import type { XMLBuilder } from 'xmlbuilder2/lib/interfaces';
import { create as create_xml } from 'xmlbuilder2';
import { BuildState } from './state';
import { write_text } from '../fs';
import { resolve as path_resolve } from 'path';

export async function write_sitemap_if_needed(state: BuildState) {
	if (! state.conf.sitemap) {
		return;
	}

	const doc = create_xml({ version: '1.0', encoding: 'UTF-8' });
	const urlset = doc.ele('urlset', {
		'xmlns': 'http://www.sitemaps.org/schemas/sitemap/0.9',
		'xmlns:xsi': 'http://www.w3.org/2001/XMLSchema-instance',
		'xsi:schemaLocation': 'http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd'
	});

	for (const entry of state.sitemap) {
		url_elem(urlset, entry.url, entry.lastmod, entry.change_freq, entry.priority);
	}

	const out_file = state.conf.sitemap.out_file || path_resolve(state.conf.output.root, 'sitemap.xml');
	const xml = doc.toString({
		indent: '  ',
		prettyPrint: true,
	});

	await write_text(out_file, xml);
}

export interface SitemapEntry {
	url: string;
	lastmod: string;
	change_freq?: ChangeFreq;
	priority?: number;
}

export type ChangeFreq = 'always' | 'hourly' | 'daily' | 'weekly' | 'monthly' | 'yearly' | 'never';

function url_elem(urlset: XMLBuilder, loc: string, lastmod: string, change_freq?: ChangeFreq, priority?: number) {
	const url = urlset.ele('url');

	url.ele('loc').txt(loc);
	url.ele('lastmod').txt(lastmod);

	if (change_freq) {
		url.ele('changefreq').txt(change_freq);
	}

	if (priority != null) {
		url.ele('priority').txt(priority.toFixed(1));
	}

	return url;
}