import DOMPurify from 'dompurify';
import { toast } from 'svelte-sonner';

import { createNewNote } from '$lib/apis/notes';
import { safeImageUrl } from '$lib/utils/safeImageUrl';

export const downloadPdf = async (note) => {
	const [{ default: jsPDF }, { default: html2canvas }] = await Promise.all([
		import('jspdf'),
		import('html2canvas-pro')
	]);

	// Define a fixed virtual screen size
	const virtualWidth = 1024; // Fixed width (adjust as needed)
	const virtualHeight = 1400; // Fixed height (adjust as needed)

	// STEP 1. Get a DOM node to render
	const html = DOMPurify.sanitize(note.data?.content?.html ?? '');
	const isDarkMode = document.documentElement.classList.contains('dark');

	let node;
	if (html instanceof HTMLElement) {
		node = html;
	} else {
		const virtualWidth = 800; // px, fixed width for cloned element

		// Clone and style
		node = document.createElement('div');

		// title node
		const titleNode = document.createElement('div');
		titleNode.textContent = note.title;
		titleNode.style.fontSize = '24px';
		titleNode.style.fontWeight = 'medium';
		titleNode.style.paddingBottom = '20px';
		titleNode.style.color = isDarkMode ? 'white' : 'black';
		node.appendChild(titleNode);

		const contentNode = document.createElement('div');

		contentNode.innerHTML = html;

		for (const img of contentNode.querySelectorAll('img[src^="data://"]')) {
			const fileId = img.getAttribute('src').replace('data://', '');
			const file = (note.data?.files ?? []).find((f) => f.id === fileId);
			if (file) {
				img.setAttribute('src', safeImageUrl(file.url || ''));
			}
		}

		node.appendChild(contentNode);

		node.classList.add('text-black');
		node.classList.add('dark:text-white');
		node.style.width = `${virtualWidth}px`;
		node.style.position = 'absolute';
		node.style.left = '-9999px';
		node.style.height = 'auto';
		node.style.padding = '40px 40px';

		console.log(node);
		document.body.appendChild(node);
	}

	await Promise.all(
		Array.from(node.querySelectorAll('img')).map((img) => img.decode().catch(() => {}))
	);

	// A4 page settings
	const pdf = new jsPDF('p', 'mm', 'a4');
	const pageWidthMM = 210; // A4 width in mm
	const pageHeightMM = 297; // A4 height in mm

	const pagePixelHeight = Math.floor((virtualWidth * pageHeightMM) / pageWidthMM);
	const rootTop = node.getBoundingClientRect().top;
	const contentHeight = Math.ceil(node.getBoundingClientRect().height);

	const blocks = [];
	const trackedElements = new Set();
	const collectBlocks = (element) => {
		const children = Array.from(element.children);
		const splittable =
			children.length > 0 &&
			(getComputedStyle(element).display === 'contents' ||
				(element.getBoundingClientRect().height > pagePixelHeight / 4 &&
					!Array.from(element.childNodes).some(
						(childNode) => childNode.nodeType === Node.TEXT_NODE && childNode.textContent?.trim()
					) &&
					children.every((child) => !getComputedStyle(child).display.startsWith('inline'))));

		if (element !== node) trackedElements.add(element);

		if (splittable) {
			children.forEach(collectBlocks);
		} else {
			const { top, bottom } = element.getBoundingClientRect();
			blocks.push({ element, top: top - rootTop, bottom: bottom - rootTop });
		}
	};
	collectBlocks(node);

	node.setAttribute('data-pdf-root', '');

	let offsetY = 0;
	let page = 0;

	while (offsetY < contentHeight) {
		const sliceHeight = Math.min(pagePixelHeight, contentHeight - offsetY);
		const sliceBlocks = blocks.filter(
			(block) => block.bottom > offsetY && block.top < offsetY + sliceHeight
		);

		const keptElements = new Set();
		for (const { element } of sliceBlocks) {
			for (let current = element; current && current !== node; current = current.parentElement) {
				keptElements.add(current);
			}
		}

		const anchor = sliceBlocks.find((block) => block.bottom > block.top);
		anchor?.element.setAttribute('data-pdf-anchor', '');

		const canvas = await html2canvas(node, {
			useCORS: true,
			logging: false,
			backgroundColor: isDarkMode ? '#000' : '#fff',
			scale: 2, // Keep at 1x to avoid unexpected enlargements
			width: virtualWidth, // Set fixed virtual screen width
			windowWidth: virtualWidth, // Ensure consistent rendering
			windowHeight: virtualHeight,
			height: sliceHeight,
			y: offsetY,
			ignoreElements: (element) =>
				(element.parentElement === document.body &&
					element !== node &&
					!['STYLE', 'LINK'].includes(element.tagName)) ||
				(trackedElements.has(element) && !keptElements.has(element)),
			onclone: (clonedDocument) => {
				const clonedRoot = clonedDocument.querySelector('[data-pdf-root]');
				const clonedAnchor = clonedDocument.querySelector('[data-pdf-anchor]');
				if (!clonedRoot || !clonedAnchor) return;

				const spacer = clonedDocument.createElement('div');
				clonedRoot.prepend(spacer);

				let spacerHeight = 0;
				for (let pass = 0; pass < 2; pass++) {
					spacerHeight +=
						anchor.top -
						(clonedAnchor.getBoundingClientRect().top - clonedRoot.getBoundingClientRect().top);
					spacer.style.height = `${spacerHeight}px`;
				}
			}
		});

		anchor?.element.removeAttribute('data-pdf-anchor');

		const imgData = canvas.toDataURL('image/jpeg', 0.7);
		const imgHeightMM = (sliceHeight * pageWidthMM) / virtualWidth;

		if (page > 0) pdf.addPage();

		if (isDarkMode) {
			pdf.setFillColor(0, 0, 0);
			pdf.rect(0, 0, pageWidthMM, pageHeightMM, 'F'); // black bg
		}

		pdf.addImage(imgData, 'JPEG', 0, 0, pageWidthMM, imgHeightMM);

		offsetY += sliceHeight;
		page++;
	}

	// Remove hidden node if needed
	if (!(html instanceof HTMLElement)) {
		document.body.removeChild(node);
	}

	pdf.save(`${note.title}.pdf`);
};

export const createNoteHandler = async (title: string, md?: string, html?: string) => {
	//  $i18n.t('New Note'),
	const res = await createNewNote(localStorage.token, {
		// YYYY-MM-DD
		title: title,
		data: {
			content: {
				json: null,
				html: html || md || '',
				md: md || ''
			}
		},
		meta: null,
		access_grants: []
	}).catch((error) => {
		toast.error(`${error}`);
		return null;
	});

	if (res) {
		return res;
	}
};