// Copyright (c) 2003-2008 by Leif Frenzel - see http://leiffrenzel.de

// This code is made available under the terms of the Eclipse Public License,

// version 1.0 (EPL). See http://www.eclipse.org/legal/epl-v10.html

package net.sf.eclipsefp.haskell.ui.internal.editors.haskell.text;



import java.util.HashMap;

import java.util.Iterator;

import java.util.Map;

import net.sf.eclipsefp.haskell.ui.HaskellUIPlugin;

import net.sf.eclipsefp.haskell.ui.internal.preferences.editor.IEditorPreferenceNames;

import org.eclipse.core.runtime.Assert;

import org.eclipse.jface.preference.IPreferenceStore;

import org.eclipse.jface.preference.PreferenceConverter;

import org.eclipse.jface.resource.StringConverter;

import org.eclipse.swt.graphics.Color;

import org.eclipse.swt.graphics.RGB;

import org.eclipse.swt.widgets.Display;





/** Provides colors for syntax coloring in the editor.

  *

  * This is implemented as singleton to make it accessible from

  * everywhere and also to reduce resource management to one single place.

  *

  * @author Leif Frenzel

  */

public class ColorProvider implements IEditorPreferenceNames {



  public static final RGB DEFAULT_COMMENT           = new RGB( 63, 127, 95 );

  public static final RGB DEFAULT_LITERATE_COMMENT  = new RGB( 63, 95, 191 );

  public static final RGB DEFAULT_DOC               = new RGB( 63, 95, 191 );

  public static final RGB DEFAULT_PRAGMA            = new RGB( 63, 95, 191 );

  public static final RGB DEFAULT_KEYWORD           = new RGB( 0, 0, 196 );

  public static final RGB DEFAULT_FUNCTION          = new RGB( 64, 192, 192 );

  public static final RGB DEFAULT_STRING            = new RGB( 128, 64, 64 );

  public static final RGB DEFAULT_CHAR              = new RGB( 96, 96, 96 );

  public static final RGB DEFAULT_NUMBER            = new RGB( 0, 0, 0 );

  public static final RGB DEFAULT_VAR               = new RGB( 0, 0, 0 );

  public static final RGB DEFAULT_VARSYM            = new RGB( 155, 0, 0 );

  public static final RGB DEFAULT_CON               = new RGB( 200, 0, 0 );

  public static final RGB DEFAULT_CPP               = new RGB( 63, 95, 191 );

  public static final RGB DEFAULT_TH                = new RGB( 0, 0, 0 );

  public static final RGB DEFAULT_SYMBOL            = new RGB( 128, 128, 0 );

  public static final RGB DEFAULT_OTHER             = new RGB( 0, 0, 0 );



  /** The internal singleton reference to ColorProvider. */

  private static class SingletonHolder {

    private static final ColorProvider theInstance = new ColorProvider();

  }



  private final Map<RGB, Color> colors;

  private final Map<String, RGB> rgbs;



  private IPreferenceStore prefStore;



  /** <p>constructs the singleton instance of ColorProvider. Private in order

   * to ensure the singleton pattern.</p> */

  private ColorProvider() {

    colors = new HashMap<RGB, Color>( 10 );

    rgbs = new HashMap<String, RGB>( 10 );

    initializeRgbs();

  }



  public static final ColorProvider getInstance() {

    return SingletonHolder.theInstance;

  }



  public ColorProvider(final IPreferenceStore store){

    prefStore=store;

    colors = new HashMap<RGB, Color>( 10 );

    rgbs = new HashMap<String, RGB>( 10 );

    initializeRgbs();

  }



  /** <p>releases all of the color resources held by this ColorProvider.</p> */

  public void dispose() {

    Iterator<Color> it = colors.values().iterator();

    while( it.hasNext() ) {

      it.next().dispose();

      it.remove();

    }

  }



  public Color getColor( final String key ) {

    RGB rgb = rgbs.get( key );

    Assert.isNotNull( rgb );

    return getColor( rgb );

  }



  void changeColor( final String key, final Object newValue ) {

    RGB oldRgb = rgbs.get( key );

    if( oldRgb != null ) {

      RGB newRgb = getNewRgb( newValue );

      if( newRgb != null ) {

        rgbs.put( key, newRgb );

      }

    }

  }





  // helping methods

  //////////////////



  private RGB getNewRgb( final Object value ) {

    RGB result = null;

    if( value instanceof RGB ) {

      result = ( RGB )value;

    } else if( value instanceof String ) {

      result = StringConverter.asRGB( ( String )value );

    }

    return result;

  }



  private Color getColor( final RGB rgb ) {

    Color color = colors.get( rgb );

    if( color == null || color.isDisposed()) {

      color = new Color( Display.getCurrent(), rgb );

      colors.put( rgb, color );

    }

    return color;

  }



  private void initializeRgbs() {

    putRgb( EDITOR_COMMENT_COLOR, DEFAULT_COMMENT );

    putRgb( EDITOR_DOC_COLOR, DEFAULT_DOC);

    putRgb( EDITOR_PRAGMA_COLOR, DEFAULT_PRAGMA );

    putRgb( EDITOR_LITERATE_COMMENT_COLOR, DEFAULT_LITERATE_COMMENT );

    putRgb( EDITOR_FUNCTION_COLOR, DEFAULT_FUNCTION );

    putRgb( EDITOR_KEYWORD_COLOR, DEFAULT_KEYWORD );

    putRgb( EDITOR_DEFAULT_COLOR, DEFAULT_OTHER );

    putRgb( EDITOR_STRING_COLOR, DEFAULT_STRING );

    putRgb( EDITOR_CHAR_COLOR, DEFAULT_CHAR );

    putRgb( EDITOR_NUMBER_COLOR, DEFAULT_NUMBER );

    putRgb( EDITOR_VAR_COLOR, DEFAULT_VAR );

    putRgb( EDITOR_VARSYM_COLOR, DEFAULT_VARSYM );

    putRgb( EDITOR_CON_COLOR, DEFAULT_CON );

    putRgb( EDITOR_CPP_COLOR, DEFAULT_CPP );

    putRgb( EDITOR_TH_COLOR, DEFAULT_TH );

    putRgb( EDITOR_SYMBOL_COLOR, DEFAULT_SYMBOL );

  }



  private void putRgb( final String key, final RGB defaultRgb ) {

    RGB rgb = PreferenceConverter.getColor( getPreferenceStore(), key );

    if( rgb == null ) {

      rgb = defaultRgb;

    }

    rgbs.put( key, rgb );

  }



  private IPreferenceStore getPreferenceStore() {

    if (prefStore!=null){

      return prefStore;

    }

    return HaskellUIPlugin.getDefault().getPreferenceStore();

  }

}