/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
// Token estimation constants
// ASCII characters (0-127) are roughly 4 chars per token
const ASCII_TOKENS_PER_CHAR = 0.25;
// Non-ASCII characters (including CJK) are often 1-2 tokens per char.
// We use 1.3 as a conservative estimate to avoid underestimation.
const NON_ASCII_TOKENS_PER_CHAR = 1.3;
/**
 * Estimates token count for parts synchronously using a heuristic.
 * - Text: character-based heuristic (ASCII vs CJK).
 * - Non-text (Tools, etc): JSON string length / 4.
 */
export function estimateTokenCountSync(parts) {
    let totalTokens = 0;
    for (const part of parts) {
        if (typeof part.text === 'string') {
            for (const char of part.text) {
                if (char.codePointAt(0) <= 127) {
                    totalTokens += ASCII_TOKENS_PER_CHAR;
                }
                else {
                    totalTokens += NON_ASCII_TOKENS_PER_CHAR;
                }
            }
        }
        else {
            // For non-text parts (functionCall, functionResponse, executableCode, etc.),
            // we fallback to the JSON string length heuristic.
            // Note: This is an approximation.
            totalTokens += JSON.stringify(part).length / 4;
        }
    }
    return Math.floor(totalTokens);
}
/**
 * Calculates the token count of the request.
 * If the request contains only text or tools, it estimates the token count locally.
 * If the request contains media (images, files), it uses the countTokens API.
 */
export async function calculateRequestTokenCount(request, contentGenerator, model) {
    const parts = Array.isArray(request)
        ? request.map((p) => (typeof p === 'string' ? { text: p } : p))
        : typeof request === 'string'
            ? [{ text: request }]
            : [request];
    // Use countTokens API only for heavy media parts that are hard to estimate.
    const hasMedia = parts.some((p) => {
        const isMedia = 'inlineData' in p || 'fileData' in p;
        return isMedia;
    });
    if (hasMedia) {
        try {
            const response = await contentGenerator.countTokens({
                model,
                contents: [{ role: 'user', parts }],
            });
            return response.totalTokens ?? 0;
        }
        catch {
            // Fallback to local estimation if the API call fails
            return estimateTokenCountSync(parts);
        }
    }
    return estimateTokenCountSync(parts);
}
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