fix: make virtual keyboard work better on touchscreen devices

apps/lluis/HorizontalScroller.svelte

@@ -0,0 +1,82 @@
+<script>
+  import { onMount } from "svelte"
+  import Icon from "./Icon.svelte"
+
+  let scroller
+  let scrollPosition = 0
+  let scrollWidth = 200
+  let containerWidth = 100
+  let needsScroll = scrollWidth > containerWidth
+
+  const updateScrollPosition = () => {
+    scrollPosition = scroller.scrollLeft
+    containerWidth = scroller.offsetWidth
+    scrollWidth = scroller.scrollWidth - containerWidth
+  }
+
+  onMount(() => {
+    window.addEventListener("resize", updateScrollPosition)
+    updateScrollPosition()
+
+    return () => {
+      window.removeEventListener("resize", updateScrollPosition)
+    }
+  })
+</script>
+
+<div class="wrapper">
+  <div class="content" bind:this={scroller} on:scroll={updateScrollPosition}>
+    <slot />
+  </div>
+
+  {#if scrollPosition > 0}
+    <div class="shadow-left"><Icon icon="circle-arrow-left" /></div>
+  {/if}
+
+  {#if needsScroll && scrollPosition < scrollWidth}
+    <div class="shadow-right"><Icon icon="circle-arrow-right" /></div>
+  {/if}
+</div>
+
+<style type="text/scss">
+  .wrapper {
+    width: 100%;
+    height: 100%;
+    position: relative;
+  }
+
+  .content {
+    position: absolute;
+    top: 0;
+    left: 0;
+    width: 100%;
+    height: 100%;
+    overflow-x: auto;
+    scrollbar-width: none;
+    &::-webkit-scrollbar {
+      display: none;
+    }
+  }
+
+  .shadow-right,
+  .shadow-left {
+    display: flex;
+    position: absolute;
+    width: 24px;
+    height: 48px;
+    top: 0;
+    bottom: 0;
+    align-items: center;
+    bottom: calc(100vh - 68px);
+  }
+
+  .shadow-left {
+    left: 0;
+    background: linear-gradient(270deg, transparent, white, white);
+  }
+
+  .shadow-right {
+    right: 0;
+    background: linear-gradient(90deg, transparent, white, white);
+  }
+</style>

apps/web/cypress/integration/common/virtual_keyboard.js

@@ -1,18 +1,24 @@
 import { Then } from "cypress-cucumber-preprocessor/steps"
 
 Then("I see a virtual keyboard with {int} keys", (n) => {
-  cy.get(".virtual-keyboard").find(">*").should("have.length", n)
+  cy.get(".virtual-keyboard .keys").find(">*").should("have.length", n)
 })
 
 Then("the keys on the virtual keyboard have proper labels", () => {
-  cy.get(".virtual-keyboard").find(">*").contains("á").should("be.visible")
+  cy.get(".virtual-keyboard .keys")
+    .find(">*")
+    .contains("á")
+    .should("be.visible")
 })
 
 Then("clicking on a key types into the input field", () => {
-  cy.get(".virtual-keyboard").find(">*").contains("á").click()
+  cy.get(".virtual-keyboard .keys").find(">*").contains("á").click()
   cy.get("input").should("have.value", "á")
 })
 
 Then("the virtual keyboard is inactive", () => {
-  cy.get(".virtual-keyboard").find(">*").contains("á").should("be.disabled")
+  cy.get(".virtual-keyboard .keys")
+    .find(">*")
+    .contains("á")
+    .should("be.disabled")
 })

apps/web/src/client.js

@@ -12,6 +12,8 @@ import {
   faEnvelope,
   faHeart,
   faSpinner,
+  faCircleArrowRight,
+  faCircleArrowLeft,
 } from "@fortawesome/free-solid-svg-icons"
 import { faTwitter } from "@fortawesome/free-brands-svg-icons"
 
@@ -25,6 +27,8 @@ library.add(faLock)
 library.add(faEnvelope)
 library.add(faHeart)
 library.add(faSpinner)
+library.add(faCircleArrowRight)
+library.add(faCircleArrowLeft)
 dom.watch()
 
 window.startMsw = () => {

apps/web/src/components/InputFieldWithVirtualKeyboard/VirtualKeyboard.svelte

@@ -1,29 +1,62 @@
 <script lang="typescript">
+  // Manual test: http://localhost:3000/course/test/skill/short-input-test-3?testChallenge=86665e4f61fa
   import Button from "../../../../lluis/Button.svelte"
+  import HorizontalScroller from "../../../../lluis/HorizontalScroller.svelte"
 
   export let characters: Array<string>
   export let disabled: boolean
   export let handleVirtualKey
 </script>
 
 <div class="virtual-keyboard">
-  {#each characters as character}
-    <Button
-      style="key"
-      tabIndex={-1}
-      size="small"
-      disabled="{disabled}"
-      on:click="{handleVirtualKey(character)}"
-    >
-      {character}
-    </Button>
-  {/each}
+  <HorizontalScroller>
+    <slot>
+      <div class="keys">
+        {#each characters as character}
+          <Button
+            style="key"
+            tabIndex={-1}
+            size="small"
+            {disabled}
+            on:click={handleVirtualKey(character)}
+          >
+            {character}
+          </Button>
+        {/each}
+      </div>
+    </slot>
+  </HorizontalScroller>
 </div>
 
 <style type="text/scss">
   .virtual-keyboard {
     display: flex;
     flex-wrap: wrap;
     margin-top: 2em;
+    height: 100%;
+  }
+
+  .virtual-keyboard .keys {
+    display: flex;
+    flex-wrap: wrap;
+  }
+
+  @media only screen and (pointer: coarse) {
+    .virtual-keyboard .keys {
+      display: flex;
+      flex-wrap: nowrap;
+      padding-left: 12px;
+      padding-right: 12px;
+    }
+
+    .virtual-keyboard {
+      height: 48px;
+      position: fixed;
+      bottom: 68px;
+      left: 0;
+      right: 0;
+      background-color: white;
+      z-index: 100;
+    }
   }
 </style>