/**
 * <copyright> Copyright 2006 by Know-Center, Graz, Austria </copyright>
 * PDF-AS has been contracted by the E-Government Innovation Center EGIZ, a
 * joint initiative of the Federal Chancellery Austria and Graz University of
 * Technology.
 *
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * http://www.osor.eu/eupl/
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 *
 * $Id: PDFPage.java,v 1.5 2006/10/31 08:09:33 wprinz Exp $
 */
package at.knowcenter.wag.egov.egiz.pdf;

import java.awt.Rectangle;
import java.awt.geom.GeneralPath;
import java.io.IOException;
import java.util.List;
import java.util.Map;

import org.apache.commons.lang.math.NumberUtils;
import org.apache.log4j.Logger;
import org.pdfbox.cos.COSName;
import org.pdfbox.cos.COSStream;
import org.pdfbox.pdmodel.PDPage;
import org.pdfbox.pdmodel.PDResources;
import org.pdfbox.pdmodel.common.PDRectangle;
import org.pdfbox.pdmodel.common.PDStream;
import org.pdfbox.pdmodel.graphics.xobject.PDXObject;
import org.pdfbox.pdmodel.graphics.xobject.PDXObjectForm;
import org.pdfbox.util.Matrix;
import org.pdfbox.util.PDFOperator;
import org.pdfbox.util.PDFTextStripper;
import org.pdfbox.util.TextPosition;
import org.pdfbox.util.operator.OperatorProcessor;

import at.knowcenter.wag.egov.egiz.cfg.ConfigLogger;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.construction.ClosePath;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.construction.CurveTo;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.construction.CurveToReplicateFinalPoint;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.construction.CurveToReplicateInitialPoint;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.construction.LineTo;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.construction.MoveTo;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.painting.CloseAndStrokePath;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.painting.CloseFillEvenOddAndStrokePath;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.painting.CloseFillNonZeroAndStrokePath;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.painting.EndPath;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.painting.FillEvenOddAndStrokePath;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.painting.FillNonZeroAndStrokePath;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.painting.FillPathEvenOddRule;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.painting.FillPathNonZeroWindingNumberRule;
import at.knowcenter.wag.egov.egiz.pdf.operator.path.painting.StrokePath;

/**
 * PDFPage is an inner class that is used to calculate the page length of a PDF
 * Document page. It extends the PDFTextStripper class and implement one
 * interested method: {@link PDFPage#showCharacter(TextPosition)}<br>
 * This method is called when processing the FileStream. By calling the method
 * {@link org.pdfbox.util.PDFStreamEngine#processStream(org.pdfbox.pdmodel.PDPage, org.pdfbox.pdmodel.PDResources, org.pdfbox.cos.COSStream)}
 * the implemented method showCharacter is called.
 *
 * @author wlackner
 * @see PDFTextStripper
 */
public class PDFPage extends PDFTextStripper
{
  /**
   * The logger definition.
   */
  private static final Logger logger_ = ConfigLogger.getLogger(PDFPage.class);

  /**
   * The maximum (lowest) y position of a character.
   */
  protected float max_character_ypos = Float.NEGATIVE_INFINITY;

  /**
   * The maximum (lowest y position of an image.
   */
  protected float max_image_ypos = Float.NEGATIVE_INFINITY;

  /**
   * The effective page height.
   */
  protected float effectivePageHeight;

  /**
   * The path currently being constructed.
   */
  private GeneralPath currentPath = new GeneralPath();

  /**
   * The lowest position of a drawn path (originating from top).
   */
  private float maxPathRelatedYPositionFromTop = Float.NEGATIVE_INFINITY;

  /**
   * Constructor.
   *
   * @param effectivePageHeight The height of the page to be evaluated. PDF elements outside this height will not be considered.
   *
   * @throws IOException
   */
  public PDFPage(float effectivePageHeight) throws IOException
  {
    super();

    this.effectivePageHeight = effectivePageHeight;

    OperatorProcessor newInvoke = new MyInvoke();
    newInvoke.setContext(this);
    operators.put("Do", newInvoke);

    registerCustomPathOperators();
  }

	/**
	 * Registers operators responsible for path construction and painting in order to fix auto positioning on pages with
	 * path elements.
	 *
	 * @author Datentechnik Innovation GmbH
	 */
	@SuppressWarnings("unchecked")
	private void registerCustomPathOperators() {

		// *** path construction

		operators.put("m", new MoveTo(this));
		operators.put("l", new LineTo(this));
		operators.put("c", new CurveTo(this));
		operators.put("y", new CurveToReplicateFinalPoint(this));
		operators.put("v", new CurveToReplicateInitialPoint(this));
		operators.put("h", new ClosePath(this));

		// *** path painting

		// "S": stroke path
		operators.put("S", new StrokePath(this));
		operators.put("s", new CloseAndStrokePath(this));
		operators.put("f", new FillPathNonZeroWindingNumberRule(this));
		operators.put("F", new FillPathNonZeroWindingNumberRule(this));
		operators.put("f*", new FillPathEvenOddRule(this));
		operators.put("b", new CloseFillNonZeroAndStrokePath(this));
		operators.put("B", new FillNonZeroAndStrokePath(this));
		operators.put("b*", new CloseFillEvenOddAndStrokePath(this));
		operators.put("B*", new FillEvenOddAndStrokePath(this));
		operators.put("n", new EndPath(this));

		// Note: The graphic context (org.pdfbox.pdmodel.graphics.PDGraphicsState) of the underlying pdfbox library does
		// not yet support clipping. This prevents feasible usage of clipping operators (W, W*).
//		operators.put("W", new ...(this));
//		operators.put("W*", new ...(this));

	}

	/**
	 * Returns the path currently being constructed.
	 *
	 * @return The path currently being constructed.
	 */
	public GeneralPath getCurrentPath() {
		return currentPath;
	}

	/**
	 * Sets the current path.
	 * @param currentPath The new current path.
	 */
	public void setCurrentPath(GeneralPath currentPath) {
		this.currentPath = currentPath;
	}

	/**
	 * Registers a rectangle that bounds the path currently being drawn.
	 *
	 * @param bounds
	 *            A rectangle depicting the bounds (coordinates originating from bottom left).
	 * @author Datentechnik Innovation GmbH
	 */
	public void registerPathBounds(Rectangle bounds) {
		if (!bounds.isEmpty()) {
			logger_.trace("Registering path bounds: " + bounds);

			// vertical start of rectangle (counting from top of page)
			float upperBoundYPositionFromTop;

			// vertical end of rectangle (counting from top of page)
			// this depicts the current end of path-related page content
			float lowerBoundYPositionFromTop;

			PDRectangle boundaryBox = page.findMediaBox();
			float pageHeight;

			switch (page.findRotation()) {
			case 90: // CW
				pageHeight = boundaryBox.getWidth();
				upperBoundYPositionFromTop = (float) bounds.getMinX();
				lowerBoundYPositionFromTop = (float) bounds.getMaxX();
				break;
			case 180:
				pageHeight = boundaryBox.getHeight();
				upperBoundYPositionFromTop = (float) bounds.getMinY();
				lowerBoundYPositionFromTop = (float) bounds.getMaxY();
				break;
			case 270: // CCW
				pageHeight = boundaryBox.getWidth();
				upperBoundYPositionFromTop = pageHeight - (float) bounds.getMaxX();
				lowerBoundYPositionFromTop = pageHeight - (float) bounds.getMinX();
				break;
			default:
				pageHeight = boundaryBox.getHeight();
				upperBoundYPositionFromTop = pageHeight - (float) bounds.getMaxY();
				lowerBoundYPositionFromTop = pageHeight - (float) bounds.getMinY();
				break;
			}

			// new maximum ?
			if (lowerBoundYPositionFromTop > maxPathRelatedYPositionFromTop) {
				// Is the rectangle (at least partly) located above the footer line?
				// (effective page height := page height - footer line)
				if (upperBoundYPositionFromTop <= effectivePageHeight) {
					// yes: update current end of path-related page content
					maxPathRelatedYPositionFromTop = lowerBoundYPositionFromTop;
					logger_.trace("New max path related y position (from top): " + maxPathRelatedYPositionFromTop);
				} else {
					// no: rectangle is fully located below the footer line -> ignore
					logger_.trace("Ignoring path bound below the footer line.");
				}
			}
		}
	}

  protected void processOperator(PDFOperator operator, List arguments) throws IOException
  {
//    logger_.debug("operator = " + operator);
	  super.processOperator(operator, arguments);
  }

  // exthex
  /**
   * A method provided as an event interface to allow a subclass to perform some
   * specific functionality when a character needs to be displayed. This method
   * is used to calculate the latest position of a text in the page. Sorry for
   * this missinterpretation of the method, but it is the only way to do this
   * (provided by PDFBox)!!!
   *
   * @param text
   *          the character to be displayed -> calculate there y position.
   */
  protected void showCharacter(TextPosition text)
  {
    float current_y = text.getY();
    final String character = text.getCharacter();

    int pageRotation = page.findRotation();
    //logger_.debug("PageRotation = " + pageRotation);
    if (pageRotation == 0)
    {
    	current_y = text.getY();
    }
    if (pageRotation == 90)
    {
    	current_y = text.getX();
    }
    if (pageRotation == 180)
    {
      float page_height = page.findMediaBox().getHeight();
      current_y = page_height - text.getY();
    }
    if (pageRotation == 270)
    {
    	float page_height = page.findMediaBox().getHeight();
        current_y = page_height - text.getX();
    }

    if (current_y > this.effectivePageHeight)
    {
      //logger_.debug("character is below footer_line. footer_line = " + this.footer_line + ", text.character=" + character + ", y=" + current_y);
      return;
    }

    // store ypos of the char if it is not empty
    if (!character.equals(" ") && current_y > this.max_character_ypos)
    {
      this.max_character_ypos = current_y;
    }

  }

  // use this funtion getting an unsorted text output
  // public void showString(byte[] string) {
  // logger_.debug(new String(string));
  // }

	/**
	 * Returns the calculated page length.
	 *
	 * @return the max page length value
	 */
	public float getMaxPageLength() {
		if (logger_.isDebugEnabled()) {
			logger_.debug("Determining page content length: text=" + max_character_ypos + ", image=" + max_image_ypos
					+ ", path=" + maxPathRelatedYPositionFromTop);
		}
		return NumberUtils.max(max_character_ypos, max_image_ypos, maxPathRelatedYPositionFromTop);
	}

  public class MyInvoke extends OperatorProcessor
  {

    public void process(PDFOperator operator, List arguments) throws IOException
    {
      COSName name = (COSName) arguments.get(0);

      // PDResources res = context.getResources();

      Map xobjects = context.getXObjects();
      PDXObject xobject = (PDXObject) xobjects.get(name.getName());

      PDStream stream = xobject.getPDStream();
      COSStream cos_stream = stream.getStream();

      COSName subtype = (COSName) cos_stream.getDictionaryObject(COSName.SUBTYPE);
      if (subtype.equals(COSName.IMAGE))
      {
        logger_.debug("XObject Image");

        Matrix ctm = context.getGraphicsState().getCurrentTransformationMatrix();
        logger_.debug("ctm = " + ctm);

        Pos [] coordinates = new Pos [] {
        new Pos(0, 0, 1),
        new Pos(1, 0, 1),
        new Pos(0, 1, 1),
        new Pos(1, 1, 1) };

        Pos [] transformed_coordinates = transtormCoordinates(coordinates, ctm);

        /**********************************************************
         * pdf-as fix:
         * calculating min and max point of an image to look where
         * the signature should be placed
         * fix solves problems with footer and images and
         * placement of the signature in an image only pdf document
         **********************************************************/

        float actual_lowest_point = Float.NaN;
        float actual_starting_point = Float.NaN;

        int pageRotation = page.findRotation();
        logger_.debug("PageRotation = " + pageRotation);
        if (pageRotation == 0)
        {
          float min_y = findMinY(transformed_coordinates);
          logger_.debug("min_y = " + min_y);
          float page_height = page.findMediaBox().getHeight();
          logger_.debug("page_height = " + page_height);

          actual_lowest_point = page_height - min_y;
          actual_starting_point = page_height - findMaxY(transformed_coordinates);
        }
        if (pageRotation == 90)
        {
          float max_x = findMaxX(transformed_coordinates);
          logger_.debug("max_x = " + max_x);
          float page_width = page.findMediaBox().getWidth();
          logger_.debug("page_width = " + page_width);

          actual_lowest_point = max_x;
          actual_starting_point = findMinX(transformed_coordinates);
        }
        if (pageRotation == 180)
        {
          float min_y = findMinY(transformed_coordinates);
          logger_.debug("min_y = " + min_y);
          float page_height = page.findMediaBox().getHeight();
          actual_lowest_point = page_height - findMaxY(transformed_coordinates);
          actual_starting_point = page_height - min_y;
        }
        if (pageRotation == 270)
        {
          float min_x = findMinX(transformed_coordinates);
          logger_.debug("min_x = " + min_x);

          float page_width = page.findMediaBox().getWidth();
          logger_.debug("page_width = " + page_width);

          actual_lowest_point = page_width - min_x;
          actual_starting_point = page_width - findMaxX(transformed_coordinates);
        }


        logger_.debug("actual_lowest_point = " + actual_lowest_point);

        if (actual_lowest_point > PDFPage.this.effectivePageHeight && actual_starting_point > PDFPage.this.effectivePageHeight)
        {
          logger_.debug("image is below footer_line");
          return;
        }

        if (actual_lowest_point > PDFPage.this.max_image_ypos)
        {
          PDFPage.this.max_image_ypos = actual_lowest_point;
        }

        return;
      }

      if (xobject instanceof PDXObjectForm)
      {
        PDXObjectForm form = (PDXObjectForm) xobject;
        COSStream invoke = (COSStream) form.getCOSObject();
        PDResources pdResources = form.getResources();
        PDPage page = context.getCurrentPage();
        if (pdResources == null)
        {
          pdResources = page.findResources();
        }

        getContext().processSubStream(page, pdResources, invoke);
      }
    }
  }

  public static Pos [] transtormCoordinates (Pos [] coordinates, Matrix m)
  {
    Pos [] transformed = new Pos [coordinates.length];
    for (int i = 0; i < coordinates.length; i++)
    {
      transformed[i] = transtormCoordinate(coordinates[i], m);
    }
    return transformed;
  }

  public static Pos transtormCoordinate (Pos pos, Matrix m)
  {
    Pos transformed = new Pos();
    transformed.x = pos.x * m.getValue(0, 0) + pos.y * m.getValue(1, 0) + pos.z * m.getValue(2, 0);
    transformed.y = pos.x * m.getValue(0, 1) + pos.y * m.getValue(1, 1) + pos.z * m.getValue(2, 1);
    transformed.z = pos.x * m.getValue(0, 2) + pos.y * m.getValue(1, 2) + pos.z * m.getValue(2, 2);

    logger_.debug(" transformed " + pos + " --> " + transformed);
    return transformed;
  }

  public static float findMinY (Pos [] coordinates)
  {
    float min = Float.POSITIVE_INFINITY;
    for (int i = 0; i < coordinates.length; i++)
    {
      if (coordinates[i].y < min)
      {
        min = coordinates[i].y;
      }
    }
    return min;
  }

	public static float findMaxY(Pos[] coordinates) {
		float max = 0;
		for (int i = 0; i < coordinates.length; i++) {
			if (coordinates[i].y > max) {
				max = coordinates[i].y;
			}
		}
		return max;
	}

  public static float findMaxX (Pos [] coordinates)
  {
    float max = Float.NEGATIVE_INFINITY;
    for (int i = 0; i < coordinates.length; i++)
    {
      if (coordinates[i].x > max)
      {
        max = coordinates[i].x;
      }
    }
    return max;
  }
  public static float findMinX (Pos [] coordinates)
  {
    float min = Float.POSITIVE_INFINITY;
    for (int i = 0; i < coordinates.length; i++)
    {
      if (coordinates[i].x < min)
      {
        min = coordinates[i].x;
      }
    }
    return min;
  }

}