Port navigation.

src/components/navigation/left/common.ts

@@ -0,0 +1,74 @@
+import { Channel } from "revolt.js";
+import { useLayoutEffect } from "preact/hooks";
+import { WithDispatcher } from "../../../redux/reducers";
+import { Unreads } from "../../../redux/reducers/unreads";
+import { HookContext, useForceUpdate } from "../../../context/revoltjs/hooks";
+
+type UnreadProps = WithDispatcher & {
+    channel: Channel;
+    unreads: Unreads;
+}
+
+export function useUnreads({ channel, unreads, dispatcher }: UnreadProps, context?: HookContext) {
+    const ctx = useForceUpdate(context);
+
+    useLayoutEffect(() => {
+        function checkUnread(target?: Channel) {
+            if (!target) return;
+            if (target._id !== channel._id) return;
+            if (target?.channel_type === "SavedMessages") return;
+
+            const unread = unreads[channel._id]?.last_id;
+            if (target.last_message) {
+                const message = typeof target.last_message === 'string' ? target.last_message : target.last_message._id;
+                if (!unread || (unread && message.localeCompare(unread) > 0)) {
+                    dispatcher({
+                        type: "UNREADS_MARK_READ",
+                        channel: channel._id,
+                        message,
+                        request: true
+                    });
+                }
+            }
+        }
+
+        checkUnread(channel);
+
+        ctx.client.channels.addListener("mutation", checkUnread);
+        return () => ctx.client.channels.removeListener("mutation", checkUnread);
+    }, [channel, unreads]);
+}
+
+export function mapChannelWithUnread(channel: Channel, unreads: Unreads) {
+    let last_message_id;
+    if (channel.channel_type === 'DirectMessage' || channel.channel_type === 'Group') {
+        last_message_id = channel.last_message?._id;
+    } else if (channel.channel_type === 'TextChannel') {
+        last_message_id = channel.last_message;
+    } else {
+        return { ...channel, unread: undefined, alertCount: undefined, timestamp: channel._id };
+    }
+
+    let unread: 'mention' | 'unread' | undefined;
+    let alertCount: undefined | number;
+    if (last_message_id && unreads) {
+        const u = unreads[channel._id];
+        if (u) {
+            if (u.mentions && u.mentions.length > 0) {
+                alertCount = u.mentions.length;
+                unread = 'mention';
+            } else if (u.last_id && last_message_id.localeCompare(u.last_id) > 0) {
+                unread = 'unread';
+            }
+        } else {
+            unread = 'unread';
+        }
+    }
+
+    return {
+        ...channel,
+        timestamp: last_message_id ?? channel._id,
+        unread,
+        alertCount
+    };
+}