How should I make series of API calls with the middle one needing time?

I need to make a series of calls to an API. Here is what should happen:

• Call 1: Make the first call which returns an ID.
• Call 2: Use the ID to make the second call. The second call will come back with an object which includes a status of either 'P', 'C', or 'E' (Processing, Complete, or Error). Once the second call comes back with 'C', make the third call (or stop the process with an error)
• Call 3: Use the ID again to get final processing details.

This is what I have so far, but it does not work and does not include the third call.

this.firstCall(formData)
  .pipe(
    interval(3000)
    .pipe(
      switchMap(res => {
        this.secondCall(res)
          .pipe(
            catchError(error => {
              return of(null);
            })
        )
      }),
      takeUntil(res => res.code !== 'P'),
      timeout(21000)
    )
  )
  .subscribe({
    next: (data) => {
      console.log('SUCCESS DATA', data)
    },
    error: (error) => {
      console.log('PROCESSING ERROR', error)
    }
  })

We can use expand to recursively call the second API, until we achieve C (Complete), then we trigger the third API.

I am assuming the third API does not return an object with the property code. I use this assumption to break the expand using EMPTY which immediately completes the stream.

I use filter operator to block out the emissions where code is P.

import { of, expand, switchMap, EMPTY, delay, filter } from 'rxjs';

let i = 0;
const firstAPI = () => of('123');
const secondAPI = (id: any) => {
  console.log('second API called');
  i++;
  return i > 10 ? of({ code: 'C' }) : of({ code: 'P' });
};
const thirdAPI = (id: any) => of(`hello ${id}`);

firstAPI()
  .pipe(
    switchMap((id: any) =>
      secondAPI(id).pipe(
        // we use expand to recurisvely call the second API.
        expand((val: any) => {
          // when the third API gets call use some property to break the expand loop
          if (!val?.code) {
            // immediately complete the stream
            return EMPTY;
          }
          // it is still processing so call the second api again with a small delay
          if (val.code === 'P') {
            return secondAPI(id).pipe(delay(500));
          } else if (val.code === 'E') {
            // an error has occoured, so we can throw an error, feel free to add a catchError in the stream.
            throw new Error('Some Error Occoured');
          } else {
            // the second API is completed so trigger the third API.
            return thirdAPI(id);
          }
        }),
        filter((item: any) => item?.code !== 'P')
      )
    )
  )
  .subscribe({
    next: (data: any) => {
      console.log('SUCCESS DATA', data);
    },
    error: (error: any) => {
      console.log('PROCESSING ERROR', error);
    },
  });

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