/*
    * #%L
    * Native ARchive plugin for Maven
    * %%
    * Copyright (C) 2002 - 2014 NAR Maven Plugin developers.
    * %%
    * 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.
   * #L%
   */
  package com.github.maven_nar.cpptasks.trolltech;
  
  import java.io.IOException;
  import java.io.Reader;
  
  import com.github.maven_nar.cpptasks.parser.AbstractParser;
  import com.github.maven_nar.cpptasks.parser.AbstractParserState;
  import com.github.maven_nar.cpptasks.parser.LetterState;
  import com.github.maven_nar.cpptasks.parser.WhitespaceOrLetterState;
  
  /**
   * Scans a source file for Q_OBJECT.
   *
   * @author Curt Arnold
   */
  public final class MetaObjectParser extends AbstractParser {
    /**
     * Parser state that matches file T character.
     */
    private static final class FinalTState extends AbstractParserState {
      /**
       * Parser.
       */
      private final MetaObjectParser mocParser;
  
      /**
       * Constructor.
       * 
       * @param parser
       *          MetaObjectParser parser
       */
      public FinalTState(final MetaObjectParser parser) {
        super(parser);
        this.mocParser = parser;
      }
  
      /**
       * Consumes a character and returns the next state for the parser.
       *
       * @param ch
       *          next character
       * @return the configured nextState if ch is the expected character or the
       *         configure noMatchState otherwise.
       */
      @Override
      public AbstractParserState consume(final char ch) {
        if (ch == 'T') {
          this.mocParser.setQObject(true);
          return null;
        }
        if (ch == '\n') {
          getParser().getNewLineState();
        }
        return null;
      }
    }
  
    /**
     * Determines if source file contains Q_OBJECT.
     * 
     * @param reader
     *          Reader source reader
     * @throws IOException
     *           if unable to read source file
     * @return boolean true if source contains Q_OBJECT
     */
    public static boolean hasQObject(final Reader reader) throws IOException {
      final MetaObjectParser parser = new MetaObjectParser();
      parser.parse(reader);
      return parser.hasQObject;
  
    }
  
    /**
     * Has Q_OBJECT been encountered.
     */
    private boolean hasQObject = false;
  
    /**
     * Parser state for start of new line.
    */
   private final AbstractParserState newLineState;
 
   /**
    * Constructor.
    *
    */
   private MetaObjectParser() {
     //
     // search for Q_OBJECT
     //
     final AbstractParserState t = new FinalTState(this);
     final AbstractParserState c = new LetterState(this, 'C', t, null);
     final AbstractParserState e = new LetterState(this, 'E', c, null);
     final AbstractParserState j = new LetterState(this, 'J', e, null);
     final AbstractParserState b = new LetterState(this, 'B', j, null);
     final AbstractParserState o = new LetterState(this, 'O', b, null);
     final AbstractParserState underline = new LetterState(this, '_', o, null);
     this.newLineState = new WhitespaceOrLetterState(this, 'Q', underline);
   }
 
   /**
    * Adds a filename to the list of included files.
    *
    * @param filename
    *          filename to be added
    */
   @Override
   protected void addFilename(final String filename) {
 
   }
 
   /**
    * Gets new line state.
    * 
    * @return AbstractParserState new line state.
    */
   @Override
   public AbstractParserState getNewLineState() {
     return this.newLineState;
   }
 
   /**
    * Parse input file.
    * 
    * @param reader
    *          Reader source file
    * @throws IOException
    *           if error reading source file
    */
   @Override
   public void parse(final Reader reader) throws IOException {
     this.hasQObject = false;
     super.parse(reader);
   }
 
   /**
    * Called FinalTState to set that Q_OBJECT was found.
    * 
    * @param value
    *          boolean new value for hasQObject
    */
   public void setQObject(final boolean value) {
     this.hasQObject = value;
   }
 }