From 8b7cba1edeee88695bacefb726f8a5a009c4eeac Mon Sep 17 00:00:00 2001
From: syuilo <4439005+syuilo@users.noreply.github.com>
Date: Thu, 3 Apr 2025 15:34:13 +0900
Subject: [PATCH] =?UTF-8?q?=F0=9F=8E=A8?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 packages/frontend/src/pages/chat/room.vue     | 25 +++++++-
 .../src/utility/timeline-date-separate.ts     | 63 +++++++++++++++++++
 2 files changed, 87 insertions(+), 1 deletion(-)
 create mode 100644 packages/frontend/src/utility/timeline-date-separate.ts

diff --git a/packages/frontend/src/pages/chat/room.vue b/packages/frontend/src/pages/chat/room.vue
index dcce70ae89..9942dbeee9 100644
--- a/packages/frontend/src/pages/chat/room.vue
+++ b/packages/frontend/src/pages/chat/room.vue
@@ -38,7 +38,14 @@ SPDX-License-Identifier: AGPL-3.0-only
 				:moveClass="prefer.s.animation ? $style.transition_x_move : ''"
 				tag="div" class="_gaps"
 			>
-				<XMessage v-for="message in messages.toReversed()" :key="message.id" :message="message"/>
+				<template v-for="item in timeline.toReversed()" :key="item.id">
+					<XMessage v-if="item.type === 'item'" :message="item.data"/>
+					<div v-else-if="item.type === 'date'" :class="$style.dateDivider">
+						<span><i class="ti ti-chevron-up"></i> {{ item.nextText }}</span>
+						<span style="height: 1em; width: 1px; background: var(--MI_THEME-divider);"></span>
+						<span>{{ item.prevText }} <i class="ti ti-chevron-down"></i></span>
+					</div>
+				</template>
 			</TransitionGroup>
 		</div>
 
@@ -101,6 +108,7 @@ import MkButton from '@/components/MkButton.vue';
 import { useRouter } from '@/router.js';
 import { useMutationObserver } from '@/use/use-mutation-observer.js';
 import MkInfo from '@/components/MkInfo.vue';
+import { makeDateSeparatedTimelineComputedRef } from '@/utility/timeline-date-separate.js';
 
 const $i = ensureSignin();
 const router = useRouter();
@@ -126,6 +134,7 @@ const room = ref<Misskey.entities.ChatRoom | null>(null);
 const connection = ref<Misskey.IChannelConnection<Misskey.Channels['chatUser']> | Misskey.IChannelConnection<Misskey.Channels['chatRoom']> | null>(null);
 const showIndicator = ref(false);
 const timelineEl = useTemplateRef('timelineEl');
+const timeline = makeDateSeparatedTimelineComputedRef(messages);
 
 const SCROLL_HEAD_THRESHOLD = 200;
 
@@ -489,4 +498,18 @@ definePage(computed(() => {
 	transition: opacity 0.5s;
 	opacity: 0;
 }
+
+.dateDivider {
+	display: flex;
+	font-size: 85%;
+	align-items: center;
+	justify-content: center;
+	gap: 0.5em;
+	opacity: 0.75;
+	border: solid 0.5px var(--MI_THEME-divider);
+	border-radius: 999px;
+	width: fit-content;
+	padding: 0.5em 1em;
+	margin: 0 auto;
+}
 </style>
diff --git a/packages/frontend/src/utility/timeline-date-separate.ts b/packages/frontend/src/utility/timeline-date-separate.ts
new file mode 100644
index 0000000000..f9876a20ff
--- /dev/null
+++ b/packages/frontend/src/utility/timeline-date-separate.ts
@@ -0,0 +1,63 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { computed } from 'vue';
+import type { Ref } from 'vue';
+
+function getDateText(dateInstance: Date) {
+	const date = dateInstance.getDate();
+	const month = dateInstance.getMonth() + 1;
+	return `${month.toString()}/${date.toString()}`;
+}
+
+export type DateSeparetedTimelineItem<T> = {
+	id: string;
+	type: 'item';
+	data: T;
+} | {
+	id: string;
+	type: 'date';
+	prev: Date;
+	prevText: string;
+	next: Date;
+	nextText: string;
+};
+
+export function makeDateSeparatedTimelineComputedRef<T extends { id: string; createdAt: string; }>(items: Ref<T[]>) {
+	return computed<DateSeparetedTimelineItem<T>[]>(() => {
+		const tl: DateSeparetedTimelineItem<T>[] = [];
+		for (let i = 0; i < items.value.length; i++) {
+			const item = items.value[i];
+
+			const date = new Date(item.createdAt);
+			const nextDate = items.value[i + 1] ? new Date(items.value[i + 1].createdAt) : null;
+
+			tl.push({
+				id: item.id,
+				type: 'item',
+				data: item,
+			});
+
+			if (
+				i !== items.value.length - 1 &&
+					nextDate != null && (
+					date.getFullYear() !== nextDate.getFullYear() ||
+						date.getMonth() !== nextDate.getMonth() ||
+						date.getDate() !== nextDate.getDate()
+				)
+			) {
+				tl.push({
+					id: `date-${item.id}`,
+					type: 'date',
+					prev: date,
+					prevText: getDateText(date),
+					next: nextDate,
+					nextText: getDateText(nextDate),
+				});
+			}
+		}
+		return tl;
+	});
+}