/*
 * Copyright 2010 Google Inc.
 * 
 * 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.google.gwt.sample.expenses.server.domain;

import java.util.List;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.EntityManager;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Query;
import javax.persistence.Transient;
import javax.persistence.Version;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;

/**
 * The Employee domain object.
 */
@Entity
public class Employee {

  public static long countEmployees() {
    EntityManager em = entityManager();
    try {
      return ((Number) em.createQuery("select count(o) from Employee o").getSingleResult()).longValue();
    } finally {
      em.close();
    }
  }

  public static long countEmployeesByDepartment(String department) {
    EntityManager em = entityManager();
    try {
      Query query = em.createQuery("select count(o) from Employee o where o.department=:department");
      query.setParameter("department", department);
      return ((Number) query.getSingleResult()).longValue();
    } finally {
      em.close();
    }
  }

  public static final EntityManager entityManager() {
    return EMF.get().createEntityManager();
  }

  @SuppressWarnings("unchecked")
  public static List<Employee> findAllEmployees() {
    EntityManager em = entityManager();
    try {
      List<Employee> list = em.createQuery("select o from Employee o").getResultList();
      // force to get all the employees
      list.size();
      return list;
    } finally {
      em.close();
    }
  }

  public static Employee findEmployee(Long id) {
    if (id == null) {
      return null;
    }
    EntityManager em = entityManager();
    try {
      Employee employee = em.find(Employee.class, id);
      return employee;
    } finally {
      em.close();
    }
  }

  @SuppressWarnings("unchecked")
  public static List<Employee> findEmployeeEntries(int firstResult,
      int maxResults) {
    EntityManager em = entityManager();
    try {
      List resultList = em.createQuery("select o from Employee o").setFirstResult(
          firstResult).setMaxResults(maxResults).getResultList();
      // force it to materialize
      resultList.size();
      return resultList;
    } finally {
      em.close();
    }
  }

  @SuppressWarnings("unchecked")
  public static List<Employee> findEmployeeEntriesByDepartment(
      String department, int firstResult, int maxResults) {
    EntityManager em = entityManager();
    try {
      Query query = em.createQuery("select o from Employee o WHERE o.department =:department");
      query.setFirstResult(firstResult);
      query.setMaxResults(maxResults);
      query.setParameter("department", department);
      List resultList = query.getResultList();
      // force it to materialize
      resultList.size();
      return resultList;
    } finally {
      em.close();
    }
  }

  @Size(min = 3, max = 30)
  private String userName;

  private String department;

  @NotNull
  private String displayName;

  private String password;

  // @JoinColumn
  private Long supervisorKey;

  @Id
  @Column(name = "id")
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;

  @Version
  @Column(name = "version")
  private Integer version;

  @Transient
  private Employee supervisor;

  public String getDepartment() {
    return department;
  }

  public String getDisplayName() {
    return this.displayName;
  }

  public Long getId() {
    return this.id;
  }

  public String getPassword() {
    return this.password;
  }

  public Employee getSupervisor() {
    return supervisorKey != null ? findEmployee(supervisorKey) : null;
  }

  public Long getSupervisorKey() {
    return supervisorKey;
  }

  public String getUserName() {
    return this.userName;
  }

  public Integer getVersion() {
    return this.version;
  }

  public void persist() {
    EntityManager em = entityManager();
    try {
      em.persist(this);
    } finally {
      em.close();
    }
  }

  public void remove() {
    EntityManager em = entityManager();
    try {
      Employee attached = em.find(Employee.class, this.id);
      em.remove(attached);
    } finally {
      em.close();
    }
  }

  public void setDepartment(String department) {
    this.department = department;
  }

  public void setDisplayName(String displayName) {
    this.displayName = displayName;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public void setPassword(String password) {
    this.password = password;
  }

  public void setSupervisor(Employee supervisor) {
    supervisorKey = supervisor == null ? null : supervisor.getId();
  }

  public void setSupervisorKey(Long supervisorKey) {
    this.supervisorKey = supervisorKey;
  }

  public void setUserName(String userName) {
    this.userName = userName;
  }

  public void setVersion(Integer version) {
    this.version = version;
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder();
    sb.append("Id: ").append(getId()).append(", ");
    sb.append("Version: ").append(getVersion()).append(", ");
    sb.append("UserName: ").append(getUserName()).append(", ");
    sb.append("DisplayName: ").append(getDisplayName()).append(", ");
    sb.append("Password: ").append(getPassword()).append(", ");
    return sb.toString();
  }
}