base.ts

import { google } from "googleapis";
import { Tool } from "@langchain/core/tools";
import { getEnvironmentVariable } from "@langchain/core/utils/env";
import { BaseLLM } from "@langchain/core/language_models/llms";

export interface GoogleCalendarAgentParams {
  credentials?: {
    clientEmail?: string;
    privateKey?: string;
    calendarId?: string;
  };
  scopes?: string[];
  model?: BaseLLM;
}

export class GoogleCalendarBase extends Tool {
  name = "Google Calendar";

  description =
    "A tool to lookup Google Calendar events and create events in Google Calendar";

  protected clientEmail: string;

  protected privateKey: string;

  protected calendarId: string;

  protected scopes: string[];

  protected llm: BaseLLM;

  constructor(
    fields: GoogleCalendarAgentParams = {
      credentials: {
        clientEmail: getEnvironmentVariable("GOOGLE_CALENDAR_CLIENT_EMAIL"),
        privateKey: getEnvironmentVariable("GOOGLE_CALENDAR_PRIVATE_KEY"),
        calendarId: getEnvironmentVariable("GOOGLE_CALENDAR_CALENDAR_ID"),
      },
      scopes: [
        "https://www.googleapis.com/auth/calendar",
        "https://www.googleapis.com/auth/calendar.events",
      ],
    }
  ) {
    super(...arguments);

    if (!fields.model) {
      throw new Error("Missing llm instance to interact with Google Calendar");
    }

    if (!fields.credentials) {
      throw new Error("Missing credentials to authenticate to Google Calendar");
    }

    if (!fields.credentials.clientEmail) {
      throw new Error(
        "Missing GOOGLE_CALENDAR_CLIENT_EMAIL to interact with Google Calendar"
      );
    }

    if (!fields.credentials.privateKey) {
      throw new Error(
        "Missing GOOGLE_CALENDAR_PRIVATE_KEY to interact with Google Calendar"
      );
    }

    if (!fields.credentials.calendarId) {
      throw new Error(
        "Missing GOOGLE_CALENDAR_CALENDAR_ID to interact with Google Calendar"
      );
    }

    this.clientEmail = fields.credentials.clientEmail;
    this.privateKey = fields.credentials.privateKey;
    this.calendarId = fields.credentials.calendarId;
    this.scopes = fields.scopes || [];
    this.llm = fields.model;
  }

  getModel() {
    return this.llm;
  }

  async getAuth() {
    const auth = new google.auth.JWT(
      this.clientEmail,
      undefined,
      this.privateKey,
      this.scopes
    );

    return auth;
  }

  async _call(input: string) {
    return input;
  }
}