From 57e925e4ac877906c07eb24b8663ac34606f9b31 Mon Sep 17 00:00:00 2001
From: Volpeon <git@volpeon.ink>
Date: Wed, 29 Dec 2021 20:20:17 +0100
Subject: Keyboard-friendly lightbox

---
 assets/css/components/_lightbox.scss |  2 +-
 content/lightbox.js                  | 50 +++++++++++++++++++++++++++++++-----
 2 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/assets/css/components/_lightbox.scss b/assets/css/components/_lightbox.scss
index ece2b4b..b23943a 100644
--- a/assets/css/components/_lightbox.scss
+++ b/assets/css/components/_lightbox.scss
@@ -24,7 +24,7 @@
         justify-content: center;
         width:           100%;
         height:          100%;
-        padding:         2em calc(3em + 1rem);
+        padding:         1em calc(3em + 1rem);
         transition:      opacity .2s, visibility .2s;
         opacity:         0;
 
diff --git a/content/lightbox.js b/content/lightbox.js
index e57d37c..a3e3bc0 100644
--- a/content/lightbox.js
+++ b/content/lightbox.js
@@ -1,5 +1,7 @@
 (() => {
     let currentIndex = 0;
+    let visible = false;
+
     const mainEl = document.querySelector("main");
     const lightboxEl = document.querySelector(".c-lightbox");
     const lightboxBgEl = document.querySelector(".c-lightbox__bg");
@@ -10,26 +12,34 @@
     const figureEls = Array.from(mainEl.querySelectorAll("figure")).map(el => el.querySelector("a"));
 
     const show = () => {
+        visible = true;
         lightboxEl.classList.add("is-shown");
     }
 
     const hide = () => {
+        visible = false;
         lightboxEl.classList.remove("is-shown");
     }
 
     const setIndex = (i) => {
         currentIndex = i;
         lightboxImgEl.src = figureEls[i].href;
+        lightboxPrevEl.classList.toggle("u-dn", i === 0);
+        lightboxNextEl.classList.toggle("u-dn", i === figureEls.length - 1);
+    };
+
+    const prev = () => {
+        setIndex(currentIndex === 0 ? currentIndex : currentIndex - 1);
+    };
+
+    const next = () => {
+        setIndex(currentIndex === figureEls.length - 1 ? currentIndex : currentIndex + 1);
     };
 
     lightboxBgEl.addEventListener("click", hide);
     lightboxCloseEl.addEventListener("click", hide);
-    lightboxPrevEl.addEventListener("click", () => {
-        setIndex(currentIndex === 0 ? figureEls.length - 1 : currentIndex - 1);
-    });
-    lightboxNextEl.addEventListener("click", () => {
-        setIndex(currentIndex === figureEls.length - 1 ? 0 : currentIndex + 1);
-    });
+    lightboxPrevEl.addEventListener("click", prev);
+    lightboxNextEl.addEventListener("click", next);
     
     figureEls.forEach((figureEl, i) => {
         figureEl.addEventListener("click", e => {
@@ -38,4 +48,32 @@
             setIndex(i);
         })
     });
+
+    window.addEventListener("keydown", e => {
+        if (e.defaultPrevented || !visible) {
+            return;
+        }
+
+        switch (e.key) {
+            case "Left":
+            case "ArrowLeft":
+                prev();
+                break;
+
+            case "Right":
+            case "ArrowRight":
+                next();
+                break;
+
+            case "Esc":
+            case "Escape":
+                hide();
+                break;
+
+            default:
+                return;
+        }
+
+        e.preventDefault();
+    }, true);
 })();
-- 
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