AI Chat Conversation Memory

interface Message {
  role: 'system' | 'user' | 'assistant';
  content: string;
}

class ConversationMemory {
  private messages: Message[] = [];
  private maxMessages: number;
  private systemPrompt: string;

  constructor(systemPrompt: string, maxMessages = 20) {
    this.systemPrompt = systemPrompt;
    this.maxMessages = maxMessages;
  }

  add(role: 'user' | 'assistant', content: string): void {
    this.messages.push({ role, content });
    if (this.messages.length > this.maxMessages) {
      this.messages = this.messages.slice(-this.maxMessages);
    }
  }

  getContext(): Message[] {
    return [
      { role: 'system', content: this.systemPrompt },
      ...this.messages,
    ];
  }

  summarize(summary: string): void {
    this.messages = [
      { role: 'system', content: `Previous conversation summary: ${summary}` },
      ...this.messages.slice(-4),
    ];
  }

  clear(): void {
    this.messages = [];
  }

  get length(): number {
    return this.messages.length;
  }
}

const memory = new ConversationMemory('You are a helpful assistant.', 20);
memory.add('user', 'What is TypeScript?');
memory.add('assistant', 'TypeScript is a typed superset of JavaScript.');
console.log(memory.getContext());