platform/vcs-log/impl/src/com/intellij/vcs/log/ui/VcsLogColorManagerImpl.java

package com.intellij.vcs.log.ui;

import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.ui.JBColor;
import com.intellij.util.containers.ContainerUtil;
import org.jetbrains.annotations.NotNull;

import java.awt.*;
import java.util.*;
import java.util.List;

/**
 * @author Kirill Likhodedov
 */
public class VcsLogColorManagerImpl implements VcsLogColorManager {

  private static final Color REF_BORDER = JBColor.GRAY;
  private static final Color ROOT_INDICATOR_BORDER = JBColor.LIGHT_GRAY;

  // TODO select colors carefully
  private static Color[] ROOT_COLORS = { Color.RED, Color.YELLOW, Color.LIGHT_GRAY, Color.BLUE, Color.MAGENTA };

  @NotNull private final List<VirtualFile> myRoots;

  @NotNull private final Map<VirtualFile, Color> myRoots2Colors;

  public VcsLogColorManagerImpl(@NotNull Collection<VirtualFile> roots) {
    myRoots = new ArrayList<VirtualFile>(roots);
    Collections.sort(myRoots, new Comparator<VirtualFile>() { // TODO add a common util method to sort roots
      @Override
      public int compare(VirtualFile o1, VirtualFile o2) {
        return o1.getName().compareTo(o2.getName());
      }
    });
    myRoots2Colors = ContainerUtil.newHashMap();
    int i = 0;
    for (VirtualFile root : roots) {
      myRoots2Colors.put(root, ROOT_COLORS[i]);
      i++; // TODO handle the case when there are more roots than colors
    }
  }

  @Override
  public boolean isMultipleRoots() {
    return myRoots.size() > 1;
  }

  @NotNull
  @Override
  public Color getRootColor(@NotNull VirtualFile root) {
    return myRoots2Colors.get(root);
  }

  @NotNull
  @Override
  public Color getReferenceBorderColor() {
    return REF_BORDER;
  }

  @NotNull
  @Override
  public Color getRootIndicatorBorder() {
    return ROOT_INDICATOR_BORDER;
  }

}