/**
 * createRadioGroup - the HEADLESS core behind <SvRadioGroup>: an accessible
 * single-select radio group (WAI-ARIA `radiogroup`) with roving tabindex + full
 * arrow-key navigation, exposed as **prop-getters** you spread onto YOUR OWN
 * markup. Keyboard/ARIA/roving-focus come from the core, the DOM is yours.
 *
 * ```svelte
 * <script lang="ts">
 *   import { createRadioGroup, type RadioOption } from '@svgrid/grid'
 *   let value = $state<string | number | null>('a')
 *   const rg = createRadioGroup({ options: () => options, value: () => value, onChange: (v) => (value = v) })
 * </script>
 * <div {...rg.groupProps()}>
 *   {#each options as opt (opt.value)}
 *     <button {...rg.radioProps(opt)}>{opt.label}</button>
 *   {/each}
 * </div>
 * ```
 *
 * The styled <SvRadioGroup> is just one renderer over this core.
 */
export type RadioOption = {
    value: string | number;
    label: string;
    disabled?: boolean;
};
/** Reactive inputs are passed as getters so the core tracks live prop changes. */
export type RadioGroupConfig = {
    options: () => ReadonlyArray<RadioOption>;
    value: () => string | number | null;
    onChange?: (value: string | number) => void;
    disabled?: () => boolean;
    ariaLabel?: () => string | undefined;
    id?: () => string | undefined;
    invalid?: () => boolean;
    required?: () => boolean;
    error?: () => string | undefined;
    hint?: () => string | undefined;
};
export type RadioProps = {
    type: 'button';
    role: 'radio';
    'aria-checked': boolean;
    'data-idx': number;
    'data-checked': '' | undefined;
    disabled: boolean;
    tabindex: number;
    onclick: () => void;
};
export type RadioGroupProps = {
    role: 'radiogroup';
    id: string | undefined;
    'aria-label': string | undefined;
    'aria-invalid': 'true' | undefined;
    'aria-required': 'true' | undefined;
    'aria-describedby': string | undefined;
    'aria-disabled': boolean;
    onkeydown: (e: KeyboardEvent) => void;
};
export type RadioGroup = {
    /** Currently selected value. */
    readonly value: string | number | null;
    readonly disabled: boolean;
    isChecked: (option: RadioOption) => boolean;
    /** Select by value (no-op when disabled / option disabled / unknown). */
    select: (value: string | number) => void;
    onKeydown: (e: KeyboardEvent) => void;
    /** Spread onto the group container element. */
    groupProps: () => RadioGroupProps;
    /** Spread onto each option element. */
    radioProps: (option: RadioOption) => RadioProps;
};
export declare function createRadioGroup(config: RadioGroupConfig): RadioGroup;