/**
* Gemini API client utility
*/
import { GoogleGenAI } from '@google/genai';
import { logger } from './logger';
export class GeminiClient {
private client: GoogleGenAI;
private model: string;
private lastRequestTime: number = 0;
private readonly RATE_LIMIT_DELAY = 5000; // 5 seconds between requests
constructor(apiKey: string, model: string = 'gemini-2.5-flash-lite-preview-06-17') {
this.client = new GoogleGenAI({ apiKey });
this.model = model;
logger.info('Gemini client initialized', { model });
}
/**
* Enforce rate limiting by waiting if necessary
*/
private async enforceRateLimit(): Promise<void> {
const now = Date.now();
const timeSinceLastRequest = now - this.lastRequestTime;
if (timeSinceLastRequest < this.RATE_LIMIT_DELAY) {
const waitTime = this.RATE_LIMIT_DELAY - timeSinceLastRequest;
logger.debug('Rate limiting: waiting', { waitTime });
await new Promise(resolve => setTimeout(resolve, waitTime));
}
this.lastRequestTime = Date.now();
}
/**
* Generate content with automatic retry and JSON parsing
*/
async generateContent(prompt: string, maxRetries: number = 3): Promise<any> {
await this.enforceRateLimit();
for (let attempt = 1; attempt <= maxRetries; attempt++) {
try {
logger.debug('Generating content', { attempt, maxRetries });
const result = await this.client.models.generateContent({
model: this.model,
contents: [{ role: 'user', parts: [{ text: prompt }] }]
});
let text = result.candidates?.[0]?.content?.parts?.[0]?.text || '';
// Remove markdown code blocks if present
text = text.replace(/```json\s*|\s*```/g, '').trim();
logger.debug('Raw response received', { textLength: text.length });
// Try to parse as JSON
try {
const jsonData = JSON.parse(text);
logger.info('Content generated successfully', { attempt });
return jsonData;
} catch (parseError) {
const errorMessage = parseError instanceof Error ? parseError.message : String(parseError);
logger.warn('JSON parse failed, attempting auto-fix', { attempt, parseError: errorMessage });
// Try to fix JSON with AI
const fixedJson = await this.fixJsonWithAI(text);
if (fixedJson) {
logger.info('JSON auto-fix successful', { attempt });
return fixedJson;
}
throw new Error(`JSON parsing failed: ${errorMessage}`);
}
} catch (error) {
const errorMessage = error instanceof Error ? error.message : String(error);
logger.error('Content generation failed', {
attempt,
maxRetries,
error: errorMessage
});
if (attempt === maxRetries) {
throw new Error(`Failed to generate content after ${maxRetries} attempts: ${errorMessage}`);
}
// Wait before retry
await new Promise(resolve => setTimeout(resolve, 2000 * attempt));
}
}
}
/**
* Attempt to fix malformed JSON using AI
*/
private async fixJsonWithAI(malformedJson: string): Promise<any | null> {
try {
const fixPrompt = `
以下のテキストは有効なJSONになるはずですが、構文エラーがあります。
正しいJSONフォーマットに修正してください。
修正されたJSONのみを返してください。説明や追加のテキストは不要です。
修正対象:
${malformedJson}
`;
await this.enforceRateLimit();
const result = await this.client.models.generateContent({
model: this.model,
contents: [{ role: 'user', parts: [{ text: fixPrompt }] }]
});
let fixedText = result.candidates?.[0]?.content?.parts?.[0]?.text || '';
// Remove markdown code blocks
fixedText = fixedText.replace(/```json\s*|\s*```/g, '').trim();
return JSON.parse(fixedText);
} catch (error) {
const errorMessage = error instanceof Error ? error.message : String(error);
logger.error('JSON auto-fix failed', { error: errorMessage });
return null;
}
}
}
let geminiClient: GeminiClient | null = null;
/**
* Get or create Gemini client instance
*/
export function getGeminiClient(): GeminiClient {
if (!geminiClient) {
const apiKey = process.env.GEMINI_API_KEY;
if (!apiKey) {
throw new Error('GEMINI_API_KEY environment variable is required');
}
const model = process.env.GEMINI_MODEL || 'gemini-2.5-flash-lite-preview-06-17';
geminiClient = new GeminiClient(apiKey, model);
}
return geminiClient;
}
