import type { V2Store } from './store-facade.js';
/**
 * A segment selected for extraction. Contains everything the caller needs to
 * fetch unextracted events and write the marker afterward.
 *
 * Unextracted events in this segment:
 *   `seq > fromSeqExclusive AND seq >= from_seq AND seq <= toSeqInclusive`
 */
export interface SelectedSegment {
    /** Which session this binding belongs to. */
    session_id: string;
    /** The `from_seq` of the binding row — start of this segment. */
    from_seq: number;
    /**
     * `last_extracted_seq` from `segment_extractions` (0 if no marker exists).
     * Callers use `seq > fromSeqExclusive` to skip already-extracted events.
     * Note: this may be less than `from_seq` for never-extracted segments
     * that are not the first segment of a session.
     */
    fromSeqExclusive: number;
    /**
     * Upper bound of this segment (inclusive):
     *   - closed segment: `to_seq`
     *   - open segment:   `MAX(seq)` of events for this session_id
     */
    toSeqInclusive: number;
}
export interface SelectOptions {
    /** The session_id of the currently-active session (open binding). */
    currentSessionId: string;
    /** Only consider bindings for this project_uid. */
    projectUid: string;
    /**
     * Minimum unextracted event count for the CURRENT segment to be eligible.
     * Backlog segments only need `unextracted > 0`.
     * Default: 20.
     */
    cadence?: number;
    /**
     * Maximum number of segments to return. Current segment counts toward cap.
     * Default: 10.
     */
    cap?: number;
}
/**
 * Select segments eligible for checkpoint extraction this run.
 *
 * Selection rules (deterministic, pure read):
 *  1. Scope to `projectUid` only.
 *  2. For each candidate compute `unextracted = #events with seq > last_extracted_seq`
 *     within the segment's `[from_seq .. toSeqInclusive]` range.
 *  3. Current segment (`session_id === currentSessionId AND to_seq IS NULL`):
 *     eligible iff `unextracted >= cadence`.
 *  4. Backlog segments (all others in the project): eligible iff `unextracted > 0`.
 *  5. Segments with `unextracted === 0` are skipped entirely.
 *  6. Order: current first (if eligible), then backlog by `sessions.updated_at DESC`,
 *     tiebroken by `(session_id, from_seq)` ASC for determinism.
 *  7. Return at most `cap` segments total.
 */
export declare function selectSegmentsForExtraction(store: V2Store, opts: SelectOptions): SelectedSegment[];