Chat message date display (#824)

* Date handling

* Apply suggestion from @Copilot

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: philon- <philon-@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

packages/web/public/i18n/locales/en/common.json

@@ -55,7 +55,12 @@
       "suffix": "ms"
     },
     "second": { "one": "Second", "plural": "Seconds" },
-    "day": { "one": "Day", "plural": "Days" },
+    "day": {
+      "one": "Day",
+      "plural": "Days",
+      "today": "Today",
+      "yesterday": "Yesterday"
+    },
     "month": { "one": "Month", "plural": "Months" },
     "year": { "one": "Year", "plural": "Years" },
     "snr": "SNR",

packages/web/src/components/PageComponents/Messages/ChannelChat.tsx

@@ -1,12 +1,80 @@
 import { MessageItem } from "@components/PageComponents/Messages/MessageItem.tsx";
+import { Separator } from "@components/UI/Seperator";
 import type { Message } from "@core/stores/messageStore/types.ts";
+import type { TFunction } from "i18next";
 import { InboxIcon } from "lucide-react";
+import { Fragment, useMemo } from "react";
 import { useTranslation } from "react-i18next";
 
 export interface ChannelChatProps {
   messages?: Message[];
 }
 
+function toTs(d: Message["date"]): number {
+  return typeof d === "number" ? d : Date.parse(String(d));
+}
+
+function startOfLocalDay(ts: number): number {
+  const d = new Date(ts);
+  d.setHours(0, 0, 0, 0);
+  return d.getTime();
+}
+
+function formatDateLabelFromDayKey(
+  dayKey: number,
+  t: TFunction<"common", undefined>,
+  fmt: Intl.DateTimeFormat,
+): string {
+  const todayKey = startOfLocalDay(Date.now());
+  const yestKey = todayKey - 24 * 60 * 60 * 1000;
+
+  if (dayKey === todayKey) {
+    return t("unit.day.today"); // "Today" from common.json
+  }
+  if (dayKey === yestKey) {
+    return t("unit.day.yesterday"); // "Yesterday" from common.json
+  }
+  return fmt.format(new Date(dayKey));
+}
+
+type DayGroup = { dayKey: number; label: string; items: Message[] };
+
+function groupMessagesByDay(
+  messages: Message[],
+  t: TFunction<"common", undefined>,
+  fmt: Intl.DateTimeFormat,
+): DayGroup[] {
+  const out: DayGroup[] = [];
+
+  for (const msg of messages) {
+    const ts = toTs(msg.date);
+    const dayKey = startOfLocalDay(ts);
+    const last = out[out.length - 1];
+    if (last && last.dayKey === dayKey) {
+      last.items.push(msg);
+    } else {
+      out.push({
+        dayKey,
+        label: formatDateLabelFromDayKey(dayKey, t, fmt),
+        items: [msg],
+      });
+    }
+  }
+  return out;
+}
+
+const DateDelimiter = ({ label }: { label: string }) => (
+  <li aria-label={label}>
+    <div className="my-2 flex h-3 items-center justify-center">
+      <Separator className="bg-slate-100 dark:bg-slate-800" />
+      <div className="mx-5 whitespace-nowrap text-center text-xs text-slate-400">
+        {label}
+      </div>
+      <Separator className="bg-slate-100 dark:bg-slate-800" />
+    </div>
+  </li>
+);
+
 const EmptyState = () => {
   const { t } = useTranslation("messages");
   return (
@@ -18,7 +86,37 @@ const EmptyState = () => {
 };
 
 export const ChannelChat = ({ messages = [] }: ChannelChatProps) => {
-  if (!messages?.length) {
+  const { i18n, t } = useTranslation();
+
+  const locale = useMemo(
+    () =>
+      i18n.language ||
+      (typeof navigator !== "undefined" ? navigator.language : "en-US"),
+    [i18n.language],
+  );
+
+  const dayLabelFmt = useMemo(
+    () =>
+      new Intl.DateTimeFormat(locale, {
+        year: "numeric",
+        month: "long",
+        day: "numeric",
+      }),
+    [locale],
+  );
+
+  // Sort messages by date in case they are stored out of order
+  const sorted = useMemo(
+    () => [...messages].sort((a, b) => toTs(b.date) - toTs(a.date)),
+    [messages],
+  );
+
+  const groups = useMemo(
+    () => groupMessagesByDay(sorted, t, dayLabelFmt),
+    [sorted, dayLabelFmt, t],
+  );
+
+  if (!messages.length) {
     return (
       <div className="flex flex-1 flex-col items-center justify-center">
         <EmptyState />
@@ -28,12 +126,18 @@ export const ChannelChat = ({ messages = [] }: ChannelChatProps) => {
 
   return (
     <ul className="flex flex-col-reverse flex-grow overflow-y-auto px-3 py-2">
-      {messages?.map((message) => (
+      {groups.map(({ dayKey, label, items }) => (
+        <Fragment key={dayKey}>
+          {/* Render messages first, then delimiter — with flex-col-reverse this shows the delimiter above that day's messages */}
+          {items.map((message) => (
             <MessageItem
               key={message.messageId ?? `${message.from}-${message.date}`}
               message={message}
             />
           ))}
+          <DateDelimiter label={label} />
+        </Fragment>
+      ))}
     </ul>
   );
 };