import { useCallback, useRef } from "react";
import { useHttpService } from "../services/HttpService.tsx";
import { useStaffPermissionServiceContext } from "../services";
import { environment } from "../environments/environment.ts";
import { SaveRetiredError } from "../utils/saveOperation";

/**
 * Asking the laboratory that confirmed an order for its results now, rather than at the next scheduled read. This only
 * asks: the reads happen elsewhere, and what comes back is filed on the order or held for a person to match. Nothing
 * reaches a patient until someone releases it.
 */

export const NO_LONGER_ALLOWED = "You can no longer ask laboratories for results here.";

export const useOrderResultRead = () => {
  const { post } = useHttpService();
  const { canManage } = useStaffPermissionServiceContext();
  // Read again just before the request leaves, after the sign-in and proof waits; an answer to a sent ask is kept.
  const mayAsk = useRef(false);
  mayAsk.current = canManage("diagnostics");

  /**
   * True only when the server says the read was queued. `owns` is the caller's claim on the ask: once it is false,
   * nothing more is sent for it. An answer to an ask already sent is kept either way.
   */
  const askForResults = useCallback(async (orderId: string, owns?: () => boolean): Promise<boolean> => {
    const admit = (phase?: "answer") => {
      if (phase === "answer") return;
      if (!mayAsk.current) throw new Error(NO_LONGER_ALLOWED);
      if (owns && !owns()) throw new SaveRetiredError();
    };
    const answer = await post<{ queued?: boolean }>(
      `${environment.fhirClinicalApi}/diagnostic-order/${encodeURIComponent(orderId)}/result-read`, {}, { admit },
    );
    return answer?.queued === true;
  }, [post]);

  return { askForResults };
};