Add back/forward buttons to switch between images in tasks

ui/media/js/image-modal.js

@@ -1,6 +1,28 @@
 "use strict"
 
+/**
+ * @typedef {object} ImageModalRequest
+ * @property {string} src
+ * @property {ImageModalRequest | () => ImageModalRequest | undefined} previous
+ * @property {ImageModalRequest | () => ImageModalRequest | undefined} next
+ */
+
+/**
+ * @type {(() => (string | ImageModalRequest) | string | ImageModalRequest) => {}}
+ */
 const imageModal = (function() {
+    const backElem = createElement(
+        'i',
+        undefined,
+        ['fa-solid', 'fa-arrow-left', 'tertiaryButton'],
+    )
+
+    const forwardElem = createElement(
+        'i',
+        undefined,
+        ['fa-solid', 'fa-arrow-right', 'tertiaryButton'],
+    )
+
     const zoomElem = createElement(
         'i',
         undefined,
@@ -13,7 +35,7 @@ const imageModal = (function() {
         ['fa-solid', 'fa-xmark', 'tertiaryButton'],
     )
 
-    const menuBarElem = createElement('div', undefined, 'menu-bar', [zoomElem, closeElem])
+    const menuBarElem = createElement('div', undefined, 'menu-bar', [backElem, forwardElem, zoomElem, closeElem])
 
     const imageContainer = createElement('div', undefined, 'image-wrapper')
 
@@ -63,15 +85,87 @@ const imageModal = (function() {
         () => setZoomLevel(imageContainer.querySelector('img')?.classList?.contains('natural-zoom')),
     )
 
-    const close = () => {
+    const state = {
+        previous: undefined,
+        next: undefined,
+    }
+
+    const clear = () => {
         imageContainer.innerHTML = ''
+
+        Object.keys(state).forEach(key => delete state[key])
+    }
+
+    const close = () => {
+        clear()
         modalElem.classList.remove('active')
         document.body.style.overflow = 'initial'
     }
 
-    window.addEventListener('keydown', (e) => {
-        if (e.key === 'Escape' && modalElem.classList.contains('active')) {
+    /**
+     * @param {() => (string | ImageModalRequest) | string | ImageModalRequest} optionsFactory
+     */
+    function init(optionsFactory) {
+        if (!optionsFactory) {
             close()
+            return
+        }
+
+        clear()
+
+        const options = typeof optionsFactory === 'function' ? optionsFactory() : optionsFactory
+        const src = typeof options === 'string' ? options : options.src
+
+        const imgElem = createElement('img', { src }, 'natural-zoom')
+        imageContainer.appendChild(imgElem)
+        modalElem.classList.add('active')
+        document.body.style.overflow = 'hidden'
+        setZoomLevel(false)
+
+        if (typeof options === 'object' && options.previous) {
+            state.previous = options.previous
+            backElem.style.display = 'unset'
+        } else {
+            backElem.style.display = 'none'
+        }
+
+        if (typeof options === 'object' && options.next) {
+            state.next = options.next
+            forwardElem.style.display = 'unset'
+        } else {
+            forwardElem.style.display = 'none'
+        }
+    }
+
+    const back = () => {
+        if (state.previous) {
+            init(state.previous)
+        } else {
+            backElem.style.display = 'none'
+        }
+    }
+
+    const forward = () => {
+        if (state.next) {
+            init(state.next)
+        } else {
+            forwardElem.style.display = 'none'
+        }
+    }
+
+    window.addEventListener('keydown', (e) => {
+        if (modalElem.classList.contains('active')) {
+            switch (e.key) {
+                case 'Escape':
+                    close()
+                    break
+                case 'ArrowLeft':
+                    back()
+                    break
+                case 'ArrowRight':
+                    forward()
+                    break
+            }
         }
     })
     window.addEventListener('click', (e) => {
@@ -86,15 +180,12 @@ const imageModal = (function() {
         }
     })
 
-    return (optionsFactory) => {
-        const options = typeof optionsFactory === 'function' ? optionsFactory() : optionsFactory
-        const src = typeof options === 'string' ? options : options.src
+    backElem.addEventListener('click', back)
 
-        // TODO center it if < window size
-        const imgElem = createElement('img', { src }, 'natural-zoom')
-        imageContainer.appendChild(imgElem)
-        modalElem.classList.add('active')
-        document.body.style.overflow = 'hidden'
-        setZoomLevel(false)
-    }
+    forwardElem.addEventListener('click', forward)
+
+    /**
+     * @param {() => (string | ImageModalRequest) | string | ImageModalRequest} optionsFactory
+     */
+    return (optionsFactory) => init(optionsFactory)
 })()

ui/media/js/main.js

@@ -398,7 +398,30 @@ function showImages(reqBody, res, outputContainer, livePreview) {
         if ('seed' in result && !imageElem.hasAttribute('data-seed')) {
             const imageExpandBtn = imageItemElem.querySelector('.imgExpandBtn')
             imageExpandBtn.addEventListener('click', function() {
-                imageModal(imageElem.src)
+                function previousImage(img) {
+                    const allImages = Array.from(outputContainer.parentNode.querySelectorAll('.imgItem img'))
+                    const index = allImages.indexOf(img)
+                    return allImages.slice(0, index).reverse()[0]
+                }
+
+                function nextImage(img) {
+                    const allImages = Array.from(outputContainer.parentNode.querySelectorAll('.imgItem img'))
+                    const index = allImages.indexOf(img)
+                    return allImages.slice(index + 1)[0]
+                }
+
+                function imageModalParameter(img) {
+                    const previousImg = previousImage(img)
+                    const nextImg = nextImage(img)
+
+                    return {
+                        src: img.src,
+                        previous: previousImg ? () => imageModalParameter(previousImg) : undefined,
+                        next: nextImg ? () => imageModalParameter(nextImg) : undefined,
+                    }
+                }
+
+                imageModal(imageModalParameter(imageElem))
             })
 
             const req = Object.assign({}, reqBody, {