import { _decorator, Component, Node, Graphics, Color, UITransform } from 'cc';
const { ccclass, property } = _decorator;

@ccclass('Shadow2D')
export class Shadow2D extends Component {

  @property(Node)
  target: Node | null = null;   // 角色节点

  @property
  shadowWidth: number = 60;

  @property
  shadowHeight: number = 20;

  @property
  shadowAlpha: number = 80; // 0-255

  private shadowNode: Node | null = null;

  start() {
    if (!this.target) {
      console.warn("Shadow2D: 未绑定角色节点 target");
      return;
    }

    // 创建影子节点
    this.shadowNode = new Node("Shadow");
    let g = this.shadowNode.addComponent(Graphics);
    this.target.addChild(this.shadowNode);

    // 调整大小
    let ui = this.shadowNode.addComponent(UITransform);
    ui.setContentSize(this.shadowWidth, this.shadowHeight);

    // 画椭圆
    g.fillColor = new Color(0, 0, 0, this.shadowAlpha);
    g.ellipse(0, 0, this.shadowWidth / 2, this.shadowHeight / 2);
    g.fill();

    // 放到角色脚下
    this.shadowNode.setPosition(0, -this.target.getComponent(UITransform).height / 2);
  }

  update(dt: number) {
    if (!this.shadowNode || !this.target) return;

    if (!this.target.active) {
      this.shadowNode.active = false;
      return;
    }

    // 始终保持在角色底部（比如角色动画高度变化时也能跟随）
    let ui = this.target.getComponent(UITransform);

    if (!ui) return;

    this.shadowNode.setPosition(0, -ui.height / 2);
  }
}