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/*
 * Copyright 2015 Objectos, Fábrica de Software LTDA.
 *
 * 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 br.com.objectos.io.flat;

import java.io.IOException;
import java.io.LineNumberReader;
import java.io.Reader;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;

import com.google.common.annotations.VisibleForTesting;

/**
 * @author [email protected] (Marcio Endo)
 */
public class FlatFileReader implements AutoCloseable {

  private final LineNumberReader reader;

  private String text;

  private FlatFileReader(LineNumberReader reader) {
    this.reader = reader;
  }

  public static FlatFileReader get(Reader reader) {
    return reader instanceof LineNumberReader
        ? new FlatFileReader((LineNumberReader) reader)
        : new FlatFileReader(new LineNumberReader(reader));
  }

  @VisibleForTesting
  static FlatFileReader get(String string) {
    StringReader reader = new StringReader(string);
    return get(reader);
  }

  @Override
  public void close() throws Exception {
    reader.close();
  }

  public  Result> parseList(RecordMatcher matcher, RecordParser parser) {
    try {
      List list = new ArrayList<>();
      List parseErrorList = new ArrayList<>();
      while (matchesLine(matcher)) {
        try {
          T element = parser.parse(this);
          list.add(element);

        } catch (RecordParseException e) {
          e.addParseErrorTo(parseErrorList);

        } finally {
          consumeLine();

        }
      }
      return Result.mixed(list, parseErrorList);

    } catch (IOException e) {
      return Result.ofException(line(), e);

    }
  }

  public  Result parseOne(RecordParser parser) {
    try {
      prepareLine();
      return text != null
          ? Result.of(parser.parse(this))
          : Result.empty(line());

    } catch (IOException e) {
      return Result.ofException(line(), e);

    } catch (RecordParseException e) {
      return Result.ofException(e);

    } finally {
      consumeLine();

    }
  }

  public RecordReader recordReader() {
    return RecordReader.get(line());
  }

  FlatFileReader prepareLine() throws IOException {
    if (text == null) {
      text = reader.readLine();
    }
    return this;
  }

  private void consumeLine() {
    text = null;
  }

  private Line line() {
    int number = reader.getLineNumber();
    return new Line(number, text);
  }

  private boolean matchesLine(RecordMatcher matcher) throws IOException {
    prepareLine();
    return matcher.matches(text);
  }

}