frontend: animate sidebar on small viewports

frontend/src/components/ChannelTopBar.svelte

@@ -13,7 +13,7 @@
 
 <div class="top-bar">
     {#if !$showSidebar}
-        <button class="icon-button menu-button" on:click="{ () => selectedChannel.set({ id: -1, name: "none", creator_id: -1 }) }">
+        <button class="icon-button menu-button" on:click="{ () => showSidebar.set(true) }">
             <MenuIcon />
         </button>
     {/if}

frontend/src/components/ChannelView.svelte

@@ -1,4 +1,5 @@
 <script>
+    import { showChannelView } from "../stores";
     import ChannelTopBar from "./ChannelTopBar.svelte";
     import MessageInput from "./MessageInput.svelte";
     import Messages from "./Messages.svelte";
@@ -15,9 +16,13 @@
         width: 100%;
         height: 100%;
     }
+
+    .hidden {
+        display: none;
+    }
 </style>
 
-<div class="main-container">
+<div class="main-container" class:hidden={ !$showChannelView }>
     <ChannelTopBar channel={ channel } />
     <Messages channelId="{ channel.id }" />
     <MessageInput channel={ channel } />

frontend/src/components/Main.svelte

@@ -1,6 +1,6 @@
 <script>
     import { CloudIcon } from "svelte-feather-icons";
-    import { gatewayStatus, showSidebar, selectedChannel } from "../stores";
+    import { gatewayStatus, showSidebar, selectedChannel, smallViewport, showChannelView } from "../stores";
     import ChannelView from "./ChannelView.svelte";
     import OverlayProvider from "./overlays/OverlayProvider.svelte";
     import Sidebar from "./Sidebar.svelte";
@@ -26,17 +26,10 @@
 {/if}
 
 <div class="flex-container">
-    {#if $selectedChannel.id === -1}
-        <Sidebar />
-        {#if $showSidebar}
-            <div class="fullscreen-message">
-                no channel selected.
-            </div>
-        {/if}
-    {:else}
     {#if $showSidebar}
         <Sidebar />
     {/if}
+    {#if !($smallViewport && $showSidebar)}
         <ChannelView channel={$selectedChannel} />
     {/if}
 </div>

frontend/src/components/Sidebar.svelte

@@ -1,14 +1,41 @@
 <script>
     import { HashIcon, PlusIcon, MoreVerticalIcon } from "svelte-feather-icons";
-    import { channels, overlayStore, selectedChannel } from "../stores";
+    import { quadInOut } from "svelte/easing";
+    import { fly } from "svelte/transition";
+    import { channels, overlayStore, selectedChannel, showChannelView, showSidebar, smallViewport } from "../stores";
     import UserTopBar from "./UserTopBar.svelte";
+
+    let pendingSelectChannel = null;
+
+    const selectChannel = (channel) => $selectedChannel = channel;
+
+    // janky code to hide the channel view during animation
+    // this will make a smooth sidebar animation on smaller viewports (such as a phone, where you switch between sidebar being active)
+
+    const scheduleSelectChannel = (channel) => {
+        if ($smallViewport) {
+            $showChannelView = false;
+            pendingSelectChannel = channel;
+            $showSidebar = false;
+        } else {
+            selectChannel(channel);
+        }
+    };
+
+    const outroEnd = () => {
+        if (pendingSelectChannel) {
+            selectChannel(pendingSelectChannel);
+            pendingSelectChannel = null;
+            $showChannelView = true;
+        }
+    };
 </script>
 
-<div class="sidebar-container">
+<div class="sidebar-container" transition:fly="{{ duration: 200, easing: quadInOut, x: -10 }}" on:outroend="{ outroEnd }">
     <UserTopBar />
     <div class="sidebar">
         {#each $channels as channel (channel.id)}
-            <button on:click="{ () => $selectedChannel = channel }" class="sidebar-button" class:selected={ channel.id === $selectedChannel.id }>
+            <button on:click="{ scheduleSelectChannel(channel) }" class="sidebar-button"  class:selected={ channel.id === $selectedChannel.id }>
                 <div>
                     <HashIcon />
                 </div>

frontend/src/responsive.js

@@ -1,10 +1,11 @@
-import { showSidebar } from "./stores";
+import { showSidebar, smallViewport } from "./stores";
 
 export function initResponsiveHandlers() {
     const mediaQuery = window.matchMedia('(min-width: 768px)');
 
     const update = ({ matches }) => {
         showSidebar.set(matches);
+        smallViewport.set(!matches);
     };
 
     mediaQuery.addEventListener("change", update);

frontend/src/stores.js

@@ -36,6 +36,7 @@ class ChannelsStore extends Store {
 
         gateway.subscribe(GatewayEventType.Ready, ({ channels }) => {
             this.value = channels;
+            selectedChannel.set(channels.length ? channels[0] : null);
             this.updated();
         });
         gateway.subscribe(GatewayEventType.ChannelCreate, (channel) => {
@@ -265,3 +266,5 @@ export const userInfoStore = new UserInfoStore();
 export const overlayStore = new OverlayStore();
 export const selectedChannel = writable({ id: -1, name: "none", creator_id: -1 });
 export const showSidebar = writable(false);
+export const showChannelView = writable(true);
+export const smallViewport = writable(false);