const sharp = require('sharp');
const stream = require('stream');

class ImageProcessor {
    /**
     * Processes an image from a readable stream.
     * @param {stream.Readable} input - The incoming stream of image data.
     * @param {Object} options - Processing options including quality and format.
     * @returns {stream.Readable} - A readable stream of the processed image.
     */
    processImage(input, options = {}) {
        const { quality = 80, format = 'jpeg' } = options;

        try {
            // Create a Sharp instance for streaming.
            let sharpInstance = sharp();

            // Apply format and quality options.
            switch (format.toLowerCase()) {
                case 'jpeg':
                    sharpInstance = sharpInstance.jpeg({ quality: parseInt(quality), mozjpeg: true });
                    break;
                case 'png':
                    sharpInstance = sharpInstance.png({ quality: parseInt(quality), compressionLevel: 1 });
                    break;
                case 'webp':
                    sharpInstance = sharpInstance.webp({ quality: parseInt(quality), speed: 8 });
                    break;
                case 'avif':
                    sharpInstance = sharpInstance.avif({ quality: parseInt(quality), speed: 8 });
                    break;
                case 'heif':
                    sharpInstance = sharpInstance.heif({ quality: parseInt(quality), speed: 8 });
                    break;
                case 'tiff':
                    sharpInstance = sharpInstance.tiff({ quality: parseInt(quality) });
                    break;
                default:
                    throw new Error('Unsupported format');
            }

            // Pipe the input stream to the sharp pipeline and return the output stream.
            return input.pipe(sharpInstance);

        } catch (error) {
            console.error('Error setting up image processing stream:', error);
            throw error;
        }
    }
}

module.exports = new ImageProcessor();