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

/**
 * 背包字块拖拽到地图时，ui_line 从字块中心指向目标格中心。
 * 仅设置 ui_line 根节点 Content Size 的 width（配合 Mask 裁剪子节点线条图），不拉伸子图。
 */
export class DragPlaceLinePresenter {
    private _root: Node | null = null;
    private _defaultHeight = 9;

    bind(root: Node | null): void {
        this._root = root?.isValid ? root : null;
        if (!this._root) return;
        const ut = this._root.getComponent(UITransform);
        if (ut) {
            this._defaultHeight = ut.contentSize.height;
        }
        this.hide();
    }

    unbind(): void {
        this.hide();
        this._root = null;
    }

    /** 从起点世界坐标拉线到终点世界坐标 */
    show(fromWorld: Readonly<Vec3>, toWorld: Readonly<Vec3>): void {
        if (!this._root?.isValid) return;

        const parent = this._root.parent;
        const parentUt = parent?.getComponent(UITransform);
        if (!parentUt) return;

        const startLocal = parentUt.convertToNodeSpaceAR(new Vec3(fromWorld.x, fromWorld.y, fromWorld.z));
        const endLocal = parentUt.convertToNodeSpaceAR(new Vec3(toWorld.x, toWorld.y, toWorld.z));
        const dx = endLocal.x - startLocal.x;
        const dy = endLocal.y - startLocal.y;
        const dist = Math.sqrt(dx * dx + dy * dy);
        if (dist < 1) {
            this.hide();
            return;
        }

        const angle = Math.atan2(dy, dx) * 180 / Math.PI;
        this._root.active = true;
        this._root.setPosition(startLocal);
        this._root.angle = angle;

        const ut = this._root.getComponent(UITransform);
        ut?.setContentSize(dist, this._defaultHeight);
    }

    hide(): void {
        if (this._root?.isValid) {
            this._root.active = false;
        }
    }
}