/*
 * Copyright 2000-2009 JetBrains s.r.o.
 *
 * 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.lang;

import com.intellij.lexer.Lexer;
import com.intellij.openapi.util.Condition;
import com.intellij.psi.FileViewProvider;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import com.intellij.psi.templateLanguages.TemplateLanguage;
import com.intellij.util.containers.ContainerUtil;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.Comparator;
import java.util.List;
import java.util.Set;

public final class LanguageUtil {
  private LanguageUtil() {
  }

  public static final Comparator<Language> LANGUAGE_COMPARATOR = new Comparator<Language>() {
    @Override
    public int compare(Language o1, Language o2) {
      return o1.getDisplayName().compareToIgnoreCase(o2.getDisplayName());
    }
  };

  public static ParserDefinition.SpaceRequirements canStickTokensTogetherByLexer(ASTNode left, ASTNode right, Lexer lexer) {
    String textStr = left.getText() + right.getText();

    lexer.start(textStr, 0, textStr.length());
    if(lexer.getTokenType() != left.getElementType()) return ParserDefinition.SpaceRequirements.MUST;
    if(lexer.getTokenEnd() != left.getTextLength()) return ParserDefinition.SpaceRequirements.MUST;
    lexer.advance();
    if(lexer.getTokenEnd() != textStr.length()) return ParserDefinition.SpaceRequirements.MUST;
    if(lexer.getTokenType() != right.getElementType()) return ParserDefinition.SpaceRequirements.MUST;
    return ParserDefinition.SpaceRequirements.MAY;
  }

  @NotNull
  public static Language[] getLanguageDialects(final Language base) {
    final List<Language> list = ContainerUtil.findAll(Language.getRegisteredLanguages(), new Condition<Language>() {
      @Override
      public boolean value(final Language language) {
        return language.getBaseLanguage() == base;
      }
    });
    return list.toArray(new Language[list.size()]);
  }

  public static boolean isInTemplateLanguageFile(@Nullable final PsiElement element) {
    if (element == null) return false;

    final PsiFile psiFile = element.getContainingFile();
    if(psiFile == null) return false;

    final Language language = psiFile.getViewProvider().getBaseLanguage();
    return language instanceof TemplateLanguage;
  }

  public static boolean isInjectableLanguage(Language language) {
    if (language == Language.ANY) {
      return false;
    }
    if (language.getID().startsWith("$")) {
      return false;
    }
    if (language instanceof InjectableLanguage) {
      return true;
    }
    if (language instanceof TemplateLanguage || language instanceof DependentLanguage) {
      return false;
    }
    if (LanguageParserDefinitions.INSTANCE.forLanguage(language) == null) {
      return false;
    }
    return true;
  }

  @NotNull
  public static Language getRootLanguage(@NotNull PsiElement element) {
    final FileViewProvider provider = element.getContainingFile().getViewProvider();
    final Set<Language> languages = provider.getLanguages();
    if (languages.size() > 1) {
      PsiElement current = element;
      while (current != null) {
        final Language language = current.getLanguage();
        if (languages.contains(language)) return language;
        current = current.getParent();
      }
    }
    return provider.getBaseLanguage();
  }
}