import { Node, UITransform, v3, Vec3 } from 'cc';

export interface PopTransformBase {
    x: number;
    y: number;
    z: number;
    angle: number;
}

const _baseMap = new WeakMap<Node, PopTransformBase>();

/** 记录节点初始位姿，动画结束 reset */
export function capturePopBase(node: Node): PopTransformBase {
    const p = node.position;
    const base = { x: p.x, y: p.y, z: p.z, angle: node.angle };
    _baseMap.set(node, base);
    return base;
}

export function getPopBase(node: Node): PopTransformBase {
    return _baseMap.get(node) ?? capturePopBase(node);
}

export function resetPopTransform(node: Node): void {
    const base = _baseMap.get(node);
    if (!base || !node.isValid) return;
    node.setPosition(base.x, base.y, base.z);
    node.setScale(Vec3.ONE);
    node.angle = base.angle;
}

/**
 * 底部锚点缩放补偿：scaleY 变化时保持底边不动（Disney squash 落地感）
 * transform-origin: 50% 100%
 */
export function yForBottomAnchor(node: Node, baseY: number, scaleY: number): number {
    const ut = node.getComponent(UITransform);
    if (!ut) return baseY;
    const h = ut.contentSize.height;
    const anchorY = ut.anchorPoint.y;
    return baseY + h * anchorY * (1 - scaleY);
}

export function setSquash(node: Node, base: PopTransformBase, scaleX: number, scaleY: number): void {
    node.setScale(scaleX, scaleY, 1);
    node.setPosition(base.x, yForBottomAnchor(node, base.y, scaleY), base.z);
}

export function posWithYOffset(base: PopTransformBase, offsetY: number) {
    return v3(base.x, base.y + offsetY, base.z);
}