const express = require('express');
const cors = require('cors');
const imageProcessor = require('./image-processing-logic');

const app = express();
const PORT = process.env.PORT || 7860;

// Use standard middleware.
app.use(cors());
app.use(express.json());

// Health check endpoint.
app.get('/ping', (req, res) => {
    res.status(200).send('pong');
});

/**
 * Single-image processing endpoint (Stream-based).
 * This endpoint uses streaming to process a single image from the request body.
 */
app.post('/api/process-stream', async (req, res) => {
    try {
        const { quality,  format } = req.query;

        if (req.is('multipart/form-data')) {
            // Streaming multipart/form-data is complex without a library like busboy.
            // For simplicity, this example assumes the client sends the image directly
            // as the request body with the correct Content-Type header.
            // This is a more memory-efficient approach for a single image.
            return res.status(400).json({ error: 'Please send image directly as request body, not as form data.' });
        }
        
        // Create a sharp instance from the request stream.
        const processedImageStream = imageProcessor.processImage(req, {
            quality: quality,
            
            format: format
        });
        
        // Set headers for the response.
        res.setHeader('Content-Type', `image/${format}`);
        res.setHeader('Content-Disposition', `attachment; filename=compressed_image.${format}`);
        
        // Pipe the processed stream directly to the response stream.
        processedImageStream.on('error', (error) => {
            console.error('Error in streaming pipeline:', error);
            res.status(500).json({ error: 'Image processing failed' });
        });
        
        processedImageStream.pipe(res);

    } catch (error) {
        console.error('Error in streaming compression route:', error);
        res.status(500).json({ error: error.message });
    }
});

// Global error handler middleware.
app.use((err, req, res, next) => {
    console.error(err.stack);
    res.status(500).json({ error: err.message });
});

app.listen(PORT, () => {
    console.log(`Server running on port ${PORT}`);
});