// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of OpenEthereum.

// OpenEthereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// OpenEthereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with OpenEthereum.  If not, see <http://www.gnu.org/licenses/>.

//! Notifier for new transaction hashes.

use std::{fmt, sync::Arc};

use ethereum_types::H256;
use txpool::{self, VerifiedTransaction};

use pool::VerifiedTransaction as Transaction;

type Listener = Box<dyn Fn(&[H256]) + Send + Sync>;

/// Manages notifications to pending transaction listeners.
#[derive(Default)]
pub struct Notifier {
    listeners: Vec<Listener>,
    pending: Vec<H256>,
}

impl fmt::Debug for Notifier {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        fmt.debug_struct("Notifier")
            .field("listeners", &self.listeners.len())
            .field("pending", &self.pending)
            .finish()
    }
}

impl Notifier {
    /// Add new listener to receive notifications.
    pub fn add(&mut self, f: Listener) {
        self.listeners.push(f)
    }

    /// Notify listeners about all currently pending transactions.
    pub fn notify(&mut self) {
        if self.pending.is_empty() {
            return;
        }

        for l in &self.listeners {
            (l)(&self.pending);
        }

        self.pending.clear();
    }
}

impl txpool::Listener<Transaction> for Notifier {
    fn added(&mut self, tx: &Arc<Transaction>, _old: Option<&Arc<Transaction>>) {
        self.pending.push(*tx.hash());
    }
}

/// Transaction pool logger.
#[derive(Default, Debug)]
pub struct Logger;

impl txpool::Listener<Transaction> for Logger {
    fn added(&mut self, tx: &Arc<Transaction>, old: Option<&Arc<Transaction>>) {
        debug!(target: "txqueue", "[{:?}] Added to the pool.", tx.hash());
        debug!(
            target: "txqueue",
            "[{hash:?}] Sender: {sender}, nonce: {nonce}, gasPrice: {gas_price}, gas: {gas}, value: {value}, dataLen: {data}))",
            hash = tx.hash(),
            sender = tx.sender(),
            nonce = tx.signed().tx().nonce,
            gas_price = tx.signed().tx().gas_price,
            gas = tx.signed().tx().gas,
            value = tx.signed().tx().value,
            data = tx.signed().tx().data.len(),
        );

        if let Some(old) = old {
            debug!(target: "txqueue", "[{:?}] Dropped. Replaced by [{:?}]", old.hash(), tx.hash());
        }
    }

    fn rejected<H: fmt::Debug + fmt::LowerHex>(
        &mut self,
        _tx: &Arc<Transaction>,
        reason: &txpool::Error<H>,
    ) {
        trace!(target: "txqueue", "Rejected {}.", reason);
    }

    fn dropped(&mut self, tx: &Arc<Transaction>, new: Option<&Transaction>) {
        match new {
            Some(new) => {
                debug!(target: "txqueue", "[{:?}] Pushed out by [{:?}]", tx.hash(), new.hash())
            }
            None => debug!(target: "txqueue", "[{:?}] Dropped.", tx.hash()),
        }
    }

    fn invalid(&mut self, tx: &Arc<Transaction>) {
        debug!(target: "txqueue", "[{:?}] Marked as invalid by executor.", tx.hash());
    }

    fn canceled(&mut self, tx: &Arc<Transaction>) {
        debug!(target: "txqueue", "[{:?}] Canceled by the user.", tx.hash());
    }

    fn culled(&mut self, tx: &Arc<Transaction>) {
        debug!(target: "txqueue", "[{:?}] Culled or mined.", tx.hash());
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use ethereum_types::H160;
    use parking_lot::Mutex;
    use txpool::Listener;
    use types::transaction;

    #[test]
    fn should_notify_listeners() {
        // given
        let received = Arc::new(Mutex::new(vec![]));
        let r = received.clone();
        let listener = Box::new(move |hashes: &[H256]| {
            *r.lock() = hashes.iter().map(|x| *x).collect();
        });

        let mut tx_listener = Notifier::default();
        tx_listener.add(listener);

        // when
        let tx = new_tx();
        tx_listener.added(&tx, None);
        assert_eq!(*received.lock(), vec![]);

        // then
        tx_listener.notify();
        assert_eq!(
            *received.lock(),
            vec![
                "de96bdcdf864c95eb7f81eff1e3290be24a0f327732e0c4251c1896a565a80db"
                    .parse()
                    .unwrap()
            ]
        );
    }

    fn new_tx() -> Arc<Transaction> {
        let signed = transaction::TypedTransaction::Legacy(transaction::Transaction {
            action: transaction::Action::Create,
            data: vec![1, 2, 3],
            nonce: 5.into(),
            gas: 21_000.into(),
            gas_price: 5.into(),
            value: 0.into(),
        })
        .fake_sign(H160::from_low_u64_be(5));

        Arc::new(Transaction::from_pending_block_transaction(signed))
    }
}