import { useCallback, useEffect, useState } from "react";
import { useHttpService } from "../services/HttpService.tsx";
import { environment } from "../environments/environment.ts";
import { relayServerFailure } from "../utils/fetchFailureMessage";

/**
 * The studies that could answer one imaging order.
 *
 * IT ASKS ABOUT AN ORDER, NEVER ABOUT A PATIENT, and that is the whole reason the route exists.
 * `GET /R4/ImagingStudy` admits practitioners, patients and related persons and is gated on patient
 * access -- an imaging tech is none of those. The lab queue also withholds the patient id on purpose,
 * carrying a display name because whoever works the row has to know who it is for. So this client
 * cannot search a patient's studies, and must not be able to: the server resolves the patient from
 * the order and never returns it.
 *
 * THE LIST GRANTS NOTHING. Choosing from it does not attach anything; the result route reads the
 * study again and refuses one whose subject is not the order's patient. This is an affordance, not a
 * permission.
 *
 * On the base API, where 02-fhir-base.yaml declares the diagnostic-order routes.
 */

export interface DiagnosticOrderStudy {
  id?: string;
  description?: string;
  started?: string;
  modalities?: string[];
  numberOfSeries?: number;
  numberOfInstances?: number;
  /** Filed against the order being reported, rather than another of the patient's studies. */
  forThisOrder?: boolean;
}

interface StudiesResponse {
  studies?: DiagnosticOrderStudy[];
}

export const useDiagnosticOrderStudies = (orderId?: string, enabled = true) => {
  const { get } = useHttpService();

  const [studies, setStudies] = useState<DiagnosticOrderStudy[] | null>(null);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string>();

  const load = useCallback(async () => {
    if (!orderId || !enabled) return;

    setLoading(true);
    setError(undefined);
    try {
      const response = await get<StudiesResponse>(
        `${environment.fhirBaseApi}/diagnostic-order/${orderId}/imaging-studies`,
      );
      setStudies(response?.studies ?? []);
    } catch (failure: unknown) {
      // STATED, NOT SHOWN AS AN EMPTY LIST. "No studies have been imported" and "we could not ask"
      // look identical on screen and mean opposite things to somebody deciding whether to file a
      // result without one.
      setError(relayServerFailure(failure, "We could not load this order's studies just now."));
      setStudies(null);
    } finally {
      setLoading(false);
    }
  }, [get, orderId, enabled]);

  useEffect(() => {
    void load();
  }, [load]);

  return { studies, loading, error, reload: load };
};