/*
 * The MIT License
 * Copyright © 2014-2019 Ilkka Seppälä
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package com.iluwatar.datamapper;

import java.util.ArrayList;
import java.util.List;
import java.util.Optional;

/**
 * Implementation of Actions on Students Data.
 */
public final class StudentDataMapperImpl implements StudentDataMapper {

  /* Note: Normally this would be in the form of an actual database */
  private List<Student> students = new ArrayList<>();

  @Override
  public Optional<Student> find(int studentId) {
    return this.getStudents().stream().filter(x -> x.getStudentId() == studentId).findFirst();
  }

  @Override
  public void update(Student studentToBeUpdated) throws DataMapperException {
    String name = studentToBeUpdated.getName();
    Integer index = Optional.of(studentToBeUpdated)
        .map(Student::getStudentId)
        .flatMap(this::find)
        .map(students::indexOf)
        .orElseThrow(() -> new DataMapperException("Student [" + name + "] is not found"));
    students.set(index, studentToBeUpdated);
  }

  @Override
  public void insert(Student studentToBeInserted) throws DataMapperException {
    Optional<Student> student = find(studentToBeInserted.getStudentId());
    if (student.isPresent()) {
      String name = studentToBeInserted.getName();
      throw new DataMapperException("Student already [" + name + "] exists");
    }

    students.add(studentToBeInserted);
  }

  @Override
  public void delete(Student studentToBeDeleted) throws DataMapperException {
    if (!students.remove(studentToBeDeleted)) {
      String name = studentToBeDeleted.getName();
      throw new DataMapperException("Student [" + name + "] is not found");
    }
  }

  public List<Student> getStudents() {
    return this.students;
  }
}