BalloonCoinDaemon

use std::sync::{Arc, Mutex};
use std::thread;
use std::time::{Instant, Duration};
use std::collections::HashMap;
use sha2::{Sha256, Digest};
use chrono::{DateTime, Utc};
use serde::{Serialize, Deserialize};

// Define the maximum supply of coins
const MAX_SUPPLY: u64 = 21_000_000;

// Define the block reward for each block
const BLOCK_REWARD: u64 = 50;

// Define the halving interval in blocks
const HALVING_INTERVAL: u64 = 210_000;

// Define the target block time in seconds
const BLOCK_TIME: u64 = 60;

// Define the maximum number of transactions per block
const MAX_TRANSACTIONS_PER_BLOCK: usize = 100;

// Define the maximum number of connections per node
const MAX_CONNECTIONS: usize = 10;

// Define the maximum number of unconfirmed transactions in the pool
const MAX_UNCONFIRMED_TRANSACTIONS: usize = 1000;

// Define the port number to listen for incoming connections
const LISTEN_PORT: u16 = 8333;

// Define the version number of the protocol
const PROTOCOL_VERSION: u32 = 70015;

// Define the magic bytes for the Ballooncoin network
const MAGIC_BYTES: [u8; 4] = [0xFA, 0xBF, 0xB5, 0xDA];

// Define the struct for a Ballooncoin transaction
#[derive(Clone, Serialize, Deserialize)]
struct Transaction {
    inputs: Vec<Input>,
    outputs: Vec<Output>,
    timestamp: DateTime<Utc>,
    signature: Vec<u8>,
}

// Define the struct for a Ballooncoin transaction input
#[derive(Clone, Serialize, Deserialize)]
struct Input {
    transaction_hash: Vec<u8>,
    output_index: usize,
    signature: Vec<u8>,
}

// Define the struct for a Ballooncoin transaction output
#[derive(Clone, Serialize, Deserialize)]
struct Output {
    address: Vec<u8>,
    value: u64,
}

// Define the struct for a Ballooncoin block header
#[derive(Clone, Serialize, Deserialize)]
struct BlockHeader {
    version: u32,
    prev_block_hash: Vec<u8>,
    merkle_root: Vec<u8>,
    timestamp: u32,
    nonce: u32,
}

// Define the struct for a Ballooncoin block
#[derive(Clone, Serialize, Deserialize)]
struct Block {
    header: BlockHeader,
    transactions: Vec<Transaction>,
}

// Define the struct for a Ballooncoin node
struct Node {
    address: String,
    peers: Vec<String>,
    mempool: Arc<Mutex<HashMap<Vec<u8>, Transaction>>>,
    blockchain: Arc<Mutex<Vec<Block>>>,
}

impl Node {
    // Start the node and listen for incoming connections
    fn start(&self) {
        // Spawn a new thread to handle incoming connections
        let mempool = self.mempool.clone();
        let blockchain = self.blockchain.clone();
        let listen_thread = thread::spawn(move || {
            // TODO: implement incoming connection handling
        });

        // Spawn a new thread to mine new blocks
        let mining_thread = self.start_mining();

        // Wait for both threads to exit
        listen_thread.join().unwrap();
        mining_thread.join().unwrap();
    }

    // Start mining new blocks
    fn start_mining(&self) -> thread::JoinHandle<()> {
        let mempool = self.mempool.clone();
        let blockchain = self.block
    let block_time = Duration::from_secs(BLOCK_TIME);
    let mining_thread = thread::spawn(move || {
        let mut rng = rand::thread_rng();
        let mut nonce = rng.gen_range(0, u32::MAX);
        let mut last_block_time = Instant::now();

        loop {
            // Check if the block time has elapsed
            if Instant::now().duration_since(last_block_time) >= block_time {
                // Generate a new block if there are any transactions in the mempool
                let mut mempool = mempool.lock().unwrap();
                let mut blockchain = blockchain.lock().unwrap();
                if !mempool.is_empty() {
                    // Create a new block and add the coinbase transaction
                    let mut block = Block {
                        header: BlockHeader {
                            version: PROTOCOL_VERSION,
                            prev_block_hash: blockchain.last().unwrap().hash(),
                            merkle_root: vec![],
                            timestamp: Utc::now().timestamp() as u32,
                            nonce: nonce,
                        },
                        transactions: vec![],
                    };
                    let coinbase = Transaction {
                        inputs: vec![],
                        outputs: vec![Output {
                            address: vec![],
                            value: BLOCK_REWARD,
                        }],
                        timestamp: Utc::now(),
                        signature: vec![],
                    };
                    block.transactions.push(coinbase);

                    // Add as many transactions from the mempool as possible
                    let mut transaction_count = 0;
                    for (_, transaction) in mempool.iter() {
                        if transaction_count >= MAX_TRANSACTIONS_PER_BLOCK {
                            break;
                        }
                        if self.validate_transaction(&transaction) {
                            block.transactions.push(transaction.clone());
                            transaction_count += 1;
                        }
                    }

                    // Update the merkle root and hash the block header
                    block.header.merkle_root = self.calculate_merkle_root(&block.transactions);
                    let block_hash = self.hash_block_header(&block.header);

                    // Check if the block meets the difficulty target
                    if self.check_difficulty(&block_hash) {
                        // Add the block to the blockchain and remove the transactions from the mempool
                        blockchain.push(block);
                        for transaction in block.transactions.iter().skip(1) {
                            mempool.remove(&self.hash_transaction(&transaction));
                        }

                        // Update the nonce and reset the last block time
                        nonce = rng.gen_range(0, u32::MAX);
                        last_block_time = Instant::now();

                        // Check if a halving event has occurred
                        if blockchain.len() as u64 % HALVING_INTERVAL == 0 {
                            // Calculate the new block reward and check if it's below the minimum
                            let block_reward = BLOCK_REWARD >> (blockchain.len() / HALVING_INTERVAL);
                            if block_reward > 0 {
                                // Add the coinbase output for the new block reward
                                let coinbase_output = Output {
                                    address: vec![],
                                    value: block_reward,
                                };
                                blockchain.last_mut().unwrap().transactions[0].outputs.push(coinbase_output);
                            }
                        }

                        // Check if the maximum supply has been reached
                        if blockchain.len() as u64 * BLOCK_REWARD > MAX_SUPPLY {
                            break;
                        }
                    }
                }
            }
        }
    });

    mining_thread
}

// Calculate the merkle root of a list of transactions
fn calculate_merkle_root(&self, transactions: &Vec<Transaction>) -> Vec<u8> {
    let mut hashes = transactions.iter().map(|transaction| self.hash_transaction(&transaction)).collect::<Vec<_>>();
    while hashes.len() > 1 {
        if hashes.len() % 2 == 1 {
            hashes.push(hashes.last
            .unwrap()
            .clone();
        }

        let mut new_hashes = Vec::new();
        for chunk in hashes.chunks(2) {
            let mut hasher = Sha256::new();
            let (left, right) = (chunk[0].clone(), chunk[1].clone());
            hasher.update(&left);
            hasher.update(&right);
            new_hashes.push(hasher.finalize().to_vec());
        }
        hashes = new_hashes;
    }

    hashes[0].clone()
}

// Calculate the hash of a transaction
fn hash_transaction(&self, transaction: &Transaction) -> Vec<u8> {
    let mut hasher = Sha256::new();
    hasher.update(&bincode::serialize(&transaction).unwrap());
    hasher.finalize().to_vec()
}

// Hash the header of a block
fn hash_block_header(&self, header: &BlockHeader) -> Vec<u8> {
    let mut hasher = Sha256::new();
    hasher.update(&bincode::serialize(&header).unwrap());
    hasher.finalize().to_vec()
}

// Check if a block hash meets the difficulty target
fn check_difficulty(&self, hash: &Vec<u8>) -> bool {
    let target = self.difficulty_target();
    let hash_int = BigUint::from_bytes_be(hash);
    let target_int = BigUint::from_bytes_be(&target);
    hash_int <= target_int
}

// Get the difficulty target for the current block height
fn difficulty_target(&self) -> Vec<u8> {
    let blockchain = self.blockchain.lock().unwrap();
    let last_block = blockchain.last().unwrap();
    let last_difficulty = &last_block.header.difficulty;

    // Calculate the new difficulty based on the last block and the block time
    let time_difference = last_block.timestamp - blockchain[blockchain.len() - BLOCK_TIME_INTERVAL as usize].timestamp;
    let expected_time_difference = BLOCK_TIME * BLOCK_TIME_INTERVAL;
    let mut new_difficulty = last_difficulty.clone();
    if time_difference > expected_time_difference {
        let adjustment = last_difficulty * BigUint::from(expected_time_difference) / BigUint::from(time_difference);
        new_difficulty = last_difficulty + adjustment;
    } else if time_difference < expected_time_difference {
        let adjustment = last_difficulty * BigUint::from(time_difference) / BigUint::from(expected_time_difference);
        new_difficulty = last_difficulty - adjustment;
    }

    // Make sure the new difficulty is within the acceptable range
    let max_difficulty = BigUint::from_bytes_be(&[0xff; 32]);
    if new_difficulty > max_difficulty {
        new_difficulty = max_difficulty;
    } else if new_difficulty.is_zero() {
        new_difficulty = BigUint::from(1u32);
    }

    new_difficulty.to_bytes_be()
}
}

fn main() {
// Create the blockchain, mempool, and node
let blockchain = Arc::new(Mutex::new(vec![Block::genesis()]));
let mempool = Arc::new(Mutex::new(HashMap::new()));
let node = Node::new(blockchain.clone(), mempool.clone());
// Start the node and mining threads
node.start();
let mining_thread = node.start_mining();

// Listen for incoming connections
let listener = TcpListener::bind("0.0.0.0:8333").unwrap();
for stream in listener.incoming() {
    let mut node_clone = node.clone();
    thread::spawn(move || {
        let mut stream = stream.unwrap();
        loop {
            let message = read_message
use std::collections::HashMap;

// Define the blockchain struct
pub struct Blockchain {
    pub chain: Vec<Block>,
    pub current_transactions: Vec<Transaction>,
    pub nodes: HashSet<String>,
    pub difficulty: u32,
    pub max_coinbase: u64,
    pub total_coinbase: u64,
    pub halving_period: u32,
}

impl Blockchain {
    // Implement the mining method
    pub fn mine_block(&mut self, miner_address: String) -> Block {
        let previous_hash = self.last_block().hash();
        let mut nonce = 0;
        loop {
            let timestamp = SystemTime::now()
                .duration_since(SystemTime::UNIX_EPOCH)
                .unwrap()
                .as_secs();
            let block = Block::new(
                timestamp,
                self.current_transactions.clone(),
                self.difficulty,
                previous_hash.clone(),
                nonce,
            );
            if block.hash().starts_with(&"0".repeat(self.difficulty as usize)) {
                let mut coinbase = Transaction {
                    sender: String::from("COINBASE"),
                    recipient: miner_address.clone(),
                    amount: self.calculate_coinbase(),
                };
                coinbase.sign(&String::from("COINBASE"));
                self.current_transactions.push(coinbase);
                self.chain.push(block.clone());
                self.total_coinbase += block.transactions[0].amount;
                if self.total_coinbase >= self.max_coinbase {
                    panic!("Maximum coinbase reached");
                }
                return block;
            }
            nonce += 1;
        }
    }

    // Implement the calculate coinbase method
    fn calculate_coinbase(&self) -> u64 {
        let total_blocks = self.chain.len() as u32;
        let halvings = (total_blocks / self.halving_period) as u64;
        let coinbase = 50u64 * (10u64).pow(8) / (2u64).pow(halvings);
        coinbase
    }
}

fn main() {
    let mut blockchain = Blockchain {
        chain: vec![Block::genesis()],
        current_transactions: vec![],
        nodes: HashSet::new(),
        difficulty: 2,
        max_coinbase: 21_000_000_0000,
        total_coinbase: 0,
        halving_period: 210_000,
    };
    // Add nodes to the blockchain
    blockchain.register_node(String::from("http://localhost:5000"));
    blockchain.register_node(String::from("http://localhost:5001"));

    // Mine a block
    let block = blockchain.mine_block(String::from("miner_address"));
    println!("Block mined: {:?}", block);

    // Print the blockchain
    println!("Blockchain: {:?}", blockchain.chain);
}