// AI聊天API - 使用Gemini API
import { NextRequest, NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/lib/auth';

// POST - 发送消息到AI
export async function POST(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions);
    if (!session) {
      return NextResponse.json(
        { error: '未授权' },
        { status: 401 }
      );
    }

    const { messages, model } = await request.json();

    const apiKey = process.env.GEMINI_API_KEY;
    const apiBaseUrl = process.env.GEMINI_API_BASE_URL || 'https://generativelanguage.googleapis.com/v1beta';
    const modelName = model || process.env.GEMINI_MODEL || 'gemini-2.0-flash-exp';

    if (!apiKey) {
      return NextResponse.json(
        { error: 'Gemini API未配置' },
        { status: 500 }
      );
    }

    // 转换消息格式为Gemini格式
    const geminiMessages = messages.map((msg: any) => {
      // 文本消息
      if (typeof msg.content === 'string') {
        return {
          role: msg.role === 'assistant' ? 'model' : 'user',
          parts: [{ text: msg.content }],
        };
      }

      // 多模态消息（文本+图片）
      if (Array.isArray(msg.content)) {
        const parts = msg.content.map((part: any) => {
          if (part.type === 'text') {
            return { text: part.text };
          }
          if (part.type === 'image_url') {
            // 解析base64图片
            const match = part.image_url.url.match(/data:image\/([^;]+);base64,(.+)/);
            if (match) {
              return {
                inlineData: {
                  mimeType: `image/${match[1]}`,
                  data: match[2],
                },
              };
            }
          }
          return null;
        }).filter(Boolean);

        return {
          role: msg.role === 'assistant' ? 'model' : 'user',
          parts,
        };
      }

      return null;
    }).filter(Boolean);

    // 调用Gemini API
    const response = await fetch(
      `${apiBaseUrl}/models/${modelName}:generateContent?key=${apiKey}`,
      {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({
          contents: geminiMessages,
          generationConfig: {
            temperature: 1,
            topK: 40,
            topP: 0.95,
            maxOutputTokens: 8192,
          },
        }),
      }
    );

    if (!response.ok) {
      const errorData = await response.json().catch(() => ({}));
      console.error('Gemini API error:', errorData);
      return NextResponse.json(
        { error: errorData.error?.message || '调用Gemini API失败' },
        { status: response.status }
      );
    }

    const data = await response.json();
    return NextResponse.json(data);
  } catch (error) {
    console.error('AI chat error:', error);
    return NextResponse.json(
      { error: error instanceof Error ? error.message : '处理失败' },
      { status: 500 }
    );
  }
}

// GET - 获取AI配置状态
export async function GET() {
  const apiKey = process.env.GEMINI_API_KEY;
  const apiBaseUrl = process.env.GEMINI_API_BASE_URL || 'https://generativelanguage.googleapis.com/v1beta';
  const model = process.env.GEMINI_MODEL || 'gemini-2.0-flash-exp';

  return NextResponse.json({
    configured: !!apiKey,
    apiBaseUrl,
    model,
  });
}