// The rule for a required FREE-TEXT field, and where a trimmed value comes from.
//
// React Hook Form's `required: true` tests truthiness, and `" "` is truthy. So every required text box in
// this plugin accepted a value made only of whitespace, and the save succeeded: an empty name is refused
// by the server with a validation dump, a single space is stored. Nothing errored, and every screen that
// lists the resource then rendered a gap where the name should be.
//
// TRIM BEFORE VALIDATING, NEVER AFTER. Validating first and trimming on the way out is the same defect
// with an extra step - the whitespace passes the gate and becomes the empty string the server rejects, so
// the user gets the raw dump instead of a field-level message.
//
// FREE TEXT ONLY. A field whose value comes from a picker (a state code, a status, a coding) cannot hold
// whitespace, and adding this to one buys nothing while implying its options might.

/** The rule a `Controller` should carry instead of a bare `required: true`. */
export const requiredText = {
    required: true,
    validate: (value: string | undefined | null): true | string =>
        (value ?? '').trim().length > 0 ? true : 'Enter a value — spaces alone are not enough.',
};

/**
 * The same rule applied to a field that is required only in some positions - the first address line is
 * required and later ones are not, and an optional line that is left as spaces must still not be stored.
 */
export const requiredTextWhen = (isRequired: boolean) => (
    isRequired ? requiredText : { required: false, validate: () => true as const }
);

/**
 * What to STORE. `undefined` rather than `''` on purpose: an empty string is a value the server refuses
 * with a raw OperationOutcome, while omitting the element says the same thing in FHIR's own terms.
 */
export const trimmedOrUndefined = (value: string | undefined | null): string | undefined => {
    const trimmed = (value ?? '').trim();
    return trimmed.length > 0 ? trimmed : undefined;
};