import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;
import java.util.*;

public class MonsterSprite
    extends Sprite {
  private Random rand;
  private int speed;
  private int speed3;
  private TiledLayer barrier;
  private Sprite actor;
  private int aggression; // 0 - 10

  public MonsterSprite(Image image, int frameWidth, int frameHeight,
                       int monsterSpeed,
                       TiledLayer barrierLayer, Sprite actorSprite,
                       int aggressionLevel) {
    super(image, frameWidth, frameHeight);
    rand = new Random(); // 初始化隨機數
    speed = monsterSpeed; //設置速度
    speed3 = 3 * speed;
    barrier = barrierLayer; // 設置圖層障礙
    actor = actorSprite; // 設置被追逐者
    aggression = aggressionLevel; // 設置攻擊級別
  }

  public void update() {
    int xPos = getX();
    int yPos = getY(); // 臨時保存位置

    // 根據攻擊性追逐或隨機移動
    if (Math.abs(rand.nextInt() % (aggression + 1)) > 0) { // 追逐
      if (getX() > (actor.getX() + actor.getWidth() / 2)) {
        move( -speed, 0); //左
        if (barrier != null && collidesWith(barrier, true)) { // 檢測與障礙物之間的沖突
          move(speed3, 0); //左
        }
      }
      else if ( (getX() + getWidth() / 2) < actor.getX()) {
        move(speed, 0); //右
        if (barrier != null && collidesWith(barrier, true)) { // 檢測與障礙物之間的沖突
          move( -speed3, 0); //左
        }
      }
      if (getY() > (actor.getY() + actor.getHeight() / 2)) {
        move(0, -speed); //上
        if (barrier != null && collidesWith(barrier,true)) { // 檢測與障礙物之間的沖突
          move(0, speed3); //左
        }
      }
      else if ( (getY() + getHeight() / 2) < actor.getY()) {
        move(0, speed); // 下
        if (barrier != null && collidesWith(barrier, true)) { // 檢測與障礙物之間的沖突
          move(0, -speed3); //左
        }
      }
    }
    else { // 隨機移動
      switch (Math.abs(rand.nextInt() % 4)) {
        case 0: // 左
          move( -speed, 0);
          break;
        case 1: // 右
          move(speed, 0);
          break;
        case 2: // 上
          move(0, -speed);
          break;
        case 3: // 下
          move(0, speed);
          break;
      }

      if (barrier != null && collidesWith(barrier, true)) { // 檢測與障礙物之間的沖突
        setPosition(xPos, yPos); // 回到初始位置
      }
    }
    nextFrame();
  }
}