/**
 * MT-side derived SharedValue registry (#710).
 *
 * A *derived* SharedValue is computed on the Main Thread from one or more
 * SOURCE SharedValues via a NAMED reducer (`max` / `min` / `sum` / `scale`).
 * It exists to compose SVs without the silent-summation footgun: two
 * `translateY` bindings on one element CONCATENATE (so they SUM — see
 * `animated-bridge-mt.ts`), which is wrong for "sit above whichever of the
 * keyboard or the sheet is taller". `useDerivedValue([kbLift, sheetH], 'max')`
 * yields ONE SV a single `translateY` binds — the max, not the sum.
 *
 * Reducers are selected by NAME, mirroring the mapper registry: a string is a
 * primitive the BG→MT op layer ships trivially, whereas an arbitrary reducer
 * function can't be captured into the flush loop (the loop is plain MT code,
 * not a worklet). Custom reducers register via `registerReducer`.
 *
 * `flushDerivedValues()` runs FIRST inside the wrapped `__FlushElementTree`
 * (before publishes and style bindings): for each derived whose sources
 * changed since the last compute, it folds the live source values through the
 * reducer and writes the result onto the derived SV's envelope. Because that
 * write lands before `flushAnimatedStyleBindings`, a `useAnimatedStyle` bound
 * to the derived sees the fresh value the SAME frame; because the derived SV
 * is itself a registered auto-flush bridge, `flushAvBridgePublishes` also
 * ships the new value to BG.
 */
import type { DerivedReducer } from '@sigx/lynx-runtime-internal';
/** Look up a reducer by name; `undefined` → the derived recompute is skipped. */
export declare function lookupReducer(name: string): DerivedReducer | undefined;
/** Register a custom MT-side reducer (last write wins per name). */
export declare function registerReducer(name: string, reducer: DerivedReducer): void;
/** Reset hook — restore exactly the built-ins (drops custom reducers AND
 * any that overrode a built-in name) for HMR / tests. */
export declare function resetReducers(): void;
/**
 * Register (or, for the same `derivedWvid`, RE-register) a derived value.
 * Re-registration swaps the reducer/params/sources while keeping the derived
 * SV identity — this is how a reactive factor (e.g. the active sheet's travel)
 * rebinds without breaking the consumers already bound to the derived SV.
 */
export declare function registerDerivedValue(derivedWvid: number, reducerName: string, params: unknown, sourceWvids: number[]): void;
export declare function unregisterDerivedValue(derivedWvid: number): void;
export declare function resetDerivedValues(): void;
export declare function derivedValueCount(): number;
/**
 * Recompute every derived whose source values changed since the last flush,
 * writing the result onto the derived SV's envelope. Runs before the style
 * bindings and the BG publish so downstream consumers see the fresh value the
 * same frame. Skip cases are silent: a missing source/derived envelope (race
 * with unregister) or an unknown reducer name.
 */
export declare function flushDerivedValues(): void;