import express from 'express';
import cors from 'cors';
import dotenv from 'dotenv';
import { GoogleGenerativeAI } from '@google/generative-ai';

dotenv.config();

const app = express();
const port = 3001;

app.use(cors());
app.use(express.json());

// Initialize Gemini API
const genAI = new GoogleGenerativeAI(process.env.GEMINI_API_KEY || '');

app.post('/api/generate', async (req, res) => {
    try {
        const { theme, age, sections } = req.body;
        console.log('Received generation request:', { theme, age, sections });

        if (!process.env.GEMINI_API_KEY) {
            console.warn('Missing GEMINI_API_KEY');
            return res.status(500).json({ error: 'Server configuration error: Missing API Key' });
        }

        const model = genAI.getGenerativeModel({ model: "gemini-2.5-flash" });

        const prompt = `
        Create educational worksheet metadata for a ${age}-year-old. 
Theme: ${theme}
Sections: ${sections.join(', ')}

Return ONLY a valid JSON object. 

STRICT SVG REQUIREMENTS:
1. Viewbox: '0 0 500 500'. 
2. Style: Black stroke (#000000), white fill (#ffffff), no gradients/filters.
3. Pathing: All paths must be CLOSED and colorable. Use smooth curves.
4. Completeness: DO NOT TRUNCATE. Ensure the SVG code is 100% complete and valid XML.
5. Age-Appropriateness:
   - For 3-4: Use 8px strokes, bold outlines, and 'toddler-friendly' shapes (huge circles, squares).
   - For 5-7: Use 3px strokes, add interior textures (scales, leaves, stars), and more realistic proportions.

JSON Structure:
{
  "title": "Title",
  "subtitle": "Subtitle",
  "sections": [
    {
       "id": "id",
       "type": "coloring|writing|numbers",
       "content_svg": "<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 500 500'>...</svg>"
    }
  ]
}

CRITICAL: The 'content_svg' string must use SINGLE QUOTES for all XML attributes to prevent JSON parsing errors.
        `;

        const result = await model.generateContent(prompt);
        const response = await result.response;
        const text = response.text();

        // Cleanup markdown code blocks if present
        const jsonStr = text.replace(/```json/g, '').replace(/```/g, '').trim();
        const data = JSON.parse(jsonStr);

        res.json(data);
    } catch (error) {
        console.error('Generation error:', error);
        res.status(500).json({ error: 'Failed to generate content' });
    }
});

app.listen(port, () => {
    console.log(`Server running at http://localhost:${port}`);
});