// SPDX-FileCopyrightText: Copyright Orangebot, Inc. and Medplum contributors
// SPDX-License-Identifier: Apache-2.0
import type { MedplumClient } from '@medplum/core';
import { deepEquals, isReference, isResource, normalizeOperationOutcome } from '@medplum/core';
import type { OperationOutcome, Reference, Resource } from '@medplum/fhirtypes';
import { useCallback, useEffect, useState } from 'react';
import { useMedplum } from '../MedplumProvider/MedplumProvider.context';
/**
* React Hook to use a FHIR reference.
* Handles the complexity of resolving references and caching resources.
* @param value - The resource or reference to resource.
* @param setOutcome - Optional callback to set the OperationOutcome.
* @returns The resolved resource.
*/
export function useResource<T extends Resource>(
value: Reference<T> | Partial<T> | undefined,
setOutcome?: (outcome: OperationOutcome) => void
): T | undefined {
const medplum = useMedplum();
const [resource, setResource] = useState<T | undefined>(() => {
return getInitialResource(medplum, value);
});
const setResourceIfChanged = useCallback(
(r: T | undefined) => {
if (!deepEquals(r, resource)) {
setResource(r);
}
},
[resource]
);
useEffect(() => {
let subscribed = true;
const newValue = getInitialResource(medplum, value);
if (!newValue && isReference(value)) {
medplum
.readReference(value as Reference<T>)
.then((r) => {
if (subscribed) {
setResourceIfChanged(r);
}
})
.catch((err) => {
if (subscribed) {
setResourceIfChanged(undefined);
if (setOutcome) {
setOutcome(normalizeOperationOutcome(err));
}
}
});
} else {
setResourceIfChanged(newValue);
}
return (() => (subscribed = false)) as () => void;
}, [medplum, value, setResourceIfChanged, setOutcome]);
return resource;
}
/**
* Returns the initial resource value based on the input value.
* If the input value is a resource, returns the resource.
* If the input value is a reference to a resource available in the cache, returns the resource.
* Otherwise, returns undefined.
* @param medplum - The medplum client.
* @param value - The resource or reference to resource.
* @returns An initial resource if available; undefined otherwise.
*/
function getInitialResource<T extends Resource>(
medplum: MedplumClient,
value: Reference<T> | Partial<T> | undefined
): T | undefined {
if (value) {
if (isResource(value)) {
return value as T;
}
if (isReference(value)) {
return medplum.getCachedReference(value as Reference<T>);
}
}
return undefined;
}
