AI 기능 구현: OpenAI/Claude API 연동

// app/api/chat/route.ts
import { streamText } from 'ai';
import { openai } from '@ai-sdk/openai';
import { anthropic } from '@ai-sdk/anthropic';

export async function POST(req: Request) {
  const { messages, model = 'claude-sonnet-4-6' } = await req.json();

  const result = streamText({
    model: model.startsWith('claude')
      ? anthropic(model)
      : openai(model),
    messages,
    maxTokens: 2000,
    temperature: 0.7,
    system: 'You are a helpful AI assistant.',
  });

  return result.toDataStreamResponse();
}

'use client';
import { useChat } from 'ai/react';

export function Chat() {
  const { messages, input, handleInputChange, handleSubmit, isLoading } = useChat({
    api: '/api/chat',
  });

  return (
    <div>
      <div className="space-y-4">
        {messages.map(m => (
          <div key={m.id} className={m.role === 'user' ? 'text-right' : ''}>
            <div className="inline-block px-4 py-2 rounded-lg bg-muted">
              {m.content}
            </div>
          </div>
        ))}
        {isLoading && <Skeleton />}
      </div>

      <form onSubmit={handleSubmit} className="mt-4">
        <input
          value={input}
          onChange={handleInputChange}
          placeholder="메시지..."
          disabled={isLoading}
        />
        <button disabled={isLoading}>전송</button>
      </form>
    </div>
  );
}

import { streamText, tool } from 'ai';
import { z } from 'zod';

const result = streamText({
  model: anthropic('claude-sonnet-4-6'),
  messages,
  tools: {
    searchDatabase: tool({
      description: 'Search the database for user data',
      parameters: z.object({
        query: z.string(),
        limit: z.number().default(10),
      }),
      execute: async ({ query, limit }) => {
        const results = await db.user.findMany({
          where: { name: { contains: query } },
          take: limit,
        });
        return { results };
      },
    }),
    sendEmail: tool({
      description: 'Send email to user',
      parameters: z.object({
        to: z.string().email(),
        subject: z.string(),
        body: z.string(),
      }),
      execute: async ({ to, subject, body }) => {
        await resend.emails.send({ to, subject, text: body });
        return { sent: true };
      },
    }),
  },
});

function selectModel(task: string, complexity: 'simple' | 'medium' | 'complex') {
  if (complexity === 'simple') {
    return google('gemini-2.5-flash');  // 무료~저렴
  }
  if (complexity === 'medium') {
    return anthropic('claude-sonnet-4-6');  // 표준
  }
  return anthropic('claude-opus-4-7');  // 가장 강력
}


// 자동 분류
async function classifyComplexity(message: string) {
  const result = await generateText({
    model: google('gemini-2.5-flash'),
    prompt: `Classify: simple, medium, complex\n${message}`,
  });
  return result.text.trim() as any;
}

Gemini 2.5 Flash: $0.10 input / $0.40 output
GPT-4o-mini: $0.15 / $0.60
Claude Haiku 4.5: $0.80 / $4
GPT-4o: $2.50 / $10
Claude Sonnet 4.6: $3 / $15
Claude Opus 4.7: $15 / $75


→ 80% 작업은 Flash/Mini로 충분
→ 복잡한 작업만 Sonnet/Opus
→ 비용 1/10~1/100 절감

try {
  const result = streamText({ model, messages });
  return result.toDataStreamResponse();
} catch (err: any) {
  if (err.statusCode === 429) {
    return new Response('Rate limit exceeded', { status: 429 });
  }
  if (err.statusCode === 402) {
    return new Response('Quota exceeded', { status: 402 });
  }
  Sentry.captureException(err);
  return new Response('AI 일시 오류', { status: 503 });
}