/*
 * $Id: ScaleOpBitmapImpl.java 5917 2009-08-11 21:15:21Z uckelman $
 *
 * Copyright (c) 2007 by Joel Uckelman
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License (LGPL) as published by the Free Software Foundation.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, copies are available
 * at http://www.opensource.org.
 */

package VASSAL.tools.imageop;

import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.awt.image.WritableRaster;
import java.util.Collections;
import java.util.List;

import VASSAL.tools.HashCode;
import VASSAL.tools.image.GeneralFilter;
import VASSAL.tools.image.ImageUtils;

/**
 * An {@link ImageOp} which scales its source.
 *
 * @since 3.1.0
 * @author Joel Uckelman
 */
public class ScaleOpBitmapImpl extends AbstractTiledOpImpl
                               implements ScaleOp {
  private final ImageOp sop;
  private final double scale;
  private final RenderingHints hints;
  private final int hash;

  // FIXME: We try to always use the same hints object because hints is
  // used in our equals() and RenderingHints.equals() is ridiculously slow
  // if a full comparison is made. This way hints == defaultHints, usually,
  // and so a quick equality comparison succeeds.
  private static final RenderingHints defaultHints =
    ImageUtils.getDefaultHints();

  /**
   * Constructs an <code>ImageOp</code> which will scale
   * the image produced by its source <code>ImageOp</code>.
   *
   * @param sop the source operation
   * @param scale the scale factor
   */
  public ScaleOpBitmapImpl(ImageOp sop, double scale) {
    this(sop, scale, defaultHints);
  }

  /**
   * Constructs an <code>ImageOp</code> which will scale
   * the image produced by its source <code>ImageOp</code>.
   *
   * @param sop the source operation
   * @param scale the scale factor
   * @param hints rendering hints
   */
  public ScaleOpBitmapImpl(ImageOp sop, double scale, RenderingHints hints) {
    if (sop == null)
      throw new IllegalArgumentException("Attempt to scale null image");
    if (scale <= 0)
      throw new IllegalArgumentException("Cannot scale image at " + scale);

    this.sop = sop;
    this.scale = scale;
    this.hints = hints;

    hash = HashCode.hash(scale) ^
           HashCode.hash(hints) ^
           HashCode.hash(sop);
  }

  public List<VASSAL.tools.opcache.Op<?>> getSources() {
    return Collections.<VASSAL.tools.opcache.Op<?>>singletonList(sop);
  }

  /**
   * {@inheritDoc}
   *
   * @throws Exception passed up from the source <code>ImageOp</code>.
   */
  public BufferedImage eval() throws Exception {
    return ImageUtils.transform(sop.getImage(null), scale, 0.0, hints);
  }

  /** {@inheritDoc} */
  protected void fixSize() {
    if ((size = getSizeFromCache()) == null) {
      size = ImageUtils.transform(
        new Rectangle(sop.getSize()), scale, 0.0).getSize();
    }
  }

  protected ImageOp createTileOp(int tileX, int tileY) {
    return new TileOp(this, tileX, tileY);
  }

  private static class TileOp extends AbstractTileOpImpl {
     private final ImageOp sop;
     private final int dx0, dy0, dw, dh;
     private final double scale;
     @SuppressWarnings("unused")
     private final RenderingHints hints;
     private final int hash;
 
     private static final GeneralFilter.Filter downFilter =
       new GeneralFilter.Lanczos3Filter();
     private static final GeneralFilter.Filter upFilter =
       new GeneralFilter.MitchellFilter();
 
     public TileOp(ScaleOpBitmapImpl rop, int tileX, int tileY) {
       if (rop == null) throw new IllegalArgumentException();
 
       if (tileX < 0 || tileX >= rop.getNumXTiles() ||
           tileY < 0 || tileY >= rop.getNumYTiles())
         throw new IndexOutOfBoundsException();
 
      sop = rop.sop;
 
      scale = rop.getScale();
      hints = rop.getHints();
 
      final Rectangle sr =
         new Rectangle(0, 0,
                       (int)(sop.getWidth()*scale),
                       (int)(sop.getHeight()*scale));
 
      dx0 = tileX*rop.getTileWidth();
      dy0 = tileY*rop.getTileHeight();
      dw = Math.min(rop.getTileWidth(), sr.width - dx0);
      dh = Math.min(rop.getTileHeight(), sr.height - dy0);
 
      size = new Dimension(dw,dh);
 
      final int PRIME = 31;
      int result = 1;
      result = PRIME * result + HashCode.hash(sop);
      result = PRIME * result + HashCode.hash(dx0);
      result = PRIME * result + HashCode.hash(dy0);
      result = PRIME * result + HashCode.hash(dw);
      result = PRIME * result + HashCode.hash(dh);
      hash = result;
    }

    public List<VASSAL.tools.opcache.Op<?>> getSources() {
      return Collections.<VASSAL.tools.opcache.Op<?>>singletonList(sop);
    }

    public BufferedImage eval() throws Exception {
      if (dw < 1 || dh < 1) return ImageUtils.NULL_IMAGE;
 
      // ensure that src is a type which GeneralFilter can handle
      final BufferedImage src = ImageUtils.coerceToIntType(sop.getImage(null));

      final Rectangle sr =
        new Rectangle(0, 0,
                      (int)(sop.getWidth()*scale),
                      (int)(sop.getHeight()*scale));

      final WritableRaster dstR = src.getColorModel()
                                     .createCompatibleWritableRaster(dw, dh)
                                     .createWritableTranslatedChild(dx0, dy0);
      // zoom! zoom!
      GeneralFilter.zoom(dstR, sr, src, scale < 1.0f ? downFilter : upFilter);

      return ImageUtils.toCompatibleImage(new BufferedImage(
        src.getColorModel(),
        dstR.createWritableTranslatedChild(0,0),
        src.isAlphaPremultiplied(),
        null
      ));
    }

    protected void fixSize() { }
 
    @Override
    public boolean equals(Object o) {
      if (this == o) return true;
      if (o == null || !(o instanceof TileOp)) return false;

      final TileOp op = (TileOp) o;
      return dx0 == op.dx0 &&
             dy0 == op.dy0 &&
             dw == op.dw &&
             dh == op.dh &&
             scale == op.scale &&
             sop.equals(op.sop);
    }
 
    @Override
    public int hashCode() {
      return hash;
    }
  }

  public RenderingHints getHints() {
    return hints;
  }

  /**
   * Returns the scale factor.
   *
   * @return the scale factor, in the range <code>(0,Double.MAX_VALUE]</code>.
   */
  public double getScale() {
    return scale;
  }
  
  /** {@inheritDoc} */
  @Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || !(o instanceof ScaleOpBitmapImpl)) return false;

    final ScaleOpBitmapImpl op = (ScaleOpBitmapImpl) o;
    return scale == op.getScale() && 
           sop.equals(op.sop) && 
           hints.equals(op.getHints());
  }

  /** {@inheritDoc} */
  @Override
  public int hashCode() {
    return hash;
  }
}
