Improve chat's input UX

src/lib/actions/autogrow.ts

@@ -0,0 +1,48 @@
+import type { Action } from "svelte/action";
+
+type AutogrowParams = {
+  // When false the action is inert, leaving the textarea at its native size.
+  enabled?: boolean;
+  // Max height in lines before the textarea starts scrolling.
+  maxRows?: number;
+  // A value to watch; resize is re-run whenever it changes (e.g. after a reset).
+  value?: unknown;
+};
+
+// Grow a textarea with its content up to maxRows lines, then scroll.
+export const autogrow: Action<
+  HTMLTextAreaElement,
+  AutogrowParams | undefined
+> = (node, params) => {
+  let enabled = params?.enabled ?? true;
+  let maxRows = params?.maxRows ?? 10;
+
+  function resize() {
+    if (!enabled) return;
+    const cs = getComputedStyle(node);
+    const lh = parseFloat(cs.lineHeight) || 20;
+    const vPad = parseFloat(cs.paddingTop) + parseFloat(cs.paddingBottom);
+    const vBorder =
+      parseFloat(cs.borderTopWidth) + parseFloat(cs.borderBottomWidth);
+    const max = lh * maxRows + vPad + vBorder;
+    node.style.height = "auto";
+    const next = Math.min(node.scrollHeight, max);
+    node.style.height = `${next}px`;
+    node.style.overflowY = node.scrollHeight > max ? "auto" : "hidden";
+  }
+
+  node.addEventListener("input", resize);
+  resize();
+
+  return {
+    update(next) {
+      enabled = next?.enabled ?? true;
+      maxRows = next?.maxRows ?? 10;
+      // Re-run on watched-value changes, including programmatic resets.
+      resize();
+    },
+    destroy() {
+      node.removeEventListener("input", resize);
+    },
+  };
+};

src/lib/components/ChatSidebar.svelte

@@ -207,11 +207,13 @@
       sendError = e instanceof Error ? e.message : "Failed to send";
     } finally {
       sending = false;
+      // Re-enable runs first, then focus lands on the now-interactive textarea.
+      tick().then(() => inputEl?.focus({ caretAtEnd: true }));
     }
   }
 
   function onKeydown(e: KeyboardEvent) {
-    if (e.key === "Enter" && !e.shiftKey) {
+    if (e.key === "Enter" && (e.metaKey || e.ctrlKey)) {
       e.preventDefault();
       submit();
     } else if (e.key === "Escape" && replyTarget) {
@@ -462,16 +464,43 @@
         Join to chat
       </button>
     {:else}
-      <MentionAutocomplete
-        bind:this={inputEl}
-        bind:value={inputValue}
-        onkeydown={onKeydown}
-        rows={1}
-        disabled={sending}
-        placeholder={auth.user ? "Message..." : "Login to send messages"}
-        {contextPubkeys}
-        textareaClass="w-full resize-none rounded border border-neutral-200 dark:border-neutral-700 px-3 py-2 text-sm focus:outline-none focus:ring-1 focus:ring-accent disabled:opacity-50"
-      />
+      <div class="relative">
+        <MentionAutocomplete
+          bind:this={inputEl}
+          bind:value={inputValue}
+          onkeydown={onKeydown}
+          rows={1}
+          autoGrow
+          maxRows={10}
+          disabled={sending}
+          placeholder={auth.user ? "Message..." : "Login to send messages"}
+          {contextPubkeys}
+          textareaClass="block w-full resize-none rounded border border-neutral-200 dark:border-neutral-700 py-2 pl-3 pr-11 text-sm focus:outline-none focus:ring-1 focus:ring-accent disabled:opacity-50"
+        />
+        <button
+          type="button"
+          onclick={submit}
+          disabled={sending || !inputValue.trim()}
+          title="Send (⌘/Ctrl + Enter)"
+          aria-label="Send message"
+          class="bg-accent hover:bg-accent-hover absolute right-1.5 bottom-1.5 flex h-6 w-6 items-center justify-center rounded-full text-white transition-colors disabled:cursor-not-allowed disabled:bg-transparent disabled:opacity-40"
+        >
+          <svg
+            xmlns="http://www.w3.org/2000/svg"
+            class="h-4 w-4 -translate-x-px translate-y-px"
+            viewBox="0 0 24 24"
+            fill="none"
+            stroke="currentColor"
+            stroke-width="2"
+            stroke-linecap="round"
+            stroke-linejoin="round"
+            aria-hidden="true"
+          >
+            <path d="M22 2 11 13" />
+            <path d="M22 2 15 22l-4-9-9-4 20-7z" />
+          </svg>
+        </button>
+      </div>
     {/if}
   </div>
 </aside>

src/lib/components/MentionAutocomplete.svelte

@@ -8,6 +8,7 @@
     searchRemoteProfiles,
     type ProfileEntry,
   } from "$lib/profiles.svelte";
+  import { autogrow } from "$lib/actions/autogrow";
 
   type Props = {
     value: string;
@@ -16,6 +17,8 @@
     placeholder?: string;
     contextPubkeys?: string[];
     textareaClass?: string;
+    autoGrow?: boolean;
+    maxRows?: number;
     onkeydown?: (e: KeyboardEvent) => void;
     onfocus?: () => void;
     onblur?: () => void;
@@ -28,6 +31,8 @@
     placeholder = "",
     contextPubkeys = [],
     textareaClass = "",
+    autoGrow = false,
+    maxRows = 10,
     onkeydown,
     onfocus,
     onblur,
@@ -298,6 +303,7 @@
   <textarea
     bind:this={textareaEl}
     bind:value
+    use:autogrow={{ enabled: autoGrow, maxRows, value }}
     {disabled}
     {rows}
     {placeholder}