/* Tueday pm lecture - Part 4: Sorting
             +---------------------------------+            
             | ALoCourse                       |<---------------------------+
             +---------------------------------+                            |
             | ALoCourse sort()                |                            |
             | ALoCourse insert(Course course) |                            |
             +---------------------------------+                            | 
                           / \                                              |
                            |                                               |
         - - - - - - - - - - - - - - - - - - - - - - - -                    |
         |                                             |                    |
 +---------------------------------+   +---------------------------------+  |
 | MTLoCourse                      |   | ConsLoCourse                    |  |
 +---------------------------------+   +---------------------------------+  |
 | ALoCourse sort()                | +-| Course first                    |  |
 | ALoCourse insert(Course course) | | | ALoCourse rest                  |--+ 
 +---------------------------------+ | +---------------------------------+     
                                     | | ALoCourse sort()                |
                                     | | ALoCourse insert(Course course) |                 
                                     | +---------------------------------+
                                     |             
                                     v             
                    +---------------------------+
                    | Course                    |
                    +---------------------------+
                    | String title              |
                    | int number                |
                    +---------------------------+
                    +---------------------------+
*/                                

// to represent a Course
class Course {
  String title;
  int number;

  Course(String title, int number) {
    this.title = title;
    this.number = number;
  }   
}

// to represent a list of Courses
interface ALoCourse {

  // sort this list of Courses in ascending order of the number of number
  ALoCourse sort();

  // insert the given Course into this sorted list
  ALoCourse insert(Course course);
}

// to represent an empty llist of Courses
class MTLoCourse implements ALoCourse {

  MTLoCourse() {}

  // sort this list of Courses in ascending order of the number of number
  ALoCourse sort(){
    return this;
  }

  // insert the given Course into this sorted list
  ALoCourse insert(Course course){
    return new ConsLoCourse(course, this);
  }

}

// to represent a non-empty list of Courses
class ConsLoCourse implements ALoCourse {
  Course first;
  ALoCourse rest;

  ConsLoCourse(Course first, ALoCourse rest) {
    this.first = first;
    this.rest = rest;
  }

  // sort this list of Courses in ascending order of the number of number
  ALoCourse sort(){
    return this.rest.sort().insert(this.first);
  }

  // insert the given Course into this sorted list
  ALoCourse insert(Course course){
    if (course.number < this.first.number){
      return new ConsLoCourse(course, this);
    }
    else{
      return new ConsLoCourse(this.first, this.rest.insert(course));      
    }
  }

}

// client class for the list of Courses
class Examples {
  Examples(){}
 
  Course lab1 = new Course("CS Lab 1", 212);
  Course eng1 = new Course("English 1", 128);
  Course opsys = new Course("Operating Systems", 313);
  Course biol = new Course("Biology 1", 210);

  ALoCourse mtcourses = new MTLoCourse();
  ALoCourse list1 = new ConsLoCourse(this.lab1, this.mtcourses);
  ALoCourse list2 = new ConsLoCourse(this.eng1,this.list1);
  ALoCourse list4 = new ConsLoCourse(this.opsys,
                      new ConsLoCourse(this.biol, this.list2));

  // test the method insert
boolean testInsert(){
  return (check this.mtcourses.insert(this.opsys)
            expect new ConsLoCourse(this.opsys, this.mtcourses))
      && (check this.list1.insert(this.eng1) 
            expect new ConsLoCourse(this.eng1, this.list1))
      && (check this.list1.insert(this.opsys)
            expect new ConsLoCourse(this.lab1, 
                     new ConsLoCourse(this.opsys, this.mtcourses)))
      && (check
             new ConsLoCourse(this.eng1, 
              new ConsLoCourse(this.biol, 
               new ConsLoCourse(this.opsys, this.mtcourses))).insert(this.lab1)
            expect 
              new ConsLoCourse(this.eng1, 
               new ConsLoCourse(this.biol, 
                new ConsLoCourse(this.lab1, 
                 new ConsLoCourse(this.opsys,this.mtcourses)))));
  }

  boolean testSort(){
    return (check this.mtcourses.sort() expect new MTLoCourse())
        && (check this.list1.sort() expect this.list1)
        && (check this.list4.sort() 
               expect new ConsLoCourse(this.eng1, 
                       new ConsLoCourse(this.biol, 
                        new ConsLoCourse(this.lab1, 
                         new ConsLoCourse(this.opsys, this.mtcourses)))));
  }

  boolean testAll(){
    return this.testInsert()
        && this.testSort();
  }
}