/* --- THE OCEAN WORLD -----------------------------------------------
Fish swim across the screen from right to left. There may be one fish,
or a whole school of fish, or none at a time. A hungry shark swims in
place at the left side, moving only up and down, controlled by the
\scheme{"up"} and \scheme{"down"} keys. It tries to catch and eat the
fish. It gets bigger with each fish it eats, it keeps getting hungrier
and hungrier as the time goes on between the catches. It dies of
starvation, if not fed in time.
--------------------------------------------------------------------*/

import colors.*;
import draw.*;
import geometry.*;
import java.util.Random;

/*
+----------+
| Shark    |
+----------+
| Posn loc |
| int life |
+----------+

*/

// to represent a shark in an ocean world
class Shark {
  Posn loc;
  int life;
  
  Shark(Posn loc, int life) {
    this.loc = loc;
    this.life = life;
  }
  
  // produce a new shark from this shark moved in response to the key press
  Shark onKeyEvent(String ke){
    if (ke.equals("up")){
      return new Shark(new Posn(this.loc.x, this.loc.y - 3), this.life);
    }
    else {if (ke.equals("down")){
      return new Shark(new Posn(this.loc.x, this.loc.y + 3), this.life);
    }
    else{
      return this;
    }}
  }
  
  // draw this shark on the given Canvas
  boolean draw(Canvas c){
    return c.drawDisk(this.loc, this.life / 10 + 2, new Black()) &&
           c.drawLine(this.loc, 
                      new Posn(this.loc.x + 25, this.loc.y), 
                      new Black());
  }
  

  // produce a shark hungrier by a minute than this one
  Shark onTick(){
    if (this.life > 0){
      return new Shark(this.loc, this.life - 1);
    }
    else {
      return this;
    }
  }
    
  // produce a shark after this one ate one fish
  // for now every fish tastes the same
  // later, fish nutrition value may be determined by the size or the color 
  Shark getFatter(){
    return new Shark(this.loc, this.life + 30);
  }
  
  // is this shark dead?
  boolean isDead(){
    return this.life <= 0;
  }
  
}

/*
+-----------------+
| Fish            |
+-----------------+
| Posn loc        |
| boolean escaped |
+-----------------+

*/

// to represent a fish in an ocean world
class Fish {
  Posn loc;
  boolean hasEscaped;

  Fish(Posn loc, boolean hasEscaped) {
    this.loc = loc;
    this.hasEscaped = hasEscaped;
  }
  
  // produce from this fish the one that swam for a minute more
  Fish onTick(){
    if (hasEscaped){
      return this.makeFish(200, 200);
    }
    else {if (this.loc.x < 0){
      return new Fish(this.loc, true);
    }
    else {
      return new Fish(new Posn(this.loc.x - 3, 
                               this.loc.y + new Random().nextInt() % 7 - 3),
                               false);
    }}
  }
  
  // has this fish escaped?
  boolean escaped(){
    return (this.loc.x < 0) || this.hasEscaped;
  }
  
  // is this fish a food for the given shark?
  boolean isFood(Shark shark){
    return
      Math.sqrt((this.loc.x - shark.loc.x) * (this.loc.x - shark.loc.x) +
                (this.loc.y - shark.loc.y) * (this.loc.y - shark.loc.y)) < 25;     
  }

  // draw this fish on the given Canvas
  boolean draw(Canvas c){
    return c.drawDisk(this.loc, 10, new Red());
  }
  
  // produce a new fish at the right quarter of the canvas at random height
  Fish makeFish(int WIDTH, int HEIGHT){
    return new Fish(new Posn(WIDTH - WIDTH / 4 + this.randomLimited(WIDTH / 4), 
                    this.randomLimited(HEIGHT)), false);
  }
    
  // produce a random initial coordinate of the fish
  int randomLimited(int LIMIT){
    return new Random().nextInt() % LIMIT;
  }
  
  // replace this fish with a new one
  Fish feedShark(Shark shark){
    return this.makeFish(200, 200); 
  }
}

/*
+-------------+
| OceanWorld  |
+-------------+
| Shark shark |
| Fish fish   |
+-------------+

*/


// to represent an ocean world
class OceanWorld extends World{
  Shark shark;
  Fish fish;
  int WIDTH =  200;
  int HEIGHT = 200;

  OceanWorld(Shark shark, Fish fish) {
    this.shark = shark;
    this.fish = fish;
  }
  
  // start the world and the timer
  boolean go() { return this.bigBang(200, 200, 0.05); }

  // produce a new OceanWorld after one minute elapsed: 
  // move the fish, starve the shark, check if the fish is eaten or has escaped
  World onTick(){
    // if the shark found fish, fed the shark, replace the fish with a new one                        
    if (this.fish.isFood(this.shark)){
      return new OceanWorld(this.shark.getFatter(),
                            this.fish.feedShark(shark));
    }
                            
    // if the shark starved to death, end the world
    else {if(this.shark.isDead()) {
      return this.endOfWorld("The shark starved to death");
    }
    
    // no special events, just move the fish and starve the shark 
    else {
      return new OceanWorld(this.shark.onTick(), this.fish.onTick());
    }}
  }
  
  // produce a new OceanWorld in response to the given key press
  World onKeyEvent(String ke){
    return new OceanWorld(this.shark.onKeyEvent(ke), this.fish);
  }
  
  // draw this world
  boolean draw(){
    return this.theCanvas.drawRect(new Posn(0, 0), 
                            this.WIDTH, this.HEIGHT, new Blue()) &&
           this.fish.draw(this.theCanvas) &&
           this.shark.draw(this.theCanvas);
  }
 
}

// Examples of the classes Fish, Shark, OceanWorld and tests for all methods
class Examples{
  Examples(){}
  
  Shark mac = new Shark(new Posn(10, 100), 200);
  Shark mac2 = new Shark(new Posn(10, 100), 100);
  Shark mac3 = new Shark(new Posn(10, 100), -1);
  
  Fish fishy = new Fish(new Posn(190, 100), false);
  Fish yummy = new Fish(new Posn(15, 98), false);
  Fish gone = new Fish(new Posn(15, 98), true);
  Fish gone2 = new Fish(new Posn(-2, 98), false);

  
    
  OceanWorld sfw = new OceanWorld(this.mac, this.fishy); 
  
  Canvas c = new Canvas(200, 200);
  
  boolean go(){
    return sfw.bigBang(200, 200, 0.1);
  }
  
  // test the method onKeyEvent in the class Shark
  boolean testSharkOnKeyEvent(){
    return
      (check this.mac.onKeyEvent("left") expect this.mac) && 
      (check this.mac.onKeyEvent("up") expect 
        new Shark(new Posn(10, 97), 200)) && 
      (check this.mac.onKeyEvent("down") expect 
        new Shark(new Posn(10, 103), 200));
  }
  
  // a visual test for drawing a Shark
  boolean drawShark(){
    return c.show() && this.mac.draw(c);
  }
  
  // test the method onTick in the class Shark
  boolean testSharkOnTick(){
    return
      (check this.mac.onTick()
        expect new Shark(new Posn(10, 100), 199)) && 
      (check (new Shark(new Posn(10, 100), 0)).onTick() 
        expect new Shark(new Posn(10, 100), 0)); 
  }
  
  // test the method getFatter in the class Shark
  boolean testGetFatter(){
    return (check mac.getFatter()
             expect new Shark(new Posn(10, 100), 230)) &&
           (check mac2.getFatter()
             expect new Shark(new Posn(10, 100), 130));
  }

  // test the method isDead in the class Shark
  boolean testisDead(){
    return (check mac.isDead() expect false) &&
           (check mac3.isDead() expect true);
  }


  // test the method onTick in the class Fish
  // results are correct if the random move is replaced with exactly 5
  boolean testFishOnTick(){
    return 
      (check this.fishy.onTick() 
        expect new Fish(new Posn(187, 105), false)) &&
      (check (new Fish(new Posn(-2, 100), true)).onTick() 
        expect new Fish(new Posn(-2, 100), true)) && 
      (check (new Fish(new Posn(-2, 100), false)).onTick() 
        expect new Fish(new Posn(-2, 100), true)); 
  }
  
  // test the method escaped in the class Fish
  boolean testFishEscaped(){
    return 
      (check this.fishy.escaped() expect false) && 
      (check (new Fish(new Posn(-2, 100), true)).escaped() expect true) &&
      (check (new Fish(new Posn(-2, 100), false)).escaped() expect true); 
  }

  // test the method isFood in the class Fish
  boolean testFishIsFood(){
    return 
      (check this.fishy.isFood(this.mac) expect false) &&
      (check this.yummy.isFood(new Shark(new Posn(10, 100), 20)) expect true);
  } 

  // a visual test for drawing a Fish
  boolean drawFish(){
    return c.show() && this.fishy.draw(c);
  }
  
  // test for the method randomLimited in the class Fish
  boolean testRandomLimited(){
    return check (this.fishy.randomLimited(5) < 6 && 
                  this.fishy.randomLimited(5) > 0)
           expect true;
  }

  // test the method makeFish in the class Fish
  boolean testMakeFish(){
    return (check this.fishy.makeFish(200, 200).hasEscaped expect false) &&
           (check this.fishy.makeFish(200, 200).loc.y < 200 expect true) &&
           (check this.fishy.makeFish(200, 200).loc.y >   0 expect true) &&
           (check this.fishy.makeFish(200, 200).loc.x < 200 expect true) &&
           (check this.fishy.makeFish(200, 200).loc.x > 150 expect true);
  }
  

  // test the method onKeyEvent in the class OceanWorld
  boolean testOceanOnKeyEvent(){
    return
      (check this.sfw.onKeyEvent("left") 
        expect new OceanWorld(this.mac, this.fishy)) && 
      (check this.sfw.onKeyEvent("up") expect 
        new OceanWorld(new Shark(new Posn(10, 97), 200), this.fishy)) && 
      (check this.sfw.onKeyEvent("down") expect 
        new OceanWorld(new Shark(new Posn(10, 103), 200), this.fishy));
  }
  
  OceanWorld sfwEnd = new OceanWorld(this.mac3, this.fishy);
  OceanWorld sfwReg = new OceanWorld(this.mac, this.fishy);
  OceanWorld sfwYum = new OceanWorld(this.mac, this.fishy);
  
  // test the method onTick in the class OceanWorld
  boolean testOceanOnTick(){
    return
      // world goes on
      (check this.sfwReg.onTick() 
        expect new OceanWorld(this.mac.onTick(), this.fishy.onTick())) &&

      // fish is eaten, shark is fatter, new fish appears
      (check this.sfwYum.onTick() 
        expect new OceanWorld(this.mac.getFatter(), 
                              this.fishy.makeFish(200, 200)));

      // world ends - the shark starves to death --- fails due to randomness
      // cannot invoke method in the teachpack - no test is possible
      //(check this.sfwEnd.onTick() 
      //  expect this.sfw.endWorld("The shark has starved to death"));
  }
  
/*
  // a visual test for drawing the OceanWorld
  boolean drawOcean(){
    return this.sfw.draw();
  }
*/

/*
To run the world, run the program, 
  then type in the following two line in the Interactions window:
  
Examples e = new Examples();
e.go();
*/

}