import type { PackumentVersion, RegistryAdapter } from '../registry/types.js';
import type { RejectedCandidate } from './diagnostics.js';
export type Awaitable<T> = T | Promise<T>;
export type Verdict = {
    ok: true;
} | {
    ok: false;
    reason?: string;
} | {
    ok: 'unevaluable';
    reason?: string;
};
export interface ConditionContext {
    readonly name: string;
    readonly version: string;
    readonly corgi: PackumentVersion;
    manifest(): Promise<PackumentVersion | undefined>;
    readonly registry: RegistryAdapter;
}
export interface Condition {
    readonly kind: string;
    readonly cost?: number;
    evaluate(ctx: ConditionContext): Awaitable<Verdict>;
}
export type OnUnevaluable = 'reject' | 'accept';
export interface SelectResult {
    selected?: PackumentVersion;
    rejected: RejectedCandidate[];
}
export declare function engines(required: Record<string, string>, opts?: {
    mode?: 'lenient' | 'strict';
}): Condition;
export declare function license(policy: {
    allow?: readonly string[];
    deny?: readonly string[];
}): Condition;
export declare function selectConstrained(registry: RegistryAdapter, name: string, range: string, constraints: readonly Condition[], onUnevaluable: OnUnevaluable): Promise<SelectResult>;
export declare function constrainedCandidates(registry: RegistryAdapter, name: string, range: string, constraints: readonly Condition[], onUnevaluable: OnUnevaluable): AsyncGenerator<{
    version: string;
    node: PackumentVersion;
}>;