/**
 * @copyright Sister Software
 * @license AGPL-3.0
 * @author Teffen Ellis, et al.
 * @file Route an already-written overlay parquet through the holdout policy.
 *
 * A parquet row has no `components` map, so each component is read back from `raw` over the `span_starts` /
 * `span_ends` / `span_tags` triple that `alignRow` wrote.
 */
import { type PathBuilderLike } from "path-ts";
import type { CanonicalRow } from "#types";
import { type CountryHoldout, type SplitName } from "#utils/split";
/**
 * The fields {@linkcode holdoutComponents} reads, with the span triple optional
 * so the absent-triple refusal is reachable from a test rather than only from a corrupt file.
 */
export interface SpannedRow {
    raw: string;
    source_id: string;
    span_starts?: readonly number[];
    span_ends?: readonly number[];
    span_tags?: readonly string[];
}
/**
 * Read the components a holdout decision needs back out of one labeled row.
 *
 * Raises on an absent or non-parallel span triple, because treating an unreadable row
 * as one with no held-out component would put it in the train split.
 */
export declare function holdoutComponents(row: SpannedRow, index: number, input: string): CanonicalRow["components"];
export interface SplitSliceOptions {
    /**
     * The parquet to route.
     * Its rows are read once and held per split in memory.
     */
    input: PathBuilderLike;
    /**
     * Where the per-split parquets are written.
     * Each filename combines the input and its split.
     */
    outputDir: PathBuilderLike;
    /**
     * Defaults to `defaultHoldouts()`, which is the policy the base build applies.
     */
    holdouts?: Record<string, CountryHoldout>;
}
export interface SplitSliceResult {
    input: string;
    rows: number;
    counts: Record<SplitName, number>;
    /**
     * The file written per split.
     *
     * A split with zero rows has no output file.
     * An empty parquet would suggest that the writer lost its rows.
     */
    outputs: Partial<Record<SplitName, string>>;
}
/**
 * Split one overlay parquet into up to three, by the same policy the base build applies.
 *
 * Each output filename combines the input name and split name.
 * The function leaves the input file in place.
 */
export declare function splitOverlaySlice(options: SplitSliceOptions): Promise<SplitSliceResult>;
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