Function handleEditMessage

frontend/components/chat-panel.tsx:941–986

(messageIndex: number, newText: string)

    }

    const handleEditMessage = async (messageIndex: number, newText: string) => {
        const isProcessing = status === "streaming" || status === "submitted"
        if (isProcessing) return

        const message = messages[messageIndex]
        if (!message || message.role !== "user") return

        // Get the saved XML snapshot for this user message
        const savedXml = xmlSnapshotsRef.current.get(messageIndex)
        if (!savedXml) {
            console.error(
                "No saved XML snapshot for message index:",
                messageIndex,
            )
            return
        }

        // Get previous XML and restore diagram state
        const previousXml = getPreviousXml(messageIndex)
        restoreDiagramFromSnapshot(savedXml)

        // Clean up snapshots for messages after the user message (they will be removed)
        cleanupSnapshotsAfter(messageIndex)

        // Create new parts with updated text
        const newParts = message.parts?.map((part: any) => {
            if (part.type === "text") {
                return { ...part, text: newText }
            }
            return part
        }) || [{ type: "text", text: newText }]

        // Remove the user message AND assistant message onwards (sendMessage will re-add the user message)
        // Use flushSync to ensure state update is processed synchronously before sending
        const newMessages = messages.slice(0, messageIndex)
        flushSync(() => {
            setMessages(newMessages)
        })

        // Check all quota limits
        if (!checkAllQuotaLimits()) return

        // Now send the edited message after state is guaranteed to be updated
        sendChatMessage(newParts, savedXml, previousXml, sessionId)
        // Token count is tracked in onFinish with actual server usage
    }

    // Collapsed view (desktop only)
    if (!isVisible && !isMobile) {