api/routes/external.ts

import { Router, type Response } from 'express';
import { verifyApiKey } from '../middleware/api-auth.js';
import { AIService } from '../services/ai.service.js';
import { ConcurrencyService } from '../services/concurrency.service.js';
import db from '../lib/db.js';

const router = Router();

/**
 * 外部 API: Chat Completion (类似 OpenAI 接口)
 * POST /api/v1/chat/completions
 */
router.post('/chat/completions', verifyApiKey, async (req: any, res) => {
  const { model, messages, stream = false } = req.body;
  const userId = req.user.userId;

  // 1. 参数校验
  if (!messages || !Array.isArray(messages)) {
    return res.status(400).json({ error: { message: "'messages' must be an array" } });
  }

  // 2. 检查配额
  try {
    const user = db.prepare('SELECT quota_remaining FROM users WHERE id = ?').get(userId) as any;
    if (!user || user.quota_remaining <= 0) {
      return res.status(402).json({ 
        error: { 
          message: "You have exceeded your current quota.", 
          type: "insufficient_quota",
          code: "quota_exceeded" 
        } 
      });
    }

    // 3. 执行 AI 调用 (仅提取最后一条用户消息)
    const lastUserMsg = messages.reverse().find((m: any) => m.role === 'user');
    const query = lastUserMsg?.content || '';

    if (!query) {
      return res.status(400).json({ error: { message: "No user message found" } });
    }

    // 4. 调用内部服务
    const result = await AIService.chatWithKnowledge(userId, query);

    // 5. 扣除额度 (简单起见，每次调用扣 1 点)
    db.prepare('UPDATE users SET quota_remaining = quota_remaining - 1 WHERE id = ?').run(userId);

    if (stream) {
      // 流式响应 (SSE)
      res.setHeader('Content-Type', 'text/event-stream');
      res.setHeader('Cache-Control', 'no-cache');
      res.setHeader('Connection', 'keep-alive');

      for await (const chunk of result.stream) {
        const content = chunk.choices[0]?.delta?.content || '';
        if (content) {
          const sseData = JSON.stringify({
            id: `chatcmpl-${Date.now()}`,
            object: 'chat.completion.chunk',
            created: Math.floor(Date.now() / 1000),
            model: model || 'codex-ai-v1',
            choices: [{ delta: { content }, index: 0, finish_reason: null }]
          });
          res.write(`data: ${sseData}\n\n`);
        }
      }
      res.write('data: [DONE]\n\n');
      res.end();
    } else {
      // 非流式响应
      let fullContent = '';
      for await (const chunk of result.stream) {
        fullContent += chunk.choices[0]?.delta?.content || '';
      }

      res.json({
        id: `chatcmpl-${Date.now()}`,
        object: 'chat.completion',
        created: Math.floor(Date.now() / 1000),
        model: model || 'codex-ai-v1',
        usage: { prompt_tokens: query.length, completion_tokens: fullContent.length, total_tokens: query.length + fullContent.length },
        choices: [{ message: { role: 'assistant', content: fullContent }, finish_reason: 'stop', index: 0 }]
      });
    }

  } catch (err: any) {
    res.status(500).json({ error: { message: err.message, type: "server_error" } });
  }
});

/**
 * 外部 API: 获取用户余额
 * GET /api/v1/user/quota
 */
router.get('/user/quota', verifyApiKey, (req: any, res) => {
  const userId = req.user.userId;
  const user = db.prepare('SELECT email, plan, quota_remaining FROM users WHERE id = ?').get(userId);
  res.json(user);
});

export default router;