From d6f7995f4b7600fcba06cfdf48e9ef3b2e494a00 Mon Sep 17 00:00:00 2001
From: Rhiannon Morris <rhi@rhiannon.website>
Date: Wed, 5 Aug 2020 01:43:27 +0200
Subject: [PATCH] add pushState stuff for single.js

---
 script/single.js | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/script/single.js b/script/single.js
index ded26aa..8062c4f 100644
--- a/script/single.js
+++ b/script/single.js
@@ -46,9 +46,26 @@ function setImage(id, src, href, cw) {
   mainlink.href = href;
 }
 
-function activateButton(button) {
+function activateButton(button, doPush = true) {
   setImage(button.id, button.value,
            button.dataset.link, button.dataset.warning);
+
+  if (doPush) history.pushState(null, '', '#' + button.id);
+}
+
+function useFragment() {
+  let button = document.querySelector('#alts input');
+
+  let frag = document.location.hash.replace(/^#/, '');
+  if (frag) {
+    let button0 = document.getElementById(frag);
+    if (button0) button = button0;
+  }
+
+  if (button) {
+    button.checked = true;
+    activateButton(button, false);
+  }
 }
 
 function setup() {
@@ -61,6 +78,9 @@ function setup() {
   }
 
   addCWListeners(document.getElementById('cw'));
+
+  window.addEventListener('popstate', useFragment);
+  useFragment();
 }
 
 window.addEventListener('DOMContentLoaded', setup);