import { useEffect } from 'react';
import { MedicationStatement } from 'fhir/r4';
import {
    useMedicationStatementServiceContext,
    useFhirServiceContext,
    usePatientServiceContext,
    useWebSocketServiceContext
} from '../services';

export const useFhirMedicationStatementBroadcast = () => {
    const { subscribe, unsubscribe } = useWebSocketServiceContext();
    const { medicationStatementsList, publishMedicationStatement } = useMedicationStatementServiceContext();
    const { patientState } = usePatientServiceContext();
    const { extractReferenceId } = useFhirServiceContext();

    useEffect(() => {
        if (!patientState) {
            return;
        }

        const handleMedicationStatementEvent = (cloudEvent: any) => {
            const medicationStatement: MedicationStatement = cloudEvent.data;
            const eventType = cloudEvent.type;
            const patientId = extractReferenceId(medicationStatement.subject);

            // Through the service's floor, as its searches and save answers are: an older event never replaces a newer row.
            if (patientState.id === patientId) {
                if (eventType === 'com.akashichealthrecords.fhir.medicationstatement.created') publishMedicationStatement(medicationStatement, 'created');
                else if (eventType === 'com.akashichealthrecords.fhir.medicationstatement.updated') publishMedicationStatement(medicationStatement, 'updated');
                else if (eventType === 'com.akashichealthrecords.fhir.medicationstatement.deleted') publishMedicationStatement(medicationStatement, 'deleted');
            }
        };

        subscribe('com.akashichealthrecords.fhir.medicationstatement.created', handleMedicationStatementEvent);
        subscribe('com.akashichealthrecords.fhir.medicationstatement.updated', handleMedicationStatementEvent);
        subscribe('com.akashichealthrecords.fhir.medicationstatement.deleted', handleMedicationStatementEvent);

        return () => {
            unsubscribe('com.akashichealthrecords.fhir.medicationstatement.created', handleMedicationStatementEvent);
            unsubscribe('com.akashichealthrecords.fhir.medicationstatement.updated', handleMedicationStatementEvent);
            unsubscribe('com.akashichealthrecords.fhir.medicationstatement.deleted', handleMedicationStatementEvent);
        };
    }, [patientState, subscribe, unsubscribe, extractReferenceId, medicationStatementsList, publishMedicationStatement]);
};