content: /*
   *  Copyright 2010 Richard Nichols.
   *
   *  Licensed 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.
   *  under the License.
   */
  package ro.isdc.wro.model.resource.processor.support;
  
  import java.util.HashMap;
  import java.util.LinkedHashSet;
  import java.util.Map;
  import java.util.Set;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  
  /**
   * Transforms colors from long format in a shorter one.
   *
   * @author Richard Nichols
   */
  public class Lessify {
    private static final Pattern PATTERN_COLOR = Pattern.compile("#[0-9a-fA-F]{3,6}[^0-9a-fA-F]");
    private static final Pattern PATTERN_WORD_COLOR = Pattern.compile(getGiantCssColorRegex());
  
  
    public String variablizeColors(String css) {
      final Set<String> colors = new LinkedHashSet<String>();
      css = conformColors(css);
      final Matcher m = PATTERN_COLOR.matcher(css);
      final Map<String, Integer> colorCount = new HashMap<String, Integer>();
      while (m.find()) {
        final String color = m.group().substring(1, m.group().length() - 1);
        colors.add(color);
        if (colorCount.get(color) == null) {
          colorCount.put(color, 1);
        } else {
          colorCount.put(color, colorCount.get(color) + 1);
        }
      }
      final StringBuffer result = new StringBuffer();
      int idx = 0;
      final Map<String, String> colorMap = new HashMap<String, String>();
      for (final String color : colors) {
        colorMap.put(color, "color" + minLeading(idx, 3));
        idx++;
        result.append("@").append(colorMap.get(color)).append(": #").append(conformColor(color)).append("; /* used ").append(
          colorCount.get(color)).append(" times */\n");
      }
      for (final String color : colors) {
        css = css.replace("#" + color, "@" + colorMap.get(color));
      }
      result.append(css);
      return result.toString();
    }
  
  
    public String conformColors(String css) {
      Matcher m = PATTERN_COLOR.matcher(css);
      final Map<String, String> colGroup = new HashMap<String, String>();
      while (m.find()) {
        final String color = m.group().substring(1, m.group().length() - 1);
        colGroup.put(m.group(), conformColor(color));
      }
      m = PATTERN_WORD_COLOR.matcher(css);
      while (m.find()) {
        final String color = m.group().substring(1, m.group().length() - 1);
        colGroup.put(m.group(), "#" + conformColor(color));
      }
      // conform all
      for (final String col : colGroup.keySet()) {
        css = css.replace(col, col.charAt(0) + colGroup.get(col) + col.charAt(col.length() - 1));
      }
      return css;
    }
  
  
    private String conformColor(final String color) {
      if (CssColors.forName(color) != null) {
        return CssColors.forName(color).getColorAsHexString().toLowerCase();
      }
      if (color.length() == 3) {
        final StringBuffer sb = new StringBuffer();
        for (int n = 0; n < color.length(); n++) {
          sb.append(color.charAt(n));
          sb.append(color.charAt(n));
        }
        return sb.toString().toLowerCase();
      } else {
        return minLeading(color, 6).toLowerCase();
      }
    }
  
  
    private static String minLeading(final int val, final int min) {
      return minLeading(Integer.toString(val), min);
    }
  
  
    private static String minLeading(final String val, final int min) {
      final StringBuffer result = new StringBuffer(val);
      while (result.length() < min) {
        result.insert(0, "0");
      }
      return result.toString();
    }
  
  
    private static String getGiantCssColorRegex() {
      final StringBuffer sb = new StringBuffer("");
      boolean first = true;
      for (final CssColors col : CssColors.values()) {
        if (!first)
          sb.append("|");
        sb.append("(").append(buildRegexForCssColor(col)).append(")");
        first = false;
      }
      return sb.toString();
    }
  
  
    private static String buildRegexForCssColor(final CssColors col) {
      final StringBuffer sb = new StringBuffer("[\\s\\n\\r\\:]");
      for (int n = 0; n < col.name().length(); n++) {
        sb.append("[").append(Character.toLowerCase(col.name().charAt(n))).append(
          Character.toUpperCase(col.name().charAt(n))).append("]");
      }
      sb.append("[\\s\\n\\r;]");
      return sb.toString();
    }
  }
  