//! Test helpers for `reth-exex`

#![doc(
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#![cfg_attr(docsrs, feature(doc_cfg))]
#![cfg_attr(not(test), warn(unused_crate_dependencies))]

use std::{
    fmt::Debug,
    future::{poll_fn, Future},
    sync::Arc,
    task::Poll,
};

use alloy_eips::BlockNumHash;
use futures_util::FutureExt;
use reth_chainspec::{ChainSpec, MAINNET};
use reth_consensus::test_utils::TestConsensus;
use reth_db::{
    test_utils::{
        create_test_rocksdb_dir, create_test_rw_db, create_test_static_files_dir, TempDatabase,
    },
    DatabaseEnv,
};
use reth_db_common::init::init_genesis;
use reth_ethereum_primitives::{EthPrimitives, TransactionSigned};
use reth_evm_ethereum::MockEvmConfig;
use reth_execution_types::Chain;
use reth_exex::{ExExContext, ExExEvent, ExExNotification, ExExNotifications, Wal};
use reth_network::{config::rng_secret_key, NetworkConfigBuilder, NetworkManager};
use reth_node_api::{
    FullNodeTypes, FullNodeTypesAdapter, NodePrimitives, NodeTypes, NodeTypesWithDBAdapter,
};
use reth_node_builder::{
    components::{
        BasicPayloadServiceBuilder, Components, ComponentsBuilder, ConsensusBuilder,
        ExecutorBuilder, PoolBuilder,
    },
    BuilderContext, Node, NodeAdapter, RethFullAdapter,
};
use reth_node_core::node_config::NodeConfig;
use reth_node_ethereum::{
    node::{
        EthereumAddOns, EthereumEngineValidatorBuilder, EthereumEthApiBuilder,
        EthereumNetworkBuilder, EthereumPayloadBuilder,
    },
    EthEngineTypes,
};
use reth_payload_builder::noop::NoopPayloadBuilderService;
use reth_primitives_traits::{Block as _, RecoveredBlock};
use reth_provider::{
    providers::{BlockchainProvider, RocksDBProvider, StaticFileProvider},
    BlockReader, EthStorage, ProviderFactory,
};
use reth_tasks::Runtime;
use reth_transaction_pool::test_utils::{testing_pool, TestPool};
use tempfile::TempDir;
use thiserror::Error;
use tokio::sync::mpsc::{Sender, UnboundedReceiver};

/// A test [`PoolBuilder`] that builds a [`TestPool`].
#[derive(Debug, Default, Clone, Copy)]
#[non_exhaustive]
pub struct TestPoolBuilder;

impl<Node, Evm: Send> PoolBuilder<Node, Evm> for TestPoolBuilder
where
    Node: FullNodeTypes<Types: NodeTypes<Primitives: NodePrimitives<SignedTx = TransactionSigned>>>,
{
    type Pool = TestPool;

    async fn build_pool(
        self,
        _ctx: &BuilderContext<Node>,
        _evm_config: Evm,
    ) -> eyre::Result<Self::Pool> {
        Ok(testing_pool())
    }
}

/// A test [`ExecutorBuilder`] that builds a [`MockEvmConfig`] for testing.
#[derive(Debug, Default, Clone, Copy)]
#[non_exhaustive]
pub struct TestExecutorBuilder;

impl<Node> ExecutorBuilder<Node> for TestExecutorBuilder
where
    Node: FullNodeTypes<Types: NodeTypes<ChainSpec = ChainSpec, Primitives = EthPrimitives>>,
{
    type EVM = MockEvmConfig;

    async fn build_evm(self, _ctx: &BuilderContext<Node>) -> eyre::Result<Self::EVM> {
        let evm_config = MockEvmConfig::default();
        Ok(evm_config)
    }
}

/// A test [`ConsensusBuilder`] that builds a [`TestConsensus`].
#[derive(Debug, Default, Clone, Copy)]
#[non_exhaustive]
pub struct TestConsensusBuilder;

impl<Node> ConsensusBuilder<Node> for TestConsensusBuilder
where
    Node: FullNodeTypes,
{
    type Consensus = Arc<TestConsensus>;

    async fn build_consensus(self, _ctx: &BuilderContext<Node>) -> eyre::Result<Self::Consensus> {
        Ok(Arc::new(TestConsensus::default()))
    }
}

/// A test [`Node`].
#[derive(Debug, Default, Clone, Copy)]
#[non_exhaustive]
pub struct TestNode;

impl NodeTypes for TestNode {
    type Primitives = EthPrimitives;
    type ChainSpec = ChainSpec;
    type Storage = EthStorage;
    type Payload = EthEngineTypes;
}

impl<N> Node<N> for TestNode
where
    N: FullNodeTypes<Types = Self>,
{
    type ComponentsBuilder = ComponentsBuilder<
        N,
        TestPoolBuilder,
        BasicPayloadServiceBuilder<EthereumPayloadBuilder>,
        EthereumNetworkBuilder,
        TestExecutorBuilder,
        TestConsensusBuilder,
    >;
    type AddOns =
        EthereumAddOns<NodeAdapter<N>, EthereumEthApiBuilder, EthereumEngineValidatorBuilder>;

    fn components_builder(&self) -> Self::ComponentsBuilder {
        ComponentsBuilder::default()
            .node_types::<N>()
            .pool(TestPoolBuilder::default())
            .executor(TestExecutorBuilder::default())
            .payload(BasicPayloadServiceBuilder::default())
            .network(EthereumNetworkBuilder::default())
            .consensus(TestConsensusBuilder::default())
    }

    fn add_ons(&self) -> Self::AddOns {
        EthereumAddOns::default()
    }
}

/// A shared [`TempDatabase`] used for testing
pub type TmpDB = Arc<TempDatabase<DatabaseEnv>>;
/// The [`NodeAdapter`] for the [`TestExExContext`]. Contains type necessary to
/// boot the testing environment
pub type Adapter = NodeAdapter<RethFullAdapter<TmpDB, TestNode>>;
/// An [`ExExContext`] using the [`Adapter`] type.
pub type TestExExContext = ExExContext<Adapter>;

/// A helper type for testing Execution Extensions.
#[derive(Debug)]
pub struct TestExExHandle {
    /// Genesis block that was inserted into the storage
    pub genesis: RecoveredBlock<reth_ethereum_primitives::Block>,
    /// Provider Factory for accessing the emphemeral storage of the host node
    pub provider_factory: ProviderFactory<NodeTypesWithDBAdapter<TestNode, TmpDB>>,
    /// Channel for receiving events from the Execution Extension
    pub events_rx: UnboundedReceiver<ExExEvent>,
    /// Channel for sending notifications to the Execution Extension
    pub notifications_tx: Sender<ExExNotification>,
    /// Node task runtime
    pub runtime: Runtime,
    /// WAL temp directory handle
    _wal_directory: TempDir,
}

impl TestExExHandle {
    /// Send a notification to the Execution Extension that the chain has been committed
    pub async fn send_notification_chain_committed(&self, chain: Chain) -> eyre::Result<()> {
        self.notifications_tx
            .send(ExExNotification::ChainCommitted { new: Arc::new(chain) })
            .await?;
        Ok(())
    }

    /// Send a notification to the Execution Extension that the chain has been reorged
    pub async fn send_notification_chain_reorged(
        &self,
        old: Chain,
        new: Chain,
    ) -> eyre::Result<()> {
        self.notifications_tx
            .send(ExExNotification::ChainReorged { old: Arc::new(old), new: Arc::new(new) })
            .await?;
        Ok(())
    }

    /// Send a notification to the Execution Extension that the chain has been reverted
    pub async fn send_notification_chain_reverted(&self, chain: Chain) -> eyre::Result<()> {
        self.notifications_tx
            .send(ExExNotification::ChainReverted { old: Arc::new(chain) })
            .await?;
        Ok(())
    }

    /// Asserts that the Execution Extension did not emit any events.
    #[track_caller]
    pub fn assert_events_empty(&self) {
        assert!(self.events_rx.is_empty());
    }

    /// Asserts that the Execution Extension emitted a `FinishedHeight` event with the correct
    /// height.
    #[track_caller]
    pub fn assert_event_finished_height(&mut self, height: BlockNumHash) -> eyre::Result<()> {
        let event = self.events_rx.try_recv()?;
        assert_eq!(event, ExExEvent::FinishedHeight(height));
        Ok(())
    }
}

/// Creates a new [`ExExContext`].
///
/// This is a convenience function that does the following:
/// 1. Sets up an [`ExExContext`] with all dependencies.
/// 2. Inserts the genesis block of the provided (chain spec)[`ChainSpec`] into the storage.
/// 3. Creates a channel for receiving events from the Execution Extension.
/// 4. Creates a channel for sending notifications to the Execution Extension.
///
/// # Warning
/// The genesis block is not sent to the notifications channel. The caller is responsible for
/// doing this.
pub async fn test_exex_context_with_chain_spec(
    chain_spec: Arc<ChainSpec>,
) -> eyre::Result<(ExExContext<Adapter>, TestExExHandle)> {
    let transaction_pool = testing_pool();
    let evm_config = MockEvmConfig::default();
    let consensus = Arc::new(TestConsensus::default());

    let (static_dir, _) = create_test_static_files_dir();
    let (rocksdb_dir, _) = create_test_rocksdb_dir();
    let db = create_test_rw_db();
    let provider_factory = ProviderFactory::<NodeTypesWithDBAdapter<TestNode, _>>::new(
        db,
        chain_spec.clone(),
        StaticFileProvider::read_write(static_dir.keep()).expect("static file provider"),
        RocksDBProvider::builder(rocksdb_dir.keep()).with_default_tables().build().unwrap(),
        reth_tasks::Runtime::test(),
    )?;

    let genesis_hash = init_genesis(&provider_factory)?;
    let provider = BlockchainProvider::new(provider_factory.clone())?;

    let runtime = Runtime::test();
    let network_manager = NetworkManager::new(
        NetworkConfigBuilder::new(rng_secret_key(), runtime.clone())
            .with_unused_discovery_port()
            .with_unused_listener_port()
            .build(provider_factory.clone()),
    )
    .await?;
    let network = network_manager.handle().clone();
    let task_executor = runtime.clone();
    runtime.spawn_task(network_manager);

    let (_, payload_builder_handle) = NoopPayloadBuilderService::<EthEngineTypes>::new();

    let components = NodeAdapter::<FullNodeTypesAdapter<_, _, _>, _> {
        components: Components {
            transaction_pool,
            evm_config,
            consensus,
            network,
            payload_builder_handle,
        },
        task_executor,
        provider,
    };

    let genesis = provider_factory
        .block_by_hash(genesis_hash)?
        .ok_or_else(|| eyre::eyre!("genesis block not found"))?
        .seal_slow()
        .try_recover()?;

    let head = genesis.num_hash();

    let wal_directory = tempfile::tempdir()?;
    let wal = Wal::new(wal_directory.path())?;

    let (events_tx, events_rx) = tokio::sync::mpsc::unbounded_channel();
    let (notifications_tx, notifications_rx) = tokio::sync::mpsc::channel(1);
    let notifications = ExExNotifications::new(
        head,
        components.provider.clone(),
        components.components.evm_config.clone(),
        notifications_rx,
        wal.handle(),
    );

    let ctx = ExExContext {
        head,
        config: NodeConfig::test(),
        reth_config: reth_config::Config::default(),
        events: events_tx,
        notifications,
        components,
    };

    Ok((
        ctx,
        TestExExHandle {
            genesis,
            provider_factory,
            events_rx,
            notifications_tx,
            runtime,
            _wal_directory: wal_directory,
        },
    ))
}

/// Creates a new [`ExExContext`] with (mainnet)[`MAINNET`] chain spec.
///
/// For more information see [`test_exex_context_with_chain_spec`].
pub async fn test_exex_context() -> eyre::Result<(ExExContext<Adapter>, TestExExHandle)> {
    test_exex_context_with_chain_spec(MAINNET.clone()).await
}

/// An extension trait for polling an Execution Extension future.
pub trait PollOnce {
    /// Polls the given Execution Extension future __once__. The future should be
    /// (pinned)[`std::pin::pin`].
    ///
    /// # Returns
    /// - `Ok(())` if the future returned [`Poll::Pending`]. The future can be polled again.
    /// - `Err(PollOnceError::FutureIsReady)` if the future returned [`Poll::Ready`] without an
    ///   error. The future should never resolve.
    /// - `Err(PollOnceError::FutureError(err))` if the future returned [`Poll::Ready`] with an
    ///   error. Something went wrong.
    fn poll_once(&mut self) -> impl Future<Output = Result<(), PollOnceError>> + Send;
}

/// An Execution Extension future polling error.
#[derive(Error, Debug)]
pub enum PollOnceError {
    /// The future returned [`Poll::Ready`] without an error, but it should never resolve.
    #[error("Execution Extension future returned Ready, but it should never resolve")]
    FutureIsReady,
    /// The future returned [`Poll::Ready`] with an error.
    #[error(transparent)]
    FutureError(#[from] eyre::Error),
}

impl<F: Future<Output = eyre::Result<()>> + Unpin + Send> PollOnce for F {
    async fn poll_once(&mut self) -> Result<(), PollOnceError> {
        poll_fn(|cx| match self.poll_unpin(cx) {
            Poll::Ready(Ok(())) => Poll::Ready(Err(PollOnceError::FutureIsReady)),
            Poll::Ready(Err(err)) => Poll::Ready(Err(PollOnceError::FutureError(err))),
            Poll::Pending => Poll::Ready(Ok(())),
        })
        .await
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[tokio::test]
    async fn check_test_context_creation() {
        let _ = test_exex_context().await.unwrap();
    }
}
