import { Node, Tween, tween } from 'cc';

type LeanProxy = { angle: number; sx: number; sy: number };

const PROXY_KEY = '_hitLeanProxy';

/**
 * 受击后仰（搞笑向）：按来击反方向旋转后仰 + 压扁/拉伸。
 * hitDir = 击退方向（目标 - 来源），单位任意。
 * 注：部分运行时无 UISkew，故用 angle 表达斜切感。
 */
export function playHitLeanBack(target: Node, hitDirX: number, hitDirY = 0): void {
    if (!target?.isValid) return;

    const len = Math.hypot(hitDirX, hitDirY);
    let nx = len > 1e-3 ? hitDirX / len : 0;
    let ny = len > 1e-3 ? hitDirY / len : 0;
    if (Math.abs(nx) < 0.08 && Math.abs(ny) < 0.08) {
        nx = 1;
        ny = 0;
    }

    // 击退向右 → 身体顺时针后仰（负 angle 在 2D UI 常见朝向需实测；取 -nx）
    const peakAngle = -nx * (18 + Math.abs(nx) * 10); // 约 ±18°~28°
    const squashX = 1.22 + Math.abs(nx) * 0.08;
    const squashY = 0.68 - Math.abs(ny) * 0.06;
    const stretchX = 0.86;
    const stretchY = 1.18;

    const old = (target as Node & { [PROXY_KEY]?: LeanProxy })[PROXY_KEY];
    if (old) Tween.stopAllByTarget(old);
    Tween.stopAllByTarget(target);

    const proxy: LeanProxy = { angle: 0, sx: 1, sy: 1 };
    (target as Node & { [PROXY_KEY]?: LeanProxy })[PROXY_KEY] = proxy;
    target.angle = 0;
    target.setScale(1, 1, 1);

    const apply = (): void => {
        if (!target.isValid) return;
        target.angle = proxy.angle;
        target.setScale(proxy.sx, proxy.sy, 1);
    };

    tween(proxy)
        .to(0.045, { angle: peakAngle * 0.4, sx: squashX, sy: squashY }, {
            easing: 'quadOut',
            onUpdate: apply,
        })
        .to(0.09, { angle: peakAngle, sx: stretchX, sy: stretchY }, {
            easing: 'backOut',
            onUpdate: apply,
        })
        .to(0.18, { angle: 0, sx: 1, sy: 1 }, {
            easing: 'elasticOut',
            onUpdate: apply,
        })
        .call(() => {
            if (!target.isValid) return;
            target.angle = 0;
            target.setScale(1, 1, 1);
        })
        .start();
}