// Whose agreement answers these are. A tick, a recorded answer or a held answer belongs to the viewer signed in, the
// practice and the person answered for; it is withheld the moment any of them changes, and never comes back.
import { useRef } from 'react';
import { viewerEpoch } from '../../utils/writeThroughHold';

/** The account a screen is rendered for, as that render sees it; the global viewer epoch moves an effect later. */
export const renderedViewer = (currentUser: { fhir?: { resourceType?: string; id?: string } } | null | undefined): string =>
    currentUser?.fhir?.id ? `${currentUser.fhir.resourceType ?? ''}/${currentUser.fhir.id}` : '';

export const agreementOwner = (
    viewer: string,
    organizationId: string | undefined,
    actingAs: { relatedPersonId?: string; subjectPatientId?: string } | null | undefined,
    subjectPatientId?: string,
): string => [viewerEpoch(), viewer, organizationId ?? '', actingAs?.relatedPersonId ?? '', actingAs?.subjectPatientId ?? '', subjectPatientId ?? ''].join('|');

/** A generation that moves on whenever the owner changes, so returning to an earlier owner starts empty. */
export const useOwnerGeneration = (owner: string): { generation: number; current: () => number } => {
    const last = useRef(owner);
    const generation = useRef(0);
    if (last.current !== owner) {
        last.current = owner;
        generation.current += 1;
    }
    const current = useRef(() => generation.current);
    return { generation: generation.current, current: current.current };
};

/** Which practice the agreements are about: none yet resolved, the neutral patients host, or a resolved practice. */
export type AgreementPracticeScope = 'unresolved' | 'neutral' | 'practice';

// Only a patient or helper session whose practice check answered none is neutral; until then the practice is unknown.
export const agreementPracticeScope = (
    organizationId: string | undefined, organizationCheckComplete: boolean, patientExperience: boolean,
): AgreementPracticeScope => {
    if (organizationId) return 'practice';
    return organizationCheckComplete && patientExperience ? 'neutral' : 'unresolved';
};