/**
 * WHAT A PERSON TYPED INTO THE STATE FIELD, RESOLVED TO A STATE - or nothing.
 *
 * The address form's State control is a WordPress `ComboboxControl`, which keeps the typed text in its
 * own internal filter state and calls `onChange` ONLY when a suggestion is clicked. So typing `IL` and
 * pressing Save refused with "State is required" **while the field visibly contained IL** - the user
 * looking straight at the value the form said was missing. Every other address field is a plain bound
 * input; this was the one control that accepted keystrokes and threw them away.
 *
 * EXACT MATCHES ONLY, and that is the whole safety argument. A prefix match would resolve `M` to
 * whichever of Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri or Montana
 * happens to sort first, and silently write it into an address. Guessing a state on somebody's
 * behalf is worse than the defect being fixed: a wrong address that saves is not recoverable by
 * looking at the screen, which is exactly the property that made the original bug so hard to reason
 * about.
 *
 * Three spellings are accepted because all three are things a person actually types into a field
 * labelled State: the code, the full name, and the label the dropdown itself shows them.
 */
export interface UspsStateOption {
    code?: string;
    display?: string;
}

const normalise = (value: string): string => value.trim().toLowerCase();

export const matchUspsState = (
    options: UspsStateOption[],
    typed: string | undefined,
): UspsStateOption | undefined => {
    const needle = normalise(typed ?? '');
    if (!needle) return undefined;

    return options.find((option) => {
        const code = normalise(option.code ?? '');
        const display = normalise(option.display ?? '');
        // The dropdown renders "Illinois (IL)", so somebody copying what they saw types that.
        const label = code && display ? `${display} (${code})` : '';

        return (Boolean(code) && needle === code)
            || (Boolean(display) && needle === display)
            || (Boolean(label) && needle === label);
    });
};