---
import type { CollectionEntry } from 'astro:content';
import { getCollection } from 'astro:content';

export interface Props {
	headingLevel?: 1 | 2 | 3 | 4 | 5 | 6,
	hideAuthor?: boolean,
};

const { headingLevel = 2, hideAuthor = false } = Astro.props;

const posts = (await getCollection('blog'));

const distinctYears: number[] = posts
	.map(post => post.data.pubDate.year)
	.reduce<number[]>((acc, curr) => acc.includes(curr) ? acc : [...acc, curr], [])
	.sort((a, b) => b - a);

function matchesYear(year: number) {
	return (post: CollectionEntry<'blog'>) => post.data.pubDate.year === year;
}

function sortByPubDateDescending(post1: CollectionEntry<'blog'>, post2: CollectionEntry<'blog'>) {
	const year1 = post1.data.pubDate.year;
	const year2 = post2.data.pubDate.year;
	const month1 = post1.data.pubDate.month;
	const month2 = post2.data.pubDate.month;
	const day1 = post1.data.pubDate.day;
	const day2 = post2.data.pubDate.day;

	if (year1 !== year2) {
		return year2 - year1;
	} else if (month1 !== month2) {
		return month2 - month1;
	} else {
		return day2 - day1;
	}
}

const headingElem = `h${headingLevel}`;

const canonicalBlogUrl = new URL('blog', Astro.site)
---

<section class="h-feed">
	<Fragment set:html={`
		<${headingElem} class="p-name">
		My blog
		</${headingElem}>
	`} />

	<aside>
		<p class={hideAuthor ? 'hidden' : ''}>
			This blog is written by <a class="p-author h-card" href="/">Joe Carstairs</a>
		</p>

		<p>
			<a class="u-url" href={canonicalBlogUrl}>Permalink</a>
		</p>
	</aside>

	<ul>
		{ distinctYears.map(year => (
			<li>
				{year}
				<ul>
					{ posts.filter(matchesYear(year)).sort(sortByPubDateDescending).map(post => (
						<li class="h-entry">
							<a class="u-url p-name" href={`/blog/${post.slug}`}>{post.data.title}</a>
						</li>
					)) }
				</ul>
			</li>
		)) }
	</ul>
</section>