import type { CodeableConcept, Resource } from 'fhir/r4';
import type { ProposalKind } from './recordProposals';

/** One item of one kind, however it was written: the key a decision and a filed resource share. */
export const proposalKey = (kind: string, title: string): string => kind + ':' + title.trim().toLowerCase();

type Filed = Resource & { encounter?: { reference?: string } };

// The concept each kind is named by. Diet and vision have no single name to match, so none is claimed.
const CONCEPT: Partial<Record<ProposalKind, (resource: Record<string, unknown>) => unknown>> = {
    condition: (r) => r.code,
    allergy: (r) => r.code,
    medication: (r) => r.medicationCodeableConcept,
    immunization: (r) => r.vaccineCode,
    observation: (r) => r.code,
    procedure: (r) => r.code,
    risk: (r) => r.code,
};

const namesOf = (concept: CodeableConcept | undefined): string[] =>
    [concept?.text, ...(concept?.coding ?? []).map((coding) => coding.display)]
        .filter((name): name is string => Boolean(name && name.trim()));

/**
 * Whether a proposal is among the filed keys. The coded name a clinician picks usually extends what the note
 * said ("loratadine 10 MG Oral Tablet" for "Loratadine 10 mg"), so a filed name that begins with the
 * proposal's whole title, then a word, counts too.
 */
export const isFiledAs = (filed: Set<string>, key: string): boolean =>
    filed.has(key) || [...filed].some((name) => name.startsWith(key + ' '));

/** The keys of what this kind's resources show as filed to this encounter. */
export const filedKeysFor = (kind: ProposalKind, resources: Filed[], encounterId: string): string[] => {
    const conceptOf = CONCEPT[kind];
    if (!conceptOf) return [];
    return resources
        .filter((resource) => resource.encounter?.reference === 'Encounter/' + encounterId)
        .flatMap((resource) => namesOf(conceptOf(resource as unknown as Record<string, unknown>) as CodeableConcept | undefined))
        .map((name) => proposalKey(kind, name));
};