Chat Window

Component Documentation: ChatWindow .tsx

Overview

ChatWindow is a React chat interface component that enables users to interact with a financial agent backend hosted on the Internet Computer blockchain. It displays a conversation history, handles user input, and manages API communication with the backend service.

Key Features

• Real-time message display with user/system differentiation

• Asynchronous communication with blockchain backend

• Loading states and error handling

• Responsive UI with Tailwind CSS styling

State Management

State Variable	Type	Description
chat	Array	Stores chat history objects with user/system messages
inputValue	string	Tracks current value of message input field
isLoading	boolean	Indicates when backend request is in progress (disables UI interactions)

Core Functions

1. formatDate(date: Date) Formats timestamps to HH:MM (currently unused in UI)

2. askAgent(messages: any[]) Handles backend communication:

   • Sends conversation history to backend.chat() endpoint

   • Updates chat with response on success

   • Implements error parsing for blockchain-specific errors

   • Manages loading states

3. handleSubmit(e: React.FormEvent) Message submission handler:

   • Validates input

   • Updates chat with user message + "Thinking..." placeholder

   • Triggers backend request

   • Resets input field

Component Structure

<div className="flex flex-col flex-1 overflow-hidden">
  {/* Message history container */}
  <div className="flex-1 overflow-auto p-6 space-y-4 flex flex-col">
    {chat.map(/* renders message bubbles */)}
  </div>

  {/* Input area */}
  <div className="p-4 border-t border-zinc-700 bg-zinc-900">
    <form onSubmit={handleSubmit}>
      <input /* message input */ />
      <button /* submit button */ />
    </form>
  </div>
</div>

Message Rendering Logic

chat.map((message, index) => {
  const isUser = !!message.user;
  return (
    <div key={index} className={`flex ${isUser ? 'justify-end' : 'justify-start'}`}>
      <div className={`p-4 rounded-lg ${isUser ? 'bg-blue-600' : 'bg-zinc-800'}`}>
        {isUser ? message.user.content : message.system.content}
      </div>
    </div>
  );
})

Backend Integration

• Uses backend.chat() method from declarations/backend

• Payload structure: Array of message objects

• Error handling for Internet Computer-specific errors:

  const match = String(e).match(/(SysTransient|CanisterReject), \\+"([^\\"]+)/);

UI Features

• Message bubbles color-coded by sender (blue for user, dark gray for system)

• Responsive layout with flexbox

• Input disabled during loading states

• Auto-scroll functionality (currently commented out)

Usage Notes

1. Initial State: Displays welcome message from system agent

2. Submit Workflow: User input → Add user message → Show "Thinking..." → API call → Replace with response

3. Error Handling:

   • Alerts user with parsed error message

   • Removes "Thinking..." placeholder on failure

Optimization Opportunities

1. Enable auto-scroll (uncomment useEffect)

2. Add message timestamps using formatDate()

3. Implement markdown rendering for system messages

4. Add rate limiting for submissions

Dependencies

import { useEffect, useRef, useState } from 'react';
import { backend } from 'declarations/backend'; // Internet Computer backend interface

Styling Reference

Element	Tailwind Classes
User Message	bg-blue-600 text-white justify-end
System Message	bg-zinc-800 text-white justify-start
Input Field	bg-zinc-800 text-white outline-none
Submit Button	bg-blue-600 hover:bg-blue-500 text-white
Container	bg-zinc-900 border-zinc-700