/*
 * Copyright 2000-2013 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.lexer;

import com.intellij.lang.java.JavaParserDefinition;
import com.intellij.pom.java.LanguageLevel;
import com.intellij.psi.JavaTokenType;
import com.intellij.psi.tree.IElementType;
import junit.framework.TestCase;

/**
 * @author max
 */
public class LayeredLexerTest extends TestCase {
  public void testInTheMiddle() throws Exception {
    Lexer lexer = setupLexer("s=\"abc\\ndef\";");

    assertEquals("s", nextToken(lexer));
    assertEquals("=", nextToken(lexer));
    assertEquals("\"abc", nextToken(lexer));
    assertEquals("\\n", nextToken(lexer));
    assertEquals("def\"", nextToken(lexer));
    assertEquals(";", nextToken(lexer));
    assertEquals(null, lexer.getTokenType());
  }

  public void testModification() throws Exception {
    Lexer lexer = setupLexer("s=\"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\";");
    assertEquals("s", nextToken(lexer));
    assertEquals("=", nextToken(lexer));
    assertEquals("\"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\"", nextToken(lexer));
    assertEquals(";", nextToken(lexer));
    assertEquals(null, lexer.getTokenType());

    lexer.start(lexer.getBufferSequence(), 2, lexer.getBufferEnd(), (short) 1);
    assertEquals("\"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\"", nextToken(lexer));
    assertEquals(";", nextToken(lexer));
    assertEquals(null, lexer.getTokenType());
  }


  public void testInTheAtStartup() throws Exception {
    Lexer lexer = setupLexer("s=\"\\ndef\";");

    assertEquals("s", nextToken(lexer));
    assertEquals("=", nextToken(lexer));
    assertEquals("\"", nextToken(lexer));
    assertEquals("\\n", nextToken(lexer));
    assertEquals("def\"", nextToken(lexer));
    assertEquals(";", nextToken(lexer));
    assertEquals(null, lexer.getTokenType());
  }

  public void testInTheAtEnd() throws Exception {
    Lexer lexer = setupLexer("s=\"abc\\n\";");

    assertEquals("s", nextToken(lexer));
    assertEquals("=", nextToken(lexer));
    assertEquals("\"abc", nextToken(lexer));
    assertEquals("\\n", nextToken(lexer));
    assertEquals("\"", nextToken(lexer));
    assertEquals(";", nextToken(lexer));
    assertEquals(null, lexer.getTokenType());
  }

  public void testNonTerminated() throws Exception {
    Lexer lexer = setupLexer("s=\"abc\\n");

    assertEquals("s", nextToken(lexer));
    assertEquals("=", nextToken(lexer));
    assertEquals("\"abc", nextToken(lexer));
    assertEquals("\\n", nextToken(lexer));
    assertEquals(null, lexer.getTokenType());
  }

  public void testNonTerminated2() throws Exception {
    Lexer lexer = setupLexer("s=\"abc\\");

    assertEquals("s", nextToken(lexer));
    assertEquals("=", nextToken(lexer));
    assertEquals("\"abc", nextToken(lexer));
    assertEquals("\\", nextToken(lexer));
    assertEquals(null, lexer.getTokenType());
  }

  public void testUnicode() throws Exception {
    Lexer lexer = setupLexer("s=\"\\uFFFF\";");
    assertEquals("s", nextToken(lexer));
    assertEquals("=", nextToken(lexer));
    assertEquals("\"", nextToken(lexer));
    assertEquals("\\uFFFF", nextToken(lexer));
    assertEquals("\"", nextToken(lexer));
    assertEquals(";", nextToken(lexer));
    assertEquals(null, lexer.getTokenType());
  }

  private static Lexer setupLexer(String text) {
    LayeredLexer lexer = new LayeredLexer(JavaParserDefinition.createLexer(LanguageLevel.JDK_1_3));
    lexer.registerSelfStoppingLayer(new StringLiteralLexer('\"', JavaTokenType.STRING_LITERAL),
                                    new IElementType[]{JavaTokenType.STRING_LITERAL},
                                    IElementType.EMPTY_ARRAY);
    lexer.start(text);
    return lexer;
  }

  private static String nextToken(Lexer lexer) {
    assertTrue(lexer.getTokenType() != null);
    final String s = lexer.getBufferSequence().subSequence(lexer.getTokenStart(), lexer.getTokenEnd()).toString();
    lexer.advance();
    return s;
  }
}