import type { Coding, Extension } from "fhir/r4";

// Enrolment is three-state: absent `isEnrolled` is Not given, never No. It lives inside a tribe's extension.
export const TRIBAL_AFFILIATION_URL = "http://hl7.org/fhir/us/core/StructureDefinition/us-core-tribal-affiliation";

/** The stored answer: true, false, or undefined when nobody answered. */
export const enrolledOf = (tribal: Extension | undefined): boolean | undefined =>
  tribal?.extension?.find((child) => child.url === "isEnrolled")?.valueBoolean;

/** The extension for one tribe, with `isEnrolled` only when the answer is Yes or No. */
export const tribalAffiliationExtension = (tribe: Coding, enrolled: boolean | undefined): Extension => ({
  url: TRIBAL_AFFILIATION_URL,
  extension: [
    { url: "tribalAffiliation", valueCodeableConcept: { coding: [tribe], text: tribe.display } },
    ...(typeof enrolled === "boolean" ? [{ url: "isEnrolled", valueBoolean: enrolled }] : []),
  ],
});

export type EnrolledChoice = "not-given" | "yes" | "no";

/** The three answers a form offers, in the deck's order. */
export const ENROLLED_OPTIONS: { value: EnrolledChoice; label: string }[] = [
  { value: "not-given", label: "Not given" },
  { value: "yes", label: "Yes" },
  { value: "no", label: "No" },
];

export const enrolledChoice = (enrolled: boolean | undefined): EnrolledChoice =>
  enrolled === undefined ? "not-given" : enrolled ? "yes" : "no";

export const enrolledFromChoice = (choice: string): boolean | undefined =>
  choice === "yes" ? true : choice === "no" ? false : undefined;

/** What a read view shows. No tribe means the question cannot have been answered. */
export const enrolledLabel = (hasTribe: boolean, enrolled: boolean | undefined): string =>
  hasTribe && enrolled !== undefined ? (enrolled ? "Yes" : "No") : "";