import { _decorator, Camera, Component, find, Node, Vec3 } from 'cc';

const { ccclass, property } = _decorator;

/**
 * CameraController 摄像机控制器
 * 负责让摄像机跟随指定的目标物体，并提供摄像机坐标转换功能
 * 支持世界摄像机和UI摄像机的概念
 */
@ccclass('CameraController')
export class CameraController extends Component {
    /** 跟随目标 */
    private target: Node = null;

    /** 世界摄像机节点 (Main Camera) */
    private worldCameraNode: Node = null;

    /** 世界摄像机组件 */
    private worldCamera: Camera = null;

    /** UI摄像机节点 (Canvas/Camera) */
    private uiCameraNode: Node = null;

    /** UI摄像机组件 */
    private uiCamera: Camera = null;

    /** 相对偏移量 */
    private offset: Vec3 = new Vec3(0, 10, 8);

    /** 跟随速度 */
    @property({ displayName: '跟随速度' })
    public followSpeed: number = 5;

    /** 是否平滑跟随 */
    @property({ displayName: '平滑跟随' })
    public smoothFollow: boolean = true;

    onLoad() {
        this.findCameras();
    }

    /**
     * 查找所有摄像机
     */
    private findCameras(): void {
        this.findWorldCamera();
        this.findUICamera();
    }

    /**
     * 查找世界摄像机 (Main Camera)
     */
    private findWorldCamera(): void {
        // 查找名为 "Main Camera" 的世界摄像机
        const mainCameraNode = find('Main Camera', this.node.scene);
        if (mainCameraNode) {
            this.worldCameraNode = mainCameraNode;
            this.worldCamera = mainCameraNode.getComponent(Camera);
            console.log('[CameraController] 找到世界摄像机:', mainCameraNode.name);
        } else {
            console.error('[CameraController] 未找到世界摄像机(Main Camera)');
        }
    }

    /**
     * 查找UI摄像机 (Canvas/Camera)
     */
    private findUICamera(): void {
        // 查找Canvas下的Camera作为UI摄像机
        const canvasNode = find('Canvas', this.node.scene);
        if (canvasNode) {
            const uiCameraNode = canvasNode.getChildByName('Camera');
            if (uiCameraNode) {
                this.uiCameraNode = uiCameraNode;
                this.uiCamera = uiCameraNode.getComponent(Camera);
                console.log('[CameraController] 找到UI摄像机:', uiCameraNode.name);
            } else {
                console.error('[CameraController] 未找到Canvas下的Camera节点');
            }
        } else {
            console.error('[CameraController] 未找到Canvas节点');
        }
    }

    /**
     * 设置跟随目标
     * @param target 跟随的目标节点
     */
    public setTarget(target: Node): void {
        this.target = target;

        if (this.target && this.worldCameraNode) {
            // 立即设置初始位置
            this.updateCameraPosition(false);
            console.log('[CameraController] 设置跟随目标:', target.name);
        }
    }

    /**
     * 设置摄像机偏移量
     * @param offset 相对于目标的偏移量
     */
    public setOffset(offset: Vec3): void {
        this.offset.set(offset);
    }

    /**
     * 获取当前跟随目标
     */
    public getTarget(): Node {
        return this.target;
    }

    /**
     * 获取世界摄像机节点
     */
    public getWorldCameraNode(): Node {
        return this.worldCameraNode;
    }

    /**
     * 获取世界摄像机组件
     */
    public getWorldCamera(): Camera {
        return this.worldCamera;
    }

    /**
     * 获取UI摄像机节点
     */
    public getUICameraNode(): Node {
        return this.uiCameraNode;
    }

    /**
     * 获取UI摄像机组件
     */
    public getUICamera(): Camera {
        return this.uiCamera;
    }

    update(deltaTime: number) {
        if (this.target && this.worldCameraNode) {
            this.updateCameraPosition(this.smoothFollow, deltaTime);
        }
    }

    /**
     * 更新摄像机位置
     * @param smooth 是否使用平滑跟随
     * @param deltaTime 帧时间(smooth为true时需要)
     */
    private updateCameraPosition(smooth: boolean = true, deltaTime: number = 0): void {
        if (!this.target || !this.worldCameraNode) {
            return;
        }

        // 计算目标位置
        const targetPosition = new Vec3();
        Vec3.add(targetPosition, this.target.worldPosition, this.offset);

        if (smooth && deltaTime > 0) {
            // 平滑跟随
            const currentPosition = this.worldCameraNode.worldPosition;
            const newPosition = new Vec3();
            Vec3.lerp(newPosition, currentPosition, targetPosition, this.followSpeed * deltaTime);
            this.worldCameraNode.setWorldPosition(newPosition);
        } else {
            // 立即跟随
            this.worldCameraNode.setWorldPosition(targetPosition);
        }

        // 让摄像机看向目标
        this.worldCameraNode.lookAt(this.target.worldPosition);
    }

    /**
     * 停止跟随
     */
    public stopFollow(): void {
        this.target = null;
        console.log('[CameraController] 停止跟随');
    }

    /**
     * 将世界坐标转换为指定摄像机的屏幕坐标
     * @param worldPosition 世界坐标（Vec3）
     * @param camera 目标摄像机
     * @returns 摄像机坐标系下的屏幕坐标（Vec3），z为深度
     */
    public worldToCameraPosition(worldPosition: Vec3, camera: Camera): Vec3 {
        if (!camera) {
            console.warn('[CameraController] 摄像机参数为空，无法进行坐标转换');
            return new Vec3(0, 0, 0);
        }

        // 使用摄像机的worldToScreen方法将世界坐标转换为屏幕坐标
        const screenPos = new Vec3();
        camera.worldToScreen(worldPosition, screenPos);
        return screenPos;
    }

    /**
     * 将摄像机屏幕坐标转换为指定Node的本地坐标
     * 计算流程：摄像机坐标 -> 世界坐标 -> Node本地坐标
     * @param screenPosition 摄像机屏幕坐标
     * @param sourceCamera 源摄像机
     * @param targetNode 目标Node节点
     * @returns 目标Node的本地坐标
     */
    public CameraToNode(screenPosition: Vec3, sourceCamera: Camera, targetNode: Node): Vec3 {
        if (!sourceCamera || !targetNode) {
            console.warn('[CameraController] 摄像机或目标节点参数为空，无法进行坐标转换');
            return new Vec3(0, 0, 0);
        }

        // 第一步：摄像机屏幕坐标转世界坐标
        const worldPosition = new Vec3();
        sourceCamera.screenToWorld(screenPosition, worldPosition);

        // 第二步：世界坐标转Node本地坐标
        const localPosition = new Vec3();
        targetNode.inverseTransformPoint(localPosition, worldPosition);

        return localPosition;
    }

    /**
     * 将世界坐标转换为UI摄像机节点的本地坐标
     * @param worldPosition 世界坐标
     * @returns UI摄像机节点的本地坐标
     */
    public worldToUICamera(worldPosition: Vec3, node: Node): Vec3 {
        if (!this.worldCamera || !this.uiCameraNode) {
            console.warn('[CameraController] 世界摄像机或UI摄像机节点未初始化');
            return new Vec3(0, 0, 0);
        }

        // 第一步：世界坐标转世界摄像机屏幕坐标
        const worldCameraPos = this.worldToCameraPosition(worldPosition, this.worldCamera);

        // 第二步：世界摄像机屏幕坐标转UI摄像机节点本地坐标
        const uiCameraLocalPos = this.CameraToNode(worldCameraPos, this.uiCamera, node);
        return uiCameraLocalPos;

        // // 世界坐标转Node本地坐标
        // const localPosition = new Vec3();
        // node.inverseTransformPoint(localPosition, worldPosition);

        return worldPosition;
    }

    /**
     * 销毁控制器
     */
    onDestroy(): void {
        this.target = null;
        this.worldCameraNode = null;
        this.worldCamera = null;
        this.uiCameraNode = null;
        this.uiCamera = null;
        console.log('[CameraController] 摄像机控制器已销毁');
    }
}