import { type UnitConfig } from './config';
import { type TemperatureUnit } from './units';
/** Construction options: any {@link UnitConfig} field plus an explicit seed. */
export type UnitStateOptions = Partial<UnitConfig> & {
    /** Force the initial unit (e.g. an explicit SSR value). */
    initial?: TemperatureUnit;
};
export declare class TemperatureUnitState {
    #private;
    /** The active unit. Reactive — reading it in markup/`$derived` auto-updates. */
    current: TemperatureUnit;
    /** Resolved configuration (names/knobs). */
    readonly config: UnitConfig;
    constructor(options?: UnitStateOptions);
    /** Set the unit explicitly: persist, update the attribute, notify others. */
    set(unit: TemperatureUnit): void;
    /** Flip to the other unit and persist. */
    toggle(): void;
    /** Remove the window listener (teardown for tests/short-lived hosts). */
    destroy(): void;
    /** Degree suffix for the active unit, e.g. `°F`. */
    get suffix(): string;
    /** Convert an absolute Celsius value to the active unit. */
    toDisplay(celsius: number): number;
    /** Convert a Celsius delta (anomaly) to the active unit. */
    toDisplayDelta(celsius: number): number;
}
/** Provide a state instance to descendants via Svelte context. */
export declare function setUnitContext(state: TemperatureUnitState): TemperatureUnitState;
/**
 * Read the nearest provided state, falling back to the shared default singleton
 * when no provider is present (so the components work with zero setup).
 */
export declare function getUnitContext(): TemperatureUnitState;
/** Shared, app-wide state used when no context provider is set. */
export declare const defaultUnitState: TemperatureUnitState;