/**
 * 720 全景引擎管理器
 * 负责管理 720° 全景渲染引擎的初始化、全景加载和生命周期
 *
 * 设计原则：
 * - 镜像 Engine2dManager 的设计模式
 * - Engine720Manager 只暴露面向外部用户的公共 API
 * - 内部管理器通过 getEngine720Component() 直接访问 Engine720 组件
 */
import { Engine720, type Engine720Options, type PanoramaLoadOptions } from '../components/engine-720';
import { BaseManager } from '../core/base-manager';
import { ManagerRegistry } from '../core/manager-registry';

/**
 * 720 全景引擎管理器
 * 封装底层 720 引擎，提供全景加载、视角控制等公共 API
 */
export class Engine720Manager extends BaseManager {
    /** 容器元素 */
    private container: HTMLElement;
    /** 720 引擎组件实例 */
    private engineInstance: Engine720 | null = null;

    constructor(container: HTMLElement, registry: ManagerRegistry) {
        super(registry);
        this.container = container;
    }

    /**
     * 获取 Engine720 组件实例
     * 内部管理器通过此方法直接访问 Engine720 组件的全部能力
     * @returns Engine720 组件实例，未初始化时返回 null
     */
    public getEngine720Component(): Engine720 | null {
        return this.engineInstance;
    }

    /**
     * 初始化 720 引擎
     * @param options 引擎配置选项
     * @returns 是否初始化成功
     */
    public initialize(options?: Omit<Engine720Options, 'container'>): boolean {
        if (this.engineInstance && this.engineInstance.isInitialized()) {
            console.warn('[Engine720Manager] 720 Engine already initialized. Destroying old instance...');
            this.engineInstance.destroy();
            this.engineInstance = null;
        }

        try {
            this.engineInstance = new Engine720({
                container: this.container,
                ...options,
            }, this.registry);

            this.engineInstance.init();

            return this.engineInstance.isInitialized();
        } catch (error) {
            console.error('[Engine720Manager] Failed to initialize 720 engine:', error);
            this.engineInstance = null;
            return false;
        }
    }

    /**
     * 检查引擎是否已初始化
     * @returns 是否已初始化
     */
    public isInitialized(): boolean {
        return this.engineInstance !== null && this.engineInstance.isInitialized();
    }

    /**
     * 加载全景图
     * @param url 全景图片 URL
     * @param options 加载选项
     */
    public async loadPanorama(url: string, options?: PanoramaLoadOptions): Promise<void> {
        if (!this.engineInstance) {
            console.warn('[Engine720Manager] 720 Engine not initialized.');
            return;
        }
        await this.engineInstance.loadPanorama(url, options);
    }

    /**
     * 预加载多个全景图
     * @param urls 全景图 URL 列表
     */
    public async preloadPanoramas(urls: string[]): Promise<void> {
        if (!this.engineInstance) {
            console.warn('[Engine720Manager] 720 Engine not initialized.');
            return;
        }
        await this.engineInstance.preloadPanoramas(urls);
    }

    /**
     * 设置视场角
     * @param fov 视场角值
     */
    public setFov(fov: number): void {
        this.engineInstance?.setFov(fov);
    }

    /**
     * 获取当前视场角
     * @returns 当前视场角值
     */
    public getFov(): number {
        return this.engineInstance?.getFov() ?? 75;
    }

    /**
     * 重置视图
     */
    public resetView(): void {
        this.engineInstance?.resetView();
    }

    /** 销毁 720 引擎管理器 */
    public destroy(): void {
        if (this.engineInstance) {
            this.engineInstance.destroy();
            this.engineInstance = null;
        }
        super.destroy();
    }
}