use std::{path::PathBuf, sync::Arc, time::Duration};

use clap::Parser;
use eyre::Context;
use reth_basic_payload_builder::{BasicPayloadJobGenerator, BasicPayloadJobGeneratorConfig};
use reth_beacon_consensus::{hooks::EngineHooks, BeaconConsensusEngine, EthBeaconConsensus};
use reth_blockchain_tree::{
    BlockchainTree, BlockchainTreeConfig, ShareableBlockchainTree, TreeExternals,
};
use reth_cli_commands::common::{AccessRights, Environment, EnvironmentArgs};
use reth_cli_runner::CliContext;
use reth_cli_util::get_secret_key;
use reth_config::Config;
use reth_consensus::Consensus;
use reth_db::DatabaseEnv;
use reth_engine_util::engine_store::{EngineMessageStore, StoredEngineApiMessage};
use reth_fs_util as fs;
use reth_network::{BlockDownloaderProvider, NetworkHandle};
use reth_network_api::NetworkInfo;
use reth_payload_builder::{PayloadBuilderHandle, PayloadBuilderService};
use reth_provider::{
    providers::BlockchainProvider, CanonStateSubscriptions, ChainSpecProvider, ProviderFactory,
};
use reth_prune::PruneModes;
use reth_stages::Pipeline;
use reth_static_file::StaticFileProducer;
use reth_tasks::TaskExecutor;
use reth_transaction_pool::noop::NoopTransactionPool;
use tokio::sync::oneshot;
use tracing::*;

use crate::{args::NetworkArgs, macros::block_executor};

/// `reth debug replay-engine` command
/// This script will read stored engine API messages and replay them by the timestamp.
/// It does not require
#[derive(Debug, Parser)]
pub struct Command {
    #[command(flatten)]
    env: EnvironmentArgs,

    #[command(flatten)]
    network: NetworkArgs,

    /// The path to read engine API messages from.
    #[arg(long = "engine-api-store", value_name = "PATH")]
    engine_api_store: PathBuf,

    /// The number of milliseconds between Engine API messages.
    #[arg(long = "interval", default_value_t = 1_000)]
    interval: u64,
}

impl Command {
    async fn build_network(
        &self,
        config: &Config,
        task_executor: TaskExecutor,
        provider_factory: ProviderFactory<Arc<DatabaseEnv>>,
        network_secret_path: PathBuf,
        default_peers_path: PathBuf,
    ) -> eyre::Result<NetworkHandle> {
        let secret_key = get_secret_key(&network_secret_path)?;
        let network = self
            .network
            .network_config(config, provider_factory.chain_spec(), secret_key, default_peers_path)
            .with_task_executor(Box::new(task_executor))
            .build(provider_factory)
            .start_network()
            .await?;
        info!(target: "reth::cli", peer_id = %network.peer_id(), local_addr = %network.local_addr(), "Connected to P2P network");
        debug!(target: "reth::cli", peer_id = ?network.peer_id(), "Full peer ID");
        Ok(network)
    }

    /// Execute `debug replay-engine` command
    pub async fn execute(self, ctx: CliContext) -> eyre::Result<()> {
        let Environment { provider_factory, config, data_dir } = self.env.init(AccessRights::RW)?;

        let consensus: Arc<dyn Consensus> =
            Arc::new(EthBeaconConsensus::new(provider_factory.chain_spec()));

        let executor = block_executor!(provider_factory.chain_spec());

        // Configure blockchain tree
        let tree_externals =
            TreeExternals::new(provider_factory.clone(), Arc::clone(&consensus), executor);
        let tree = BlockchainTree::new(
            tree_externals,
            BlockchainTreeConfig::default(),
            PruneModes::none(),
        )?;
        let blockchain_tree = Arc::new(ShareableBlockchainTree::new(tree));

        // Set up the blockchain provider
        let blockchain_db = BlockchainProvider::new(provider_factory.clone(), blockchain_tree)?;

        // Set up network
        let network_secret_path =
            self.network.p2p_secret_key.clone().unwrap_or_else(|| data_dir.p2p_secret());
        let network = self
            .build_network(
                &config,
                ctx.task_executor.clone(),
                provider_factory.clone(),
                network_secret_path,
                data_dir.known_peers(),
            )
            .await?;

        // Set up payload builder
        #[cfg(not(feature = "optimism"))]
        let payload_builder = reth_ethereum_payload_builder::EthereumPayloadBuilder::default();

        // Optimism's payload builder is implemented on the OptimismPayloadBuilder type.
        #[cfg(feature = "optimism")]
        let payload_builder = reth_node_optimism::OptimismPayloadBuilder::new(
            reth_node_optimism::OptimismEvmConfig::default(),
        );

        let payload_generator = BasicPayloadJobGenerator::with_builder(
            blockchain_db.clone(),
            NoopTransactionPool::default(),
            ctx.task_executor.clone(),
            BasicPayloadJobGeneratorConfig::default(),
            provider_factory.chain_spec(),
            payload_builder,
        );

        #[cfg(feature = "optimism")]
        let (payload_service, payload_builder): (
            _,
            PayloadBuilderHandle<reth_node_optimism::OptimismEngineTypes>,
        ) = PayloadBuilderService::new(payload_generator, blockchain_db.canonical_state_stream());

        #[cfg(not(feature = "optimism"))]
        let (payload_service, payload_builder): (
            _,
            PayloadBuilderHandle<reth_node_ethereum::EthEngineTypes>,
        ) = PayloadBuilderService::new(payload_generator, blockchain_db.canonical_state_stream());

        ctx.task_executor.spawn_critical("payload builder service", payload_service);

        // Configure the consensus engine
        let network_client = network.fetch_client().await?;
        let (beacon_consensus_engine, beacon_engine_handle) = BeaconConsensusEngine::new(
            network_client,
            Pipeline::builder().build(
                provider_factory.clone(),
                StaticFileProducer::new(provider_factory.clone(), PruneModes::none()),
            ),
            blockchain_db.clone(),
            Box::new(ctx.task_executor.clone()),
            Box::new(network),
            None,
            payload_builder,
            None,
            u64::MAX,
            EngineHooks::new(),
        )?;
        info!(target: "reth::cli", "Consensus engine initialized");

        // Run consensus engine to completion
        let (tx, rx) = oneshot::channel();
        info!(target: "reth::cli", "Starting consensus engine");
        ctx.task_executor.spawn_critical_blocking("consensus engine", async move {
            let res = beacon_consensus_engine.await;
            let _ = tx.send(res);
        });

        let engine_api_store = EngineMessageStore::new(self.engine_api_store.clone());
        for filepath in engine_api_store.engine_messages_iter()? {
            let contents =
                fs::read(&filepath).wrap_err(format!("failed to read: {}", filepath.display()))?;
            let message = serde_json::from_slice(&contents)
                .wrap_err(format!("failed to parse: {}", filepath.display()))?;
            debug!(target: "reth::cli", filepath = %filepath.display(), ?message, "Forwarding Engine API message");
            match message {
                StoredEngineApiMessage::ForkchoiceUpdated { state, payload_attrs } => {
                    let response =
                        beacon_engine_handle.fork_choice_updated(state, payload_attrs).await?;
                    debug!(target: "reth::cli", ?response, "Received for forkchoice updated");
                }
                StoredEngineApiMessage::NewPayload { payload, cancun_fields } => {
                    let response = beacon_engine_handle.new_payload(payload, cancun_fields).await?;
                    debug!(target: "reth::cli", ?response, "Received for new payload");
                }
            };

            // Pause before next message
            tokio::time::sleep(Duration::from_millis(self.interval)).await;
        }

        info!(target: "reth::cli", "Finished replaying engine API messages");

        match rx.await? {
            Ok(()) => info!("Beacon consensus engine exited successfully"),
            Err(error) => {
                error!(target: "reth::cli", %error, "Beacon consensus engine exited with an error")
            }
        };

        Ok(())
    }
}