/**
 * Monthly Chunk Generator
 *
 * Groups messages by calendar month and generates fingerprints for deduplication.
 * See project_docs/CHAT_FINGERPRINTING.md for algorithm details.
 *
 * CRITICAL: Fingerprints do NOT include timestamps.
 * WhatsApp exports are not idempotent - same message can have different timestamps
 * across exports (±1-2 seconds drift). Identity comes from:
 * - Who said what (sender + content)
 * - In what order (first N messages of the month)
 * - How many messages (count detects partial uploads)
 */
import type { ParsedMessage } from '../types/parser';
import type { FingerprintConfig, MonthlyChunk } from './types';
/**
 * Get the UTC month start date for a timestamp.
 * Returns the first day of the month at 00:00:00 UTC.
 */
export declare function getMonthStart(timestamp: Date): Date;
/**
 * Get a sortable month key in "YYYY-MM" format.
 */
export declare function getMonthKey(timestamp: Date): string;
/**
 * Generate a SHA-256 fingerprint for a monthly chunk.
 *
 * The fingerprint is based on:
 * - Month key (YYYY-MM format)
 * - Message count (for detecting partial exports)
 * - First N messages (sender + content ONLY - no timestamps!)
 *
 * CRITICAL: Timestamps are NOT included in the fingerprint.
 * WhatsApp exports are not idempotent - the same message can have different
 * timestamps across exports (±1-2 seconds drift between iOS/Desktop/etc).
 * Identity comes from: who said what, in what order.
 *
 * @param monthMessages - All messages in this month
 * @param monthStart - First day of the month (UTC)
 * @param config - Optional configuration
 * @returns SHA-256 hex string
 */
export declare function generateChunkFingerprint(monthMessages: readonly ParsedMessage[], monthStart: Date, config?: FingerprintConfig): string;
/**
 * Group messages by calendar month.
 * Returns a map of month key to messages in that month.
 */
export declare function groupMessagesByMonth(messages: readonly ParsedMessage[]): Map<string, ParsedMessage[]>;
/**
 * Generate monthly chunks with fingerprints for a set of messages.
 *
 * @param messages - All messages to chunk
 * @param config - Optional configuration
 * @returns Array of monthly chunks, sorted by month (oldest first)
 */
export declare function generateMonthlyChunks(messages: readonly ParsedMessage[], config?: FingerprintConfig): MonthlyChunk[];
/**
 * Create a deduplication plan by comparing chunks against known fingerprints.
 *
 * @param chunks - Monthly chunks from the current upload
 * @param knownFingerprints - Set of fingerprints already processed
 * @returns Plan showing what to process and what to skip
 */
export declare function createDeduplicationPlan(chunks: readonly MonthlyChunk[], knownFingerprints: ReadonlySet<string>): {
    chunksToProcess: MonthlyChunk[];
    duplicateChunks: MonthlyChunk[];
    messagesToProcess: number;
    messagesSkipped: number;
};
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