/**
 * Copyright 2009 Google Inc.
 *
 * 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.
 *
 */

package org.waveprotocol.wave.client.editor.content.misc;

import org.waveprotocol.wave.client.editor.content.AnnotationPainter;
import org.waveprotocol.wave.client.editor.content.AnnotationPainter.PaintFunction;
import org.waveprotocol.wave.client.editor.content.PainterRegistry;
import org.waveprotocol.wave.client.editor.content.Registries;

import org.waveprotocol.wave.model.document.AnnotationBehaviour.AnnotationFamily;
import org.waveprotocol.wave.model.document.AnnotationBehaviour.DefaultAnnotationBehaviour;
import org.waveprotocol.wave.model.document.AnnotationMutationHandler;
import org.waveprotocol.wave.model.document.util.DocumentContext;
import org.waveprotocol.wave.model.util.CollectionUtils;
import org.waveprotocol.wave.model.util.ReadableStringSet;

import java.util.HashMap;
import java.util.Map;

/**
 * Handler for regular style annotations.
 *
 * Delegates to the painter to do rendering.
 *
 * @author danilatos@google.com (Daniel Danilatos)
 */
public class StyleAnnotationHandler implements AnnotationMutationHandler {

  /**
   * Annotation key prefix
   * TODO(user): Move this to a package accessible by model code.
   */
  public static final String PREFIX = "style";

  /**
   * Handy method for getting the style suffix, given a full annotation key
   * @param key
   * @return style suffix
   */
  private static final String suffix(String key) {
    return key.substring(PREFIX.length() + 1);
  }

  /**
   * Handy method for getting the full annotation key, given a style suffix
   * @param suffix
   * @return full annotation key
   */
  public static final String key(String suffix) {
    return PREFIX + "/" + suffix;
  }

  /**
   * Create and register a style annotation handler
   *
   * @param registries registry to register on
   * @return the new handler
   */
  public static void register(Registries registries) {
    PainterRegistry painterRegistry = registries.getPaintRegistry();
    StyleAnnotationHandler handler = new StyleAnnotationHandler(painterRegistry.getPainter());
    registries.getAnnotationHandlerRegistry().registerHandler(PREFIX, handler);
    registries.getAnnotationHandlerRegistry().registerBehaviour(PREFIX,
        new DefaultAnnotationBehaviour(AnnotationFamily.CONTENT));
    painterRegistry.registerPaintFunction(KEYS, renderFunc);
  }

  private final AnnotationPainter painter;

  private static final PaintFunction renderFunc = new PaintFunction() {
    public Map<String, String> apply(Map<String, Object> from, boolean isEditing) {
      Map<String, String> map = new HashMap<String, String>();
      for (Map.Entry<String, Object> entry : from.entrySet()) {
        if (entry.getKey().startsWith(PREFIX + "/")) {
          map.put(suffix(entry.getKey()), (String) entry.getValue());
        }
      }
      return map;
    }
  };

  public static final ReadableStringSet KEYS = CollectionUtils.newStringSet(
      "style/backgroundColor",
      "style/color",
      "style/fontFamily",
      "style/fontSize",
      "style/fontStyle",
      "style/fontWeight",
      "style/textDecoration",
      "style/verticalAlign"
    );

  /**
   * @param painter painter to use for rendering
   */
  public StyleAnnotationHandler(AnnotationPainter painter) {
    this.painter = painter;
  }

  @Override
  public <N, E extends N, T extends N> void handleAnnotationChange(DocumentContext<N, E, T> bundle,
      int start, int end, String key, Object newValue) {
    painter.scheduleRepaint(bundle, start, end);
  }
}