import { dev } from '$app/environment';
import { postsPerPage } from '../config';

/* Adapted from https://github.com/josh-collinsworth/sveltekit-blog-starter/blob/main/src/lib/assets/js/fetchPosts.js */
export async function getPosts({ cursor = 0, page = 0, limit = postsPerPage, category = 'all' }) {
	let { posts, allCategories } = await fetchPosts();

	// Now, filter out any post categories we don't want
	let { sortedPosts, totalPages } = filterAndSortPosts(category, posts, cursor, page, limit);

	// Select only desired metadata information
	sortedPosts = filterMetadata(sortedPosts);

	return {
		posts: sortedPosts,
		page: page,
		total: totalPages,
		category: category,
		allCategories: allCategories
	};
}

async function fetchPosts() {
	let posts = await Promise.all(
		Object.entries(import.meta.glob('/src/routes/posts/*.md')).map(async ([path, resolver]) => {
			const { metadata } = await resolver();
			const slug = path.split('/').pop().slice(0, -3);
			return { ...metadata, slug };
		})
	);
	// Remove any unpublished posts if not in a dev environment
	posts = removeUnpublishedPosts(posts);

	// While we have everything loaded, it's also very inexpensive to get all post categories
	let allCategories = getAllPostCategories(posts);

	return { posts, allCategories };
}

function filterAndSortPosts(category, posts, cursor, page, limit) {
	if (category && category !== 'all') {
		posts = posts.filter((post) =>
			post.categories.map((a) => a.toLowerCase()).includes(category.toLowerCase())
		);
	}
	const totalPages = Math.max(Math.ceil(posts.length / postsPerPage), 1);

	// Sort by date
	posts.forEach((post) => (post.date = new Date(post.date)));
	let sortedPosts = posts.sort((a, b) => b.date - a.date);

	// Set post start
	if (cursor || page) {
		if (page) {
			sortedPosts = sortedPosts.slice((page - 1) * postsPerPage);
		} else {
			sortedPosts = sortedPosts.slice(cursor);
		}
	}

	// Set posts end
	if (limit && limit < sortedPosts.length && limit != -1) {
		sortedPosts = sortedPosts.slice(0, limit);
	}
	return { sortedPosts, totalPages, posts };
}

function filterMetadata(sortedPosts) {
	sortedPosts = sortedPosts.map((post) => ({
		title: post.title,
		date: post.date,
		updated: post.updated,
		published: post.published === undefined ? true : post.published,
		// authors: post.authors,
		tags: post.tags,
		categories: post.categories,
		description: post.description,
		thumbnail: post.thumbnail,
		image: post.image,
		slug: post.slug
	}));
	return sortedPosts;
}

function getAllPostCategories(posts) {
	let allCategories = new Set();
	for (const post in posts) {
		console.log(posts[post])

	}
	posts.forEach((post) => allCategories.add(...post.categories));
	allCategories = new Array(...allCategories).sort();
	return allCategories;
}

function removeUnpublishedPosts(posts) {
	if (!dev) {
		posts = posts.filter((post) => post.published !== false);
	}
	return posts;
}