import { useEffect } from 'react';
import { PractitionerRole } from 'fhir/r4';
import {
    usePractitionerServiceContext,
    useFhirServiceContext,
    useWebSocketServiceContext
} from '../services';

export const useFhirPractitionerRoleBroadcast = () => {
    const { subscribe, unsubscribe } = useWebSocketServiceContext();
    const { setPractitionersList } = usePractitionerServiceContext();
    const { extractReferenceId } = useFhirServiceContext();

    useEffect(() => {
        const handlePractitionerRoleEvent = (cloudEvent: any) => {
            const practitionerRole: PractitionerRole = cloudEvent.data;
            const eventType = cloudEvent.type;
            const practitionerId = extractReferenceId(practitionerRole.practitioner);

            if (practitionerId) {
                setPractitionersList(prev => {
                    return prev.map(practitionerWithRoles => {
                        if (practitionerWithRoles.practitioner.id === practitionerId) {
                            switch (eventType) {
                                case 'com.akashichealthrecords.fhir.practitionerrole.created':
                                    // Same race as every other created append: the staff list
                                    // also refetches after a write, so a role the refetch already brought
                                    // in was being added a second time - the same person listed twice
                                    // under one practitioner. The `updated` arm below already keys on id.
                                    return {
                                        ...practitionerWithRoles,
                                        roles: practitionerWithRoles.roles.some(role => role.id === practitionerRole.id)
                                            ? practitionerWithRoles.roles.map(role => role.id === practitionerRole.id ? practitionerRole : role)
                                            : [...practitionerWithRoles.roles, practitionerRole]
                                    };
                                case 'com.akashichealthrecords.fhir.practitionerrole.updated':
                                    return {
                                        ...practitionerWithRoles,
                                        roles: practitionerWithRoles.roles.map(role => role.id === practitionerRole.id ? practitionerRole : role)
                                    };
                                case 'com.akashichealthrecords.fhir.practitionerrole.deleted':
                                    return {
                                        ...practitionerWithRoles,
                                        roles: practitionerWithRoles.roles.filter(role => role.id !== practitionerRole.id)
                                    };
                                    return practitionerWithRoles;
                            }
                        }
                        return practitionerWithRoles;
                    });
                });
            }
        };

        subscribe('com.akashichealthrecords.fhir.practitionerrole.created', handlePractitionerRoleEvent);
        subscribe('com.akashichealthrecords.fhir.practitionerrole.updated', handlePractitionerRoleEvent);
        subscribe('com.akashichealthrecords.fhir.practitionerrole.deleted', handlePractitionerRoleEvent);

        return () => {
            unsubscribe('com.akashichealthrecords.fhir.practitionerrole.created', handlePractitionerRoleEvent);
            unsubscribe('com.akashichealthrecords.fhir.practitionerrole.updated', handlePractitionerRoleEvent);
            unsubscribe('com.akashichealthrecords.fhir.practitionerrole.deleted', handlePractitionerRoleEvent);
        };
    }, [subscribe, unsubscribe, extractReferenceId, setPractitionersList]);
};