/**
 * MapReduce — fan-out N LLMCalls over deterministic input shards, reduce.
 *
 * Origin: classic map-reduce (Dean & Ghemawat, 2004) applied to
 *         LLM context-window constraints. Seen in long-document
 *         summarization: split → summarize each → combine.
 *
 * Pattern: Factory → produces a Runner composing `Parallel` of N
 *          shard-aware branches. Each branch is an LLMCall wrapped so it
 *          extracts its shard index from the input by position.
 * Role:    patterns/ layer. Pure composition over existing primitives.
 *
 * Shard count is fixed at build time — consumer supplies `shardCount`
 * and a `split(input, shardCount)` function that MUST return exactly
 * `shardCount` strings. The extracted strings are packed into one
 * `message` at run time (delimiter `\u001F`) so each branch can pick
 * its own index. For run-time-variable shard counts, factor MapReduce
 * inside a wrapping Runner that rebuilds the Parallel per call.
 */
import type { LLMProvider } from '../provider-contract/types.js';
import type { Runner } from '../core/runner.js';
import type { MergeFn, MergeWithLLMOptions } from '../core-flow/Parallel.js';
export interface MapReduceOptions {
    readonly provider: LLMProvider;
    readonly model: string;
    /** System prompt applied to every shard's LLMCall. */
    readonly mapPrompt: string;
    /**
     * Number of shards to fan out. Must be >= 2 (for one-shard, use
     * `LLMCall` directly). Fixed at build time.
     */
    readonly shardCount: number;
    /**
     * Splitter invoked at run time with `(input, shardCount)`. MUST return
     * exactly `shardCount` strings. If it returns fewer, remaining shards
     * receive empty strings; more are truncated.
     */
    readonly split: (input: string, shardCount: number) => readonly string[];
    /**
     * Reducer — either a pure fn combining the N shard outputs, OR an LLM
     * synthesizer.
     */
    readonly reduce: {
        readonly kind: 'fn';
        readonly fn: MergeFn;
    } | {
        readonly kind: 'llm';
        readonly opts: MergeWithLLMOptions;
    };
    readonly temperature?: number;
    readonly maxTokens?: number;
    readonly name?: string;
    readonly id?: string;
}
/**
 * Build a MapReduce Runner. At run time:
 *   1. The splitter runs the consumer's `split(input, shardCount)` and
 *      packs the resulting N shards into a delimited string.
 *   2. Parallel fans out to N branches. Each branch's wrapper extracts
 *      its own shard from the packed input and feeds it to the shared
 *      LLMCall.
 *   3. The reducer combines the N branch outputs into the final string.
 */
export declare function mapReduce(opts: MapReduceOptions): Runner<{
    message: string;
}, string>;