import { useEffect } from 'react';
import { Communication, CommunicationRequest } from 'fhir/r4';
import {
    useCommunicationServiceContext,
    useAuthServiceContext,
    useWebSocketServiceContext
} from '../services';

interface FhirCloudEvent<T> {
    data: T;
    type: string;
}

export const useFhirCommunicationBroadcast = () => {
    const { subscribe, unsubscribe } = useWebSocketServiceContext();
    const {
        currentUser,
        userRole,
        selectedWorkspace,
        USER_ROLES,
    } = useAuthServiceContext();
    const {
        addCommunicationToState,
        updateCommunicationInState,
        deleteCommunicationFromState,
        addCommunicationRequestToState,
        updateCommunicationRequestInState,
        deleteCommunicationRequestFromState
    } = useCommunicationServiceContext();

    const effectiveUserRole = selectedWorkspace ?? userRole;
    const communicationAllowed = Boolean(
        effectiveUserRole &&
        effectiveUserRole !== USER_ROLES.PLATFORM_MANAGER
    );

    useEffect(() => {
        if (!currentUser?.fhir || !communicationAllowed) {
            return;
        }

        const currentUserReference = `${currentUser.fhir.resourceType}/${currentUser.fhir.id}`;

        const isUserInvolved = (communication: Communication): boolean => {
            const senderRef = communication.sender?.reference;
            const recipientRefs = communication.recipient?.map(r => r.reference) || [];

            return senderRef === currentUserReference || recipientRefs.includes(currentUserReference);
        };

        const isUserInvolvedInRequest = (request: CommunicationRequest): boolean => {
            const senderRef = request.sender?.reference;
            const recipientRefs = request.recipient?.map(r => r.reference) || [];

            return senderRef === currentUserReference || recipientRefs.includes(currentUserReference);
        };

        const handleCommunicationEvent = (cloudEvent: FhirCloudEvent<Communication>) => {
            const communication: Communication = cloudEvent.data;
            const eventType = cloudEvent.type;

            if (!isUserInvolved(communication)) {
                return;
            }

            switch (eventType) {
                case 'com.akashichealthrecords.fhir.communication.created':
                    addCommunicationToState(communication);
                    break;
                case 'com.akashichealthrecords.fhir.communication.updated':
                    updateCommunicationInState(communication);
                    break;
                case 'com.akashichealthrecords.fhir.communication.deleted':
                    deleteCommunicationFromState(communication);
                    break;
            }
        };

        const handleCommunicationRequestEvent = (cloudEvent: FhirCloudEvent<CommunicationRequest>) => {
            const communicationRequest: CommunicationRequest = cloudEvent.data;
            const eventType = cloudEvent.type;

            if (!isUserInvolvedInRequest(communicationRequest)) {
                return;
            }

            switch (eventType) {
                case 'com.akashichealthrecords.fhir.communicationrequest.created':
                    addCommunicationRequestToState(communicationRequest);
                    break;
                case 'com.akashichealthrecords.fhir.communicationrequest.updated':
                    updateCommunicationRequestInState(communicationRequest);
                    break;
                case 'com.akashichealthrecords.fhir.communicationrequest.deleted':
                    deleteCommunicationRequestFromState(communicationRequest.id as string);
                    break;
            }
        };

        subscribe('com.akashichealthrecords.fhir.communication.created', handleCommunicationEvent);
        subscribe('com.akashichealthrecords.fhir.communication.updated', handleCommunicationEvent);
        subscribe('com.akashichealthrecords.fhir.communication.deleted', handleCommunicationEvent);

        subscribe('com.akashichealthrecords.fhir.communicationrequest.created', handleCommunicationRequestEvent);
        subscribe('com.akashichealthrecords.fhir.communicationrequest.updated', handleCommunicationRequestEvent);
        subscribe('com.akashichealthrecords.fhir.communicationrequest.deleted', handleCommunicationRequestEvent);

        return () => {
            unsubscribe('com.akashichealthrecords.fhir.communication.created', handleCommunicationEvent);
            unsubscribe('com.akashichealthrecords.fhir.communication.updated', handleCommunicationEvent);
            unsubscribe('com.akashichealthrecords.fhir.communication.deleted', handleCommunicationEvent);

            unsubscribe('com.akashichealthrecords.fhir.communicationrequest.created', handleCommunicationRequestEvent);
            unsubscribe('com.akashichealthrecords.fhir.communicationrequest.updated', handleCommunicationRequestEvent);
            unsubscribe('com.akashichealthrecords.fhir.communicationrequest.deleted', handleCommunicationRequestEvent);
        };
    }, [
        currentUser,
        communicationAllowed,
        subscribe,
        unsubscribe,
        addCommunicationToState,
        updateCommunicationInState,
        deleteCommunicationFromState,
        addCommunicationRequestToState,
        updateCommunicationRequestInState,
        deleteCommunicationRequestFromState
    ]);
};