/*
 * 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: PDFPaintingState.java 1761020 2016-09-16 11:17:35Z ssteiner $ */

package org.apache.fop.pdf;

import java.awt.Color;
import java.awt.Paint;
import java.awt.Shape;
import java.awt.geom.Area;
import java.awt.geom.GeneralPath;

import org.apache.xmlgraphics.java2d.color.ColorUtil;

import org.apache.fop.util.AbstractPaintingState;

This keeps information about the current painting state when writing to pdf.
It allows for creating new graphics states with the q operator.
This class is only used to store the information about the state
the caller needs to handle the actual pdf operators.
When setting the state for pdf there are three possible ways of
handling the situation.
The values can be set to override previous or default values.
A new state can be added and then the values set.
The current state can be popped and values will return to a
previous state then the necessary values can be overridden.
The current transform behaves differently to other values as the
matrix is combined with the current resolved value.
/**
 * This keeps information about the current painting state when writing to pdf.
 * It allows for creating new graphics states with the q operator.
 * This class is only used to store the information about the state
 * the caller needs to handle the actual pdf operators.
 *
 * When setting the state for pdf there are three possible ways of
 * handling the situation.
 * The values can be set to override previous or default values.
 * A new state can be added and then the values set.
 * The current state can be popped and values will return to a
 * previous state then the necessary values can be overridden.
 * The current transform behaves differently to other values as the
 * matrix is combined with the current resolved value.
 */
public class PDFPaintingState extends org.apache.fop.util.AbstractPaintingState {

    private static final long serialVersionUID = 5384726143906371279L;

    
PDF State for storing graphics state.
/**
     * PDF State for storing graphics state.
     */
    public PDFPaintingState() {
    }

    
Set the current paint.
This checks if the paint will change and then sets the current paint.
Params:
p – the new paint
Returns:
true if the new paint changes the current paint/**
     * Set the current paint.
     * This checks if the paint will change and then sets the current paint.
     *
     * @param p the new paint
     * @return true if the new paint changes the current paint
     */
    public boolean setPaint(Paint p) {
        PDFData data = getPDFData();
        Paint currentPaint = data.paint;
        if (currentPaint == null) {
            if (p != null) {
                data.paint = p;
                return true;
            }
        } else if (p instanceof Color && currentPaint instanceof Color) {
            if (!ColorUtil.isSameColor((Color)p, (Color)currentPaint)) {
                data.paint = p;
                return true;
            }
        } else if (!currentPaint.equals(p)) {
            data.paint = p;
            return true;
        }
        return false;
    }

    
Check if the clip will change the current state.
A clip is assumed to be used in a situation where it will add
to any clip in the current or parent states.
A clip cannot be cleared, this can only be achieved by going to
a parent level with the correct clip.
If the clip is different then it may start a new state so that
it can return to the previous clip.
Params:
cl – the clip shape to check
Returns:
true if the clip will change the current clip./**
     * Check if the clip will change the current state.
     * A clip is assumed to be used in a situation where it will add
     * to any clip in the current or parent states.
     * A clip cannot be cleared, this can only be achieved by going to
     * a parent level with the correct clip.
     * If the clip is different then it may start a new state so that
     * it can return to the previous clip.
     *
     * @param cl the clip shape to check
     * @return true if the clip will change the current clip.
     */
    public boolean checkClip(Shape cl) {
        Shape clip = getPDFData().clip;
        if (clip == null) {
            if (cl != null) {
                return true;
            }
        } else if (!new Area(clip).equals(new Area(cl))) {
            return true;
        }
        //TODO check for clips that are larger than the current
        return false;
    }

    
Set the current clip.
This either sets a new clip or sets the clip to the intersect of
the old clip and the new clip.
Params:
cl – the new clip in the current state/**
     * Set the current clip.
     * This either sets a new clip or sets the clip to the intersect of
     * the old clip and the new clip.
     *
     * @param cl the new clip in the current state
     */
    public void setClip(Shape cl) {
        PDFData data = getPDFData();
        Shape clip = data.clip;
        if (clip != null) {
            Area newClip = new Area(clip);
            newClip.intersect(new Area(cl));
            data.clip = new GeneralPath(newClip);
        } else {
            data.clip = cl;
        }
    }

    
Sets the character spacing (Tc).
Params:
value – the new value
Returns:
true if the value was changed with respect to the previous value/**
     * Sets the character spacing (Tc).
     * @param value the new value
     * @return true if the value was changed with respect to the previous value
     */
    public boolean setCharacterSpacing(float value) {
        PDFData data = getPDFData();
        if (value != data.characterSpacing) {
            data.characterSpacing = value;
            return true;
        }
        return false;
    }

    
Returns the current character spacing (Tc) value.
Returns:
the Tc value/**
     * Returns the current character spacing (Tc) value.
     * @return the Tc value
     */
    public float getCharacterSpacing() {
        return getPDFData().characterSpacing;
    }

    
Get the current stack level.
Returns:
the current stack level/**
     * Get the current stack level.
     *
     * @return the current stack level
     */
    public int getStackLevel() {
        return getStateStack().size();
    }

    
Get the graphics state.
This gets the combination of all graphic states for
the current context.
This is the graphic state set with the gs operator not
the other graphic state changes.
Returns:
the calculated ExtGState in the current context/**
     * Get the graphics state.
     * This gets the combination of all graphic states for
     * the current context.
     * This is the graphic state set with the gs operator not
     * the other graphic state changes.
     *
     * @return the calculated ExtGState in the current context
     */
    public PDFGState getGState() {
        PDFGState defaultState = PDFGState.DEFAULT;

        PDFGState state;
        PDFGState newState = new PDFGState();
        newState.addValues(defaultState);
        for (AbstractData abstractData : getStateStack()) {
            PDFData data = (PDFData) abstractData;
            state = data.gstate;
            if (state != null) {
                newState.addValues(state);
            }
        }
        if (getPDFData().gstate != null) {
            newState.addValues(getPDFData().gstate);
        }
        return newState;
    }

    public void setLayer(String layer) {
        getPDFData().setLayer(layer);
    }

    public String getLayer() {
        return getPDFData().getLayer();
    }

    public boolean getLayerChanged() {
        String layerCurrent = getLayer();
        if (layerCurrent == null) {
            return false;
        } else if (getStateStack().isEmpty()) {
            return true;
        } else {
            for (int i = getStackLevel(); i > 0; --i) {
                String layerPrev = ((PDFData) getStateStack().get(i - 1)).getLayer();
                if (layerPrev == null) {
                    continue;
                } else {
                    // Both current and prior are set, so, if same, then we know layer
                    // didn't change (and can stop search), otherwise it did change.
                    return !layerCurrent.equals(layerPrev);
                }
            }
            // Current layer set, but no prior saved layer set, so must have changed.
            return true;
        }
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    protected AbstractData instantiateData() {
        return new PDFData();
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    protected AbstractPaintingState instantiate() {
        return new PDFPaintingState();
    }

    
Push the current state onto the stack.
This call should be used when the q operator is used
so that the state is known when popped.
/**
     * Push the current state onto the stack.
     * This call should be used when the q operator is used
     * so that the state is known when popped.
     */
    @Override
    public void save() {
        AbstractData data = getData();
        AbstractData copy = (AbstractData)data.clone();
        data.clearTransform();
        getStateStack().push(copy);
    }

    private PDFData getPDFData() {
        return (PDFData)getData();
    }

    // @SuppressFBWarnings("SE_INNER_CLASS")
    private class PDFData extends org.apache.fop.util.AbstractPaintingState.AbstractData {

        private static final long serialVersionUID = 3527950647293177764L;

        private Paint paint;
        private Paint backPaint;
        //private int lineCap = 0; //Disabled the ones that are not used, yet
        //private int lineJoin = 0;
        //private float miterLimit = 0;
        //private int dashOffset = 0;
        private Shape clip;
        private PDFGState gstate;

        //text state
        private float characterSpacing;

        
{@inheritDoc} /** {@inheritDoc} */
        @Override
        public Object clone() {
            PDFData obj = (PDFData)super.clone();
            obj.paint = this.paint;
            obj.backPaint = this.paint;
            //obj.lineCap = this.lineCap;
            //obj.lineJoin = this.lineJoin;
            //obj.miterLimit = this.miterLimit;
            //obj.dashOffset = this.dashOffset;
            obj.clip = this.clip;
            obj.gstate = this.gstate;
            obj.characterSpacing = this.characterSpacing;
            return obj;
        }

        
{@inheritDoc} /** {@inheritDoc} */
        @Override
        public String toString() {
            return super.toString()
                + ", paint=" + paint
                + ", backPaint=" + backPaint
                //+ ", lineCap=" + lineCap
                //+ ", miterLimit=" + miterLimit
                //+ ", dashOffset=" + dashOffset
                + ", clip=" + clip
                + ", gstate=" + gstate;
        }

        
{@inheritDoc} /** {@inheritDoc} */
        @Override
        protected AbstractData instantiate() {
            return new PDFData();
        }
    }

}