/*
 * Copyright 2011-present Greg Shrago
 *
 * 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.intellij.grammar.livePreview;

import com.intellij.lang.Language;
import com.intellij.lexer.Lexer;
import com.intellij.openapi.editor.DefaultLanguageHighlighterColors;
import com.intellij.openapi.editor.colors.TextAttributesKey;
import com.intellij.openapi.fileTypes.PlainSyntaxHighlighter;
import com.intellij.openapi.fileTypes.SyntaxHighlighter;
import com.intellij.openapi.fileTypes.SyntaxHighlighterBase;
import com.intellij.openapi.fileTypes.SyntaxHighlighterFactory;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.psi.tree.IElementType;
import com.intellij.testFramework.LightVirtualFile;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

/**
 * @author gregsh
 */
public class LivePreviewSyntaxHighlighterFactory extends SyntaxHighlighterFactory {

  public LivePreviewSyntaxHighlighterFactory() {
  }

  @NotNull
  @Override
  public SyntaxHighlighter getSyntaxHighlighter(@Nullable final Project project, @Nullable VirtualFile virtualFile) {
    final Language language = virtualFile instanceof LightVirtualFile ? ((LightVirtualFile)virtualFile).getLanguage() : null;
    if (!(language instanceof LivePreviewLanguage)) return new PlainSyntaxHighlighter();
    return new SyntaxHighlighterBase() {
      @NotNull
      @Override
      public Lexer getHighlightingLexer() {
        return new LivePreviewLexer(project, (LivePreviewLanguage)language) {
          @Nullable
          @Override
          public IElementType getTokenType() {
            IElementType tokenType = super.getTokenType();
            return tokenType instanceof LivePreviewElementType.TokenType
                   ? ((LivePreviewElementType.TokenType)tokenType).delegate : tokenType;
          }
        };
      }

      @NotNull
      @Override
      public TextAttributesKey[] getTokenHighlights(IElementType tokenType) {
        if (tokenType == LivePreviewParserDefinition.COMMENT) return pack(DefaultLanguageHighlighterColors.LINE_COMMENT);
        if (tokenType == LivePreviewParserDefinition.STRING) return pack(DefaultLanguageHighlighterColors.STRING);
        if (tokenType == LivePreviewParserDefinition.NUMBER) return pack(DefaultLanguageHighlighterColors.NUMBER);
        if (tokenType == LivePreviewParserDefinition.KEYWORD) return pack(DefaultLanguageHighlighterColors.KEYWORD);
        if (tokenType == com.intellij.psi.TokenType.BAD_CHARACTER) return pack(DefaultLanguageHighlighterColors.INVALID_STRING_ESCAPE);
        return EMPTY;
      }
    };
  }
}