feat(message-handling): fix repeated first token, think tag handling

closes #889

src/lib/hooks/useChat.tsx

@@ -399,6 +399,7 @@ export const ChatProvider = ({
           (m, j) =>
             j > i &&
             m.role === 'source' &&
+            m.sources &&
             (nextUserMessageIndex === -1 || j < nextUserMessageIndex),
         ) as SourceMessage | undefined;
 
@@ -417,7 +418,7 @@ export const ChatProvider = ({
             const closeThinkTag =
               processedMessage.match(/<\/think>/g)?.length || 0;
 
-            if (openThinkTag > closeThinkTag) {
+            if (openThinkTag && !closeThinkTag) {
               processedMessage += '</think> <a> </a>';
             }
           }
@@ -426,7 +427,11 @@ export const ChatProvider = ({
             thinkingEnded = true;
           }
 
-          if (sourceMessage && sourceMessage.sources.length > 0) {
+          if (
+            sourceMessage &&
+            sourceMessage.sources &&
+            sourceMessage.sources.length > 0
+          ) {
             processedMessage = processedMessage.replace(
               citationRegex,
               (_, capturedContent: string) => {
@@ -635,8 +640,8 @@ export const ChatProvider = ({
             },
           ]);
           added = true;
-        }
+          setMessageAppeared(true);
-
+        } else {
           setMessages((prev) =>
             prev.map((message) => {
               if (
@@ -649,9 +654,8 @@ export const ChatProvider = ({
               return message;
             }),
           );
-
+        }
         recievedMessage += data.data;
-        setMessageAppeared(true);
       }
 
       if (data.type === 'messageEnd') {