


public class Shading {

    public interface FunctionRenderer {

        void outputFunction(StringBuilder out);
    }

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

    
A ColorSpace representing the colorspace. "DeviceRGB" is an example.
/**
     * A ColorSpace representing the colorspace. "DeviceRGB" is an example.
     */
    private final PDFDeviceColorSpace colorSpace;

    
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.
/**
     * 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.
     */
    private final List<Double> coords;

    
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.
/**
     * 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.
     */
    private final Function function;

    
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.
/**
     * 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.
     */
    private final List<Boolean> extend;

    
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.
/**
     * 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.
     */
    private final int bitsPerCoordinate;

    
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.
/**
     * 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.
     */
    private final int bitsPerFlag;

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

    
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
/**
     * 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
     */
    private final int bitsPerComponent;

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

    public Shading(int shadingType, PDFDeviceColorSpace colorSpace,
            List<Double> coords, Function function) {
        this.shadingType = shadingType;
        this.colorSpace = colorSpace;
        this.antiAlias = false;
        this.coords = coords;
        this.function = function;
        this.extend = Arrays.asList(true, true);
        this.bitsPerCoordinate = 0;
        this.bitsPerFlag = 0;
        this.bitsPerComponent = 0;
        this.verticesPerRow = 0;
    }

    public int getShadingType() {
        return shadingType;
    }

    public PDFDeviceColorSpace getColorSpace() {
        return colorSpace;
    }

    public List<Double> getCoords() {
        return coords;
    }

    public Function getFunction() {
        return function;
    }

    public List<Boolean> getExtend() {
        return extend;
    }

    public int getBitsPerCoordinate() {
        return bitsPerCoordinate;
    }

    public int getBitsPerFlag() {
        return bitsPerFlag;
    }

    public boolean isAntiAlias() {
        return antiAlias;
    }

    public int getBitsPerComponent() {
        return bitsPerComponent;
    }

    public int getVerticesPerRow() {
        return verticesPerRow;
    }

    public void output(StringBuilder out, DoubleFormatter doubleFormatter, FunctionRenderer functionRenderer) {
        out.append("<<\n/ShadingType " + shadingType + "\n");
        if (colorSpace != null) {
            out.append("/ColorSpace /" + colorSpace.getName() + "\n");
        }

        if (antiAlias) {
            out.append("/AntiAlias " + antiAlias + "\n");
        }

        switch (shadingType) {
        // Function based shading
        case 1: outputShadingType1(out, doubleFormatter, functionRenderer); break;
        // Axial shading
        case 2:
        // Radial shading
        case 3: outputShadingType2or3(out, doubleFormatter, functionRenderer); break;
        // Free-form Gouraud-shaded triangle meshes
        case 4:
        // Coons patch meshes
        case 6:
        // Tensor product patch meshes
        case 7: outputShadingType4or6or7(out, doubleFormatter, functionRenderer); break;
        // Lattice Free form gouraud-shaded triangle mesh
        case 5: outputShadingType5(out, doubleFormatter, functionRenderer); break;
        default: throw new UnsupportedOperationException("Shading type " + shadingType);
        }

        out.append(">>");
    }

    private void outputShadingType1(StringBuilder out, DoubleFormatter doubleFormatter,
            Shading.FunctionRenderer functionRenderer) {
        outputFunction(out, functionRenderer);
    }

    private void outputShadingType2or3(StringBuilder out, DoubleFormatter doubleFormatter,
            Shading.FunctionRenderer functionRenderer) {
        if (coords != null) {
            out.append("/Coords ");
            GradientMaker.outputDoubles(out, doubleFormatter, coords);
            out.append("\n");
        }

        out.append("/Extend [ ");
        for (Boolean b : extend) {
            out.append(b);
            out.append(" ");
        }
        out.append("]\n");

        outputFunction(out, functionRenderer);
    }

    private void outputShadingType4or6or7(StringBuilder out, DoubleFormatter doubleFormatter,
            Shading.FunctionRenderer functionRenderer) {
        if (bitsPerCoordinate > 0) {
            out.append("/BitsPerCoordinate " + bitsPerCoordinate + "\n");
        } else {
            out.append("/BitsPerCoordinate 1 \n");
        }

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

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

        outputFunction(out, functionRenderer);
    }

    private void outputShadingType5(StringBuilder out, DoubleFormatter doubleFormatter,
            Shading.FunctionRenderer functionRenderer) {
        if (bitsPerCoordinate > 0) {
            out.append("/BitsPerCoordinate " + bitsPerCoordinate + "\n");
        } else {
            out.append("/BitsPerCoordinate 1 \n");
        }

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

        outputFunction(out, functionRenderer);

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

    private void outputFunction(StringBuilder out, FunctionRenderer functionRenderer) {
        if (function != null) {
            out.append("/Function ");
            functionRenderer.outputFunction(out);
            out.append("\n");
        }
    }
}