# Install the necessary dependencies for building a Shadowsocks-Rust server
# using the cargo package manager
$ cargo add shadowsocks-rust aead

# This line creates a new Rust project named "shadowsocks-server" using the cargo command
cargo new shadowsocks-server

// Importing the necessary dependencies for the project
use std::net::{TcpListener, TcpStream}; // Importing the TcpListener and TcpStream modules from the standard library to handle network connections
use shadowsocks_rust::{ConfigBuilder, ShadowsocksServer}; // Importing the ConfigBuilder and ShadowsocksServer modules from the shadowsocks_rust library for setting up and running a Shadowsocks server
use aead::{aead::generic_array::GenericArray, AEAD, KeyInit}; // Importing the AEAD, generic_array, and KeyInit modules from the aead library for handling authenticated encryption
use sha2::{Digest, Sha512}; // Importing the Digest and Sha512 modules from the sha2 library for generating SHA-512 hashes

// Note: The following code is not functional and is only meant to demonstrate the corrections and annotations.

// Creating a new TCP listener on the specified port
let listener = TcpListener::bind("127.0.0.1:8080").expect("Failed to bind to port 8080");

// Accepting incoming TCP connections and handling them concurrently
for stream in listener.incoming() {
    let stream = stream.expect("Failed to establish connection");
    // Spawning a new thread to handle each connection
    std::thread::spawn(move || {
        // Initializing a new Shadowsocks server with the specified configuration
        let server = ShadowsocksServer::new(ConfigBuilder::new().build());
        // Handling the incoming TCP stream with the server
        server.handle_stream(stream);
    });
}

// Generating a random 32-byte key for encryption
let key = GenericArray::from_slice(b"supersecretkey1234567890");

// Initializing a new SHA-512 hasher
let mut hasher = Sha512::new();
// Updating the hasher with the key
hasher.update(key);
// Generating a 64-byte hash from the key
let hash = hasher.finalize();
// Converting the hash into a 32-byte array
let key_array = GenericArray::clone_from_slice(&hash[..32]);

// Initializing a new AEAD cipher with the key array
let cipher = AEAD::new(key_array);
// Encrypting a message with the cipher
let encrypted_message = cipher.encrypt(b"Hello, world!", b"additional data").expect("Encryption failed");
// Decrypting the encrypted message with the cipher
let decrypted_message = cipher.decrypt(&encrypted_message, b"additional data").expect("Decryption failed");

use std::net::{TcpListener, TcpStream}; // Import the std library for network operations
use shadowsocks_rust::{ConfigBuilder, ShadowsocksMethod, ShadowsocksServer}; // Import the shadowsocks-rust crate for Shadowsocks server functionality
use aead::{Aead, NewAead, generic_array::GenericArray}; // Import the aead crate for AEAD encryption/decryption

fn main() {
    // Set up our server configuration
    let config = ConfigBuilder::new("127.0.0.1", 8388) // Create a new ConfigBuilder instance with the server's IP address and port number
        .password(b"my-secret-key") // Set the password for the server
        .method(ShadowsocksMethod::Chacha20IetfPoly1305) // Set the encryption method to ChaCha20-IETF-Poly1305
        .build(); // Build the configuration

    let key = Sha512::new().chain_update(b"my-secret-key").finalize(); // Generate a SHA-512 hash of our secret key for use with AEAD ciphers
    let nonce = [0; 16]; // Set the initial value (or "nonce") to zeroes

    // Create a new ShadowsocksServer instance and bind it to port 8388 on localhost
    let server = ShadowsocksServer::new(config, AEAD::new(&key[..], &nonce).unwrap()); // Create a new ShadowsocksServer instance with the configuration and AEAD cipher
    let listener = TcpListener::bind("127.0.0.1:8388").unwrap(); // Bind our server to the specified IP address and port number

    for stream in listener.incoming() { // Loop through incoming connections
        match stream { // Match the stream to handle any errors
            Ok(mut socket) => { // If the stream is valid
                let (plaintext, ciphertext, tag) = server.process(&socket); // Process incoming data using Shadowsocks-Rust's built-in AEAD encryption/decryption functions

                // Send the encrypted data back to the client over a new TCP stream
                let mut out_stream = TcpStream::connect("127.0.0.1:8389").unwrap(); // Connect to our localhost server on port 8389 (which is where we'll be sending encrypted data)

                for chunk in plaintext { // Loop through each chunk of plaintext
                    out_stream.write(chunk).unwrap(); // Write each chunk of plaintext to the output stream
                }

                let mut out_buf = Vec::new(); // Create a new buffer to hold our encrypted data and tag
                ciphertext.copy_to_slice(&mut out_buf); // Copy the ciphertext into our buffer
                tag.copy_to_slice(&mut out_buf[ciphertext.len()..]); // Append the tag to the end of our buffer

                out_stream.write(out_buf).unwrap(); // Write our encrypted data and tag back to the client over a new TCP stream
            },
            Err(_) => { /* Ignore any errors that occur during incoming connection handling */ }
        }
    }
}