/**
 * Reads and writes the review marker a diagnostic order carries as an extension, so a result can
 * name who reviewed it and when without a second resource to keep in step.
 */
import type { ServiceRequest } from "fhir/r4";

import { formatDateTime } from "./dateUtils";


export const DIAGNOSTIC_ORDER_REVIEW_EXTENSION_URL =
  "https://akashichealthrecords.com/fhir/StructureDefinition/diagnostic-order-review";

export interface DiagnosticOrderReview {
  reference: string;
  display?: string;
  at: string;
}

export const readDiagnosticOrderReview = (
  order: ServiceRequest | undefined,
): DiagnosticOrderReview | undefined => {
  for (const extension of order?.extension ?? []) {
    if (extension.url !== DIAGNOSTIC_ORDER_REVIEW_EXTENSION_URL) continue;

    const children = extension.extension ?? [];
    const by = children.find((child) => child.url === "by")?.valueReference;
    const at = children.find((child) => child.url === "at")?.valueDateTime;

    if (!by?.reference || !at) continue;

    return { reference: by.reference, display: by.display, at };
  }

  return undefined;
};

export const orderingPractitionerReference = (order: ServiceRequest): string | undefined => {
  const reference = order.requester?.reference;
  return reference?.startsWith("Practitioner/") ? reference : undefined;
};

export const mayMarkReviewed = (
  order: ServiceRequest,
  practitionerId: string | undefined,
): boolean => {
  if (!practitionerId) return false;
  const ours = orderingPractitionerReference(order);
  // Inbound paper names the outside practice, not a clinician here; any of ours may close it.
  return ours ? ours === `Practitioner/${practitionerId}` : true;
};

export const describeReviewSignature = (review: DiagnosticOrderReview): string =>
  review.display
    ? `Reviewed by ${review.display} on ${formatDateTime(review.at)}`
    : `Reviewed on ${formatDateTime(review.at)}`;

export const describeReviewPending = (order: ServiceRequest): string => {
  if (!orderingPractitionerReference(order)) {
    return "Waiting on a clinician here to review this";
  }
  const who = order.requester?.display?.trim();
  return who
    ? `Waiting on ${who} to review this`
    : "Waiting on the clinician who ordered it to review this";
};

export const withReview = (
  order: ServiceRequest,
  review: DiagnosticOrderReview,
): ServiceRequest => ({
  ...order,
  extension: [
    ...(order.extension ?? []).filter(
      (extension) => extension.url !== DIAGNOSTIC_ORDER_REVIEW_EXTENSION_URL,
    ),
    {
      url: DIAGNOSTIC_ORDER_REVIEW_EXTENSION_URL,
      extension: [
        {
          url: "by",
          valueReference: review.display
            ? { reference: review.reference, display: review.display }
            : { reference: review.reference },
        },
        { url: "at", valueDateTime: review.at },
      ],
    },
  ],
});