const fs = require('fs');
const path = require('path');
const zlib = require('zlib');

// Source and destination file paths
const sourceFile = path.join(__dirname, 'pipe-source-example.txt');
const destFile = path.join(__dirname, 'pipe-destination.txt');
const compressedFile = path.join(__dirname, 'pipe-compressed.gz');

// Create sample content
fs.writeFileSync(sourceFile, 'This is the source content for the pipe example.\n'.repeat(100));

// Create ReadStream and various WriteStreams
const readStream = fs.createReadStream(sourceFile);
const writeStream = fs.createWriteStream(destFile);
const compressStream = zlib.createGzip(); // Compression transform stream
const compressedWriteStream = fs.createWriteStream(compressedFile);

// Pipe the ReadStream directly to the WriteStream
readStream.pipe(writeStream);

// Listen for completion events
writeStream.on('finish', () => {
  console.log(`File copied from ${sourceFile} to ${destFile}`);
  
  // Create a new ReadStream to demonstrate chained pipes
  const readStream2 = fs.createReadStream(sourceFile);
  
  // Chain multiple pipes: read -> compress -> write
  readStream2.pipe(compressStream).pipe(compressedWriteStream);
  
  compressedWriteStream.on('finish', () => {
    console.log(`File compressed from ${sourceFile} to ${compressedFile}`);
    
    // Compare file sizes
    const originalSize = fs.statSync(sourceFile).size;
    const compressedSize = fs.statSync(compressedFile).size;
    console.log(`Original size: ${originalSize} bytes`);
    console.log(`Compressed size: ${compressedSize} bytes`);
    console.log(`Compression ratio: ${(compressedSize / originalSize * 100).toFixed(2)}%`);
    
    // Clean up files after demonstration
    [sourceFile, destFile, compressedFile].forEach(file => {
      fs.unlinkSync(file);
    });
    console.log('All sample files removed');
  });
});

// Handle errors
readStream.on('error', (err) => console.error(`Read error: ${err.message}`));
writeStream.on('error', (err) => console.error(`Write error: ${err.message}`));
compressStream.on('error', (err) => console.error(`Compression error: ${err.message}`));
compressedWriteStream.on('error', (err) => console.error(`Compressed write error: ${err.message}`));