// The share carries a reference only; each viewer reads the item on its own route and authorization.
import type { CarePlan, DiagnosticReport, DocumentReference, ImagingStudy, Observation } from 'fhir/r4';
import { environment } from '../../environments/environment';
import { CHANGED_HERE_TEXT, changedHere, isWithdrawnReturned, WITHDRAWN_RESULT_TEXT, withheldText } from '../../utils/returnedPublication';

// A returned result withdrawn here is said to be withdrawn, never summarised as what it once said.
const shownWords = (item: { id?: string; status?: string; extension?: DiagnosticReport['extension'] }, words: string | undefined) =>
    withheldText(item) ?? (isWithdrawnReturned(item) ? WITHDRAWN_RESULT_TEXT : words);
// A returned result this practice changed after the laboratory returned it says so wherever its words are shown.
const changedHereOf = (item: { id?: string; status?: string; extension?: DiagnosticReport['extension'] }) =>
    changedHere(item) && !withheldText(item) && !isWithdrawnReturned(item) ? { changedHere: CHANGED_HERE_TEXT } : {};
import { bloodPressureReading } from '../../utils/observationPanelValue';

/** Studies, results, plans and documents - the kinds the picker offers and the server accepts. */
export const SHAREABLE_TYPES: readonly string[] = ['DiagnosticReport', 'Observation', 'ImagingStudy', 'CarePlan', 'DocumentReference'];
const ID = /^[A-Za-z0-9.-]{1,64}$/;

export const isShareableReference = (value: string | undefined | null): value is string => {
    if (typeof value !== 'string') return false;
    const [type, id, ...rest] = value.split('/');
    return rest.length === 0 && SHAREABLE_TYPES.includes(type) && ID.test(id ?? '');
};

/** The ordinary read route for a shown item, or nothing for a reference that cannot be shown. */
export const readUrlFor = (reference: string): string | undefined => {
    if (!isShareableReference(reference)) return undefined;
    const base = reference.startsWith('DocumentReference/') ? environment.fhirFoundationApi : environment.fhirClinicalApi;
    return base + '/' + reference;
};

export interface ShownItemSummary {
    title: string;
    detail?: string;
    /** Said beside a returned result this practice changed after the laboratory returned it. */
    changedHere?: string;
    source?: string;
    when?: string;
}

export type ShownResource = DiagnosticReport | Observation | ImagingStudy | CarePlan | DocumentReference;

const conceptText = (concept?: { text?: string; coding?: { display?: string }[] }) =>
    concept?.text || concept?.coding?.find((c) => c.display)?.display || undefined;

const observationValue = (o: Observation): string | undefined => {
    const pressure = bloodPressureReading(o);
    if (pressure) return pressure;
    if (o.valueQuantity?.value !== undefined) {
        return [o.valueQuantity.value, o.valueQuantity.unit].filter((part) => part !== undefined && part !== '').join(' ');
    }
    return o.valueString ?? conceptText(o.valueCodeableConcept);
};

/** What the banner and the stage say about an item. Only fields the record holds; nothing inferred. */
export const summariseShownItem = (item: ShownResource): ShownItemSummary => {
    switch (item.resourceType) {
        case 'DiagnosticReport':
            return {
                title: conceptText(item.code) ?? 'Report',
                detail: shownWords(item, item.conclusion),
                ...changedHereOf(item),
                source: item.performer?.[0]?.display,
                when: item.effectiveDateTime ?? item.issued,
            };
        case 'Observation':
            return {
                title: conceptText(item.code) ?? 'Result',
                detail: shownWords(item, observationValue(item)),
                ...changedHereOf(item),
                source: item.performer?.[0]?.display,
                when: item.effectiveDateTime ?? item.issued,
            };
        case 'ImagingStudy':
            return {
                title: item.description ?? conceptText(item.procedureCode?.[0]) ?? 'Imaging study',
                source: item.series?.[0]?.performer?.[0]?.actor?.display,
                when: item.started,
            };
        case 'CarePlan':
            return {
                title: item.title ?? 'Care plan',
                detail: item.description,
                source: item.author?.display,
                when: item.period?.start ?? item.created,
            };
        case 'DocumentReference':
            return {
                title: item.description ?? conceptText(item.type) ?? 'Document',
                source: item.custodian?.display ?? item.author?.[0]?.display,
                when: item.date,
            };
    }
};

/** "Cedar Valley Imaging, Sep 2" - the source and the day, whichever the record holds. */
export const provenanceLine = (summary: ShownItemSummary): string | undefined => {
    const day = summary.when && !Number.isNaN(new Date(summary.when).getTime())
        ? new Date(summary.when).toLocaleDateString(undefined, { month: 'short', day: 'numeric' })
        : undefined;
    return [summary.source, day].filter(Boolean).join(', ') || undefined;
};