import type { ExecutionDetails } from "../index.ts";
import type { GrafastResultsList, Maybe, PromiseOrDirect, Thunk } from "../interfaces.ts";
import type { Multistep, UnwrapMultistep } from "../multistep.ts";
import { Step } from "../step.ts";
import type { IOEquivalence } from "./_loadCommon.ts";
export interface LoadOneInfo<TItem, TParams extends Record<string, any>, TShared = never> {
    shared: TShared;
    attributes: ReadonlyArray<keyof TItem>;
    params: Partial<TParams>;
    /** @deprecated Please use 'shared' instead. It's simply renamed */
    unary: TShared;
}
export type LoadOneCallback<TSpec, TItem, TData extends Maybe<TItem> = Maybe<TItem>, TParams extends Record<string, any> = Record<string, any>, TUnarySpec = never> = {
    (specs: ReadonlyArray<TSpec>, info: LoadOneInfo<TItem, TParams, TUnarySpec>): PromiseOrDirect<ReadonlyArray<TData>>;
    displayName?: string;
};
/**
 * A TypeScript Identity Function to help you strongly type your
 * LoadOneCallback.
 */
export declare function loadOneCallback<TSpec, TItem, TData extends Maybe<TItem> = Maybe<TItem>, TParams extends Record<string, any> = Record<string, any>, TUnarySpec = never>(load: LoadOneCallback<TSpec, TItem, TData, TParams, TUnarySpec>): LoadOneCallback<TSpec, TItem, TData, TParams, TUnarySpec>;
/**
 * A TypeScript Identity Function to help you strongly type your
 * LoadOneLoader.
 */
export declare function loadOneLoader<TSpec, TItem, TData extends Maybe<TItem> = Maybe<TItem>, TParams extends Record<string, any> = Record<string, any>, TShared extends Multistep = never>(load: LoadOneLoader<TSpec, TItem, TData, TParams, TShared>): LoadOneLoader<TSpec, TItem, TData, TParams, TShared>;
export declare class LoadOneStep<const TLookup extends Multistep, TItem, TData extends Maybe<TItem>, TParams extends Record<string, any>, const TShared extends Multistep = never> extends Step<TData> {
    static $$export: {
        moduleName: string;
        exportName: string;
    };
    isSyncAndSafe: boolean;
    loadInfo: Omit<LoadOneInfo<TItem, TParams, UnwrapMultistep<TShared>>, "shared" | "unary" | "params"> | null;
    loadInfoKey: string;
    attributes: Set<keyof TItem>;
    paramDepIdByKey: {
        [TKey in keyof TParams]: number;
    };
    sharedDepId: number | null;
    private ioEquivalence;
    private load;
    private name;
    constructor(lookup: TLookup, loader: LoadOneLoader<UnwrapMultistep<TLookup>, TItem, TData, TParams, TShared>);
    toStringMeta(): string | null;
    private _accessMap;
    private getAccessMap;
    setParam<TParamKey extends keyof TParams>(paramKey: TParamKey, value: TParams[TParamKey] | Step<TParams[TParamKey]>): void;
    addAttributes(attributes: Set<keyof TItem>): void;
    deduplicate(peers: readonly LoadOneStep<any, any, any, any, any>[]): LoadOneStep<any, any, any, any, any>[];
    deduplicatedWith(replacement: LoadOneStep<any, any, any, any, any>): void;
    _paramSig?: string;
    getParamSignature(): string;
    finalize(): void;
    execute(details: ExecutionDetails): PromiseOrDirect<GrafastResultsList<TData>>;
    get(attr: keyof TItem & (string | number)): Step<any>;
    private _getInner;
}
export interface LoadOneLoader<TSpec, TItem, TData extends Maybe<TItem> = Maybe<TItem>, TParams extends Record<string, any> = Record<string, any>, TShared extends Multistep = never> {
    /**
     * The function that actually loads data from the backend
     */
    load: LoadOneCallback<TSpec, TItem, TData, TParams, UnwrapMultistep<TShared>>;
    /** Name your function (for plan diagrams/debugging) */
    name?: string;
    /**
     * Details of anything your `load` function will need access to, for example
     * database connections, API clients, etc.
     */
    shared?: Thunk<TShared>;
    /**
     * Details of which attributes on the output are equivalent to those on the
     * input (if any), useful for reducing unnecessary fetches (e.g. load the
     * friends of a user by their id without ever loading the user).
     */
    ioEquivalence?: IOEquivalence<TSpec>;
}
/**
 * Loads an individual record identified by the `lookup` using the `loader`.
 *
 * @param lookup - A step/multistep representing the value to look up - could be an
 * identifier or combination of identifiers.
 * @param loader - The function to load this, or a LoadManyLoader object containing such a function
 */
export declare function loadOne<const TLookup extends Multistep, TItem, TData extends Maybe<TItem> = Maybe<TItem>, TParams extends Record<string, any> = Record<string, any>, const TShared extends Multistep = never>(lookup: TLookup, loader: LoadOneCallback<UnwrapMultistep<TLookup>, TItem, TData, TParams, never> | LoadOneLoader<UnwrapMultistep<TLookup>, TItem, TData, TParams, TShared>): LoadOneStep<UnwrapMultistep<TLookup>, TItem, TData, TParams, TShared>;
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