From 098be35aade77e505d692558cfb554485b8563db Mon Sep 17 00:00:00 2001
From: Kit La Touche <kit@transneptune.net>
Date: Mon, 17 Feb 2025 12:50:33 -0500
Subject: Remember last active channel and navigate there on root load

To facilitate PWA behaviour.
---
 ui/lib/constants.js      |  4 +++-
 ui/routes/+layout.svelte | 30 ++++++++++++++++++++++++++++--
 2 files changed, 31 insertions(+), 3 deletions(-)

(limited to 'ui')

diff --git a/ui/lib/constants.js b/ui/lib/constants.js
index c001f6d..5456414 100644
--- a/ui/lib/constants.js
+++ b/ui/lib/constants.js
@@ -1,2 +1,4 @@
-export const STORE_KEY_CHANNELS_DATA = 'pilcrow:channelsData';
 export const EPOCH_STRING = '1970-01-01T00:00:00Z';
+
+export const STORE_KEY_CHANNELS_DATA = 'pilcrow:channelsData';
+export const STORE_KEY_LAST_ACTIVE = 'pilcrow:lastActiveChannel';
diff --git a/ui/routes/+layout.svelte b/ui/routes/+layout.svelte
index 750f1f8..18c0541 100644
--- a/ui/routes/+layout.svelte
+++ b/ui/routes/+layout.svelte
@@ -1,11 +1,15 @@
 <script>
   import { setContext } from 'svelte';
-  import { onNavigate } from '$app/navigation';
+  import { browser } from '$app/environment';
+  import { goto, onNavigate, afterNavigate } from '$app/navigation';
+  import { page } from '$app/stores';
   import '../app.css';
   import logo from '$lib/assets/logo.png';
-
+  import { STORE_KEY_LAST_ACTIVE } from '$lib/constants';
   import { currentUser } from '$lib/store';
 
+  let activeChannel = $derived($page.params.channel);
+
   let pageContext = $state({
     showMenu: false
   });
@@ -16,6 +20,28 @@
     pageContext.showMenu = !pageContext.showMenu;
   }
 
+  function getLastActiveChannel() {
+    return (
+      browser && JSON.parse(localStorage.getItem(STORE_KEY_LAST_ACTIVE))
+    );
+  }
+
+  function setLastActiveChannel(channelId) {
+    browser && localStorage.setItem(
+      STORE_KEY_LAST_ACTIVE,
+      JSON.stringify(channelId)
+    );
+  }
+
+  afterNavigate(() => {
+    const lastActiveChannel = getLastActiveChannel();
+    if (!activeChannel && lastActiveChannel) {
+      goto(`/ch/${lastActiveChannel}`);
+    } else {
+      setLastActiveChannel(activeChannel || null);
+    }
+  });
+
   onNavigate(() => {
     pageContext.showMenu = false;
   });
-- 
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