/**
 * File Token Budget System
 *
 * Calculates how much of the remaining context window budget
 * can be used for file reads. Implements fast-path for small files
 * and preview mode for very large files.
 */
import type { BudgetFileInput } from "../types/index.js";
/** Percentage of remaining context to allocate for file reads */
export declare const FILE_READ_BUDGET_PERCENT = 0.6;
/** Files below this size skip budget validation (100KB) */
export declare const FILE_FAST_PATH_SIZE: number;
/** Files above this size get preview-only mode (5MB) */
export declare const FILE_PREVIEW_MODE_SIZE: number;
/** Default preview size in characters */
export declare const FILE_PREVIEW_CHARS = 2000;
/**
 * Calculate available token budget for file reads.
 *
 * @param contextWindow - Total context window for the model
 * @param currentTokens - Tokens already used (conversation + system prompt)
 * @param maxOutputTokens - Reserved output tokens
 * @returns Available tokens for file content
 */
export declare function calculateFileTokenBudget(contextWindow: number, currentTokens: number, maxOutputTokens: number): number;
/**
 * Determine how a file should be handled based on its size and the budget.
 */
export declare function shouldTruncateFile(fileSize: number, budget: number): {
    shouldTruncate: boolean;
    maxChars?: number;
    previewMode?: boolean;
};
/**
 * Estimate post-processing token count based on file type.
 *
 * Different file types produce vastly different amounts of text after
 * processing.  A 50 MB video file yields ~200-500 tokens of metadata,
 * while a 50 MB text file yields ~12.5 M tokens.  Using the raw byte
 * size for all types causes media files to be wrongly excluded by the
 * aggregate budget check.
 *
 * @param sizeBytes  Raw file size in bytes
 * @param fileType   Detected file type (e.g. "video", "audio", "image")
 * @returns Estimated token count after processing
 */
export declare function estimatePostProcessingTokens(sizeBytes: number, fileType?: string): number;
export declare function enforceAggregateFileBudget(files: BudgetFileInput[], availableTokens: number): {
    included: BudgetFileInput[];
    excluded: BudgetFileInput[];
    notices: string[];
};