import type { DocumentReference } from 'fhir/r4';

// An outside original filed from Records keeps the file it denotes and its binding to the source it was copied from.
// The server enforces this; the client neither offers to replace or remove that file nor drops the binding on an edit.

const AHR = 'https://akashichealthrecords.com/fhir';
export const RECORDS_INTAKE_SYSTEM = AHR + '/records-intake';
export const RECORDS_SOURCE_EXTENSION = AHR + '/StructureDefinition/records-intake-source';

/** Whether a stored document is a filed Records original: any trace of the filing makes it one. */
export const isFiledOriginal = (document: DocumentReference | undefined | null): boolean =>
    Boolean(document) && (
        (document!.identifier ?? []).some((identifier) => identifier?.system === RECORDS_INTAKE_SYSTEM)
        || (document!.extension ?? []).some((extension) => extension?.url === RECORDS_SOURCE_EXTENSION)
        || (typeof document!.id === 'string' && document!.id.startsWith('ri-'))
    );

/** An edit of a filed original, carrying its stored file and source binding over whatever the form rebuilt. */
export function keepFiledLineage(stored: DocumentReference | undefined | null, edit: DocumentReference): DocumentReference {
    if (!stored || !isFiledOriginal(stored)) return edit;
    const identifier = [
        ...(edit.identifier ?? []).filter((item) => item?.system !== RECORDS_INTAKE_SYSTEM),
        ...(stored.identifier ?? []).filter((item) => item?.system === RECORDS_INTAKE_SYSTEM),
    ];
    const extension = [
        ...(edit.extension ?? []).filter((item) => item?.url !== RECORDS_SOURCE_EXTENSION),
        ...(stored.extension ?? []).filter((item) => item?.url === RECORDS_SOURCE_EXTENSION),
    ];
    // Every Records marker comes from what is stored, including when nothing is: the form's own marker never survives.
    const { identifier: _sentIdentifiers, extension: _sentExtensions, ...rest } = edit;
    return {
        ...rest,
        content: stored.content,
        ...(identifier.length > 0 ? { identifier } : {}),
        ...(extension.length > 0 ? { extension } : {}),
    };
}

export const FILED_ORIGINAL_FILE_NOTE =
    'This is an outside original filed from Records, so its file is kept as received. To correct it, add a separate document.';