/**
 * <copyright> Copyright (c) 2006 by Know-Center, Graz, Austria </copyright>
 * 
 * This software is the confidential and proprietary information of Know-Center,
 * Graz, Austria. You shall not disclose such Confidential Information and shall
 * use it only in accordance with the terms of the license agreement you entered
 * into with Know-Center.
 * 
 * KNOW-CENTER MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
 * NON-INFRINGEMENT. KNOW-CENTER SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY
 * LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES.
 * 
 * $Id: PDFPage.java,v 1.5 2006/10/31 08:09:33 wprinz Exp $
 */
package at.knowcenter.wag.egov.egiz.pdf;

import java.io.IOException;
import java.util.List;
import java.util.Map;

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.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;

/**
 * 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 y coordinate of the footer line. PDF elements below this footer line will not be regarded.
   */
  protected float footer_line = 0.0f;
  
  /**
   * Constructor.
   * 
   * @param footer_line The y coordinate of the footer line. PDF elements below this footer line will not be regarded.
   * 
   * @throws IOException
   */
  public PDFPage(float footer_line) throws IOException
  {
    super();
    
    this.footer_line = footer_line;
    
    OperatorProcessor newInvoke = new MyInvoke();
    newInvoke.setContext(this);
    operators.put("Do", newInvoke);
  }


  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)
  {
    final float current_y = text.getY();
    final String character = text.getCharacter();
    
    if (current_y > this.footer_line)
    {
      //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;
      //logger_.debug("text.character=" + character + ", y=" + current_y);
      // System.err.println(character + "|" + current_y);
    }

    //logger_.debug("text.character=" + character + ", y=" + current_y);
    // System.err.println(character + "|" + 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()
  {
    float max_ypos = Float.NEGATIVE_INFINITY;
    
    if (this.max_character_ypos > this.max_image_ypos)
    {
      max_ypos = this.max_character_ypos;
    }
    else
    {
      max_ypos = this.max_image_ypos;
    }
    
    return max_ypos;
  }

  public class MyInvoke extends OperatorProcessor
  {

    public void process(PDFOperator operator, List arguments) throws IOException
    {
      COSName name = (COSName) arguments.get(0);
      //logger_.debug("<Do name=\"" + name.getName() + "\">");

      // 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.footer_line && actual_starting_point > PDFPage.this.footer_line)
        {
          logger_.debug("image is below footer_line. footer_line = " + PDFPage.this.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;
  }

}