fix: switch to Gemini AI, fix free-tier output, fix spinner state, upgrade prompts, multi-domain routing

lib/ai/client.ts

@@ -1,33 +1,31 @@
-import Anthropic from '@anthropic-ai/sdk';
+import { GoogleGenerativeAI } from '@google/generative-ai';
 import { getConfig } from '@/lib/db';
 
-const anthropic = new Anthropic({ apiKey: process.env.ANTHROPIC_API_KEY });
+const genAI = new GoogleGenerativeAI(process.env.GEMINI_API_KEY || '');
 
 export async function getModel(): Promise<string> {
-  return (await getConfig('openai_model')) || 'claude-3-5-sonnet-20241022';
+  return (await getConfig('gemini_model')) || 'gemini-1.5-pro';
 }
 
 export async function generate(
   systemPrompt: string,
   userPrompt: string
 ): Promise<{ text: string; tokens: number }> {
-  const model = await getModel();
-
-  const response = await anthropic.messages.create({
-    model,
-    max_tokens: 4096,
-    system: systemPrompt,
-    messages: [{ role: 'user', content: userPrompt }],
+  const modelName = await getModel();
+  const model = genAI.getGenerativeModel({
+    model: modelName,
+    systemInstruction: systemPrompt,
   });
 
-  const text = response.content
-    .filter((b) => b.type === 'text')
-    .map((b) => (b as Anthropic.TextBlock).text)
-    .join('');
+  const result = await model.generateContent(userPrompt);
+  const response = result.response;
+  const text = response.text();
 
-  const tokens = (response.usage.input_tokens ?? 0) + (response.usage.output_tokens ?? 0);
+  const inputTokens = response.usageMetadata?.promptTokenCount ?? 0;
+  const outputTokens = response.usageMetadata?.candidatesTokenCount ?? 0;
+  const tokens = inputTokens + outputTokens;
 
   return { text, tokens };
 }
 
-export default anthropic;
+export default genAI;