import React, { useState, useEffect, useMemo } from 'react';
import { useParams } from 'react-router-dom';
import { Helmet } from 'react-helmet';
import localForage from 'localforage';
import { sourceLink, infoLine, ToggleDot } from './utils.js';

function Article({ cache }) {
	const { id } = useParams();

	if (id in cache) console.log('cache hit');

	const [story, setStory] = useState(cache[id] || false);
	const [error, setError] = useState('');
	const [pConv, setPConv] = useState([]);

	useEffect(() => {
		localForage.getItem(id)
			.then(
				(value) => {
					if (value) {
						setStory(value);
					}
				}
			);

		fetch('/api/' + id)
			.then(res => {
				if (!res.ok) {
					throw new Error(`Server responded with ${res.status} ${res.statusText}`);
				}
				return res.json();
			})
			.then(
				(result) => {
					setStory(result.story);
					localForage.setItem(id, result.story);
				},
				(error) => {
					const errorMessage = `Failed to fetch new article content (ID: ${id}). Your connection may be down or the server might be experiencing issues. ${error.toString()}.`;
					setError(errorMessage);
				}
			);
	}, [id]);

	const pConvert = (n) => {
		setPConv(prevPConv => [...prevPConv, n]);
	};

	const nodes = useMemo(() => {
		if (story && story.text) {
			let div = document.createElement('div');
			div.innerHTML = story.text;
			return div.childNodes;
		}
		return null;
	}, [story]);

	return (
		<div className='article-container'>
			{error &&
				<details style={{marginBottom: '1rem'}}>
					<summary>Connection error? Click to expand.</summary>
					<p>{error}</p>
					{story && <p>Loaded article from cache.</p>}
				</details>
			}
			{story ?
				<div className='article'>
					<Helmet>
						<title>{story.title} | QotNews</title>
						<meta name="robots" content="noindex" />
					</Helmet>

					<h1>{story.title}</h1>

					<div className='info'>
						Source: {sourceLink(story)}
					</div>

					{infoLine(story)}

					{nodes ?
						<div className='story-text'>
							{Object.entries(nodes).map(([k, v]) =>
								pConv.includes(k) ?
									<React.Fragment key={k}>
										{v.innerHTML.split('\n\n').map((x, i) =>
											<p key={i} dangerouslySetInnerHTML={{ __html: x }} />
										)}
									</React.Fragment>
								:
									(v.nodeName === '#text' ?
										<p key={k}>{v.data}</p>
									:
										<React.Fragment key={k}>
											<v.localName dangerouslySetInnerHTML={v.innerHTML ? { __html: v.innerHTML } : null} />
											{v.localName === 'pre' && <button onClick={() => pConvert(k)}>Convert Code to Paragraph</button>}
										</React.Fragment>
									)
							)}
						</div>
					:
						<p>Problem getting article :(</p>
					}
				</div>
			:
				<p>Loading...</p>
			}
			<ToggleDot id={id} article={false} />
		</div>
	);
}

export default Article;