//SharkJava.java

import java.awt.Graphics;
import java.awt.Image;
import java.awt.*;
import java.util.*;

//"s_"から始まる変数はサメ(Shark)用の変数
public class SharkJava extends java.applet.Applet
 implements Runnable{
  private MediaTracker mt;

  //左右のサメの画像
  private Image left_shark;
  private Image right_shark;

  //背景画像
  private Image background;

  //オフスクリーン
  private Image offs;
  private Graphics mem_g;

  //アプレットの大きさ
  private int b_width=600;
  private int b_height=300;

  //サメの大きさ
  private int s_width=154;
  private int s_height=56;

  //サメの座標
  private int s_x=6;
  private int s_y=6;

  //サメの動きかた
  private int s_mode=0;

  //サメのマージン
  private int s_margin=5;

  //サメのスピード
  private int speed=100;

  private Thread trd=null;

  public void init()
  {
    background=getImage(getCodeBase(),"./img/4-back.gif");
    left_shark=getImage(getCodeBase(),"./img/4-l_shark.gif");
    right_shark=getImage(getCodeBase(),"./img/4-r_shark.gif");
    mt=new MediaTracker(this);
    mt.addImage(background,0);
    mt.addImage(left_shark,1);
    mt.addImage(right_shark,2);
    s_mode=0;
    offs=createImage(b_width,b_height);
    mem_g=offs.getGraphics();
  }
  public void paint(Graphics g)
  {
    update(g);
  }
  public void update(Graphics g)
  {
    if(!mt.checkID(0)){
      g.drawString("Now Loading.",0,10);
      g.drawString("残り3画像",0,20);
      return;
    }
    else if(!mt.checkID(1)){
      g.setColor(Color.lightGray);
      g.fillRect(0,0,b_width,b_height);
      g.setColor(Color.black);
      g.drawString("Now Loading..",0,10);
      g.drawString("残り2画像",0,20);
      return;
    }
    else if(!mt.checkID(2)){
      g.setColor(Color.lightGray);
      g.fillRect(0,0,b_width,b_height);
      g.setColor(Color.black);
      g.drawString("Now Loading...",0,10);
      g.drawString("残り1画像",0,20);
      return;
    }
    mem_g.drawImage(background,0,0,this);
    if(s_mode<=2)
      mem_g.drawImage(right_shark,s_x,s_y,this);
    else
      mem_g.drawImage(left_shark,s_x,s_y,this);
    g.drawImage(offs,0,0,this);
  }
  public void start()
  {
    if(trd==null){
      trd=new Thread(this);
      trd.start();
    }
  }                                                 
  public void stop()
  {
    trd=null;
  }
  public void run()
  {
    try{
      mt.waitForID(0);
      repaint();
      mt.waitForID(1);
      repaint();
      mt.waitForID(2);
      repaint();
    }catch(InterruptedException e){
       return;
    }
    int count=0;
    Thread nowTrd=Thread.currentThread();
    s_mode=0;
    while(trd==nowTrd){
      if(count>=40){
        count=0;
        int temp=(int)(Math.random()*10);
        if(temp>=6)
          temp-=5;
        s_mode=temp;
      }
      if(s_x<=s_margin){
        if(count>=20)
          s_mode=0;
        else if(count>=10)
          s_mode=1;
        else
          s_mode=2;
      }
      else if((s_x+s_width)>=(b_width-s_margin)){
        if(count>=20)
          s_mode=3;
        else if(count>=10)
          s_mode=4;
        else
          s_mode=5;
      }
      if(s_y<=s_margin){
        if((s_x+(s_width/2))/2<=b_width/2)
          s_mode=4;
        else
          s_mode=1;
      }
      else if((s_y+s_height)>=(b_height-s_margin)){
        if((s_x+(s_width/2))/2<=b_width/2)
          s_mode=5;
        else
          s_mode=2;
      }
      if(s_mode==0)
        s_x+=5;
      else if(s_mode==1){
        s_x+=5;
        s_y+=2;
      }
      else if(s_mode==2){
        s_x+=5;
        s_y-=2;
      }
      else if(s_mode==3)
        s_x-=5;
      else if(s_mode==4){
        s_x-=5;
        s_y+=2;
      }
      else if(s_mode==5){
        s_x-=5;
        s_y-=2;
      }
      count++;
      repaint();
      try{
        nowTrd.sleep(speed);
      }catch(InterruptedException e){}
    }
  }
}