// This script reads through the Markdown files in readme/news and post each of
// them as Dicourse forum posts. It then also update the news file with a link
// to that forum post.

import { readdir, readFile, writeFile } from 'fs-extra';
import { basename } from 'path';
import { rootDir } from '../tool-utils';
import { compileWithFrontMatter, MarkdownAndFrontMatter, stripOffFrontMatter } from './utils/frontMatter';
import { markdownToHtml } from './utils/render';
import { getNewsDate } from './utils/news';
import { config, createTopic, getForumTopPostByExternalId, updatePost } from '../utils/discourse';
const RSS = require('rss');

interface Post {
	id: string;
	path: string;
}

interface PostContent {
	title: string;
	body: string;
	parsed: MarkdownAndFrontMatter;
}

const ignoredPostIds = ['20180621-172112', '20180621-182112', '20180906-101039', '20180906-111039', '20180916-200431', '20180916-210431', '20180929-111053', '20180929-121053', '20181004-081123', '20181004-091123', '20181101-174335', '20181213-173459', '20190130-230218', '20190404-064157', '20190404-074157', '20190424-102410', '20190424-112410', '20190523-221026', '20190523-231026', '20190610-230711', '20190611-000711', '20190613-192613', '20190613-202613', '20190814-215957', '20190814-225957', '20190924-230254', '20190925-000254', '20190929-142834', '20190929-152834', '20191012-223121', '20191012-233121', '20191014-155136', '20191014-165136', '20191101-131852', '20191117-183855', '20191118-072700', '20200220-190804', '20200301-125055', '20200314-001555', '20200406-214254', '20200406-224254', '20200505-181736', '20200606-151446', '20200607-112720', '20200613-103545', '20200616-191918', '20200620-114515', '20200622-084127', '20200626-134029', '20200708-192444', '20200906-172325', '20200913-163730', '20200915-091108', '20201030-114530', '20201126-114649', '20201130-145937', '20201212-172039', '20201228-112150', '20210104-131645', '20210105-153008', '20210130-144626', '20210309-111950', '20210310-100852', '20210413-091132', '20210430-083248', '20210506-083359', '20210513-095238', '20210518-085514', '20210621-104753', '20210624-171844', '20210705-094247', '20210706-140228', '20210711-095626', '20210718-103538', '20210729-103234', '20210804-085003', '20210831-154354', '20210901-113415', '20210929-144036', '20210930-163458', '20211031-115215', '20211102-150403', '20211217-120324', '20220215-142000', '20220224-release-2-7', '20220308-gsoc2022-start', '20220405-gsoc-contributor-proposals'];

const getPosts = async (newsDir: string): Promise<Post[]> => {
	const filenames = await readdir(newsDir);
	const output: Post[] = [];

	for (const filename of filenames) {
		if (!filename.endsWith('.md')) continue;
		output.push({
			id: basename(filename, '.md'),
			path: `${newsDir}/${filename}`,
		});
	}

	output.sort((a: Post, b: Post) => {
		if (a.id < b.id) return -1;
		return +1;
	});

	return output;
};

const getPostContent = async (post: Post): Promise<PostContent> => {
	try {
		const raw = await readFile(post.path, 'utf8');
		const parsed = stripOffFrontMatter(raw);
		const lines = parsed.doc.split('\n');
		const titleLine = lines[0];
		if (!titleLine.startsWith('# ')) throw new Error('Cannot extract title from post: no header detected');
		lines.splice(0, 1);

		return {
			title: titleLine.substr(1).trim(),
			body: lines.join('\n').trim(),
			parsed,
		};
	} catch (error) {
		error.message = `Could not get post content: ${post.id}: ${post.path}: ${error.message}`;
		throw error;
	}
};

const generateRssFeed = async (posts: Post[]) => {
	let pubDate = null;
	let postCount = 0;
	const feedItems: any[] = [];
	for (const post of posts.reverse()) {
		const content = await getPostContent(post);
		const postDate = getNewsDate(content.parsed, post.path);
		const html = markdownToHtml(content.body);

		if (pubDate === null) pubDate = postDate;

		feedItems.push({
			title: content.title,
			description: html,
			url: `https://joplinapp.org/news/${post.id}/`,
			guid: post.id,
			date: postDate,
			custom_elements: [
				{ 'twitter-text': content.parsed.tweet },
			],
		});

		postCount++;
		if (postCount >= 20) break;
	}

	const feed = new RSS({
		title: 'Joplin',
		description: 'Joplin, the open source note-taking application',
		feed_url: 'https://joplinapp.org/rss.xml',
		site_url: 'https://joplinapp.org',
		pubDate,
	});

	for (const feedItem of feedItems) feed.item(feedItem);

	let xml = feed.xml() as string;

	// Change the build date otherwise it changes even when nothing has changed.
	// https://github.com/dylang/node-rss/pull/52
	xml = xml.replace(/<lastBuildDate>(.*?)<\/lastBuildDate>/, `<lastBuildDate>${pubDate.toUTCString()}</lastBuildDate>`);

	return xml;
};

const main = async () => {
	const argv = require('yargs').argv;
	config.key = argv._[0];
	config.username = argv._[1];

	if (!config.key || !config.username) throw new Error('API Key and Username are required');

	const posts = await getPosts(`${rootDir}/readme/news`);

	const rssFeed = await generateRssFeed(posts);
	await writeFile(`${rootDir}/Assets/WebsiteAssets/rss.xml`, rssFeed, 'utf8');

	for (const post of posts) {
		if (ignoredPostIds.includes(post.id)) continue;

		console.info(`Processing ${post.path}...`);

		try {
			const content = await getPostContent(post);
			const existingForumPost = await getForumTopPostByExternalId(post.id);

			if (existingForumPost) {
				// console.info('EXISTING ========================');
				// console.info(existingForumPost.title);
				// console.info(existingForumPost.raw);

				// console.info('NEW ========================');
				// console.info(content.title);
				// console.info(content.body);

				if (existingForumPost.title === content.title && existingForumPost.raw === content.body) {
					console.info('Post already exists and has not changed: skipping it...');
				} else {
					console.info('Post already exists and has changed: updating it...');

					await updatePost(existingForumPost.id, {
						title: content.title,
						raw: content.body,
						edit_reason: 'Auto-updated by script',
					});
				}
			} else {
				console.info('Post does not exists: creating it...');

				const topic = await createTopic({
					title: content.title,
					raw: content.body,
					category: config.newsCategoryId,
					external_id: post.id,
				});

				const postUrl = `https://discourse.joplinapp.org/t/${topic.topic_id}`;
				content.parsed.forum_url = postUrl;
				const compiled = compileWithFrontMatter(content.parsed);

				await writeFile(post.path, compiled, 'utf8');
			}
		} catch (error) {
			console.error(error);
		}
	}
};

main().catch((error) => {
	console.error('Fatal error', error);
	process.exit(1);
});