From abf8a8e3c5936273865fedb77dfe4291e4d0584e Mon Sep 17 00:00:00 2001
From: Luka Trovic <luka@nextcloud.com>
Date: Tue, 18 Jul 2023 19:00:30 +0200
Subject: [PATCH] feat: add component SkeletonLoading

Signed-off-by: Luka Trovic <luka@nextcloud.com>
---
 src/components/Editor.vue          |   3 +
 src/components/Editor/Wrapper.vue  |   6 --
 src/components/SkeletonLoading.vue | 166 +++++++++++++++++++++++++++++
 src/views/RichWorkspace.vue        |   9 +-
 4 files changed, 175 insertions(+), 9 deletions(-)
 create mode 100644 src/components/SkeletonLoading.vue

diff --git a/src/components/Editor.vue b/src/components/Editor.vue
index 4f88bc24ef0..c00f49ef5fd 100644
--- a/src/components/Editor.vue
+++ b/src/components/Editor.vue
@@ -32,6 +32,7 @@
 			:has-connection-issue="hasConnectionIssue"
 			@reconnect="reconnect" />
 
+		<SkeletonLoading v-if="!contentLoaded" />
 		<Wrapper v-if="displayed"
 			:sync-error="syncError"
 			:has-connection-issue="hasConnectionIssue"
@@ -117,10 +118,12 @@ import ContentContainer from './Editor/ContentContainer.vue'
 import Status from './Editor/Status.vue'
 import MainContainer from './Editor/MainContainer.vue'
 import Wrapper from './Editor/Wrapper.vue'
+import SkeletonLoading from './SkeletonLoading.vue'
 
 export default {
 	name: 'Editor',
 	components: {
+		SkeletonLoading,
 		DocumentStatus,
 		Wrapper,
 		MainContainer,
diff --git a/src/components/Editor/Wrapper.vue b/src/components/Editor/Wrapper.vue
index 290b4c8cf2e..7e717f1a670 100644
--- a/src/components/Editor/Wrapper.vue
+++ b/src/components/Editor/Wrapper.vue
@@ -24,7 +24,6 @@
 	<div class="text-editor__wrapper"
 		:class="{
 			'has-conflicts': hasSyncCollission,
-			'icon-loading': !contentLoaded && !hasConnectionIssue,
 			'is-rich-workspace': $isRichWorkspace,
 			'is-rich-editor': $isRichEditor,
 			'show-color-annotations': showAuthorAnnotations
@@ -159,11 +158,6 @@ export default {
 		.ProseMirror {
 			margin-top: 0 !important;
 		}
-		&.icon-loading {
-			.text-editor__main {
-				opacity: 0.3;
-			}
-		}
 	}
 
 </style>
diff --git a/src/components/SkeletonLoading.vue b/src/components/SkeletonLoading.vue
new file mode 100644
index 00000000000..1d1e2406c9a
--- /dev/null
+++ b/src/components/SkeletonLoading.vue
@@ -0,0 +1,166 @@
+<template>
+	<div class="placeholder-main placeholder-main-text">
+		<!-- Placeholder animation -->
+		<template v-for="(suffix, gradientIndex) in ['-regular', '-reverse']">
+			<svg :key="'gradient' + suffix" :class="'placeholder-gradient placeholder-gradient' + suffix">
+				<defs>
+					<linearGradient :id="'placeholder-gradient' + suffix">
+						<stop offset="0%" :stop-color="(gradientIndex === 0) ? colorPlaceholderLight : colorPlaceholderDark" />
+						<stop offset="100%" :stop-color="(gradientIndex === 0) ? colorPlaceholderDark : colorPlaceholderLight" />
+					</linearGradient>
+				</defs>
+			</svg>
+
+			<ul :key="'list' + suffix" :class="'placeholder-list placeholder-list' + suffix">
+				<li v-for="index in count" :key="'placeholder' + suffix + index">
+					<svg class="text-placeholder"
+						xmlns="http://www.w3.org/2000/svg"
+						:fill="'url(#placeholder-gradient' + suffix + ')'">
+						<rect class="text-placeholder-line-one" :style="textPlaceholderData[0]" />
+						<rect class="text-placeholder-line-two" :style="textPlaceholderData[1]" />
+						<rect class="text-placeholder-line-three" :style="textPlaceholderData[2]" />
+						<rect class="text-placeholder-line-four" :style="textPlaceholderData[3]" />
+					</svg>
+				</li>
+			</ul>
+		</template>
+	</div>
+</template>
+
+<script>
+const bodyStyles = window.getComputedStyle(document.body)
+const colorPlaceholderDark = bodyStyles.getPropertyValue('--color-placeholder-dark')
+const colorPlaceholderLight = bodyStyles.getPropertyValue('--color-placeholder-light')
+
+export default {
+	name: 'SkeletonLoading',
+
+	props: {
+		count: {
+			type: Number,
+			default: 5,
+		},
+	},
+
+	setup() {
+		return {
+			colorPlaceholderDark,
+			colorPlaceholderLight,
+		}
+	},
+
+	computed: {
+		textPlaceholderData() {
+			const data = []
+			for (let i = 0; i < 4; i++) {
+				// generate random widths
+				data.push('width: ' + (Math.floor(Math.random() * 50) + 60) + '%')
+			}
+			return data
+		},
+	},
+}
+</script>
+
+<style lang="scss" scoped>
+$margin: 8px;
+$messages-list-max-width: 670px;
+
+.placeholder-main {
+	max-width: $messages-list-max-width;
+	position: relative;
+	margin-bottom: auto;
+	z-index: 1;
+
+	&-text {
+		margin: 50px auto 0;
+		width: 100%;
+	}
+}
+
+#rich-workspace .placeholder-main-text {
+	margin: 40px 0 0;
+}
+
+.placeholder-list {
+	position: absolute;
+	transform: translateZ(0);
+}
+
+.placeholder-list-regular {
+	animation: pulse 2s;
+	animation-iteration-count: infinite;
+	animation-timing-function: linear;
+}
+
+.placeholder-list-reverse {
+	animation: pulse-reverse 2s;
+	animation-iteration-count: infinite;
+	animation-timing-function: linear;
+}
+
+.placeholder-gradient {
+	position: fixed;
+	height: 0;
+	width: 0;
+	z-index: -1;
+}
+
+.text-placeholder {
+	width: min($messages-list-max-width, 100vw);
+	height: 6em;
+	margin: $margin auto;
+	padding: 4px 8px 0 14px;
+	display: block;
+
+	&-line-one,
+	&-line-two,
+	&-line-three,
+	&-line-four {
+		width: 670px;
+		height: 1em;
+	}
+
+	&-line-one {
+		y: 0.33em;
+		width: 175px;
+	}
+
+	&-line-two {
+		y: 1.66em;
+	}
+
+	&-line-three {
+		y: 3em;
+	}
+
+	&-line-four {
+		y: 4.33em;
+	}
+}
+
+@keyframes pulse {
+	0% {
+		opacity: 1;
+	}
+	50% {
+		opacity: 0;
+	}
+	100% {
+		opacity: 1;
+	}
+}
+
+@keyframes pulse-reverse {
+	0% {
+		opacity: 0;
+	}
+	50% {
+		opacity: 1;
+	}
+	100% {
+		opacity: 0;
+	}
+}
+
+</style>
diff --git a/src/views/RichWorkspace.vue b/src/views/RichWorkspace.vue
index 3c0c123e708..9bd85e7f37b 100644
--- a/src/views/RichWorkspace.vue
+++ b/src/views/RichWorkspace.vue
@@ -21,7 +21,8 @@
   -->
 
 <template>
-	<div v-if="enabled" id="rich-workspace" :class="{'icon-loading': !loaded || !ready, 'focus': focus, 'dark': darkTheme, 'creatable': canCreate }">
+	<div v-if="enabled" id="rich-workspace" :class="{'focus': focus, 'dark': darkTheme, 'creatable': canCreate }">
+		<SkeletonLoading v-if="!loaded || !ready" />
 		<Editor v-if="file"
 			v-show="ready"
 			:key="file.path"
@@ -44,6 +45,7 @@
 import axios from '@nextcloud/axios'
 import { generateOcsUrl } from '@nextcloud/router'
 import { subscribe, unsubscribe } from '@nextcloud/event-bus'
+import SkeletonLoading from '../components/SkeletonLoading.vue'
 
 const IS_PUBLIC = !!(document.getElementById('isPublic'))
 const WORKSPACE_URL = generateOcsUrl('apps/text' + (IS_PUBLIC ? '/public' : '') + '/workspace', 2)
@@ -51,6 +53,7 @@ const WORKSPACE_URL = generateOcsUrl('apps/text' + (IS_PUBLIC ? '/public' : '')
 export default {
 	name: 'RichWorkspace',
 	components: {
+		SkeletonLoading,
 		Editor: () => import(/* webpackChunkName: "editor" */'./../components/Editor.vue'),
 	},
 	props: {
@@ -268,7 +271,7 @@ export default {
 		overflow: hidden;
 	}
 
-	#rich-workspace:not(.focus):not(.icon-loading):not(.empty):after {
+	#rich-workspace:not(.focus):not(.empty):after {
 		content: '';
 		position: absolute;
 		z-index: 1;
@@ -280,7 +283,7 @@ export default {
 		height: 4em;
 	}
 
-	#rich-workspace.dark:not(.focus):not(.icon-loading):after {
+	#rich-workspace.dark:not(.focus):after {
 		background-image: linear-gradient(to bottom, rgba(0, 0, 0, 0), var(--color-main-background));
 	}