import { DynamicStructuredTool } from "@langchain/core/tools";
import { z } from "zod";

import { env } from "../env.mjs";
import type { Booking } from "../types/booking";
import { BOOKING_STATUS } from "../types/booking";

/**
 * Fetches bookings for a user by date range.
 */
const fetchBookings = async ({
  apiKey,
  userId,
  from,
  to,
}: {
  apiKey: string;
  userId: number;
  from: string;
  to: string;
}): Promise<Booking[] | { error: string }> => {
  const params = {
    apiKey,
    userId: userId.toString(),
    dateFrom: from,
    dateTo: to,
  };

  const urlParams = new URLSearchParams(params);

  const url = `${env.BACKEND_URL}/bookings?${urlParams.toString()}`;

  const response = await fetch(url);

  if (response.status === 401) throw new Error("Unauthorized");

  const data = await response.json();

  if (response.status !== 200) {
    return { error: data.message };
  }

  const bookings: Booking[] = data.bookings
    .filter((booking: Booking) => {
      const notCancelled = booking.status !== BOOKING_STATUS.CANCELLED;

      return notCancelled;
    })
    .map(({ endTime, eventTypeId, id, startTime, status, title }: Booking) => ({
      endTime,
      eventTypeId,
      id,
      startTime,
      status,
      title,
    }));

  return bookings;
};

const getBookingsTool = (apiKey: string, userId: number) => {
  return new DynamicStructuredTool({
    description: "Get bookings for the primary user between two dates.",
    func: async ({ from, to }) => {
      return JSON.stringify(await fetchBookings({ apiKey, userId, from, to }));
    },
    name: "getBookings",
    schema: z.object({
      from: z.string().describe("ISO 8601 datetime string"),
      to: z.string().describe("ISO 8601 datetime string"),
    }),
  });
};

export default getBookingsTool;