/*
 * Copyright 2011 The authors
 * 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 com.intellij.struts2.dom.struts.action;

import com.intellij.openapi.util.TextRange;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiMethod;
import com.intellij.psi.PsiReference;
import com.intellij.util.xml.ConvertContext;
import com.intellij.util.xml.DomElement;
import com.intellij.util.xml.GenericDomValue;
import com.intellij.util.xml.converters.DelimitedListConverter;
import com.intellij.xml.util.XmlTagUtil;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.ArrayList;
import java.util.List;

/**
 * Converter for {@link com.intellij.struts2.dom.struts.action.Action#getActionMethods()}.
 *
 * @author Yann Cébron
 */
public class AllowedMethodsConverter extends DelimitedListConverter<String> {

  public AllowedMethodsConverter() {
    super(",");
  }

  @Override
  protected String convertString(@Nullable final String s, final ConvertContext convertContext) {
    final Action action = getActionElement(convertContext);
    return action.findActionMethod(s) != null ? s : null;
  }

  @Override
  protected String toString(@Nullable final String psiMethod) {
    return psiMethod;
  }

  @Override
  protected Object[] getReferenceVariants(final ConvertContext convertContext,
                                          final GenericDomValue<List<String>> listGenericDomValue) {
    final Action action = getActionElement(convertContext);
    final List<Object> variants = new ArrayList<Object>();
    for (final PsiMethod psiMethod : action.getActionMethods()) {
      variants.add(psiMethod);
    }

    return variants.toArray(new Object[variants.size()]);
  }

  @Override
  protected PsiElement resolveReference(@Nullable final String psiMethod, final ConvertContext convertContext) {
    final Action action = getActionElement(convertContext);
    return action.findActionMethod(psiMethod);
  }

  @Override
  protected String getUnresolvedMessage(final String s) {
    return "Cannot resolve action-method ''" + s + "''";
  }

  // TODO workaround to fix TextRange in tag value
  @NotNull
  @Override
  protected PsiReference createPsiReference(final PsiElement element,
                                            final int start,
                                            final int end,
                                            final ConvertContext context,
                                            final GenericDomValue<List<String>> value,
                                            final boolean delimitersOnly) {
    return new MyPsiReference(element, getTextRange(value, start, end), context, value, delimitersOnly);
  }

  private static TextRange getTextRange(final GenericDomValue value, final int start, final int end) {
    final TextRange tagRange = XmlTagUtil.getTrimmedValueRange(value.getXmlTag());
    return new TextRange(tagRange.getStartOffset() + start - 1, tagRange.getStartOffset() + end - 1);
  }

  /**
   * Gets the enclosing <code>action</code>-element for the current context.
   *
   * @param context Current context.
   * @return Action-element.
   */
  @NotNull
  private static Action getActionElement(final ConvertContext context) {
    final DomElement domElement = context.getInvocationElement();
    final Action action = domElement.getParentOfType(Action.class, false);
    assert action != null : "not triggered within <action> for " + domElement.getXmlElement();
    return action;
  }

}