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

export const useFhirQuestionnaireResponseBroadcast = () => {
    const { subscribe, unsubscribe } = useWebSocketServiceContext();
    const { questionnaireResponsesList, setQuestionnaireResponsesList } = useQuestionnaireResponseServiceContext();
    const { patientState } = usePatientServiceContext();
    const { extractReferenceId } = useFhirServiceContext();

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

        const handleQuestionnaireResponseEvent = (cloudEvent: any) => {
            const questionnaireResponse: QuestionnaireResponse = cloudEvent.data;
            const eventType = cloudEvent.type;
            const patientId = extractReferenceId(questionnaireResponse.author);

            if (patientState.id === patientId) {
                switch (eventType) {
                    /**
 * The append is CONDITIONAL, because this list has two writers and they race.
 *
 * A patient submitting an assigned questionnaire triggers BOTH a refetch (which polls
 * until the new id appears and then replaces the whole list) and this broadcast. When
 * the refetch lands first the list already holds the record, and an unconditional
 * append put a SECOND copy of it on the patient's Questionnaire Responses page -
 * observed 2026-08-20: one submission, one resource on the server at `versionId: 1`,
 * two identical rows on screen, and a reload showed one. Nothing was duplicated in
 * the record; the patient was simply told they had submitted twice.
 *
 * Replacing rather than skipping: the event body is at least as fresh as whatever
 * the refetch returned, so if both are present the broadcast's copy is the one to keep.
 */
                    case 'com.akashichealthrecords.fhir.questionnaireresponse.created':
                        setQuestionnaireResponsesList(prev =>
                            prev.some(p => p.id === questionnaireResponse.id)
                                ? prev.map(p => p.id === questionnaireResponse.id ? questionnaireResponse : p)
                                : [...prev, questionnaireResponse]
                        );
                        break;
                    case 'com.akashichealthrecords.fhir.questionnaireresponse.updated':
                        setQuestionnaireResponsesList(prev =>
                            isArchived(questionnaireResponse)
                                ? prev.filter(p => p.id !== questionnaireResponse.id)
                                : prev.map(p => p.id === questionnaireResponse.id ? questionnaireResponse : p)
                        );
                        break;
                    case 'com.akashichealthrecords.fhir.questionnaireresponse.deleted':
                        setQuestionnaireResponsesList(prev => prev.filter(p => p.id !== questionnaireResponse.id));
                        break;
                }
            }
        };

        subscribe('com.akashichealthrecords.fhir.questionnaireresponse.created', handleQuestionnaireResponseEvent);
        subscribe('com.akashichealthrecords.fhir.questionnaireresponse.updated', handleQuestionnaireResponseEvent);
        subscribe('com.akashichealthrecords.fhir.questionnaireresponse.deleted', handleQuestionnaireResponseEvent);

        return () => {
            unsubscribe('com.akashichealthrecords.fhir.questionnaireresponse.created', handleQuestionnaireResponseEvent);
            unsubscribe('com.akashichealthrecords.fhir.questionnaireresponse.updated', handleQuestionnaireResponseEvent);
            unsubscribe('com.akashichealthrecords.fhir.questionnaireresponse.deleted', handleQuestionnaireResponseEvent);
        };
    }, [patientState, subscribe, unsubscribe, extractReferenceId, questionnaireResponsesList]);
};