/*
--- CSU213 Fall 2006 Lecture Notes ---------
Copyright 2006 Viera K. Proulx

Lecture 7: September 20, 2006
Lecture 8: September 21, 2006
Methods for Unions with Containment: Self-Referential Data

Managing ITunes
---------------
*/

/*
    +--------------------------------+  
    | ISongs                         |<-+
    +--------------------------------+  |
    | int count()                    |  |
    | boolean contains(String title) |  |
    | ISongs allBy(String artist)    |  |
    | ISongs sort()                  |  |
    | ISongs insert(Song song)       |  |
    +--------------------------------+  |
                |                       |
               / \                      |
               ---                      | 
                |                       |
       ------------------               |
       |                |               |
  +---------+    +-------------+        |
  | MTSongs |    | ConsSongs   |        |
  +---------+    +-------------+        |
  +---------+  +-| Song first  |        |
               | | ISongs rest |-+      |
               | +-------------+ |      |
               |                 |      |
               v                 +--=---+
      +---------------+
      | Song          |
      +---------------+
      | String title  |
      | String artist |
      | int size      |
      | double price  |
      +---------------+

*/

// to represent a list of songs in an ITunes collection
interface ISongs {

  // count the number of songs in this list
  int count();

  // does this list contain a song with the given title
  boolean contains(String title);

  // produce a list of all songs in this list that are by the given artist
  ISongs allBy(String artist);

  // produce from this list a list sorted by the size of the files
  ISongs sort();

  // insert into this sorted list the given song (by the size of the files)
  ISongs insert(Song song);
}

// to represent an empty list of songs
class MTSongs implements ISongs {

  MTSongs() {}

  // count the number of songs in this list
  int count() { return 0; }

  // does this list contain a song with the given title
  boolean contains(String title){ return false; }

  // produce a list of all songs in this list that are by the given artist
  ISongs allBy(String artist){ return this; }

  // produce from this list a list sorted by the size of the files
  ISongs sort(){ return this; }

  // insert into this sorted list the given song (by the size of the files)
  ISongs insert(Song song){ return new ConsSongs(song, this); }
}

// to represent a nonempty list of songs
class ConsSongs implements ISongs {
  Song first;
  ISongs rest;

  ConsSongs(Song first, ISongs rest) {
    this.first = first;
    this.rest = rest;
  }

  /* TEMPLATE:
  ... this.first ...                        -- Song
      ... this.first.title ...              -- String
      ... this.first.artist ...             -- String
      ... this.first.size ...               -- int
      ... this.first.price ...              -- double
  ... this.rest ...                         -- ISongs

  ... this.rest.count() ...                 -- int
  ... this.rest.contains(Song title) ...    -- boolean
  ... this.rest.allBy(String artist) ...    -- ISongs
  ... this.rest.sort() ...                  -- ISongs (sorted)
  ... this.rest.insert(Song song) ...       -- ISongs (sorted)
  */

  // count the number of songs in this list
  int count() {
    return 1 + this.rest.count(); 
  }

  // does this list contain a song with the given title
  boolean contains(String title){
    if (this.first.title.equals(title))
      return true;
    else
      return this.rest.contains(title);
  }

  // produce a list of all songs in this list that are by the given artist
  ISongs allBy(String artist){
    if (this.first.artist.equals(artist))
      return new ConsSongs(this.first, this.rest.allBy(artist));
    else
      return this.rest.allBy(artist);
  }

  // produce from this list a list sorted by the size of the files
  ISongs sort(){
    return this.rest.sort().insert(this.first);
  }

  // insert into this sorted list the given song (by the size of the files)
  ISongs insert(Song song){ 
    if (song.size <= this.first.size)
      return new ConsSongs(song, this);
    else
      return new ConsSongs(this.first, this.rest.insert(song));
  }
}


/*
;; A Song is (make-song String String Number Number)
(define-struct song (Title Artist size price))

;; Examples:
(define help (make-song "Help" "Beatles"  3178852 0.99))
(define hc (make-song "Hotel California" "Eagles" 4405515 0.99))
*/

/*
+---------------+
| Song          |
+---------------+
| String title  |
| String artist |
| int size      |
| double price  |
+---------------+

*/

// to represent an ITunes song recording
class Song {
  String title;
  String artist;
  int size;
  double price;

  Song(String title, String artist, int size, double price) {
    this.title = title;
    this.artist = artist;
    this.size = size;
    this.price = price;
  }
}

class ExamplesSongs {
  ExamplesSongs(){}

  Song help = new Song("Help",             "Beatles", 3178852, 0.99);
  Song hcal = new Song("Hotel California", "Eagles",  4405515, 0.99);
  Song mbnz = new Song("Mercedes Benz",    "Janis",   4551534, 0.99);
  Song bmcg = new Song("Bobby McGee",      "Janis",   4234975, 0.99);
  Song midf = new Song("Midnight Fire",    "Eagles",  3426515, 0.99);

  ISongs mtsongs = new MTSongs();
  ISongs songs1 = new ConsSongs(this.help, this.mtsongs);
  ISongs songs2 = new ConsSongs(this.hcal, this.songs1);
  ISongs songs3 = new ConsSongs(this.mbnz, this.songs2);
  ISongs songs4 = new ConsSongs(this.bmcg, this.songs3);
  ISongs songs5 = new ConsSongs(this.midf, this.songs4);

  ISongs songs5janis = new ConsSongs(this.bmcg,
                       new ConsSongs(this.mbnz,
                       this.mtsongs));

  ISongs songs2sorted = new ConsSongs(this.help,
                        new ConsSongs(this.hcal,
                        this.mtsongs));

  ISongs songs3sorted = new ConsSongs(this.help,
                        new ConsSongs(this.hcal,
                        new ConsSongs(this.mbnz,
                        this.mtsongs)));

  ISongs songs5sorted = new ConsSongs(this.help,
                        new ConsSongs(this.midf,
                        new ConsSongs(this.bmcg,
                        new ConsSongs(this.hcal,
                        new ConsSongs(this.mbnz,
                        this.mtsongs)))));

  ISongs songs4sorted = new ConsSongs(this.help,
                        new ConsSongs(this.bmcg,
                        new ConsSongs(this.hcal,
                        new ConsSongs(this.mbnz,
                        this.mtsongs))));

  // test for the method count
  boolean testCount = (check this.mtsongs.count() expect 0) &&
                      (check this.songs1.count() expect 1) &&
                      (check this.songs5.count() expect 5);

  // test for the method contains
  boolean testContains = (check this.mtsongs.contains("Help") expect false) &&
                         (check this.songs1.contains("Help") expect true) &&
                         (check this.songs1.contains("Bobby McGee") expect false) &&
                         (check this.songs4.contains("Midnight Fire") expect false) &&
                         (check this.songs5.contains("Bobby McGee") expect true);
                      
  // test for the method allBy
  boolean testAllBy = (check this.mtsongs.allBy("Janis") expect this.mtsongs) &&
                      (check this.songs2.allBy("Janis") expect this.mtsongs) &&
                      (check this.songs5.allBy("Janis") expect this.songs5janis);

  // test for the method sort
  boolean testSort = (check this.mtsongs.sort() expect this.mtsongs) &&
                     (check this.songs2.sort() expect this.songs2sorted) &&
                     (check this.songs5.sort() expect this.songs5sorted);

  // test for the method insert
  boolean testInsert = (check this.mtsongs.insert(this.help) expect this.songs1) &&
                       (check this.songs2sorted.insert(this.mbnz) expect this.songs3sorted) &&
                       (check this.songs4sorted.insert(this.midf) expect this.songs5sorted);

}