import fs, {mkdirSync} from 'node:fs';
import path from 'path';
import limit from 'p-limit';
import {FontInfo, extractInfoFromCss} from './extract-info-from-css';
import {Font, googleFonts} from './google-fonts';
import {
	getCssLink,
	quote,
	removeWhitespace,
	replaceDigitsWithWords,
	unquote,
} from './utils';

const p = limit(8);

const OUTDIR = './src';
const CSS_CACHE_DIR = './.cache-css';

const generate = async (font: Font) => {
	try {
		// Prepare filename
		const importName = removeWhitespace(font.family);
		const filename = `${importName}.ts`;
		const tsFile = path.resolve(OUTDIR, filename);
		const cssname = `${font.family.toLowerCase().replace(/\s/g, '_')}_${
			font.version
		}.css`;

		// Get css link
		const url = getCssLink(font);

		//  Read css from cache, otherwise from url
		let css: null | string = null;
		let fontFamily: null | string = replaceDigitsWithWords(
			unquote(font.family),
		);
		let cssFile = path.resolve(CSS_CACHE_DIR, cssname);
		//  Get from url with user agent that support woff2
		const res = await fetch(url, {
			headers: {
				'User-Agent':
					'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36',
			},
		});

		// Save to cache
		const body = await res.text();
		await fs.promises.writeFile(cssFile, body);
		console.log('Generated', cssFile);

		css = body;

		if (!css) {
			throw new Error('no css');
		}

		// Prepare info data
		const info: FontInfo = extractInfoFromCss({
			contents: css,
			fontFamily: fontFamily,
			importName: importName,
			url: url,
			version: font.version,
			subsets: font.subsets,
		});

		let output = `import { loadFonts } from "./base";

export const getInfo = () => (${JSON.stringify(info, null, 3)})

export const fontFamily = "${fontFamily}" as const;

type Variants = {\n`;

		for (const [style, val] of Object.entries(info.fonts)) {
			output += `  ${style}: {\n`;
			output += `    weights: ${Object.keys(val).map(quote).join(' | ')},\n`;
			output += `    subsets: ${font.subsets.map(quote).join(' | ')},\n`;
			output += `  },\n`;
		}

		output += `};

export const loadFont = <T extends keyof Variants>(
  style?: T,
  options?: {
    weights?: Variants[T]['weights'][];
    subsets?: Variants[T]['subsets'][];
    document?: Document;
    ignoreTooManyRequestsWarning?: boolean;
  }
) => { 
  return loadFonts(getInfo(), style, options);
};

`;

		mkdirSync(OUTDIR, {recursive: true});
		//  Save
		const existed = fs.existsSync(tsFile);
		await fs.promises.writeFile(tsFile, output);
		if (!existed) {
			console.log('Wrote', tsFile);
		}
	} catch (e) {
		console.log('Incompatible font', font.family);
		incompatibleFonts.push(font.family);
	}
};

const date = Date.now();

// Prepare css cache dir
if (!fs.existsSync(CSS_CACHE_DIR)) {
	await fs.promises.mkdir(CSS_CACHE_DIR, {recursive: true});
}

let incompatibleFonts: string[] = [];

const promises: Promise<unknown>[] = [];

// Batch convert
for (const font of googleFonts) {
	promises.push(
		p(() => {
			return generate(font);
		}),
	);
}

await Promise.all(promises);

await Bun.write(
	__dirname + '/incompatible-fonts.ts',
	`export const incompatibleFonts = ${JSON.stringify(incompatibleFonts, null, 2)};`,
);

console.log('- Generated fonts in ' + (Date.now() - date) + 'ms');