}

}

function preserveOptimisticTailMessages(

export function preserveOptimisticTailMessages(

historyMessages: unknown[],

previousMessages: unknown[],

): unknown[] {

? previousMessages

: historyMessages;

}

const historySignatures = new Set(

historyMessages

.map((message) => messageDisplaySignature(message))

.filter((signature): signature is string => Boolean(signature)),

);

const historySignatureIndexes = new Map<string, number>();

historyMessages.forEach((message, index) => {

const signature = messageDisplaySignature(message);

if (signature) {

historySignatureIndexes.set(signature, index);

}

});

let sharedPreviousIndex = -1;

let sharedHistoryIndex = -1;

for (let index = previousMessages.length - 1; index >= 0; index--) {

const signature = messageDisplaySignature(previousMessages[index]);

if (signature && historySignatures.has(signature)) {

const historyIndex = signature ? historySignatureIndexes.get(signature) : undefined;

if (typeof historyIndex === "number") {

sharedPreviousIndex = index;

sharedHistoryIndex = historyIndex;

break;

}

}

if (sharedPreviousIndex < 0) {

return historyMessages;

}

if (sharedHistoryIndex < historyMessages.length - 1) {

return historyMessages;

}

const optimisticTail: unknown[] = [];

for (const message of previousMessages.slice(sharedPreviousIndex + 1)) {

if (!isLocallyOptimisticHistoryMessage(message) || shouldHideHistoryMessage(message)) {

return historyMessages;

}

const signature = messageDisplaySignature(message);

if (!signature || historySignatures.has(signature)) {

if (!signature || historySignatureIndexes.has(signature)) {

return historyMessages;

}

optimisticTail.push(message);

if (!msg && !hasAttachments) {

return null;

}

if (state.chatSending) {

return state.chatRunId;

}

const now = Date.now();