feat(ai): Add Google Gemini provider support and fix config loading

src/ai-providers/google.js

@@ -0,0 +1,167 @@
+/**
+ * google.js
+ * AI provider implementation for Google AI models (e.g., Gemini) using Vercel AI SDK.
+ */
+
+// import { GoogleGenerativeAI } from '@ai-sdk/google'; // Incorrect import
+import { createGoogleGenerativeAI } from '@ai-sdk/google'; // Correct import for customization
+import { generateText, streamText, generateObject } from 'ai'; // Import from main 'ai' package
+import { log } from '../../scripts/modules/utils.js'; // Import logging utility
+
+// Consider making model configurable via config-manager.js later
+const DEFAULT_MODEL = 'gemini-2.0-pro'; // Or a suitable default
+const DEFAULT_TEMPERATURE = 0.2; // Or a suitable default
+
+/**
+ * Generates text using a Google AI model.
+ *
+ * @param {object} params - Parameters for the generation.
+ * @param {string} params.apiKey - Google API Key.
+ * @param {string} params.modelId - Specific model ID to use (overrides default).
+ * @param {number} params.temperature - Generation temperature.
+ * @param {Array<object>} params.messages - The conversation history (system/user prompts).
+ * @param {number} [params.maxTokens] - Optional max tokens.
+ * @returns {Promise<string>} The generated text content.
+ * @throws {Error} If API key is missing or API call fails.
+ */
+async function generateGoogleText({
+	apiKey,
+	modelId = DEFAULT_MODEL,
+	temperature = DEFAULT_TEMPERATURE,
+	messages,
+	maxTokens // Note: Vercel SDK might handle this differently, needs verification
+}) {
+	if (!apiKey) {
+		throw new Error('Google API key is required.');
+	}
+	log('info', `Generating text with Google model: ${modelId}`);
+
+	try {
+		// const google = new GoogleGenerativeAI({ apiKey }); // Incorrect instantiation
+		const googleProvider = createGoogleGenerativeAI({ apiKey }); // Correct instantiation
+		// const model = google.getGenerativeModel({ model: modelId }); // Incorrect model retrieval
+		const model = googleProvider(modelId); // Correct model retrieval
+
+		// Construct payload suitable for Vercel SDK's generateText
+		// Note: The exact structure might depend on how messages are passed
+		const result = await generateText({
+			model, // Pass the model instance
+			messages, // Pass the messages array directly
+			temperature,
+			maxOutputTokens: maxTokens // Map to correct Vercel SDK param if available
+		});
+
+		// Assuming result structure provides text directly or within a property
+		return result.text; // Adjust based on actual SDK response
+	} catch (error) {
+		log(
+			'error',
+			`Error generating text with Google (${modelId}): ${error.message}`
+		);
+		throw error; // Re-throw for unified service handler
+	}
+}
+
+/**
+ * Streams text using a Google AI model.
+ *
+ * @param {object} params - Parameters for the streaming.
+ * @param {string} params.apiKey - Google API Key.
+ * @param {string} params.modelId - Specific model ID to use (overrides default).
+ * @param {number} params.temperature - Generation temperature.
+ * @param {Array<object>} params.messages - The conversation history.
+ * @param {number} [params.maxTokens] - Optional max tokens.
+ * @returns {Promise<ReadableStream>} A readable stream of text deltas.
+ * @throws {Error} If API key is missing or API call fails.
+ */
+async function streamGoogleText({
+	apiKey,
+	modelId = DEFAULT_MODEL,
+	temperature = DEFAULT_TEMPERATURE,
+	messages,
+	maxTokens
+}) {
+	if (!apiKey) {
+		throw new Error('Google API key is required.');
+	}
+	log('info', `Streaming text with Google model: ${modelId}`);
+
+	try {
+		// const google = new GoogleGenerativeAI({ apiKey }); // Incorrect instantiation
+		const googleProvider = createGoogleGenerativeAI({ apiKey }); // Correct instantiation
+		// const model = google.getGenerativeModel({ model: modelId }); // Incorrect model retrieval
+		const model = googleProvider(modelId); // Correct model retrieval
+
+		const stream = await streamText({
+			model, // Pass the model instance
+			messages,
+			temperature,
+			maxOutputTokens: maxTokens
+		});
+
+		return stream; // Return the stream directly
+	} catch (error) {
+		log(
+			'error',
+			`Error streaming text with Google (${modelId}): ${error.message}`
+		);
+		throw error;
+	}
+}
+
+/**
+ * Generates a structured object using a Google AI model.
+ *
+ * @param {object} params - Parameters for the object generation.
+ * @param {string} params.apiKey - Google API Key.
+ * @param {string} params.modelId - Specific model ID to use (overrides default).
+ * @param {number} params.temperature - Generation temperature.
+ * @param {Array<object>} params.messages - The conversation history.
+ * @param {import('zod').ZodSchema} params.schema - Zod schema for the expected object.
+ * @param {string} params.objectName - Name for the object generation context.
+ * @param {number} [params.maxTokens] - Optional max tokens.
+ * @returns {Promise<object>} The generated object matching the schema.
+ * @throws {Error} If API key is missing or API call fails.
+ */
+async function generateGoogleObject({
+	apiKey,
+	modelId = DEFAULT_MODEL,
+	temperature = DEFAULT_TEMPERATURE,
+	messages,
+	schema,
+	objectName, // Note: Vercel SDK might use this differently or not at all
+	maxTokens
+}) {
+	if (!apiKey) {
+		throw new Error('Google API key is required.');
+	}
+	log('info', `Generating object with Google model: ${modelId}`);
+
+	try {
+		// const google = new GoogleGenerativeAI({ apiKey }); // Incorrect instantiation
+		const googleProvider = createGoogleGenerativeAI({ apiKey }); // Correct instantiation
+		// const model = google.getGenerativeModel({ model: modelId }); // Incorrect model retrieval
+		const model = googleProvider(modelId); // Correct model retrieval
+
+		const { object } = await generateObject({
+			model, // Pass the model instance
+			schema,
+			messages,
+			temperature,
+			maxOutputTokens: maxTokens
+			// Note: 'objectName' or 'mode' might not be directly applicable here
+			// depending on how `@ai-sdk/google` handles `generateObject`.
+			// Check SDK docs if specific tool calling/JSON mode needs explicit setup.
+		});
+
+		return object; // Return the parsed object
+	} catch (error) {
+		log(
+			'error',
+			`Error generating object with Google (${modelId}): ${error.message}`
+		);
+		throw error;
+	}
+}
+
+export { generateGoogleText, streamGoogleText, generateGoogleObject };