use {
    crate::tpu_info::TpuInfo,
    crossbeam_channel::{Receiver, RecvTimeoutError},
    log::*,
    solana_metrics::{datapoint_warn, inc_new_counter_info},
    solana_runtime::{bank::Bank, bank_forks::BankForks},
    solana_sdk::{hash::Hash, nonce_account, pubkey::Pubkey, signature::Signature},
    std::{
        collections::HashMap,
        net::{SocketAddr, UdpSocket},
        sync::{Arc, RwLock},
        thread::{self, Builder, JoinHandle},
        time::{Duration, Instant},
    },
};

/// Maximum size of the transaction queue
const MAX_TRANSACTION_QUEUE_SIZE: usize = 10_000; // This seems like a lot but maybe it needs to be bigger one day
/// Default retry interval
const DEFAULT_RETRY_RATE_MS: u64 = 2_000;
/// Default number of leaders to forward transactions to
const DEFAULT_LEADER_FORWARD_COUNT: u64 = 2;
/// Default max number of time the service will retry broadcast
const DEFAULT_SERVICE_MAX_RETRIES: usize = usize::MAX;

pub struct SendTransactionService {
    thread: JoinHandle<()>,
}

pub struct TransactionInfo {
    pub signature: Signature,
    pub wire_transaction: Vec<u8>,
    pub last_valid_block_height: u64,
    pub durable_nonce_info: Option<(Pubkey, Hash)>,
    pub max_retries: Option<usize>,
    retries: usize,
}

impl TransactionInfo {
    pub fn new(
        signature: Signature,
        wire_transaction: Vec<u8>,
        last_valid_block_height: u64,
        durable_nonce_info: Option<(Pubkey, Hash)>,
        max_retries: Option<usize>,
    ) -> Self {
        Self {
            signature,
            wire_transaction,
            last_valid_block_height,
            durable_nonce_info,
            max_retries,
            retries: 0,
        }
    }
}

#[derive(Default, Debug, PartialEq)]
struct ProcessTransactionsResult {
    rooted: u64,
    expired: u64,
    retried: u64,
    max_retries_elapsed: u64,
    failed: u64,
    retained: u64,
}

#[derive(Clone, Debug)]
pub struct Config {
    pub retry_rate_ms: u64,
    pub leader_forward_count: u64,
    pub default_max_retries: Option<usize>,
    pub service_max_retries: usize,
}

impl Default for Config {
    fn default() -> Self {
        Self {
            retry_rate_ms: DEFAULT_RETRY_RATE_MS,
            leader_forward_count: DEFAULT_LEADER_FORWARD_COUNT,
            default_max_retries: None,
            service_max_retries: DEFAULT_SERVICE_MAX_RETRIES,
        }
    }
}

impl SendTransactionService {
    pub fn new<T: TpuInfo + std::marker::Send + 'static>(
        tpu_address: SocketAddr,
        bank_forks: &Arc<RwLock<BankForks>>,
        leader_info: Option<T>,
        receiver: Receiver<TransactionInfo>,
        retry_rate_ms: u64,
        leader_forward_count: u64,
    ) -> Self {
        let config = Config {
            retry_rate_ms,
            leader_forward_count,
            ..Config::default()
        };
        Self::new_with_config(tpu_address, bank_forks, leader_info, receiver, config)
    }

    pub fn new_with_config<T: TpuInfo + std::marker::Send + 'static>(
        tpu_address: SocketAddr,
        bank_forks: &Arc<RwLock<BankForks>>,
        leader_info: Option<T>,
        receiver: Receiver<TransactionInfo>,
        config: Config,
    ) -> Self {
        let thread = Self::retry_thread(
            tpu_address,
            receiver,
            bank_forks.clone(),
            leader_info,
            config,
        );
        Self { thread }
    }

    fn retry_thread<T: TpuInfo + std::marker::Send + 'static>(
        tpu_address: SocketAddr,
        receiver: Receiver<TransactionInfo>,
        bank_forks: Arc<RwLock<BankForks>>,
        mut leader_info: Option<T>,
        config: Config,
    ) -> JoinHandle<()> {
        let mut last_status_check = Instant::now();
        let mut last_leader_refresh = Instant::now();
        let mut transactions = HashMap::new();
        let send_socket = UdpSocket::bind("0.0.0.0:0").unwrap();

        if let Some(leader_info) = leader_info.as_mut() {
            leader_info.refresh_recent_peers();
        }

        Builder::new()
            .name("send-tx-sv2".to_string())
            .spawn(move || loop {
                match receiver.recv_timeout(Duration::from_millis(1000.min(config.retry_rate_ms))) {
                    Err(RecvTimeoutError::Disconnected) => break,
                    Err(RecvTimeoutError::Timeout) => {}
                    Ok(transaction_info) => {
                        inc_new_counter_info!("send_transaction_service-recv-tx", 1);
                        let addresses = leader_info.as_ref().map(|leader_info| {
                            leader_info.get_leader_tpus(config.leader_forward_count)
                        });
                        let addresses = addresses
                            .map(|address_list| {
                                if address_list.is_empty() {
                                    vec![&tpu_address]
                                } else {
                                    address_list
                                }
                            })
                            .unwrap_or_else(|| vec![&tpu_address]);
                        for address in addresses {
                            Self::send_transaction(
                                &send_socket,
                                address,
                                &transaction_info.wire_transaction,
                            );
                        }
                        if transactions.len() < MAX_TRANSACTION_QUEUE_SIZE {
                            inc_new_counter_info!("send_transaction_service-insert-tx", 1);
                            transactions.insert(transaction_info.signature, transaction_info);
                        } else {
                            datapoint_warn!("send_transaction_service-queue-overflow");
                        }
                    }
                }

                if last_status_check.elapsed().as_millis() as u64 >= config.retry_rate_ms {
                    if !transactions.is_empty() {
                        datapoint_info!(
                            "send_transaction_service-queue-size",
                            ("len", transactions.len(), i64)
                        );
                        let (root_bank, working_bank) = {
                            let bank_forks = bank_forks.read().unwrap();
                            (
                                bank_forks.root_bank().clone(),
                                bank_forks.working_bank().clone(),
                            )
                        };

                        let _result = Self::process_transactions(
                            &working_bank,
                            &root_bank,
                            &send_socket,
                            &tpu_address,
                            &mut transactions,
                            &leader_info,
                            &config,
                        );
                    }
                    last_status_check = Instant::now();
                    if last_leader_refresh.elapsed().as_millis() > 1000 {
                        if let Some(leader_info) = leader_info.as_mut() {
                            leader_info.refresh_recent_peers();
                        }
                        last_leader_refresh = Instant::now();
                    }
                }
            })
            .unwrap()
    }

    fn process_transactions<T: TpuInfo>(
        working_bank: &Arc<Bank>,
        root_bank: &Arc<Bank>,
        send_socket: &UdpSocket,
        tpu_address: &SocketAddr,
        transactions: &mut HashMap<Signature, TransactionInfo>,
        leader_info: &Option<T>,
        config: &Config,
    ) -> ProcessTransactionsResult {
        let mut result = ProcessTransactionsResult::default();

        transactions.retain(|signature, mut transaction_info| {
            if transaction_info.durable_nonce_info.is_some() {
                inc_new_counter_info!("send_transaction_service-nonced", 1);
            }
            if root_bank.has_signature(signature) {
                info!("Transaction is rooted: {}", signature);
                result.rooted += 1;
                inc_new_counter_info!("send_transaction_service-rooted", 1);
                return false;
            }
            if let Some((nonce_pubkey, durable_nonce)) = transaction_info.durable_nonce_info {
                let nonce_account = working_bank.get_account(&nonce_pubkey).unwrap_or_default();
                if !nonce_account::verify_nonce_account(&nonce_account, &durable_nonce)
                    && working_bank.get_signature_status_slot(signature).is_none()
                {
                    info!("Dropping expired durable-nonce transaction: {}", signature);
                    result.expired += 1;
                    inc_new_counter_info!("send_transaction_service-expired", 1);
                    return false;
                }
            }
            if transaction_info.last_valid_block_height < root_bank.block_height() {
                info!("Dropping expired transaction: {}", signature);
                result.expired += 1;
                inc_new_counter_info!("send_transaction_service-expired", 1);
                return false;
            }

            let max_retries = transaction_info
                .max_retries
                .or(config.default_max_retries)
                .map(|max_retries| max_retries.min(config.service_max_retries));

            if let Some(max_retries) = max_retries {
                if transaction_info.retries >= max_retries {
                    info!("Dropping transaction due to max retries: {}", signature);
                    result.max_retries_elapsed += 1;
                    inc_new_counter_info!("send_transaction_service-max_retries", 1);
                    return false;
                }
            }

            match working_bank.get_signature_status_slot(signature) {
                None => {
                    // Transaction is unknown to the working bank, it might have been
                    // dropped or landed in another fork.  Re-send it
                    info!("Retrying transaction: {}", signature);
                    result.retried += 1;
                    transaction_info.retries += 1;
                    inc_new_counter_info!("send_transaction_service-retry", 1);
                    let addresses = leader_info.as_ref().map(|leader_info| {
                        leader_info.get_leader_tpus(config.leader_forward_count)
                    });
                    let addresses = addresses
                        .map(|address_list| {
                            if address_list.is_empty() {
                                vec![tpu_address]
                            } else {
                                address_list
                            }
                        })
                        .unwrap_or_else(|| vec![tpu_address]);
                    for address in addresses {
                        Self::send_transaction(
                            send_socket,
                            address,
                            &transaction_info.wire_transaction,
                        );
                    }
                    true
                }
                Some((_slot, status)) => {
                    if status.is_err() {
                        info!("Dropping failed transaction: {}", signature);
                        result.failed += 1;
                        inc_new_counter_info!("send_transaction_service-failed", 1);
                        false
                    } else {
                        result.retained += 1;
                        true
                    }
                }
            }
        });

        result
    }

    fn send_transaction(
        send_socket: &UdpSocket,
        tpu_address: &SocketAddr,
        wire_transaction: &[u8],
    ) {
        if let Err(err) = send_socket.send_to(wire_transaction, tpu_address) {
            warn!("Failed to send transaction to {}: {:?}", tpu_address, err);
        }
    }

    pub fn join(self) -> thread::Result<()> {
        self.thread.join()
    }
}

#[cfg(test)]
mod test {
    use {
        super::*,
        crate::tpu_info::NullTpuInfo,
        crossbeam_channel::unbounded,
        solana_sdk::{
            account::AccountSharedData, genesis_config::create_genesis_config, nonce,
            pubkey::Pubkey, signature::Signer, system_program, system_transaction,
        },
    };

    #[test]
    fn service_exit() {
        let tpu_address = "127.0.0.1:0".parse().unwrap();
        let bank = Bank::default_for_tests();
        let bank_forks = Arc::new(RwLock::new(BankForks::new(bank)));
        let (sender, receiver) = unbounded();

        let send_tranaction_service = SendTransactionService::new::<NullTpuInfo>(
            tpu_address,
            &bank_forks,
            None,
            receiver,
            1000,
            1,
        );

        drop(sender);
        send_tranaction_service.join().unwrap();
    }

    #[test]
    fn process_transactions() {
        solana_logger::setup();

        let (genesis_config, mint_keypair) = create_genesis_config(4);
        let bank = Bank::new_for_tests(&genesis_config);
        let bank_forks = Arc::new(RwLock::new(BankForks::new(bank)));
        let send_socket = UdpSocket::bind("0.0.0.0:0").unwrap();
        let tpu_address = "127.0.0.1:0".parse().unwrap();
        let config = Config {
            leader_forward_count: 1,
            ..Config::default()
        };

        let root_bank = Arc::new(Bank::new_from_parent(
            &bank_forks.read().unwrap().working_bank(),
            &Pubkey::default(),
            1,
        ));
        let rooted_signature = root_bank
            .transfer(1, &mint_keypair, &mint_keypair.pubkey())
            .unwrap();

        let working_bank = Arc::new(Bank::new_from_parent(&root_bank, &Pubkey::default(), 2));

        let non_rooted_signature = working_bank
            .transfer(2, &mint_keypair, &mint_keypair.pubkey())
            .unwrap();

        let failed_signature = {
            let blockhash = working_bank.last_blockhash();
            let transaction =
                system_transaction::transfer(&mint_keypair, &Pubkey::default(), 1, blockhash);
            let signature = transaction.signatures[0];
            working_bank.process_transaction(&transaction).unwrap_err();
            signature
        };

        let mut transactions = HashMap::new();

        info!("Expired transactions are dropped...");
        transactions.insert(
            Signature::default(),
            TransactionInfo::new(
                Signature::default(),
                vec![],
                root_bank.block_height() - 1,
                None,
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert!(transactions.is_empty());
        assert_eq!(
            result,
            ProcessTransactionsResult {
                expired: 1,
                ..ProcessTransactionsResult::default()
            }
        );

        info!("Rooted transactions are dropped...");
        transactions.insert(
            rooted_signature,
            TransactionInfo::new(
                rooted_signature,
                vec![],
                working_bank.block_height(),
                None,
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert!(transactions.is_empty());
        assert_eq!(
            result,
            ProcessTransactionsResult {
                rooted: 1,
                ..ProcessTransactionsResult::default()
            }
        );

        info!("Failed transactions are dropped...");
        transactions.insert(
            failed_signature,
            TransactionInfo::new(
                failed_signature,
                vec![],
                working_bank.block_height(),
                None,
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert!(transactions.is_empty());
        assert_eq!(
            result,
            ProcessTransactionsResult {
                failed: 1,
                ..ProcessTransactionsResult::default()
            }
        );

        info!("Non-rooted transactions are kept...");
        transactions.insert(
            non_rooted_signature,
            TransactionInfo::new(
                non_rooted_signature,
                vec![],
                working_bank.block_height(),
                None,
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert_eq!(transactions.len(), 1);
        assert_eq!(
            result,
            ProcessTransactionsResult {
                retained: 1,
                ..ProcessTransactionsResult::default()
            }
        );
        transactions.clear();

        info!("Unknown transactions are retried...");
        transactions.insert(
            Signature::default(),
            TransactionInfo::new(
                Signature::default(),
                vec![],
                working_bank.block_height(),
                None,
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert_eq!(transactions.len(), 1);
        assert_eq!(
            result,
            ProcessTransactionsResult {
                retried: 1,
                ..ProcessTransactionsResult::default()
            }
        );
        transactions.clear();

        info!("Transactions are only retried until max_retries");
        transactions.insert(
            Signature::new(&[1; 64]),
            TransactionInfo::new(
                Signature::default(),
                vec![],
                working_bank.block_height(),
                None,
                Some(0),
            ),
        );
        transactions.insert(
            Signature::new(&[2; 64]),
            TransactionInfo::new(
                Signature::default(),
                vec![],
                working_bank.block_height(),
                None,
                Some(1),
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert_eq!(transactions.len(), 1);
        assert_eq!(
            result,
            ProcessTransactionsResult {
                retried: 1,
                max_retries_elapsed: 1,
                ..ProcessTransactionsResult::default()
            }
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert!(transactions.is_empty());
        assert_eq!(
            result,
            ProcessTransactionsResult {
                max_retries_elapsed: 1,
                ..ProcessTransactionsResult::default()
            }
        );
    }

    #[test]
    fn test_retry_durable_nonce_transactions() {
        solana_logger::setup();

        let (genesis_config, mint_keypair) = create_genesis_config(4);
        let bank = Bank::new_for_tests(&genesis_config);
        let bank_forks = Arc::new(RwLock::new(BankForks::new(bank)));
        let send_socket = UdpSocket::bind("0.0.0.0:0").unwrap();
        let tpu_address = "127.0.0.1:0".parse().unwrap();
        let config = Config {
            leader_forward_count: 1,
            ..Config::default()
        };

        let root_bank = Arc::new(Bank::new_from_parent(
            &bank_forks.read().unwrap().working_bank(),
            &Pubkey::default(),
            1,
        ));
        let rooted_signature = root_bank
            .transfer(1, &mint_keypair, &mint_keypair.pubkey())
            .unwrap();

        let nonce_address = Pubkey::new_unique();
        let durable_nonce = Hash::new_unique();
        let nonce_state = nonce::state::Versions::new_current(nonce::State::Initialized(
            nonce::state::Data::new(Pubkey::default(), durable_nonce, 42),
        ));
        let nonce_account =
            AccountSharedData::new_data(43, &nonce_state, &system_program::id()).unwrap();
        root_bank.store_account(&nonce_address, &nonce_account);

        let working_bank = Arc::new(Bank::new_from_parent(&root_bank, &Pubkey::default(), 2));
        let non_rooted_signature = working_bank
            .transfer(2, &mint_keypair, &mint_keypair.pubkey())
            .unwrap();

        let last_valid_block_height = working_bank.block_height() + 300;

        let failed_signature = {
            let blockhash = working_bank.last_blockhash();
            let transaction =
                system_transaction::transfer(&mint_keypair, &Pubkey::default(), 1, blockhash);
            let signature = transaction.signatures[0];
            working_bank.process_transaction(&transaction).unwrap_err();
            signature
        };

        let mut transactions = HashMap::new();

        info!("Rooted durable-nonce transactions are dropped...");
        transactions.insert(
            rooted_signature,
            TransactionInfo::new(
                rooted_signature,
                vec![],
                last_valid_block_height,
                Some((nonce_address, durable_nonce)),
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert!(transactions.is_empty());
        assert_eq!(
            result,
            ProcessTransactionsResult {
                rooted: 1,
                ..ProcessTransactionsResult::default()
            }
        );
        // Nonce expired case
        transactions.insert(
            rooted_signature,
            TransactionInfo::new(
                rooted_signature,
                vec![],
                last_valid_block_height,
                Some((nonce_address, Hash::new_unique())),
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert!(transactions.is_empty());
        assert_eq!(
            result,
            ProcessTransactionsResult {
                rooted: 1,
                ..ProcessTransactionsResult::default()
            }
        );

        // Expired durable-nonce transactions are dropped; nonce has advanced...
        info!("Expired durable-nonce transactions are dropped...");
        transactions.insert(
            Signature::default(),
            TransactionInfo::new(
                Signature::default(),
                vec![],
                last_valid_block_height,
                Some((nonce_address, Hash::new_unique())),
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert!(transactions.is_empty());
        assert_eq!(
            result,
            ProcessTransactionsResult {
                expired: 1,
                ..ProcessTransactionsResult::default()
            }
        );
        // ... or last_valid_block_height timeout has passed
        transactions.insert(
            Signature::default(),
            TransactionInfo::new(
                Signature::default(),
                vec![],
                root_bank.block_height() - 1,
                Some((nonce_address, durable_nonce)),
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert!(transactions.is_empty());
        assert_eq!(
            result,
            ProcessTransactionsResult {
                expired: 1,
                ..ProcessTransactionsResult::default()
            }
        );

        info!("Failed durable-nonce transactions are dropped...");
        transactions.insert(
            failed_signature,
            TransactionInfo::new(
                failed_signature,
                vec![],
                last_valid_block_height,
                Some((nonce_address, Hash::new_unique())), // runtime should advance nonce on failed transactions
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert!(transactions.is_empty());
        assert_eq!(
            result,
            ProcessTransactionsResult {
                failed: 1,
                ..ProcessTransactionsResult::default()
            }
        );

        info!("Non-rooted durable-nonce transactions are kept...");
        transactions.insert(
            non_rooted_signature,
            TransactionInfo::new(
                non_rooted_signature,
                vec![],
                last_valid_block_height,
                Some((nonce_address, Hash::new_unique())), // runtime advances nonce when transaction lands
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert_eq!(transactions.len(), 1);
        assert_eq!(
            result,
            ProcessTransactionsResult {
                retained: 1,
                ..ProcessTransactionsResult::default()
            }
        );
        transactions.clear();

        info!("Unknown durable-nonce transactions are retried until nonce advances...");
        transactions.insert(
            Signature::default(),
            TransactionInfo::new(
                Signature::default(),
                vec![],
                last_valid_block_height,
                Some((nonce_address, durable_nonce)),
                None,
            ),
        );
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert_eq!(transactions.len(), 1);
        assert_eq!(
            result,
            ProcessTransactionsResult {
                retried: 1,
                ..ProcessTransactionsResult::default()
            }
        );
        // Advance nonce
        let new_durable_nonce = Hash::new_unique();
        let new_nonce_state = nonce::state::Versions::new_current(nonce::State::Initialized(
            nonce::state::Data::new(Pubkey::default(), new_durable_nonce, 42),
        ));
        let nonce_account =
            AccountSharedData::new_data(43, &new_nonce_state, &system_program::id()).unwrap();
        working_bank.store_account(&nonce_address, &nonce_account);
        let result = SendTransactionService::process_transactions::<NullTpuInfo>(
            &working_bank,
            &root_bank,
            &send_socket,
            &tpu_address,
            &mut transactions,
            &None,
            &config,
        );
        assert_eq!(transactions.len(), 0);
        assert_eq!(
            result,
            ProcessTransactionsResult {
                expired: 1,
                ..ProcessTransactionsResult::default()
            }
        );
    }
}