import { GpuComputeNode, GpuFragmentParams } from '../../gpu/contract';
import { SimBindContext, SimSize, SimSlot, SimTick } from '../../gpu/scaffolds/feedbackSim';

/** The TypeGPU root, via the contract (direct `typegpu` imports are restricted to src/gpu/). */
export type FeedbackRoot = NonNullable<GpuFragmentParams['gpu']>['root'];
/** A 2D-dispatched TGSL kernel over the state grid. */
export type FeedbackKernel = (cx: number, cy: number) => void;
/** What the bind-group builders get: the scaffold's context plus the params uniform's buffer. */
export type FeedbackBindContext = SimBindContext & {
    paramsBuffer: unknown;
};
export interface FeedbackSimConfig<TParams, TGroups> {
    /** State + display resolution per axis (square — both current consumers' shape). */
    size: number;
    format: 'rgba16float' | 'rgba32float';
    /** Extra texture pairs swapping in lockstep with the state (TimeTrail's prev-live copy). */
    extraSlots?: Record<string, SimSize>;
    /** Orientation-independent extra textures. */
    textures?: Record<string, SimSize>;
    /** Prop whose value scales `dt`. */
    speedProp?: string;
    maxDeltaTime?: number;
    /** The shader's per-frame params struct — the noun owns its uniform. */
    paramsSchema: unknown;
    /** Build one orientation's bind groups (called twice, late, by the scaffold). */
    bindGroups: (ctx: FeedbackBindContext, read: SimSlot, write: SimSlot) => TGroups;
    /** Build orientation-independent bind groups (called once, late). */
    staticGroups?: (ctx: FeedbackBindContext) => unknown;
    /**
     * The state-advance kernel — ONE kernel per step, compile-time variant selected in the build
     * callback. Splitting a step into several kernels is a different simulation (and different
     * WGSL); a shader that needs a multi-dispatch step should not ride this noun's default frame.
     */
    step: FeedbackKernel;
    /** Idle-gate policy: true → skip the frame entirely (the scaffold then skips the swap too). */
    skip?: (t: SimTick<TGroups, unknown>) => boolean;
    /** The per-frame params derivation — the one runtime surface. Written before the dispatch. */
    values: (t: SimTick<TGroups, unknown>) => TParams;
    /** Extra `outputs` entries beyond the scaffold's childTexture/display. */
    outputs?: Record<string, unknown>;
}
/**
 * The feedback-simulation noun. Spread it into a definition: `...feedbackSim((params, root) => ({...}))`.
 *
 * Requires a child (these are all child-consuming echo/decoder effects): bails to `null` (fragment
 * passthrough) without one, without a device, or when the scaffold cannot allocate.
 */
export declare function feedbackSim<TParams, TGroups = unknown>(build: (params: GpuFragmentParams, root: FeedbackRoot) => FeedbackSimConfig<TParams, TGroups>): {
    compute: GpuComputeNode;
};
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