import type { Post } from '$lib/types'

type PostMetadata = {
	title: string ,
	description?: string,
	tags: [string],
	series?: [string],
	date: Date,
}
export function transformPostMeta(metadata: PostMetadata, slug: string) : Post {
	return {
		...metadata,
		date: new Date(metadata.date),
		slug,
	};
}

export async function getPosts(tag: string | null = null) : Promise<Post[]> {
	const allPostFiles = import.meta.glob('$content/post/*.md');
	const iterablePostFiles = Object.entries(allPostFiles);

	let posts: Post[] = await Promise.all(
		iterablePostFiles.map(async ([pathMarkdown, resolver]) => {
			const { metadata } = await resolver();
			const slug = pathMarkdown.slice(pathMarkdown.lastIndexOf("/") + 1, -".md".length);

			return transformPostMeta(metadata, slug);
		})
	);
	if (tag)
		posts = posts.filter(post => post.tags.includes(tag))

	posts.sort((post1, post2) => {
		const date1: Date = post1.date;
		const date2: Date = post2.date;
		return date2.getTime() - date1.getTime();
	});
	return posts;
}

export async function getTags() : Promise<Map<string, number>> {
	const allPostFiles = import.meta.glob('$content/post/*.md');
	const iterablePostFiles = Object.entries(allPostFiles);

	const allPosts: string[][] = await Promise.all(
		iterablePostFiles.map(async ([_, resolver]) => {
			const { metadata } = await resolver();
			return metadata.tags;
		})
	);
	return allPosts.flat().reduce((acc: Map<string, number>, curr: string) => {
		return acc[curr] ? ++acc[curr] : acc[curr] = 1, acc
	}, new Map());
}