/**
 * 图片沉浸式全屏灯箱（Image Lightbox / Quick Look）
 * 模拟 Apple Notes 与 macOS Quick Look 的流畅看图体验：
 * - 毛玻璃暗色背景与平滑淡入缩放
 * - 支持 ESC 键与点击背景退出
 * - 单击图片切换「适应屏幕」与「100% 原始尺寸」
 */

interface LightboxState {
	container: HTMLElement;
	img: HTMLImageElement;
	isZoomedOriginal: boolean;
	keydownListener: (e: KeyboardEvent) => void;
}

let activeLightbox: LightboxState | null = null;

export const closeImageLightbox = (): void => {
	if (!activeLightbox) return;

	const { container, keydownListener } = activeLightbox;
	window.removeEventListener('keydown', keydownListener);

	container.style.opacity = '0';
	container.style.pointerEvents = 'none';

	setTimeout(() => {
		if (container.parentElement) {
			container.parentElement.removeChild(container);
		}
	}, 200);

	activeLightbox = null;
};

export const showImageLightbox = (src: string, alt = ''): HTMLElement => {
	if (activeLightbox) {
		closeImageLightbox();
	}

	const overlay = document.createElement('div');
	overlay.className = 'cm-ext-image-lightbox-overlay';
	overlay.setAttribute('role', 'dialog');
	overlay.setAttribute('aria-modal', 'true');
	overlay.setAttribute('aria-label', alt || 'Image Preview');

	// 样式：固定全屏、深色毛玻璃、居中对齐
	Object.assign(overlay.style, {
		position: 'fixed',
		top: '0',
		left: '0',
		width: '100vw',
		height: '100vh',
		backgroundColor: 'rgba(0, 0, 0, 0.82)',
		backdropFilter: 'blur(16px)',
		WebkitBackdropFilter: 'blur(16px)',
		zIndex: '99999',
		display: 'flex',
		flexDirection: 'column',
		alignItems: 'center',
		justifyContent: 'center',
		opacity: '0',
		transition: 'opacity 0.2s cubic-bezier(0.16, 1, 0.3, 1)',
		cursor: 'zoom-out',
		padding: '24px',
		boxSizing: 'border-box',
	});

	// 顶部操作栏
	const headerBar = document.createElement('div');
	headerBar.className = 'cm-lightbox-header';
	Object.assign(headerBar.style, {
		position: 'absolute',
		top: '16px',
		right: '20px',
		display: 'flex',
		alignItems: 'center',
		gap: '12px',
		zIndex: '100001',
	});

	// 关闭按钮
	const closeBtn = document.createElement('button');
	closeBtn.className = 'cm-lightbox-close-btn';
	closeBtn.title = '关闭 (ESC)';
	closeBtn.innerHTML = '✕';
	Object.assign(closeBtn.style, {
		background: 'rgba(255, 255, 255, 0.15)',
		border: 'none',
		color: '#ffffff',
		width: '32px',
		height: '32px',
		borderRadius: '50%',
		fontSize: '16px',
		fontWeight: 'bold',
		cursor: 'pointer',
		display: 'flex',
		alignItems: 'center',
		justifyContent: 'center',
		transition: 'background 0.15s ease',
	});
	closeBtn.addEventListener('mouseenter', () => {
		closeBtn.style.background = 'rgba(255, 255, 255, 0.3)';
	});
	closeBtn.addEventListener('mouseleave', () => {
		closeBtn.style.background = 'rgba(255, 255, 255, 0.15)';
	});
	closeBtn.addEventListener('click', (e) => {
		e.stopPropagation();
		closeImageLightbox();
	});
	headerBar.appendChild(closeBtn);
	overlay.appendChild(headerBar);

	// 图片容器与图片元素
	const imgWrapper = document.createElement('div');
	imgWrapper.className = 'cm-lightbox-img-wrapper';
	Object.assign(imgWrapper.style, {
		display: 'flex',
		alignItems: 'center',
		justifyContent: 'center',
		maxWidth: '100%',
		maxHeight: '100%',
		overflow: 'auto',
	});

	const img = document.createElement('img');
	img.className = 'cm-lightbox-img';
	img.src = src;
	img.alt = alt;

	const applyFitStyle = () => {
		Object.assign(img.style, {
			maxWidth: '92vw',
			maxHeight: '88vh',
			width: 'auto',
			height: 'auto',
			objectFit: 'contain',
			borderRadius: '8px',
			boxShadow: '0 20px 48px rgba(0, 0, 0, 0.6)',
			cursor: 'zoom-in',
			transition: 'transform 0.2s cubic-bezier(0.16, 1, 0.3, 1)',
		});
	};

	const applyOriginalStyle = () => {
		Object.assign(img.style, {
			maxWidth: 'none',
			maxHeight: 'none',
			width: 'auto',
			height: 'auto',
			objectFit: 'none',
			cursor: 'zoom-out',
			transition: 'none',
		});
	};

	applyFitStyle();

	// 单击图片切换适应/原图
	let isZoomedOriginal = false;
	img.addEventListener('click', (e) => {
		e.stopPropagation();
		isZoomedOriginal = !isZoomedOriginal;
		if (isZoomedOriginal) {
			applyOriginalStyle();
		} else {
			applyFitStyle();
		}
		if (activeLightbox) {
			activeLightbox.isZoomedOriginal = isZoomedOriginal;
		}
	});

	imgWrapper.appendChild(img);
	overlay.appendChild(imgWrapper);

	// 点击背景遮罩关闭
	overlay.addEventListener('click', (e) => {
		if (e.target === overlay || e.target === imgWrapper) {
			closeImageLightbox();
		}
	});

	// ESC 键盘监听
	const keydownListener = (e: KeyboardEvent) => {
		if (e.key === 'Escape') {
			e.preventDefault();
			e.stopPropagation();
			closeImageLightbox();
		}
	};
	window.addEventListener('keydown', keydownListener);

	document.body.appendChild(overlay);

	// 渐显进入
	requestAnimationFrame(() => {
		overlay.style.opacity = '1';
	});

	activeLightbox = {
		container: overlay,
		img,
		isZoomedOriginal: false,
		keydownListener,
	};

	return overlay;
};

export const getActiveLightbox = (): LightboxState | null => activeLightbox;