Reopen the last DM that was open when navigating back to chat

src/app/components/PrimaryNav.svelte

@@ -1,6 +1,5 @@
 <script lang="ts">
   import type {Snippet} from "svelte"
-  import {goto} from "$app/navigation"
   import {splitAt} from "@welshman/lib"
   import {userProfile} from "@welshman/app"
   import Widget from "@assets/icons/widget.svg?dataurl"
@@ -19,6 +18,7 @@
   import {userSpaceUrls, PLATFORM_RELAYS, PLATFORM_LOGO} from "@app/core/state"
   import {pushModal} from "@app/util/modal"
   import {notifications} from "@app/util/notifications"
+  import {goToLastChat} from "@app/util/routes"
 
   type Props = {
     children?: Snippet
@@ -28,8 +28,6 @@
 
   const showSettingsMenu = () => pushModal(MenuSettings)
 
-  const openChat = () => goto("/chat")
-
   let windowHeight = $state(0)
 
   const itemHeight = 56
@@ -85,7 +83,7 @@
       </PrimaryNavItem>
       <PrimaryNavItem
         title="Messages"
-        onclick={openChat}
+        onclick={goToLastChat}
         class="tooltip-right"
         notification={$notifications.has("/chat")}>
         <ImageIcon alt="Messages" src={Letter} size={8} />
@@ -112,7 +110,7 @@
       </PrimaryNavItem>
       <PrimaryNavItem
         title="Messages"
-        onclick={openChat}
+        onclick={goToLastChat}
         notification={$notifications.has("/chat")}>
         <ImageIcon alt="Messages" src={Letter} size={8} />
       </PrimaryNavItem>

src/app/util/history.ts

@@ -1,10 +1,14 @@
 import {page} from "$app/stores"
 
 export const lastPageBySpaceUrl = new Map<string, string>()
+export let lastChatUrl: string | undefined = undefined
 
 export const setupHistory = () =>
   page.subscribe($page => {
     if ($page.params.relay) {
       lastPageBySpaceUrl.set($page.params.relay, $page.url.pathname)
     }
+    if ($page.params.chat) {
+      lastChatUrl = $page.url.pathname
+    }
   })

src/app/util/routes.ts

@@ -27,7 +27,7 @@ import {
   DM_KINDS,
   ROOM,
 } from "@app/core/state"
-import {lastPageBySpaceUrl} from "@app/util/history"
+import {lastPageBySpaceUrl, lastChatUrl} from "@app/util/history"
 
 export const makeSpacePath = (url: string, ...extra: (string | undefined)[]) => {
   let path = `/spaces/${encodeRelay(url)}`
@@ -56,6 +56,10 @@ export const goToSpace = async (url: string) => {
   }
 }
 
+export const goToLastChat = () => {
+  goto(lastChatUrl ?? "/chat")
+}
+
 export const makeChatPath = (pubkeys: string[]) => `/chat/${makeChatId(pubkeys)}`
 
 export const makeRoomPath = (url: string, h: string) => `/spaces/${encodeRelay(url)}/${h}`