import java.applet.*;
import java.awt.*;

/////////////////////////////////////////////////////////////////
public class Tricytreme extends BitmapLoop
	implements Intersect {

  byte state;

  //  Tricytreme states
  static final byte STANDBY = 0;
  static final byte LAND = 1;
  static final byte EXPLODE = 2;

  // probability of state transitions
  static final double STANDBY_EXIT = .95;
  static final double LAND_EXIT = .95;
  static final double FLIP_X = 0.9;

  // bitmap animations
  protected Image tricytreme[];             // tricytreme animation
  protected Image explode[];         // explosion sequence

  // instance vars
  int max_x, max_y;                  // max coords of this tricytreme
  int explosion_counter;             // counter for explosion bitmaps

  TricytremeManager tManager;

  // class vars
  static Intersect target;           // refers to the ship
  static int ship_y;                  // the y-coord of ship
  static GameManager game;           // ptr to game manager

  // constructor: initialize image references, instance vars
  public Tricytreme(Image trImages[], Image explodeImages[], int max_x,int max_y,
	     							TricytremeManager tManager, Applet applet) {
    super(0,0,null,trImages,applet);
    this.max_x = max_x;
    this.max_y = max_y;
    currentImage = getRand(trImages.length);
    tricytreme = trImages;
    explode = explodeImages;
    game = (GameManager)applet;
    this.tManager = tManager;
    startStandby();
  }

  // finish initializing info about the player's ship
  // this way, the tricytreme can communicate with the ship
  static public void initialize(ShipManager gm) {
    target = gm.getShip();            // refers to ship sprite
    ship_y = gm.getShipY();            // get ship y-coordinate
  }

  // implement Intersect interface:
  public boolean intersect(int x1,int y1,int x2,int y2) {
    return visible && (x2 >= locx) && (locx+width >= x1)
      && (y2 >= locy) && (locy+height >= y1);
  }

  // This is called if a missile hits the tricytreme
  public void hit(int type) {
    if (state != EXPLODE) {
      startExplode();              // start explode state
      game.decrementScore();       // add to score
    }
  }


  // set state and images loop
  public void init() {
    startStandby();
    images = tricytreme;
    restore();
  }

  // this implements the state machine
  public void update() {
    // if tricytreme hits target, notify target, and increment the score if
    if ((locy + height >= ship_y) && state != EXPLODE &&
				 target.intersect(locx,locy,locx+width,locy+height)) {
			target.hit(ShipSprite.GATHER);
			game.gathered();
			suspend();
    }

    // otherwise, update alien state

    double r1 = Math.random();
    double r2 = Math.random();

    switch (state) {
    case STANDBY:
      if (r1 > STANDBY_EXIT) {
			  startLand();
      }

      // flip tricytreme's x-direction if it goes too far right
      //   or left, or if random variable passes threshold
      else if ((locx < width) || (locx > max_x - width) ||
	  					(r2 > FLIP_X)) {
				vx = -vx;
      }
      break;
    case LAND:
      if (r1 > LAND_EXIT) {
				startStandby();
      }
      else if (locy >= max_y-height) {
				landingRoutine();
      }
      break;
    case EXPLODE:
      explosion_counter++;     // bump counter

                               // suspend once animation
                               //   is finished
      if (explosion_counter == explode.length) {
				suspend();
      }
    }

    super.update();            // call BitmapLoop's update()
  }

  // when the tricytreme mineral lands successfully
  protected void landingRoutine() {
	  suspend();
  }

  // start standby state
  protected void startStandby() {
    vx = getRand(8)-4 ;
    vy = 0;
    state = STANDBY;
  }

  // start landing state
  protected void startLand() {
    vx = 0;
    vy = getRand(3) + 2;
    state = LAND;
  }

  // start explosion state
  protected void startExplode() {
    images = explode;        // set bitmap to explosion sequence
    currentImage = 0;        // start at beginning of animation
    explosion_counter = 0;   // count the number of frames
    tManager.playExplosion();      // play explosion sound
    state = EXPLODE;
  }

  // return a random int from 0 to x
  static public int getRand(int x) {
    return (int)(x * Math.random());
  }
}