feat: goto message

src/lib/components/chat/Messages.svelte

@@ -107,6 +107,47 @@
 		}
 	};
 
+	const gotoMessage = async (message, idx) => {
+		// Determine the correct sibling list (either parent's children or root messages)
+		let siblings;
+		if (message.parentId !== null) {
+			siblings = history.messages[message.parentId].childrenIds;
+		} else {
+			siblings = Object.values(history.messages)
+				.filter((msg) => msg.parentId === null)
+				.map((msg) => msg.id);
+		}
+
+		// Clamp index to a valid range
+		idx = Math.max(0, Math.min(idx, siblings.length - 1));
+
+		let messageId = siblings[idx];
+
+		// If we're navigating to a different message
+		if (message.id !== messageId) {
+			// Drill down to the deepest child of that branch
+			let messageChildrenIds = history.messages[messageId].childrenIds;
+			while (messageChildrenIds.length !== 0) {
+				messageId = messageChildrenIds.at(-1);
+				messageChildrenIds = history.messages[messageId].childrenIds;
+			}
+
+			history.currentId = messageId;
+		}
+
+		await tick();
+
+		// Optional auto-scroll
+		if ($settings?.scrollOnBranchChange ?? true) {
+			const element = document.getElementById('messages-container');
+			autoScroll = element.scrollHeight - element.scrollTop <= element.clientHeight + 50;
+
+			setTimeout(() => {
+				scrollToBottom();
+			}, 100);
+		}
+	};
+
 	const showPreviousMessage = async (message) => {
 		if (message.parentId !== null) {
 			let messageId =
@@ -408,6 +449,7 @@
 							messageId={message.id}
 							idx={messageIdx}
 							{user}
+							{gotoMessage}
 							{showPreviousMessage}
 							{showNextMessage}
 							{updateChat}