/*
 * 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.tiles;

import com.intellij.codeInsight.daemon.EmptyResolveMessageProvider;
import com.intellij.codeInsight.lookup.LookupElementBuilder;
import com.intellij.openapi.module.Module;
import com.intellij.openapi.module.ModuleUtil;
import com.intellij.openapi.paths.PathReference;
import com.intellij.openapi.util.Comparing;
import com.intellij.openapi.util.text.StringUtil;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import com.intellij.psi.PsiReference;
import com.intellij.psi.PsiReferenceBase;
import com.intellij.psi.xml.XmlElement;
import com.intellij.psi.xml.XmlTag;
import com.intellij.struts.StrutsIcons;
import com.intellij.struts.StrutsManager;
import com.intellij.struts.TilesModel;
import com.intellij.struts.dom.tiles.Definition;
import com.intellij.struts2.dom.struts.impl.path.StrutsResultContributor;
import com.intellij.util.ArrayUtil;
import com.intellij.util.Function;
import com.intellij.util.containers.ContainerUtil;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

/**
 * Provides path to Tiles definition.
 *
 * @author Yann Cébron
 */
public class TilesResultContributor extends StrutsResultContributor {

  @NonNls
  private static final String TILES_RESULT_TYPE = "tiles";

  @Override
  protected boolean matchesResultType(@NotNull @NonNls final String resultType) {
    return Comparing.equal(resultType, TILES_RESULT_TYPE);
  }

  public boolean createReferences(@NotNull final PsiElement psiElement,
                                  @NotNull final List<PsiReference> psiReferences,
                                  final boolean soft) {
    final String currentPackage = getNamespace(psiElement);
    if (currentPackage == null) {
      return false;
    }

    final List<TilesModel> allTilesModels = getAllTilesModels(psiElement);
    psiReferences.add(new TilesDefinitionReference((XmlTag) psiElement, allTilesModels));
    return true;
  }

  public PathReference getPathReference(@NotNull final String path, @NotNull final PsiElement psiElement) {
    return createDefaultPathReference(path, psiElement, StrutsIcons.TILE_ICON);
  }

  private static List<TilesModel> getAllTilesModels(@NotNull final PsiElement psiElement) {
    final Module module = ModuleUtil.findModuleForPsiElement(psiElement);
    if (module == null) {
      return Collections.emptyList();
    }
    return StrutsManager.getInstance().getAllTilesModels(module);
  }

  /**
   * Reference to a Tiles definition.
   */
  private static class TilesDefinitionReference extends PsiReferenceBase<XmlTag> implements EmptyResolveMessageProvider {

    private final List<TilesModel> allTilesModels;
    private final String definitionName;

    private static final Function<TilesModel, Collection<? extends Definition>> DEFINITION_COLLECTOR =
      new Function<TilesModel, Collection<? extends Definition>>() {
        public Collection<? extends Definition> fun(final TilesModel tilesModel) {
          return tilesModel.getDefinitions();
        }
      };

    private TilesDefinitionReference(@NotNull final XmlTag xmlElement,
                                     @NotNull final List<TilesModel> allTilesModels) {
      super(xmlElement, true);
      this.allTilesModels = allTilesModels;
      this.definitionName = xmlElement.getValue().getTrimmedText();
    }

    public PsiElement resolve() {
      for (final TilesModel tilesModel : allTilesModels) {
        final XmlTag definition = tilesModel.getTileTag(definitionName);
        if (definition != null) {
          return definition;
        }
      }

      return null;
    }

    @SuppressWarnings({"unchecked"})
    @NotNull
    public Object[] getVariants() {
      final List<Definition> definitions = ContainerUtil.concat(allTilesModels, DEFINITION_COLLECTOR);
      final List variants = new ArrayList();
      for (final Definition definition : definitions) {
        final String definitionName = definition.getName().getStringValue();
        final XmlElement xmlElement = definition.getXmlElement();
        assert xmlElement != null;
        final PsiFile psiFile = xmlElement.getContainingFile();

        if (psiFile != null &&
            StringUtil.isNotEmpty(definitionName)) {
          //noinspection ConstantConditions
          final LookupElementBuilder builder =
            LookupElementBuilder.create(definition, definitionName)
              .setIcon(StrutsIcons.TILE_ICON)
              .setTypeText(psiFile.getName());
          variants.add(builder);
        }
      }

      return ArrayUtil.toObjectArray(variants);
    }

    public String getUnresolvedMessagePattern() {
      return "Cannot resolve Tiles definition ''" + getValue() + "''";
    }
  }

}