//! EVM config for vanilla ethereum.

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#![cfg_attr(not(test), warn(unused_crate_dependencies))]
#![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
#![cfg_attr(not(feature = "std"), no_std)]

extern crate alloc;

use alloc::vec::Vec;
use alloy_primitives::{Address, Bytes, TxKind, U256};
use reth_chainspec::{ChainSpec, Head};
use reth_evm::{ConfigureEvm, ConfigureEvmEnv, NextBlockEnvAttributes};
use reth_primitives::{transaction::FillTxEnv, Header, TransactionSigned};
use revm_primitives::{
    AnalysisKind, BlobExcessGasAndPrice, BlockEnv, CfgEnv, CfgEnvWithHandlerCfg, Env, SpecId, TxEnv,
};
use std::sync::Arc;

mod config;
pub use config::{revm_spec, revm_spec_by_timestamp_after_merge};
use reth_ethereum_forks::EthereumHardfork;
use reth_primitives::constants::EIP1559_INITIAL_BASE_FEE;

pub mod execute;

/// Ethereum DAO hardfork state change data.
pub mod dao_fork;

/// [EIP-6110](https://eips.ethereum.org/EIPS/eip-6110) handling.
pub mod eip6110;

/// Ethereum-related EVM configuration.
#[derive(Debug, Clone)]
pub struct EthEvmConfig {
    chain_spec: Arc<ChainSpec>,
}

impl EthEvmConfig {
    /// Creates a new Ethereum EVM configuration with the given chain spec.
    pub const fn new(chain_spec: Arc<ChainSpec>) -> Self {
        Self { chain_spec }
    }

    /// Returns the chain spec associated with this configuration.
    pub fn chain_spec(&self) -> &ChainSpec {
        &self.chain_spec
    }
}

impl ConfigureEvmEnv for EthEvmConfig {
    type Header = Header;

    fn fill_tx_env(&self, tx_env: &mut TxEnv, transaction: &TransactionSigned, sender: Address) {
        transaction.fill_tx_env(tx_env, sender);
    }

    fn fill_tx_env_system_contract_call(
        &self,
        env: &mut Env,
        caller: Address,
        contract: Address,
        data: Bytes,
    ) {
        #[allow(clippy::needless_update)] // side-effect of optimism fields
        let tx = TxEnv {
            caller,
            transact_to: TxKind::Call(contract),
            // Explicitly set nonce to None so revm does not do any nonce checks
            nonce: None,
            gas_limit: 30_000_000,
            value: U256::ZERO,
            data,
            // Setting the gas price to zero enforces that no value is transferred as part of the
            // call, and that the call will not count against the block's gas limit
            gas_price: U256::ZERO,
            // The chain ID check is not relevant here and is disabled if set to None
            chain_id: None,
            // Setting the gas priority fee to None ensures the effective gas price is derived from
            // the `gas_price` field, which we need to be zero
            gas_priority_fee: None,
            access_list: Vec::new(),
            // blob fields can be None for this tx
            blob_hashes: Vec::new(),
            max_fee_per_blob_gas: None,
            // TODO remove this once this crate is no longer built with optimism
            ..Default::default()
        };
        env.tx = tx;

        // ensure the block gas limit is >= the tx
        env.block.gas_limit = U256::from(env.tx.gas_limit);

        // disable the base fee check for this call by setting the base fee to zero
        env.block.basefee = U256::ZERO;
    }

    fn fill_cfg_env(
        &self,
        cfg_env: &mut CfgEnvWithHandlerCfg,
        header: &Header,
        total_difficulty: U256,
    ) {
        let spec_id = config::revm_spec(
            self.chain_spec(),
            &Head {
                number: header.number,
                timestamp: header.timestamp,
                difficulty: header.difficulty,
                total_difficulty,
                hash: Default::default(),
            },
        );

        cfg_env.chain_id = self.chain_spec.chain().id();
        cfg_env.perf_analyse_created_bytecodes = AnalysisKind::Analyse;

        cfg_env.handler_cfg.spec_id = spec_id;
    }

    fn next_cfg_and_block_env(
        &self,
        parent: &Self::Header,
        attributes: NextBlockEnvAttributes,
    ) -> (CfgEnvWithHandlerCfg, BlockEnv) {
        // configure evm env based on parent block
        let cfg = CfgEnv::default().with_chain_id(self.chain_spec.chain().id());

        // ensure we're not missing any timestamp based hardforks
        let spec_id = revm_spec_by_timestamp_after_merge(&self.chain_spec, attributes.timestamp);

        // if the parent block did not have excess blob gas (i.e. it was pre-cancun), but it is
        // cancun now, we need to set the excess blob gas to the default value(0)
        let blob_excess_gas_and_price = parent
            .next_block_excess_blob_gas()
            .or_else(|| (spec_id == SpecId::CANCUN).then_some(0))
            .map(BlobExcessGasAndPrice::new);

        let mut basefee = parent.next_block_base_fee(
            self.chain_spec.base_fee_params_at_timestamp(attributes.timestamp),
        );

        let mut gas_limit = U256::from(parent.gas_limit);

        // If we are on the London fork boundary, we need to multiply the parent's gas limit by the
        // elasticity multiplier to get the new gas limit.
        if self.chain_spec.fork(EthereumHardfork::London).transitions_at_block(parent.number + 1) {
            let elasticity_multiplier = self
                .chain_spec
                .base_fee_params_at_timestamp(attributes.timestamp)
                .elasticity_multiplier;

            // multiply the gas limit by the elasticity multiplier
            gas_limit *= U256::from(elasticity_multiplier);

            // set the base fee to the initial base fee from the EIP-1559 spec
            basefee = Some(EIP1559_INITIAL_BASE_FEE)
        }

        let block_env = BlockEnv {
            number: U256::from(parent.number + 1),
            coinbase: attributes.suggested_fee_recipient,
            timestamp: U256::from(attributes.timestamp),
            difficulty: U256::ZERO,
            prevrandao: Some(attributes.prev_randao),
            gas_limit,
            // calculate basefee based on parent block's gas usage
            basefee: basefee.map(U256::from).unwrap_or_default(),
            // calculate excess gas based on parent block's blob gas usage
            blob_excess_gas_and_price,
        };

        (CfgEnvWithHandlerCfg::new_with_spec_id(cfg, spec_id), block_env)
    }
}

impl ConfigureEvm for EthEvmConfig {
    type DefaultExternalContext<'a> = ();

    fn default_external_context<'a>(&self) -> Self::DefaultExternalContext<'a> {}
}

#[cfg(test)]
mod tests {
    use super::*;
    use alloy_genesis::Genesis;
    use alloy_primitives::{B256, U256};
    use reth_chainspec::{Chain, ChainSpec, MAINNET};
    use reth_evm::execute::ProviderError;
    use reth_primitives::{
        revm_primitives::{BlockEnv, CfgEnv, SpecId},
        Header, KECCAK_EMPTY,
    };
    use reth_revm::{
        db::{CacheDB, EmptyDBTyped},
        inspectors::NoOpInspector,
        JournaledState,
    };
    use revm_primitives::{CfgEnvWithHandlerCfg, EnvWithHandlerCfg, HandlerCfg};
    use std::collections::HashSet;

    #[test]
    fn test_fill_cfg_and_block_env() {
        // Create a new configuration environment
        let mut cfg_env = CfgEnvWithHandlerCfg::new_with_spec_id(CfgEnv::default(), SpecId::LATEST);

        // Create a default block environment
        let mut block_env = BlockEnv::default();

        // Create a default header
        let header = Header::default();

        // Build the ChainSpec for Ethereum mainnet, activating London, Paris, and Shanghai
        // hardforks
        let chain_spec = ChainSpec::builder()
            .chain(Chain::mainnet())
            .genesis(Genesis::default())
            .london_activated()
            .paris_activated()
            .shanghai_activated()
            .build();

        // Define the total difficulty as zero (default)
        let total_difficulty = U256::ZERO;

        // Use the `EthEvmConfig` to fill the `cfg_env` and `block_env` based on the ChainSpec,
        // Header, and total difficulty
        EthEvmConfig::new(Arc::new(chain_spec.clone())).fill_cfg_and_block_env(
            &mut cfg_env,
            &mut block_env,
            &header,
            total_difficulty,
        );

        // Assert that the chain ID in the `cfg_env` is correctly set to the chain ID of the
        // ChainSpec
        assert_eq!(cfg_env.chain_id, chain_spec.chain().id());
    }

    #[test]
    #[allow(clippy::needless_update)]
    fn test_evm_configure() {
        // Create a default `EthEvmConfig`
        let evm_config = EthEvmConfig::new(MAINNET.clone());

        // Initialize an empty database wrapped in CacheDB
        let db = CacheDB::<EmptyDBTyped<ProviderError>>::default();

        // Create an EVM instance using the configuration and the database
        let evm = evm_config.evm(db);

        // Check that the EVM environment is initialized with default values
        assert_eq!(evm.context.evm.inner.env, Box::default());

        // Latest spec ID and no warm preloaded addresses
        assert_eq!(
            evm.context.evm.inner.journaled_state,
            JournaledState::new(SpecId::LATEST, HashSet::default())
        );

        // Ensure that the accounts database is empty
        assert!(evm.context.evm.inner.db.accounts.is_empty());

        // Ensure that the block hashes database is empty
        assert!(evm.context.evm.inner.db.block_hashes.is_empty());

        // Verify that there are two default contracts in the contracts database
        assert_eq!(evm.context.evm.inner.db.contracts.len(), 2);
        assert!(evm.context.evm.inner.db.contracts.contains_key(&KECCAK_EMPTY));
        assert!(evm.context.evm.inner.db.contracts.contains_key(&B256::ZERO));

        // Ensure that the logs database is empty
        assert!(evm.context.evm.inner.db.logs.is_empty());

        // No Optimism
        assert_eq!(evm.handler.cfg, HandlerCfg { spec_id: SpecId::LATEST, ..Default::default() });
    }

    #[test]
    #[allow(clippy::needless_update)]
    fn test_evm_with_env_default_spec() {
        let evm_config = EthEvmConfig::new(MAINNET.clone());

        let db = CacheDB::<EmptyDBTyped<ProviderError>>::default();

        let env_with_handler = EnvWithHandlerCfg::default();

        let evm = evm_config.evm_with_env(db, env_with_handler.clone());

        // Check that the EVM environment
        assert_eq!(evm.context.evm.env, env_with_handler.env);

        // Default spec ID
        assert_eq!(evm.handler.spec_id(), SpecId::LATEST);

        // No Optimism
        assert_eq!(evm.handler.cfg, HandlerCfg { spec_id: SpecId::LATEST, ..Default::default() });
    }

    #[test]
    #[allow(clippy::needless_update)]
    fn test_evm_with_env_custom_cfg() {
        let evm_config = EthEvmConfig::new(MAINNET.clone());

        let db = CacheDB::<EmptyDBTyped<ProviderError>>::default();

        // Create a custom configuration environment with a chain ID of 111
        let cfg = CfgEnv::default().with_chain_id(111);

        let env_with_handler = EnvWithHandlerCfg {
            env: Box::new(Env {
                cfg: cfg.clone(),
                block: BlockEnv::default(),
                tx: TxEnv::default(),
            }),
            handler_cfg: Default::default(),
        };

        let evm = evm_config.evm_with_env(db, env_with_handler);

        // Check that the EVM environment is initialized with the custom environment
        assert_eq!(evm.context.evm.inner.env.cfg, cfg);

        // Default spec ID
        assert_eq!(evm.handler.spec_id(), SpecId::LATEST);

        // No Optimism
        assert_eq!(evm.handler.cfg, HandlerCfg { spec_id: SpecId::LATEST, ..Default::default() });
    }

    #[test]
    #[allow(clippy::needless_update)]
    fn test_evm_with_env_custom_block_and_tx() {
        let evm_config = EthEvmConfig::new(MAINNET.clone());

        let db = CacheDB::<EmptyDBTyped<ProviderError>>::default();

        // Create customs block and tx env
        let block = BlockEnv {
            basefee: U256::from(1000),
            gas_limit: U256::from(10_000_000),
            number: U256::from(42),
            ..Default::default()
        };
        let tx = TxEnv { gas_limit: 5_000_000, gas_price: U256::from(50), ..Default::default() };

        let env_with_handler = EnvWithHandlerCfg {
            env: Box::new(Env { cfg: CfgEnv::default(), block, tx }),
            handler_cfg: Default::default(),
        };

        let evm = evm_config.evm_with_env(db, env_with_handler.clone());

        // Verify that the block and transaction environments are set correctly
        assert_eq!(evm.context.evm.env.block, env_with_handler.env.block);
        assert_eq!(evm.context.evm.env.tx, env_with_handler.env.tx);

        // Default spec ID
        assert_eq!(evm.handler.spec_id(), SpecId::LATEST);

        // No Optimism
        assert_eq!(evm.handler.cfg, HandlerCfg { spec_id: SpecId::LATEST, ..Default::default() });
    }

    #[test]
    #[allow(clippy::needless_update)]
    fn test_evm_with_spec_id() {
        let evm_config = EthEvmConfig::new(MAINNET.clone());

        let db = CacheDB::<EmptyDBTyped<ProviderError>>::default();

        let handler_cfg = HandlerCfg { spec_id: SpecId::CONSTANTINOPLE, ..Default::default() };

        let env_with_handler = EnvWithHandlerCfg { env: Box::new(Env::default()), handler_cfg };

        let evm = evm_config.evm_with_env(db, env_with_handler);

        // Check that the spec ID is setup properly
        assert_eq!(evm.handler.spec_id(), SpecId::CONSTANTINOPLE);

        // No Optimism
        assert_eq!(
            evm.handler.cfg,
            HandlerCfg { spec_id: SpecId::CONSTANTINOPLE, ..Default::default() }
        );
    }

    #[test]
    #[allow(clippy::needless_update)]
    fn test_evm_with_inspector() {
        let evm_config = EthEvmConfig::new(MAINNET.clone());

        let db = CacheDB::<EmptyDBTyped<ProviderError>>::default();

        // No operation inspector
        let noop = NoOpInspector;

        let evm = evm_config.evm_with_inspector(db, noop);

        // Check that the inspector is set correctly
        assert_eq!(evm.context.external, noop);

        // Check that the EVM environment is initialized with default values
        assert_eq!(evm.context.evm.inner.env, Box::default());

        // Latest spec ID and no warm preloaded addresses
        assert_eq!(
            evm.context.evm.inner.journaled_state,
            JournaledState::new(SpecId::LATEST, HashSet::default())
        );

        // Ensure that the accounts database is empty
        assert!(evm.context.evm.inner.db.accounts.is_empty());

        // Ensure that the block hashes database is empty
        assert!(evm.context.evm.inner.db.block_hashes.is_empty());

        // Verify that there are two default contracts in the contracts database
        assert_eq!(evm.context.evm.inner.db.contracts.len(), 2);
        assert!(evm.context.evm.inner.db.contracts.contains_key(&KECCAK_EMPTY));
        assert!(evm.context.evm.inner.db.contracts.contains_key(&B256::ZERO));

        // Ensure that the logs database is empty
        assert!(evm.context.evm.inner.db.logs.is_empty());

        // No Optimism
        assert_eq!(evm.handler.cfg, HandlerCfg { spec_id: SpecId::LATEST, ..Default::default() });
    }

    #[test]
    #[allow(clippy::needless_update)]
    fn test_evm_with_env_and_default_inspector() {
        let evm_config = EthEvmConfig::new(MAINNET.clone());
        let db = CacheDB::<EmptyDBTyped<ProviderError>>::default();

        let env_with_handler = EnvWithHandlerCfg::default();

        let evm =
            evm_config.evm_with_env_and_inspector(db, env_with_handler.clone(), NoOpInspector);

        // Check that the EVM environment is set to default values
        assert_eq!(evm.context.evm.env, env_with_handler.env);
        assert_eq!(evm.context.external, NoOpInspector);
        assert_eq!(evm.handler.spec_id(), SpecId::LATEST);

        // No Optimism
        assert_eq!(evm.handler.cfg, HandlerCfg { spec_id: SpecId::LATEST, ..Default::default() });
    }

    #[test]
    #[allow(clippy::needless_update)]
    fn test_evm_with_env_inspector_and_custom_cfg() {
        let evm_config = EthEvmConfig::new(MAINNET.clone());
        let db = CacheDB::<EmptyDBTyped<ProviderError>>::default();

        let cfg = CfgEnv::default().with_chain_id(111);
        let block = BlockEnv::default();
        let tx = TxEnv::default();
        let env_with_handler = EnvWithHandlerCfg {
            env: Box::new(Env { cfg: cfg.clone(), block, tx }),
            handler_cfg: Default::default(),
        };

        let evm = evm_config.evm_with_env_and_inspector(db, env_with_handler, NoOpInspector);

        // Check that the EVM environment is set with custom configuration
        assert_eq!(evm.context.evm.env.cfg, cfg);
        assert_eq!(evm.context.external, NoOpInspector);
        assert_eq!(evm.handler.spec_id(), SpecId::LATEST);

        // No Optimism
        assert_eq!(evm.handler.cfg, HandlerCfg { spec_id: SpecId::LATEST, ..Default::default() });
    }

    #[test]
    #[allow(clippy::needless_update)]
    fn test_evm_with_env_inspector_and_custom_block_tx() {
        let evm_config = EthEvmConfig::new(MAINNET.clone());
        let db = CacheDB::<EmptyDBTyped<ProviderError>>::default();

        // Create custom block and tx environment
        let block = BlockEnv {
            basefee: U256::from(1000),
            gas_limit: U256::from(10_000_000),
            number: U256::from(42),
            ..Default::default()
        };
        let tx = TxEnv { gas_limit: 5_000_000, gas_price: U256::from(50), ..Default::default() };
        let env_with_handler = EnvWithHandlerCfg {
            env: Box::new(Env { cfg: CfgEnv::default(), block, tx }),
            handler_cfg: Default::default(),
        };

        let evm =
            evm_config.evm_with_env_and_inspector(db, env_with_handler.clone(), NoOpInspector);

        // Verify that the block and transaction environments are set correctly
        assert_eq!(evm.context.evm.env.block, env_with_handler.env.block);
        assert_eq!(evm.context.evm.env.tx, env_with_handler.env.tx);
        assert_eq!(evm.context.external, NoOpInspector);
        assert_eq!(evm.handler.spec_id(), SpecId::LATEST);

        // No Optimism
        assert_eq!(evm.handler.cfg, HandlerCfg { spec_id: SpecId::LATEST, ..Default::default() });
    }

    #[test]
    #[allow(clippy::needless_update)]
    fn test_evm_with_env_inspector_and_spec_id() {
        let evm_config = EthEvmConfig::new(MAINNET.clone());
        let db = CacheDB::<EmptyDBTyped<ProviderError>>::default();

        let handler_cfg = HandlerCfg { spec_id: SpecId::CONSTANTINOPLE, ..Default::default() };
        let env_with_handler = EnvWithHandlerCfg { env: Box::new(Env::default()), handler_cfg };

        let evm =
            evm_config.evm_with_env_and_inspector(db, env_with_handler.clone(), NoOpInspector);

        // Check that the spec ID is set properly
        assert_eq!(evm.handler.spec_id(), SpecId::CONSTANTINOPLE);
        assert_eq!(evm.context.evm.env, env_with_handler.env);
        assert_eq!(evm.context.external, NoOpInspector);

        // No Optimism
        assert_eq!(
            evm.handler.cfg,
            HandlerCfg { spec_id: SpecId::CONSTANTINOPLE, ..Default::default() }
        );
    }
}