import { promises as fs } from "fs";
import path from "path";
import hljs from "highlight.js";
import ejs from "ejs";
import formatDate from "date-fns/format";
import { Metadata } from "./metadata";

export async function write(filePath: string, data: any) {
	const dest = path.join("out", filePath);
	await fs.mkdir(path.dirname(dest), {
		recursive: true
	});
	await fs.writeFile(dest, data);
}

export function getWordCount(text: string): number {
	return text.split(/\s+/).length;
}

export function getReadingTime(words: number): number {
	const avgWPM = 225;
	return Math.max(1, Math.round(words / avgWPM))
}

export function highlight(source: string, language?: string): string {
	const res = language ? hljs.highlight(source, {language}) : hljs.highlightAuto(source);
	const highlighted = res.value;
	return `<pre class="hljs"><code>${highlighted}</code></pre>`;
}

interface Chunk<T> {
	chunk: T[];
	index: number;
}

export function chunk<T>(array: T[], size: number): Chunk<T>[] {
	const chunks: Chunk<T>[] = [];

	for (let i = 0; i < array.length; i += size) {
		chunks.push({
			chunk: array.slice(i, i + size),
			index: i / size
		});
	}

	return chunks;
}

export function fancyLink(text: string, href: string, meta?: string): string {
	return `<a href="${href}" class="fancy-link" ${meta || ""}><span aria-hidden="true">{</span>${text}<span aria-hidden="true">}</span></a>`;
}

export function video(metadata: Metadata, name: string, attributes: object): string {
	if (!attributes["poster"]) {
		attributes["poster"] = `${metadata.permalink}/${name}.png`;
	}
	if (attributes["controls"] === undefined) {
		attributes["controls"] = true;
	}
	var attributesStr = "";
	for (const k of Object.keys(attributes)) {
		const v = attributes[k];
		if (typeof v == "boolean" && v) {
			attributesStr += `${k} `;
		} else if (typeof v == "string") {
			attributesStr += `${k}="${v}" `;
		} else {
			console.warn(`Unexpected attribute value for ${k}: ${v}`);
		}
	}
	return `
<video ${attributesStr}>
	<source src="${metadata.permalink}/${name}.mp4" type="video/mp4">
</video>
`;
}

const domain = process.env.DOMAIN;

export function render(template: string, data: any, filename?: string): string {
	const newData = {
		require,
		fancyLink,
		formatDate,
		video,
		domain,
		...data,
	};
	return ejs.render(template, newData, {
		filename
	});
}