/**
 * Effective History Filter
 *
 * Filters message arrays to return only "visible" messages,
 * excluding those tagged by condensation or truncation.
 * Supports non-destructive context management where messages
 * are tagged instead of deleted.
 */
import type { ChatMessage } from "../types/index.js";
/**
 * Get the effective (visible) history from a message array.
 *
 * Filters out:
 * - Messages with a condenseParent (replaced by a summary)
 * - Messages with a truncationParent (hidden by truncation)
 *
 * Keeps:
 * - Summary messages (isSummary = true)
 * - Truncation markers (isTruncationMarker = true)
 * - All other untagged messages
 */
export declare function getEffectiveHistory(messages: ChatMessage[]): ChatMessage[];
/**
 * Tag messages for condensation (non-destructive summary).
 *
 * @param messages - Full message array
 * @param fromIndex - Start index of messages to condense
 * @param toIndex - End index (exclusive) of messages to condense
 * @param condenseId - UUID for this condensation group
 * @returns Updated message array with tags applied
 */
export declare function tagForCondensation(messages: ChatMessage[], fromIndex: number, toIndex: number, condenseId: string): ChatMessage[];
/**
 * Tag messages for truncation (non-destructive hiding).
 *
 * @param messages - Full message array
 * @param fromIndex - Start index of messages to truncate
 * @param toIndex - End index (exclusive) of messages to truncate
 * @param truncationId - UUID for this truncation group
 * @returns Updated message array with tags applied
 */
export declare function tagForTruncation(messages: ChatMessage[], fromIndex: number, toIndex: number, truncationId: string): ChatMessage[];
/**
 * Remove condensation tags (rewind).
 * Makes previously condensed messages visible again.
 */
export declare function removeCondensationTags(messages: ChatMessage[], condenseId: string): ChatMessage[];
/**
 * Remove truncation tags (rewind).
 * Makes previously truncated messages visible again.
 */
export declare function removeTruncationTags(messages: ChatMessage[], truncationId: string): ChatMessage[];