Show users who sent reaction on hover (#5362)

* Show users who sent reaction on hover

* Support i18n

* detail -> details

* Extract methods

* Update on change

src/client/app/common/views/components/reactions-viewer.details.vue

@@ -0,0 +1,103 @@
+<template>
+	<transition name="zoom-in-top">
+		<div class="buebdbiu" ref="popover" v-if="show">
+			<i18n path="few-users" v-if="users.length <= 10">
+				<span slot="users">{{ users.join(', ') }}</span>
+				<mk-reaction-icon slot="reaction" :reaction="reaction" ref="icon" />
+			</i18n>
+			<i18n path="many-users" v-if="10 < users.length">
+				<span slot="users">{{ users.slice(0, 10).join(', ') }}</span>
+				<span slot="ommited">{{ users.length - 10 }}</span>
+				<mk-reaction-icon slot="reaction" :reaction="reaction" ref="icon" />
+			</i18n>
+		</div>
+	</transition>
+</template>
+
+<script lang="ts">
+import Vue from 'vue';
+import i18n from '../../../i18n';
+
+export default Vue.extend({
+	i18n: i18n('common/views/components/reactions-viewer.details.vue'),
+	props: {
+		reaction: {
+			type: String,
+			required: true,
+		},
+		users: {
+			type: Array,
+			required: true,
+		},
+		source: {
+			required: true,
+		}
+	},
+	data() {
+		return {
+			show: false
+		};
+	},
+	mounted() {
+		this.show = true;
+
+		this.$nextTick(() => {
+			const popover = this.$refs.popover as any;
+
+			const rect = this.source.getBoundingClientRect();
+
+			const x = rect.left + window.pageXOffset + (this.source.offsetWidth / 2);
+			const y = rect.top + window.pageYOffset + this.source.offsetHeight;
+			popover.style.left = (x - 28) + 'px';
+			popover.style.top = (y + 16) + 'px';
+		});
+	}
+	methods: {
+		close() {
+			this.show = false;
+			setTimeout(this.destroyDom, 300);
+		}
+	}
+})
+</script>
+
+<style lang="stylus" scoped>
+.buebdbiu
+	$bgcolor = var(--popupBg)
+	z-index 10000
+	display block
+	position absolute
+	min-width max-content
+	max-width 240px
+	font-size 0.8em
+	padding 5px 8px
+	background $bgcolor
+	text-align center
+	color var(--text)
+	border-radius 4px
+	box-shadow 0 var(--lineWidth) 4px rgba(#000, 0.25)
+
+	&:before
+		content ""
+		pointer-events none
+		display block
+		position absolute
+		top -28px
+		left 12px
+		border-top solid 14px transparent
+		border-right solid 14px transparent
+		border-bottom solid 14px rgba(#000, 0.1)
+		border-left solid 14px transparent
+
+	&:after
+		content ""
+		pointer-events none
+		display block
+		position absolute
+		top -27px
+		left 12px
+		border-top solid 14px transparent
+		border-right solid 14px transparent
+		border-bottom solid 14px $bgcolor
+		border-left solid 14px transparent
+</style>