import { useEffect } from 'react';
import { DocumentReference } from 'fhir/r4';
import {
    useDocumentReferenceServiceContext,
    useFhirServiceContext,
    usePatientServiceContext,
    useWebSocketServiceContext
} from '../services';
import { isArchived } from '../utils/archivedResource';

export const useFhirDocumentReferenceBroadcast = (options?: { isRoot: boolean; }) => {
    const { subscribe, unsubscribe } = useWebSocketServiceContext();
    const { documentReferencesList, setDocumentReferencesList } = useDocumentReferenceServiceContext();
    const { patientState } = usePatientServiceContext();
    const { extractReferenceId } = useFhirServiceContext();

    useEffect(() => {
        if (!options?.isRoot && !patientState) {
            return;
        }

        const handleDocumentReferenceEvent = (cloudEvent: any) => {
            const documentReference: DocumentReference = cloudEvent.data;
            const eventType = cloudEvent.type;

            switch (eventType) {
                case 'com.akashichealthrecords.fhir.documentreference.created':
                    // The list has two writers: this broadcast, and the service's own refetch after a write
                    // (several of which POLL until the new id appears). Refetch first and the list already holds
                    // the record, so an unconditional append put a SECOND copy of it on screen - observed on a
                    // patient's questionnaire answers, where one submission rendered as two completed forms.
                    // Keeping the broadcast's copy rather than skipping: its body is at least as fresh.
                    setDocumentReferencesList(prev =>
                        prev.some(p => p.id === documentReference.id)
                            ? prev.map(p => p.id === documentReference.id ? documentReference : p)
                            : [...prev, documentReference]
                    );
                    break;
                case 'com.akashichealthrecords.fhir.documentreference.updated':
                    setDocumentReferencesList(prev =>
                        isArchived(documentReference)
                            ? prev.filter(p => p.id !== documentReference.id)
                            : prev.map(p => p.id === documentReference.id ? documentReference : p)
                    );
                    break;
                case 'com.akashichealthrecords.fhir.documentreference.deleted':
                    setDocumentReferencesList(prev => prev.filter(p => p.id !== documentReference.id));
                    break;
            }
        };

        subscribe('com.akashichealthrecords.fhir.documentreference.created', handleDocumentReferenceEvent);
        subscribe('com.akashichealthrecords.fhir.documentreference.updated', handleDocumentReferenceEvent);
        subscribe('com.akashichealthrecords.fhir.documentreference.deleted', handleDocumentReferenceEvent);

        return () => {
            unsubscribe('com.akashichealthrecords.fhir.documentreference.created', handleDocumentReferenceEvent);
            unsubscribe('com.akashichealthrecords.fhir.documentreference.updated', handleDocumentReferenceEvent);
            unsubscribe('com.akashichealthrecords.fhir.documentreference.deleted', handleDocumentReferenceEvent);
        };
    }, [patientState, subscribe, unsubscribe, extractReferenceId, documentReferencesList]);
};