pub mod harness;

use anyhow::Result;
use async_trait::async_trait;
use futures::{
    channel::mpsc::{channel, Receiver, Sender},
    future::{select, try_join},
    pin_mut, SinkExt, StreamExt,
};
use genawaiter::GeneratorState;
use harness::{
    init_bitcoind, init_test,
    node::{run_alice_until, run_bob_until},
};
use monero_harness::Monero;
use rand::rngs::OsRng;
use std::{convert::TryInto, sync::Arc};
use testcontainers::clients::Cli;
use tokio::sync::Mutex;
use tracing::info;
use tracing_subscriber::util::SubscriberInitExt;
use xmr_btc::{
    alice::{self, ReceiveBitcoinRedeemEncsig},
    bitcoin::{BroadcastSignedTransaction, EncryptedSignature, SignTxLock},
    bob::{self, ReceiveTransferProof},
    monero::{CreateWalletForOutput, Transfer, TransferProof},
};

/// Time given to Bob to get the Bitcoin lock transaction included in a block.
const BITCOIN_TX_LOCK_TIMEOUT: u64 = 5;

type AliceNetwork = Network<EncryptedSignature>;
type BobNetwork = Network<TransferProof>;

#[derive(Debug)]
struct Network<M> {
    // TODO: It is weird to use mpsc's in a situation where only one message is expected, but the
    // ownership rules of Rust are making this painful
    pub receiver: Receiver<M>,
}

impl<M> Network<M> {
    pub fn new() -> (Network<M>, Sender<M>) {
        let (sender, receiver) = channel(1);

        (Self { receiver }, sender)
    }
}

#[async_trait]
impl ReceiveTransferProof for BobNetwork {
    async fn receive_transfer_proof(&mut self) -> TransferProof {
        self.receiver.next().await.unwrap()
    }
}

#[async_trait]
impl ReceiveBitcoinRedeemEncsig for AliceNetwork {
    async fn receive_bitcoin_redeem_encsig(&mut self) -> EncryptedSignature {
        self.receiver.next().await.unwrap()
    }
}

struct AliceBehaviour {
    lock_xmr: bool,
    redeem_btc: bool,
    cancel_btc: bool,
    punish_btc: bool,
    create_monero_wallet_for_output: bool,
}

impl Default for AliceBehaviour {
    fn default() -> Self {
        Self {
            lock_xmr: true,
            redeem_btc: true,
            cancel_btc: true,
            punish_btc: true,
            create_monero_wallet_for_output: true,
        }
    }
}

struct BobBehaviour {
    lock_btc: bool,
    send_btc_redeem_encsig: bool,
    create_monero_wallet_for_output: bool,
    cancel_btc: bool,
    refund_btc: bool,
}

impl Default for BobBehaviour {
    fn default() -> Self {
        Self {
            lock_btc: true,
            send_btc_redeem_encsig: true,
            create_monero_wallet_for_output: true,
            cancel_btc: true,
            refund_btc: true,
        }
    }
}

async fn swap_as_alice(
    network: Arc<Mutex<AliceNetwork>>,
    // FIXME: It would be more intuitive to have a single network/transport struct instead of
    // splitting into two, but Rust ownership rules make this tedious
    mut sender: Sender<TransferProof>,
    monero_wallet: Arc<harness::wallet::monero::Wallet>,
    bitcoin_wallet: Arc<harness::wallet::bitcoin::Wallet>,
    behaviour: AliceBehaviour,
    state: alice::State3,
) -> Result<()> {
    let mut action_generator = alice::action_generator(
        network,
        bitcoin_wallet.clone(),
        state,
        BITCOIN_TX_LOCK_TIMEOUT,
    );

    loop {
        let state = action_generator.async_resume().await;

        info!("resumed execution of alice generator, got: {:?}", state);

        match state {
            GeneratorState::Yielded(alice::Action::LockXmr {
                amount,
                public_spend_key,
                public_view_key,
            }) => {
                if behaviour.lock_xmr {
                    let (transfer_proof, _) = monero_wallet
                        .transfer(public_spend_key, public_view_key, amount)
                        .await?;

                    sender.send(transfer_proof).await?;
                }
            }
            GeneratorState::Yielded(alice::Action::RedeemBtc(tx)) => {
                if behaviour.redeem_btc {
                    let _ = bitcoin_wallet.broadcast_signed_transaction(tx).await?;
                }
            }
            GeneratorState::Yielded(alice::Action::CancelBtc(tx)) => {
                if behaviour.cancel_btc {
                    let _ = bitcoin_wallet.broadcast_signed_transaction(tx).await?;
                }
            }
            GeneratorState::Yielded(alice::Action::PunishBtc(tx)) => {
                if behaviour.punish_btc {
                    let _ = bitcoin_wallet.broadcast_signed_transaction(tx).await?;
                }
            }
            GeneratorState::Yielded(alice::Action::CreateMoneroWalletForOutput {
                spend_key,
                view_key,
            }) => {
                if behaviour.create_monero_wallet_for_output {
                    monero_wallet
                        .create_and_load_wallet_for_output(spend_key, view_key)
                        .await?;
                }
            }
            GeneratorState::Complete(()) => return Ok(()),
        }
    }
}

async fn swap_as_bob(
    network: BobNetwork,
    mut sender: Sender<EncryptedSignature>,
    monero_wallet: Arc<harness::wallet::monero::Wallet>,
    bitcoin_wallet: Arc<harness::wallet::bitcoin::Wallet>,
    behaviour: BobBehaviour,
    state: bob::State2,
) -> Result<()> {
    let mut action_generator = bob::action_generator(
        network,
        monero_wallet.clone(),
        bitcoin_wallet.clone(),
        state,
        BITCOIN_TX_LOCK_TIMEOUT,
    );

    loop {
        let state = action_generator.async_resume().await;

        info!("resumed execution of bob generator, got: {:?}", state);

        match state {
            GeneratorState::Yielded(bob::Action::LockBtc(tx_lock)) => {
                if behaviour.lock_btc {
                    let signed_tx_lock = bitcoin_wallet.sign_tx_lock(tx_lock).await?;
                    let _ = bitcoin_wallet
                        .broadcast_signed_transaction(signed_tx_lock)
                        .await?;
                }
            }
            GeneratorState::Yielded(bob::Action::SendBtcRedeemEncsig(tx_redeem_encsig)) => {
                if behaviour.send_btc_redeem_encsig {
                    sender.send(tx_redeem_encsig).await.unwrap();
                }
            }
            GeneratorState::Yielded(bob::Action::CreateXmrWalletForOutput {
                spend_key,
                view_key,
            }) => {
                if behaviour.create_monero_wallet_for_output {
                    monero_wallet
                        .create_and_load_wallet_for_output(spend_key, view_key)
                        .await?;
                }
            }
            GeneratorState::Yielded(bob::Action::CancelBtc(tx_cancel)) => {
                if behaviour.cancel_btc {
                    let _ = bitcoin_wallet
                        .broadcast_signed_transaction(tx_cancel)
                        .await?;
                }
            }
            GeneratorState::Yielded(bob::Action::RefundBtc(tx_refund)) => {
                if behaviour.refund_btc {
                    let _ = bitcoin_wallet
                        .broadcast_signed_transaction(tx_refund)
                        .await?;
                }
            }
            GeneratorState::Complete(()) => return Ok(()),
        }
    }
}

// NOTE: For some reason running these tests overflows the stack. In order to
// mitigate this run them with:
//
//     RUST_MIN_STACK=100000000 cargo test

#[tokio::test]
async fn on_chain_happy_path() {
    let cli = Cli::default();
    let (monero, _container) = Monero::new(&cli).unwrap();
    let bitcoind = init_bitcoind(&cli).await;

    let (alice_state0, bob_state0, mut alice_node, mut bob_node, initial_balances, swap_amounts) =
        init_test(&monero, &bitcoind, Some(100), Some(100)).await;

    // run the handshake as part of the setup
    let (alice_state, bob_state) = try_join(
        run_alice_until(
            &mut alice_node,
            alice_state0.into(),
            harness::alice::is_state3,
            &mut OsRng,
        ),
        run_bob_until(
            &mut bob_node,
            bob_state0.into(),
            harness::bob::is_state2,
            &mut OsRng,
        ),
    )
    .await
    .unwrap();
    let alice: alice::State3 = alice_state.try_into().unwrap();
    let bob: bob::State2 = bob_state.try_into().unwrap();
    let tx_lock_txid = bob.tx_lock.txid();

    let alice_bitcoin_wallet = Arc::new(alice_node.bitcoin_wallet);
    let bob_bitcoin_wallet = Arc::new(bob_node.bitcoin_wallet);
    let alice_monero_wallet = Arc::new(alice_node.monero_wallet);
    let bob_monero_wallet = Arc::new(bob_node.monero_wallet);

    let (alice_network, bob_sender) = Network::<EncryptedSignature>::new();
    let (bob_network, alice_sender) = Network::<TransferProof>::new();

    let alice_network = Arc::new(Mutex::new(alice_network));

    try_join(
        swap_as_alice(
            alice_network,
            alice_sender,
            alice_monero_wallet.clone(),
            alice_bitcoin_wallet.clone(),
            AliceBehaviour::default(),
            alice,
        ),
        swap_as_bob(
            bob_network,
            bob_sender,
            bob_monero_wallet.clone(),
            bob_bitcoin_wallet.clone(),
            BobBehaviour::default(),
            bob,
        ),
    )
    .await
    .unwrap();

    let alice_final_btc_balance = alice_bitcoin_wallet.balance().await.unwrap();
    let bob_final_btc_balance = bob_bitcoin_wallet.balance().await.unwrap();

    let lock_tx_bitcoin_fee = bob_bitcoin_wallet
        .transaction_fee(tx_lock_txid)
        .await
        .unwrap();

    let alice_final_xmr_balance = alice_monero_wallet.get_balance().await.unwrap();

    monero.wait_for_bob_wallet_block_height().await.unwrap();
    let bob_final_xmr_balance = bob_monero_wallet.get_balance().await.unwrap();

    assert_eq!(
        alice_final_btc_balance,
        initial_balances.alice_btc + swap_amounts.btc
            - bitcoin::Amount::from_sat(xmr_btc::bitcoin::TX_FEE)
    );
    assert_eq!(
        bob_final_btc_balance,
        initial_balances.bob_btc - swap_amounts.btc - lock_tx_bitcoin_fee
    );

    // Getting the Monero LockTx fee is tricky in a clean way, I think checking this
    // condition is sufficient
    assert!(alice_final_xmr_balance <= initial_balances.alice_xmr - swap_amounts.xmr);
    assert_eq!(
        bob_final_xmr_balance,
        initial_balances.bob_xmr + swap_amounts.xmr
    );
}

#[tokio::test]
async fn on_chain_both_refund_if_alice_never_redeems() {
    let cli = Cli::default();
    let (monero, _container) = Monero::new(&cli).unwrap();
    let bitcoind = init_bitcoind(&cli).await;

    let (alice_state0, bob_state0, mut alice_node, mut bob_node, initial_balances, swap_amounts) =
        init_test(&monero, &bitcoind, Some(10), Some(10)).await;

    // run the handshake as part of the setup
    let (alice_state, bob_state) = try_join(
        run_alice_until(
            &mut alice_node,
            alice_state0.into(),
            harness::alice::is_state3,
            &mut OsRng,
        ),
        run_bob_until(
            &mut bob_node,
            bob_state0.into(),
            harness::bob::is_state2,
            &mut OsRng,
        ),
    )
    .await
    .unwrap();
    let alice: alice::State3 = alice_state.try_into().unwrap();
    let bob: bob::State2 = bob_state.try_into().unwrap();
    let tx_lock_txid = bob.tx_lock.txid();

    let alice_bitcoin_wallet = Arc::new(alice_node.bitcoin_wallet);
    let bob_bitcoin_wallet = Arc::new(bob_node.bitcoin_wallet);
    let alice_monero_wallet = Arc::new(alice_node.monero_wallet);
    let bob_monero_wallet = Arc::new(bob_node.monero_wallet);

    let (alice_network, bob_sender) = Network::<EncryptedSignature>::new();
    let (bob_network, alice_sender) = Network::<TransferProof>::new();

    let alice_network = Arc::new(Mutex::new(alice_network));

    try_join(
        swap_as_alice(
            alice_network,
            alice_sender,
            alice_monero_wallet.clone(),
            alice_bitcoin_wallet.clone(),
            AliceBehaviour {
                redeem_btc: false,
                ..Default::default()
            },
            alice,
        ),
        swap_as_bob(
            bob_network,
            bob_sender,
            bob_monero_wallet.clone(),
            bob_bitcoin_wallet.clone(),
            BobBehaviour::default(),
            bob,
        ),
    )
    .await
    .unwrap();

    let alice_final_btc_balance = alice_bitcoin_wallet.balance().await.unwrap();
    let bob_final_btc_balance = bob_bitcoin_wallet.balance().await.unwrap();

    let lock_tx_bitcoin_fee = bob_bitcoin_wallet
        .transaction_fee(tx_lock_txid)
        .await
        .unwrap();

    monero.wait_for_alice_wallet_block_height().await.unwrap();
    let alice_final_xmr_balance = alice_monero_wallet.get_balance().await.unwrap();

    let bob_final_xmr_balance = bob_monero_wallet.get_balance().await.unwrap();

    assert_eq!(alice_final_btc_balance, initial_balances.alice_btc);
    assert_eq!(
        bob_final_btc_balance,
        // The 2 * TX_FEE corresponds to tx_refund and tx_cancel.
        initial_balances.bob_btc
            - bitcoin::Amount::from_sat(2 * xmr_btc::bitcoin::TX_FEE)
            - lock_tx_bitcoin_fee
    );

    // Because we create a new wallet when claiming Monero, we can only assert on
    // this new wallet owning all of `xmr_amount` after refund
    assert_eq!(alice_final_xmr_balance, swap_amounts.xmr);
    assert_eq!(bob_final_xmr_balance, initial_balances.bob_xmr);
}

#[tokio::test]
async fn on_chain_alice_punishes_if_bob_never_acts_after_fund() {
    let _guard = tracing_subscriber::fmt()
        .with_env_filter("info")
        .with_ansi(false)
        .set_default();

    let cli = Cli::default();
    let (monero, _container) = Monero::new(&cli).unwrap();
    let bitcoind = init_bitcoind(&cli).await;

    let (alice_state0, bob_state0, mut alice_node, mut bob_node, initial_balances, swap_amounts) =
        init_test(&monero, &bitcoind, Some(10), Some(10)).await;

    // run the handshake as part of the setup
    let (alice_state, bob_state) = try_join(
        run_alice_until(
            &mut alice_node,
            alice_state0.into(),
            harness::alice::is_state3,
            &mut OsRng,
        ),
        run_bob_until(
            &mut bob_node,
            bob_state0.into(),
            harness::bob::is_state2,
            &mut OsRng,
        ),
    )
    .await
    .unwrap();
    let alice: alice::State3 = alice_state.try_into().unwrap();
    let bob: bob::State2 = bob_state.try_into().unwrap();
    let tx_lock_txid = bob.tx_lock.txid();

    let alice_bitcoin_wallet = Arc::new(alice_node.bitcoin_wallet);
    let bob_bitcoin_wallet = Arc::new(bob_node.bitcoin_wallet);
    let alice_monero_wallet = Arc::new(alice_node.monero_wallet);
    let bob_monero_wallet = Arc::new(bob_node.monero_wallet);

    let (alice_network, bob_sender) = Network::<EncryptedSignature>::new();
    let (bob_network, alice_sender) = Network::<TransferProof>::new();

    let alice_network = Arc::new(Mutex::new(alice_network));

    let alice_swap = swap_as_alice(
        alice_network,
        alice_sender,
        alice_monero_wallet.clone(),
        alice_bitcoin_wallet.clone(),
        AliceBehaviour::default(),
        alice,
    );
    let bob_swap = swap_as_bob(
        bob_network,
        bob_sender,
        bob_monero_wallet.clone(),
        bob_bitcoin_wallet.clone(),
        BobBehaviour {
            send_btc_redeem_encsig: false,
            create_monero_wallet_for_output: false,
            cancel_btc: false,
            refund_btc: false,
            ..Default::default()
        },
        bob,
    );

    pin_mut!(alice_swap);
    pin_mut!(bob_swap);

    // since we model Bob as inactive after locking bitcoin, his future does not
    // resolve, so we wait for one of the two (Alice's) to resolve via select
    select(alice_swap, bob_swap).await;

    let alice_final_btc_balance = alice_bitcoin_wallet.balance().await.unwrap();
    let bob_final_btc_balance = bob_bitcoin_wallet.balance().await.unwrap();

    let lock_tx_bitcoin_fee = bob_bitcoin_wallet
        .transaction_fee(tx_lock_txid)
        .await
        .unwrap();

    let alice_final_xmr_balance = alice_monero_wallet.get_balance().await.unwrap();
    let bob_final_xmr_balance = bob_monero_wallet.get_balance().await.unwrap();

    assert_eq!(
        alice_final_btc_balance,
        initial_balances.alice_btc + swap_amounts.btc
            - bitcoin::Amount::from_sat(2 * xmr_btc::bitcoin::TX_FEE)
    );
    assert_eq!(
        bob_final_btc_balance,
        initial_balances.bob_btc - swap_amounts.btc - lock_tx_bitcoin_fee
    );

    // Getting the Monero LockTx fee is tricky in a clean way, I think checking this
    // condition is sufficient
    assert!(alice_final_xmr_balance <= initial_balances.alice_xmr - swap_amounts.xmr,);
    assert_eq!(bob_final_xmr_balance, initial_balances.bob_xmr);
}