/* popups.js — Hover preview popups.
Content providers (in dispatch priority order):
1. Local annotations — /data/annotations.json (any URL, author-defined)
2. Citations — DOM lookup, cite-link[href^="#ref-"]
3. Internal pages — same-origin fetch, title + authors + tags + abstract + stats
4. Wikipedia — MediaWiki action API, full lead section
5. arXiv — export.arxiv.org Atom API
6. DOI / CrossRef — api.crossref.org, title/authors/abstract
7. GitHub — api.github.com, repo description + stars
8. Open Library — openlibrary.org JSON API, book description
9. bioRxiv / medRxiv — api.biorxiv.org, abstract
10. YouTube — oEmbed, title + channel (no key required)
11. Internet Archive — archive.org/metadata, title + description
12. PubMed — NCBI esummary, title + authors + journal
Production nginx CSP must add:
connect-src https://en.wikipedia.org https://export.arxiv.org
https://api.crossref.org https://api.github.com
https://openlibrary.org https://api.biorxiv.org
https://www.youtube.com https://archive.org
https://eutils.ncbi.nlm.nih.gov
*/
(function () {
'use strict';
var SHOW_DELAY = 250;
var HIDE_DELAY = 150;
var popup = null;
var showTimer = null;
var hideTimer = null;
var activeTarget = null;
var cache = Object.create(null); /* url → html; only successful results stored */
var annotations = null; /* null = not yet loaded */
/* ------------------------------------------------------------------
Init — load annotations first, then bind all targets
------------------------------------------------------------------ */
function init() {
popup = document.createElement('div');
popup.className = 'link-popup';
popup.setAttribute('aria-live', 'polite');
popup.setAttribute('aria-hidden', 'true');
document.body.appendChild(popup);
popup.addEventListener('mouseenter', cancelHide);
popup.addEventListener('mouseleave', scheduleHide);
loadAnnotations().then(function () {
bindTargets(document.body);
});
}
function bindTargets(root) {
/* Citation markers */
root.querySelectorAll('a.cite-link[href^="#ref-"]').forEach(function (el) {
bind(el, citationContent);
});
/* Internal links — absolute (/foo) and relative (../../foo) same-origin hrefs.
relativizeUrls in Hakyll makes index-page links relative, so we must match both. */
root.querySelectorAll('a[href^="/"], a[href^="./"], a[href^="../"]').forEach(function (el) {
/* Author links in .meta-authors and backlink source links always get popups */
var inAuthors = el.closest('.meta-authors');
var isBacklink = el.classList.contains('backlink-source');
if (!inAuthors && !isBacklink) {
if (el.closest('nav, #toc, footer, .page-meta-footer, .metadata')) return;
if (el.classList.contains('cite-link') || el.classList.contains('meta-tag')) return;
}
bind(el, internalContent);
});
/* External links — single dispatcher handles all providers */
root.querySelectorAll('a[href^="http"]').forEach(function (el) {
if (el.closest('nav, #toc, footer, .page-meta-footer')) return;
var provider = getProvider(el.getAttribute('href') || '');
if (provider) bind(el, provider);
});
}
/* Returns the appropriate provider function for a given URL, or null. */
function getProvider(href) {
if (!href) return null;
/* Local annotation takes priority over everything */
if (annotations && annotations[href]) return annotationContent;
if (/wikipedia\.org\/wiki\//.test(href)) return wikipediaContent;
if (/arxiv\.org\/(?:abs|pdf)\/\d{4}\.\d{4,5}/.test(href)) return arxivContent;
if (/(?:dx\.)?doi\.org\/10\./.test(href)) return doiContent;
if (/github\.com\/[^/]+\/[^/?#]+/.test(href)) return githubContent;
if (/openlibrary\.org\/(?:works|books)\//.test(href)) return openlibraryContent;
if (/(?:bio|med)rxiv\.org\/content\/10\./.test(href)) return biorxivContent;
if (/(?:youtube\.com\/watch|youtu\.be\/)/.test(href)) return youtubeContent;
if (/archive\.org\/details\//.test(href)) return archiveContent;
if (/pubmed\.ncbi\.nlm\.nih\.gov\/\d/.test(href)) return pubmedContent;
return null;
}
function bind(el, provider) {
el.addEventListener('mouseenter', function () { scheduleShow(el, provider); });
el.addEventListener('mouseleave', scheduleHide);
el.addEventListener('focus', function () { scheduleShow(el, provider); });
el.addEventListener('blur', scheduleHide);
}
/* ------------------------------------------------------------------
Lifecycle
------------------------------------------------------------------ */
function scheduleShow(target, provider) {
cancelHide();
clearTimeout(showTimer);
activeTarget = target;
showTimer = setTimeout(function () {
provider(target).then(function (html) {
if (!html || activeTarget !== target) return;
popup.innerHTML = html;
positionPopup(target);
popup.classList.add('is-visible');
popup.setAttribute('aria-hidden', 'false');
}).catch(function () { /* silently fail */ });
}, SHOW_DELAY);
}
function scheduleHide() {
clearTimeout(showTimer);
hideTimer = setTimeout(function () {
popup.classList.remove('is-visible');
popup.setAttribute('aria-hidden', 'true');
activeTarget = null;
}, HIDE_DELAY);
}
function cancelHide() { clearTimeout(hideTimer); }
/* ------------------------------------------------------------------
Positioning — centres below target, flips above if clipped
------------------------------------------------------------------ */
function positionPopup(target) {
var rect = target.getBoundingClientRect();
var pw = popup.offsetWidth;
var ph = popup.offsetHeight;
var vw = window.innerWidth;
var vh = window.innerHeight;
var sy = window.scrollY;
var sx = window.scrollX;
var GAP = 10;
var left = rect.left + sx + rect.width / 2 - pw / 2;
left = Math.max(sx + GAP, Math.min(left, sx + vw - pw - GAP));
var top = (rect.bottom + GAP + ph <= vh)
? rect.bottom + sy + GAP
: rect.top + sy - ph - GAP;
popup.style.left = left + 'px';
popup.style.top = top + 'px';
}
/* ------------------------------------------------------------------
Content providers
------------------------------------------------------------------ */
/* 0. Local annotations — synchronous map lookup after eager load */
function loadAnnotations() {
if (annotations !== null) return Promise.resolve(annotations);
return fetch('/data/annotations.json', { credentials: 'same-origin' })
.then(function (r) { return r.ok ? r.json() : {}; })
.then(function (data) { annotations = data; return data; })
.catch(function () { annotations = {}; return {}; });
}
function annotationContent(target) {
var href = target.getAttribute('href');
var ann = href && annotations && annotations[href];
if (!ann) return Promise.resolve(null);
return Promise.resolve(
''
);
}
/* 1. Citations — synchronous DOM lookup */
function citationContent(target) {
return new Promise(function (resolve) {
var id = (target.getAttribute('href') || '').slice(1);
var entry = document.getElementById(id);
resolve(entry
? ''
: null);
});
}
/* 2. Internal pages — same-origin fetch, rich preview */
function internalContent(target) {
/* Resolve relative hrefs (../../foo) to canonical path (/foo) for fetch + cache. */
var raw = target.getAttribute('href');
if (!raw) return Promise.resolve(null);
var href = new URL(raw, window.location.href).pathname;
if (cache[href]) return Promise.resolve(cache[href]);
return fetch(href, { credentials: 'same-origin' })
.then(function (r) { return r.ok ? r.text() : null; })
.then(function (text) {
if (!text) return null;
var doc = new DOMParser().parseFromString(text, 'text/html');
var titleEl = doc.querySelector('h1.page-title');
if (!titleEl) return null;
/* Abstract */
var abstrEl = doc.querySelector('.meta-description');
var abstract = abstrEl ? abstrEl.textContent.trim() : '';
if (abstract.length > 300)
abstract = abstract.slice(0, 300).replace(/\s\S+$/, '') + '\u2026';
/* Authors */
var authorEls = doc.querySelectorAll('.meta-authors a');
var authors = Array.from(authorEls).map(function (a) {
return a.textContent.trim();
}).join(', ');
/* Tags */
var tagEls = doc.querySelectorAll('.meta-tags a');
var tags = Array.from(tagEls).map(function (a) {
return a.textContent.trim();
}).join(' · ');
/* Reading stats — word count and reading time from meta block */
var wcEl = doc.querySelector('.meta-word-count');
var rtEl = doc.querySelector('.meta-reading-time');
var stats = [
wcEl ? wcEl.textContent.trim() : '',
rtEl ? rtEl.textContent.trim() : ''
].filter(Boolean).join(' · ');
return store(href,
'');
})
.catch(function () { return null; });
}
/* 3. Wikipedia — MediaWiki action API, full lead section, text-only */
function wikipediaContent(target) {
var href = target.getAttribute('href');
if (!href || cache[href]) return Promise.resolve(cache[href] || null);
var m = href.match(/wikipedia\.org\/wiki\/([^#?]+)/);
if (!m) return Promise.resolve(null);
var apiUrl = 'https://en.wikipedia.org/w/api.php'
+ '?action=query&prop=extracts&exintro=1&format=json&redirects=1'
+ '&titles=' + encodeURIComponent(decodeURIComponent(m[1])) + '&origin=*';
return fetch(apiUrl)
.then(function (r) { return r.ok ? r.json() : null; })
.then(function (data) {
var pages = data && data.query && data.query.pages;
if (!pages) return null;
var page = Object.values(pages)[0];
if (!page || page.missing !== undefined) return null;
var doc = new DOMParser().parseFromString(page.extract || '', 'text/html');
/* Remove math elements before extracting text — their DOM includes both
display characters and raw LaTeX source, producing garbled output. */
doc.querySelectorAll('.mwe-math-element').forEach(function (el) {
el.parentNode.removeChild(el);
});
var text = (doc.body.textContent || '').replace(/\s+/g, ' ').trim();
if (!text) return null;
if (text.length > 600) text = text.slice(0, 600).replace(/\s\S+$/, '') + '\u2026';
return store(href,
'');
})
.catch(function () { return null; });
}
/* 4. arXiv — Atom API, title + authors + abstract */
function arxivContent(target) {
var href = target.getAttribute('href');
if (!href || cache[href]) return Promise.resolve(cache[href] || null);
var m = href.match(/arxiv\.org\/(?:abs|pdf)\/(\d{4}\.\d{4,5}(?:v\d+)?)/);
if (!m) return Promise.resolve(null);
var id = m[1].replace(/v\d+$/, '');
return fetch('https://export.arxiv.org/api/query?id_list=' + encodeURIComponent(id))
.then(function (r) { return r.ok ? r.text() : null; })
.then(function (xml) {
if (!xml) return null;
var doc = new DOMParser().parseFromString(xml, 'application/xml');
var titleEl = doc.querySelector('entry > title');
var summaryEl = doc.querySelector('entry > summary');
if (!titleEl || !summaryEl) return null;
var title = titleEl.textContent.trim().replace(/\s+/g, ' ');
var summary = summaryEl.textContent.trim().replace(/\s+/g, ' ');
if (summary.length > 500) summary = summary.slice(0, 500).replace(/\s\S+$/, '') + '\u2026';
var authors = Array.from(doc.querySelectorAll('entry > author > name'))
.map(function (el) { return el.textContent.trim(); });
var authorStr = authors.slice(0, 3).join(', ');
if (authors.length > 3) authorStr += ' et\u00a0al.';
return store(href,
'');
})
.catch(function () { return null; });
}
/* 5. DOI / CrossRef — title, authors, journal, year, abstract */
function doiContent(target) {
var href = target.getAttribute('href');
if (!href || cache[href]) return Promise.resolve(cache[href] || null);
var m = href.match(/(?:dx\.)?doi\.org\/(10\.[^?#\s]+)/);
if (!m) return Promise.resolve(null);
return fetch('https://api.crossref.org/works/' + encodeURIComponent(m[1]))
.then(function (r) { return r.ok ? r.json() : null; })
.then(function (data) {
var msg = data && data.message;
if (!msg) return null;
var title = (msg.title && msg.title[0]) || '';
if (!title) return null;
var authors = (msg.author || []).slice(0, 3)
.map(function (a) { return (a.given ? a.given + ' ' : '') + (a.family || ''); })
.join(', ');
if ((msg.author || []).length > 3) authors += ' et\u00a0al.';
var journal = (msg['container-title'] && msg['container-title'][0]) || '';
var parts = msg.issued && msg.issued['date-parts'];
var year = parts && parts[0] && parts[0][0];
var abstract = (msg.abstract || '').replace(/<[^>]+>/g, '').trim();
if (abstract.length > 500) abstract = abstract.slice(0, 500).replace(/\s\S+$/, '') + '\u2026';
var meta = [journal, year].filter(Boolean).join(', ');
return store(href,
'');
})
.catch(function () { return null; });
}
/* 6. GitHub — repo description, language, stars */
function githubContent(target) {
var href = target.getAttribute('href');
if (!href || cache[href]) return Promise.resolve(cache[href] || null);
var m = href.match(/github\.com\/([^/]+)\/([^/?#]+)/);
if (!m) return Promise.resolve(null);
return fetch('https://api.github.com/repos/' + m[1] + '/' + m[2],
{ headers: { 'Accept': 'application/vnd.github.v3+json' } })
.then(function (r) { return r.ok ? r.json() : null; })
.then(function (data) {
if (!data || !data.full_name) return null;
var meta = [data.language, data.stargazers_count != null ? '\u2605\u00a0' + data.stargazers_count : null]
.filter(Boolean).join(' \u00b7 ');
return store(href,
'');
})
.catch(function () { return null; });
}
/* 7. Open Library — book title + description */
function openlibraryContent(target) {
var href = target.getAttribute('href');
if (!href || cache[href]) return Promise.resolve(cache[href] || null);
var base = href.replace(/[?#].*$/, '');
var apiUrl = base + '.json';
return fetch(apiUrl)
.then(function (r) { return r.ok ? r.json() : null; })
.then(function (data) {
if (!data || !data.title) return null;
var desc = data.description;
if (desc && typeof desc === 'object') desc = desc.value;
desc = (desc || '').replace(/\s+/g, ' ').trim();
if (desc.length > 300) desc = desc.slice(0, 300).replace(/\s\S+$/, '') + '\u2026';
return store(href,
'');
})
.catch(function () { return null; });
}
/* 8. bioRxiv / medRxiv — abstract via biorxiv content server API */
function biorxivContent(target) {
var href = target.getAttribute('href');
if (!href || cache[href]) return Promise.resolve(cache[href] || null);
var m = href.match(/(?:bio|med)rxiv\.org\/content\/(10\.\d{4,}\/[^?#\s]+)/);
if (!m) return Promise.resolve(null);
var doi = m[1].replace(/v\d+$/, '');
var server = /medrxiv/.test(href) ? 'medrxiv' : 'biorxiv';
var label = server === 'medrxiv' ? 'medRxiv' : 'bioRxiv';
return fetch('https://api.biorxiv.org/details/' + server + '/' + encodeURIComponent(doi) + '/json')
.then(function (r) { return r.ok ? r.json() : null; })
.then(function (data) {
var paper = data && data.collection && data.collection[0];
if (!paper || !paper.title) return null;
var abstract = (paper.abstract || '').replace(/\s+/g, ' ').trim();
if (abstract.length > 500) abstract = abstract.slice(0, 500).replace(/\s\S+$/, '') + '\u2026';
var authorStr = '';
if (paper.authors) {
var list = paper.authors.split(';').map(function (s) { return s.trim(); }).filter(Boolean);
authorStr = list.slice(0, 3).join(', ');
if (list.length > 3) authorStr += ' et\u00a0al.';
}
return store(href,
'');
})
.catch(function () { return null; });
}
/* 9. YouTube — oEmbed, title + channel name */
function youtubeContent(target) {
var href = target.getAttribute('href');
if (!href || cache[href]) return Promise.resolve(cache[href] || null);
return fetch('https://www.youtube.com/oembed?url=' + encodeURIComponent(href) + '&format=json')
.then(function (r) { return r.ok ? r.json() : null; })
.then(function (data) {
if (!data || !data.title) return null;
return store(href,
'');
})
.catch(function () { return null; });
}
/* 10. Internet Archive — title, creator, description */
function archiveContent(target) {
var href = target.getAttribute('href');
if (!href || cache[href]) return Promise.resolve(cache[href] || null);
var m = href.match(/archive\.org\/details\/([^/?#]+)/);
if (!m) return Promise.resolve(null);
return fetch('https://archive.org/metadata/' + encodeURIComponent(m[1]))
.then(function (r) { return r.ok ? r.json() : null; })
.then(function (data) {
var meta = data && data.metadata;
if (!meta) return null;
var first = function (v) { return Array.isArray(v) ? v[0] : (v || ''); };
var title = first(meta.title);
var creator = first(meta.creator);
var year = first(meta.year);
var desc = first(meta.description);
if (!title) return null;
desc = desc.replace(/<[^>]+>/g, '').replace(/\s+/g, ' ').trim();
if (desc.length > 280) desc = desc.slice(0, 280).replace(/\s\S+$/, '') + '\u2026';
var byline = [creator, year].filter(Boolean).join(', ');
return store(href,
'');
})
.catch(function () { return null; });
}
/* 11. PubMed — NCBI esummary, title + authors + journal */
function pubmedContent(target) {
var href = target.getAttribute('href');
if (!href || cache[href]) return Promise.resolve(cache[href] || null);
var m = href.match(/pubmed\.ncbi\.nlm\.nih\.gov\/(\d+)/);
if (!m) return Promise.resolve(null);
var pmid = m[1];
var apiUrl = 'https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esummary.fcgi'
+ '?db=pubmed&id=' + pmid + '&retmode=json';
return fetch(apiUrl)
.then(function (r) { return r.ok ? r.json() : null; })
.then(function (data) {
var paper = data && data.result && data.result[pmid];
if (!paper || !paper.title) return null;
var authors = (paper.authors || []).slice(0, 3)
.map(function (a) { return a.name; }).join(', ');
if ((paper.authors || []).length > 3) authors += ' et\u00a0al.';
var journal = paper.fulljournalname || paper.source || '';
var year = (paper.pubdate || '').slice(0, 4);
var meta = [journal, year].filter(Boolean).join(', ');
return store(href,
'');
})
.catch(function () { return null; });
}
/* ------------------------------------------------------------------
Helpers
------------------------------------------------------------------ */
function store(href, html) {
cache[href] = html;
return html;
}
function esc(s) {
return String(s)
.replace(/&/g, '&')
.replace(//g, '>')
.replace(/"/g, '"');
}
document.addEventListener('DOMContentLoaded', init);
}());