//! Ethereum transaction validator.

use super::constants::DEFAULT_MAX_TX_INPUT_BYTES;
use crate::{
    blobstore::BlobStore,
    error::{
        Eip4844PoolTransactionError, Eip7702PoolTransactionError, InvalidPoolTransactionError,
    },
    traits::TransactionOrigin,
    validate::{ValidTransaction, ValidationTask, MAX_INIT_CODE_BYTE_SIZE},
    EthBlobTransactionSidecar, EthPoolTransaction, LocalTransactionConfig, PoolTransaction,
    TransactionValidationOutcome, TransactionValidationTaskExecutor, TransactionValidator,
};
use reth_chainspec::{ChainSpec, EthereumHardforks};
use reth_primitives::{
    constants::eip4844::MAX_BLOBS_PER_BLOCK, GotExpected, InvalidTransactionError, SealedBlock,
    EIP1559_TX_TYPE_ID, EIP2930_TX_TYPE_ID, EIP4844_TX_TYPE_ID, EIP7702_TX_TYPE_ID,
    LEGACY_TX_TYPE_ID,
};
use reth_storage_api::{AccountReader, StateProviderFactory};
use reth_tasks::TaskSpawner;
use revm::{
    interpreter::gas::validate_initial_tx_gas,
    primitives::{EnvKzgSettings, SpecId},
};
use std::{
    marker::PhantomData,
    sync::{atomic::AtomicBool, Arc},
};
use tokio::sync::Mutex;

/// Validator for Ethereum transactions.
#[derive(Debug, Clone)]
pub struct EthTransactionValidator<Client, T> {
    /// The type that performs the actual validation.
    inner: Arc<EthTransactionValidatorInner<Client, T>>,
}

impl<Client, Tx> EthTransactionValidator<Client, Tx> {
    /// Returns the configured chain spec
    pub fn chain_spec(&self) -> Arc<ChainSpec> {
        self.inner.chain_spec.clone()
    }

    /// Returns the configured client
    pub fn client(&self) -> &Client {
        &self.inner.client
    }
}

impl<Client, Tx> EthTransactionValidator<Client, Tx>
where
    Client: StateProviderFactory,
    Tx: EthPoolTransaction,
{
    /// Validates a single transaction.
    ///
    /// See also [`TransactionValidator::validate_transaction`]
    pub fn validate_one(
        &self,
        origin: TransactionOrigin,
        transaction: Tx,
    ) -> TransactionValidationOutcome<Tx> {
        self.inner.validate_one(origin, transaction)
    }

    /// Validates all given transactions.
    ///
    /// Returns all outcomes for the given transactions in the same order.
    ///
    /// See also [`Self::validate_one`]
    pub fn validate_all(
        &self,
        transactions: Vec<(TransactionOrigin, Tx)>,
    ) -> Vec<TransactionValidationOutcome<Tx>> {
        transactions.into_iter().map(|(origin, tx)| self.validate_one(origin, tx)).collect()
    }
}

impl<Client, Tx> TransactionValidator for EthTransactionValidator<Client, Tx>
where
    Client: StateProviderFactory,
    Tx: EthPoolTransaction,
{
    type Transaction = Tx;

    async fn validate_transaction(
        &self,
        origin: TransactionOrigin,
        transaction: Self::Transaction,
    ) -> TransactionValidationOutcome<Self::Transaction> {
        self.validate_one(origin, transaction)
    }

    async fn validate_transactions(
        &self,
        transactions: Vec<(TransactionOrigin, Self::Transaction)>,
    ) -> Vec<TransactionValidationOutcome<Self::Transaction>> {
        self.validate_all(transactions)
    }

    fn on_new_head_block(&self, new_tip_block: &SealedBlock) {
        self.inner.on_new_head_block(new_tip_block)
    }
}

/// A [`TransactionValidator`] implementation that validates ethereum transaction.
#[derive(Debug)]
pub(crate) struct EthTransactionValidatorInner<Client, T> {
    /// Spec of the chain
    chain_spec: Arc<ChainSpec>,
    /// This type fetches account info from the db
    client: Client,
    /// Blobstore used for fetching re-injected blob transactions.
    blob_store: Box<dyn BlobStore>,
    /// tracks activated forks relevant for transaction validation
    fork_tracker: ForkTracker,
    /// Fork indicator whether we are using EIP-2718 type transactions.
    eip2718: bool,
    /// Fork indicator whether we are using EIP-1559 type transactions.
    eip1559: bool,
    /// Fork indicator whether we are using EIP-4844 blob transactions.
    eip4844: bool,
    /// Fork indicator whether we are using EIP-7702 type transactions.
    eip7702: bool,
    /// The current max gas limit
    block_gas_limit: u64,
    /// Minimum priority fee to enforce for acceptance into the pool.
    minimum_priority_fee: Option<u128>,
    /// Stores the setup and parameters needed for validating KZG proofs.
    kzg_settings: EnvKzgSettings,
    /// How to handle [`TransactionOrigin::Local`](TransactionOrigin) transactions.
    local_transactions_config: LocalTransactionConfig,
    /// Maximum size in bytes a single transaction can have in order to be accepted into the pool.
    max_tx_input_bytes: usize,
    /// Marker for the transaction type
    _marker: PhantomData<T>,
}

// === impl EthTransactionValidatorInner ===

impl<Client, Tx> EthTransactionValidatorInner<Client, Tx> {
    /// Returns the configured chain id
    pub(crate) fn chain_id(&self) -> u64 {
        self.chain_spec.chain().id()
    }
}

impl<Client, Tx> EthTransactionValidatorInner<Client, Tx>
where
    Client: StateProviderFactory,
    Tx: EthPoolTransaction,
{
    /// Validates a single transaction.
    fn validate_one(
        &self,
        origin: TransactionOrigin,
        mut transaction: Tx,
    ) -> TransactionValidationOutcome<Tx> {
        // Checks for tx_type
        match transaction.tx_type() {
            LEGACY_TX_TYPE_ID => {
                // Accept legacy transactions
            }
            EIP2930_TX_TYPE_ID => {
                // Accept only legacy transactions until EIP-2718/2930 activates
                if !self.eip2718 {
                    return TransactionValidationOutcome::Invalid(
                        transaction,
                        InvalidTransactionError::Eip2930Disabled.into(),
                    )
                }
            }
            EIP1559_TX_TYPE_ID => {
                // Reject dynamic fee transactions until EIP-1559 activates.
                if !self.eip1559 {
                    return TransactionValidationOutcome::Invalid(
                        transaction,
                        InvalidTransactionError::Eip1559Disabled.into(),
                    )
                }
            }
            EIP4844_TX_TYPE_ID => {
                // Reject blob transactions.
                if !self.eip4844 {
                    return TransactionValidationOutcome::Invalid(
                        transaction,
                        InvalidTransactionError::Eip4844Disabled.into(),
                    )
                }
            }
            EIP7702_TX_TYPE_ID => {
                // Reject EIP-7702 transactions.
                if !self.eip7702 {
                    return TransactionValidationOutcome::Invalid(
                        transaction,
                        InvalidTransactionError::Eip7702Disabled.into(),
                    )
                }
            }

            _ => {
                return TransactionValidationOutcome::Invalid(
                    transaction,
                    InvalidTransactionError::TxTypeNotSupported.into(),
                )
            }
        };

        // Reject transactions over defined size to prevent DOS attacks
        let transaction_size = transaction.size();
        if transaction_size > self.max_tx_input_bytes {
            return TransactionValidationOutcome::Invalid(
                transaction,
                InvalidPoolTransactionError::OversizedData(
                    transaction_size,
                    self.max_tx_input_bytes,
                ),
            )
        }

        // Check whether the init code size has been exceeded.
        if self.fork_tracker.is_shanghai_activated() {
            if let Err(err) = ensure_max_init_code_size(&transaction, MAX_INIT_CODE_BYTE_SIZE) {
                return TransactionValidationOutcome::Invalid(transaction, err)
            }
        }

        // Checks for gas limit
        let transaction_gas_limit = transaction.gas_limit();
        if transaction_gas_limit > self.block_gas_limit {
            return TransactionValidationOutcome::Invalid(
                transaction,
                InvalidPoolTransactionError::ExceedsGasLimit(
                    transaction_gas_limit,
                    self.block_gas_limit,
                ),
            )
        }

        // Ensure max_priority_fee_per_gas (if EIP1559) is less than max_fee_per_gas if any.
        if transaction.max_priority_fee_per_gas() > Some(transaction.max_fee_per_gas()) {
            return TransactionValidationOutcome::Invalid(
                transaction,
                InvalidTransactionError::TipAboveFeeCap.into(),
            )
        }

        // Drop non-local transactions with a fee lower than the configured fee for acceptance into
        // the pool.
        if !self.local_transactions_config.is_local(origin, transaction.sender()) &&
            transaction.is_eip1559() &&
            transaction.max_priority_fee_per_gas() < self.minimum_priority_fee
        {
            return TransactionValidationOutcome::Invalid(
                transaction,
                InvalidPoolTransactionError::Underpriced,
            )
        }

        // Checks for chainid
        if let Some(chain_id) = transaction.chain_id() {
            if chain_id != self.chain_id() {
                return TransactionValidationOutcome::Invalid(
                    transaction,
                    InvalidTransactionError::ChainIdMismatch.into(),
                )
            }
        }

        if transaction.is_eip7702() {
            // Cancun fork is required for 7702 txs
            if !self.fork_tracker.is_prague_activated() {
                return TransactionValidationOutcome::Invalid(
                    transaction,
                    InvalidTransactionError::TxTypeNotSupported.into(),
                )
            }

            if transaction.authorization_count() == 0 {
                return TransactionValidationOutcome::Invalid(
                    transaction,
                    Eip7702PoolTransactionError::MissingEip7702AuthorizationList.into(),
                )
            }
        }

        if let Err(err) = ensure_intrinsic_gas(&transaction, &self.fork_tracker) {
            return TransactionValidationOutcome::Invalid(transaction, err)
        }

        // light blob tx pre-checks
        if transaction.is_eip4844() {
            // Cancun fork is required for blob txs
            if !self.fork_tracker.is_cancun_activated() {
                return TransactionValidationOutcome::Invalid(
                    transaction,
                    InvalidTransactionError::TxTypeNotSupported.into(),
                )
            }

            let blob_count = transaction.blob_count();
            if blob_count == 0 {
                // no blobs
                return TransactionValidationOutcome::Invalid(
                    transaction,
                    InvalidPoolTransactionError::Eip4844(
                        Eip4844PoolTransactionError::NoEip4844Blobs,
                    ),
                )
            }

            if blob_count > MAX_BLOBS_PER_BLOCK {
                // too many blobs
                return TransactionValidationOutcome::Invalid(
                    transaction,
                    InvalidPoolTransactionError::Eip4844(
                        Eip4844PoolTransactionError::TooManyEip4844Blobs {
                            have: blob_count,
                            permitted: MAX_BLOBS_PER_BLOCK,
                        },
                    ),
                )
            }
        }

        let account = match self
            .client
            .latest()
            .and_then(|state| state.basic_account(transaction.sender()))
        {
            Ok(account) => account.unwrap_or_default(),
            Err(err) => {
                return TransactionValidationOutcome::Error(*transaction.hash(), Box::new(err))
            }
        };

        // Unless Prague is active, the signer account shouldn't have bytecode.
        //
        // If Prague is active, only EIP-7702 bytecode is allowed for the sender.
        //
        // Any other case means that the account is not an EOA, and should not be able to send
        // transactions.
        if account.has_bytecode() {
            let is_eip7702 = if self.fork_tracker.is_prague_activated() {
                match self
                    .client
                    .latest()
                    .and_then(|state| state.bytecode_by_hash(account.get_bytecode_hash()))
                {
                    Ok(bytecode) => bytecode.unwrap_or_default().is_eip7702(),
                    Err(err) => {
                        return TransactionValidationOutcome::Error(
                            *transaction.hash(),
                            Box::new(err),
                        )
                    }
                }
            } else {
                false
            };

            if !is_eip7702 {
                return TransactionValidationOutcome::Invalid(
                    transaction,
                    InvalidTransactionError::SignerAccountHasBytecode.into(),
                )
            }
        }

        let tx_nonce = transaction.nonce();

        // Checks for nonce
        if tx_nonce < account.nonce {
            return TransactionValidationOutcome::Invalid(
                transaction,
                InvalidTransactionError::NonceNotConsistent { tx: tx_nonce, state: account.nonce }
                    .into(),
            )
        }

        let cost = transaction.cost();

        // Checks for max cost
        if cost > account.balance {
            return TransactionValidationOutcome::Invalid(
                transaction,
                InvalidTransactionError::InsufficientFunds(
                    GotExpected { got: account.balance, expected: cost }.into(),
                )
                .into(),
            )
        }

        let mut maybe_blob_sidecar = None;

        // heavy blob tx validation
        if transaction.is_eip4844() {
            // extract the blob from the transaction
            match transaction.take_blob() {
                EthBlobTransactionSidecar::None => {
                    // this should not happen
                    return TransactionValidationOutcome::Invalid(
                        transaction,
                        InvalidTransactionError::TxTypeNotSupported.into(),
                    )
                }
                EthBlobTransactionSidecar::Missing => {
                    // This can happen for re-injected blob transactions (on re-org), since the blob
                    // is stripped from the transaction and not included in a block.
                    // check if the blob is in the store, if it's included we previously validated
                    // it and inserted it
                    if matches!(self.blob_store.contains(*transaction.hash()), Ok(true)) {
                        // validated transaction is already in the store
                    } else {
                        return TransactionValidationOutcome::Invalid(
                            transaction,
                            InvalidPoolTransactionError::Eip4844(
                                Eip4844PoolTransactionError::MissingEip4844BlobSidecar,
                            ),
                        )
                    }
                }
                EthBlobTransactionSidecar::Present(blob) => {
                    // validate the blob
                    if let Err(err) = transaction.validate_blob(&blob, self.kzg_settings.get()) {
                        return TransactionValidationOutcome::Invalid(
                            transaction,
                            InvalidPoolTransactionError::Eip4844(
                                Eip4844PoolTransactionError::InvalidEip4844Blob(err),
                            ),
                        )
                    }
                    // store the extracted blob
                    maybe_blob_sidecar = Some(blob);
                }
            }
        }

        // Return the valid transaction
        TransactionValidationOutcome::Valid {
            balance: account.balance,
            state_nonce: account.nonce,
            transaction: ValidTransaction::new(transaction, maybe_blob_sidecar),
            // by this point assume all external transactions should be propagated
            propagate: match origin {
                TransactionOrigin::External => true,
                TransactionOrigin::Local => {
                    self.local_transactions_config.propagate_local_transactions
                }
                TransactionOrigin::Private => false,
            },
        }
    }

    fn on_new_head_block(&self, new_tip_block: &SealedBlock) {
        // update all forks
        if self.chain_spec.is_cancun_active_at_timestamp(new_tip_block.timestamp) {
            self.fork_tracker.cancun.store(true, std::sync::atomic::Ordering::Relaxed);
        }

        if self.chain_spec.is_shanghai_active_at_timestamp(new_tip_block.timestamp) {
            self.fork_tracker.shanghai.store(true, std::sync::atomic::Ordering::Relaxed);
        }

        if self.chain_spec.is_prague_active_at_timestamp(new_tip_block.timestamp) {
            self.fork_tracker.prague.store(true, std::sync::atomic::Ordering::Relaxed);
        }
    }
}

/// A builder for [`TransactionValidationTaskExecutor`]
#[derive(Debug, Clone)]
pub struct EthTransactionValidatorBuilder {
    chain_spec: Arc<ChainSpec>,
    /// Fork indicator whether we are in the Shanghai stage.
    shanghai: bool,
    /// Fork indicator whether we are in the Cancun hardfork.
    cancun: bool,
    /// Fork indicator whether we are in the Cancun hardfork.
    prague: bool,
    /// Whether using EIP-2718 type transactions is allowed
    eip2718: bool,
    /// Whether using EIP-1559 type transactions is allowed
    eip1559: bool,
    /// Whether using EIP-4844 type transactions is allowed
    eip4844: bool,
    /// Whether using EIP-7702 type transactions is allowed
    eip7702: bool,
    /// The current max gas limit
    block_gas_limit: u64,
    /// Minimum priority fee to enforce for acceptance into the pool.
    minimum_priority_fee: Option<u128>,
    /// Determines how many additional tasks to spawn
    ///
    /// Default is 1
    additional_tasks: usize,

    /// Stores the setup and parameters needed for validating KZG proofs.
    kzg_settings: EnvKzgSettings,
    /// How to handle [`TransactionOrigin::Local`](TransactionOrigin) transactions.
    local_transactions_config: LocalTransactionConfig,
    /// Max size in bytes of a single transaction allowed
    max_tx_input_bytes: usize,
}

impl EthTransactionValidatorBuilder {
    /// Creates a new builder for the given [`ChainSpec`]
    ///
    /// By default this assumes the network is on the `Cancun` hardfork and the following
    /// transactions are allowed:
    ///  - Legacy
    ///  - EIP-2718
    ///  - EIP-1559
    ///  - EIP-4844
    pub fn new(chain_spec: Arc<ChainSpec>) -> Self {
        Self {
            block_gas_limit: chain_spec.max_gas_limit,
            chain_spec,
            minimum_priority_fee: None,
            additional_tasks: 1,
            kzg_settings: EnvKzgSettings::Default,
            local_transactions_config: Default::default(),
            max_tx_input_bytes: DEFAULT_MAX_TX_INPUT_BYTES,

            // by default all transaction types are allowed
            eip2718: true,
            eip1559: true,
            eip4844: true,
            eip7702: true,

            // shanghai is activated by default
            shanghai: true,

            // cancun is activated by default
            cancun: true,

            // prague not yet activated
            prague: false,
        }
    }

    /// Disables the Cancun fork.
    pub const fn no_cancun(self) -> Self {
        self.set_cancun(false)
    }

    /// Whether to allow exemptions for local transaction exemptions.
    pub fn with_local_transactions_config(
        mut self,
        local_transactions_config: LocalTransactionConfig,
    ) -> Self {
        self.local_transactions_config = local_transactions_config;
        self
    }

    /// Set the Cancun fork.
    pub const fn set_cancun(mut self, cancun: bool) -> Self {
        self.cancun = cancun;
        self
    }

    /// Disables the Shanghai fork.
    pub const fn no_shanghai(self) -> Self {
        self.set_shanghai(false)
    }

    /// Set the Shanghai fork.
    pub const fn set_shanghai(mut self, shanghai: bool) -> Self {
        self.shanghai = shanghai;
        self
    }

    /// Disables the Prague fork.
    pub const fn no_prague(self) -> Self {
        self.set_prague(false)
    }

    /// Set the Prague fork.
    pub const fn set_prague(mut self, prague: bool) -> Self {
        self.prague = prague;
        self
    }

    /// Disables the support for EIP-2718 transactions.
    pub const fn no_eip2718(self) -> Self {
        self.set_eip2718(false)
    }

    /// Set the support for EIP-2718 transactions.
    pub const fn set_eip2718(mut self, eip2718: bool) -> Self {
        self.eip2718 = eip2718;
        self
    }

    /// Disables the support for EIP-1559 transactions.
    pub const fn no_eip1559(self) -> Self {
        self.set_eip1559(false)
    }

    /// Set the support for EIP-1559 transactions.
    pub const fn set_eip1559(mut self, eip1559: bool) -> Self {
        self.eip1559 = eip1559;
        self
    }

    /// Disables the support for EIP-4844 transactions.
    pub const fn no_eip4844(self) -> Self {
        self.set_eip4844(false)
    }

    /// Set the support for EIP-4844 transactions.
    pub const fn set_eip4844(mut self, eip4844: bool) -> Self {
        self.eip4844 = eip4844;
        self
    }

    /// Sets the [`EnvKzgSettings`] to use for validating KZG proofs.
    pub fn kzg_settings(mut self, kzg_settings: EnvKzgSettings) -> Self {
        self.kzg_settings = kzg_settings;
        self
    }

    /// Sets a minimum priority fee that's enforced for acceptance into the pool.
    pub const fn with_minimum_priority_fee(mut self, minimum_priority_fee: u128) -> Self {
        self.minimum_priority_fee = Some(minimum_priority_fee);
        self
    }

    /// Sets the number of additional tasks to spawn.
    pub const fn with_additional_tasks(mut self, additional_tasks: usize) -> Self {
        self.additional_tasks = additional_tasks;
        self
    }

    /// Configures validation rules based on the head block's timestamp.
    ///
    /// For example, whether the Shanghai and Cancun hardfork is activated at launch.
    pub fn with_head_timestamp(mut self, timestamp: u64) -> Self {
        self.cancun = self.chain_spec.is_cancun_active_at_timestamp(timestamp);
        self.shanghai = self.chain_spec.is_shanghai_active_at_timestamp(timestamp);
        self
    }

    /// Sets a max size in bytes of a single transaction allowed into the pool
    pub const fn with_max_tx_input_bytes(mut self, max_tx_input_bytes: usize) -> Self {
        self.max_tx_input_bytes = max_tx_input_bytes;
        self
    }

    /// Sets the block gas limit
    ///
    /// Transactions with a gas limit greater than this will be rejected.
    pub const fn set_block_gas_limit(mut self, block_gas_limit: u64) -> Self {
        self.block_gas_limit = block_gas_limit;
        self
    }

    /// Builds a the [`EthTransactionValidator`] without spawning validator tasks.
    pub fn build<Client, Tx, S>(
        self,
        client: Client,
        blob_store: S,
    ) -> EthTransactionValidator<Client, Tx>
    where
        S: BlobStore,
    {
        let Self {
            chain_spec,
            shanghai,
            cancun,
            prague,
            eip2718,
            eip1559,
            eip4844,
            eip7702,
            block_gas_limit,
            minimum_priority_fee,
            kzg_settings,
            local_transactions_config,
            max_tx_input_bytes,
            ..
        } = self;

        let fork_tracker = ForkTracker {
            shanghai: AtomicBool::new(shanghai),
            cancun: AtomicBool::new(cancun),
            prague: AtomicBool::new(prague),
        };

        let inner = EthTransactionValidatorInner {
            chain_spec,
            client,
            eip2718,
            eip1559,
            fork_tracker,
            eip4844,
            eip7702,
            block_gas_limit,
            minimum_priority_fee,
            blob_store: Box::new(blob_store),
            kzg_settings,
            local_transactions_config,
            max_tx_input_bytes,
            _marker: Default::default(),
        };

        EthTransactionValidator { inner: Arc::new(inner) }
    }

    /// Builds a the [`EthTransactionValidator`] and spawns validation tasks via the
    /// [`TransactionValidationTaskExecutor`]
    ///
    /// The validator will spawn `additional_tasks` additional tasks for validation.
    ///
    /// By default this will spawn 1 additional task.
    pub fn build_with_tasks<Client, Tx, T, S>(
        self,
        client: Client,
        tasks: T,
        blob_store: S,
    ) -> TransactionValidationTaskExecutor<EthTransactionValidator<Client, Tx>>
    where
        T: TaskSpawner,
        S: BlobStore,
    {
        let additional_tasks = self.additional_tasks;
        let validator = self.build(client, blob_store);

        let (tx, task) = ValidationTask::new();

        // Spawn validation tasks, they are blocking because they perform db lookups
        for _ in 0..additional_tasks {
            let task = task.clone();
            tasks.spawn_blocking(Box::pin(async move {
                task.run().await;
            }));
        }

        // we spawn them on critical tasks because validation, especially for EIP-4844 can be quite
        // heavy
        tasks.spawn_critical_blocking(
            "transaction-validation-service",
            Box::pin(async move {
                task.run().await;
            }),
        );

        let to_validation_task = Arc::new(Mutex::new(tx));

        TransactionValidationTaskExecutor { validator, to_validation_task }
    }
}

/// Keeps track of whether certain forks are activated
#[derive(Debug)]
pub struct ForkTracker {
    /// Tracks if shanghai is activated at the block's timestamp.
    pub shanghai: AtomicBool,
    /// Tracks if cancun is activated at the block's timestamp.
    pub cancun: AtomicBool,
    /// Tracks if prague is activated at the block's timestamp.
    pub prague: AtomicBool,
}

impl ForkTracker {
    /// Returns `true` if Shanghai fork is activated.
    pub fn is_shanghai_activated(&self) -> bool {
        self.shanghai.load(std::sync::atomic::Ordering::Relaxed)
    }

    /// Returns `true` if Cancun fork is activated.
    pub fn is_cancun_activated(&self) -> bool {
        self.cancun.load(std::sync::atomic::Ordering::Relaxed)
    }

    /// Returns `true` if Prague fork is activated.
    pub fn is_prague_activated(&self) -> bool {
        self.prague.load(std::sync::atomic::Ordering::Relaxed)
    }
}

/// Ensure that the code size is not greater than `max_init_code_size`.
/// `max_init_code_size` should be configurable so this will take it as an argument.
pub fn ensure_max_init_code_size<T: PoolTransaction>(
    transaction: &T,
    max_init_code_size: usize,
) -> Result<(), InvalidPoolTransactionError> {
    if transaction.kind().is_create() && transaction.input().len() > max_init_code_size {
        Err(InvalidPoolTransactionError::ExceedsMaxInitCodeSize(
            transaction.size(),
            max_init_code_size,
        ))
    } else {
        Ok(())
    }
}

/// Ensures that gas limit of the transaction exceeds the intrinsic gas of the transaction.
///
/// Caution: This only checks past the Merge hardfork.
pub fn ensure_intrinsic_gas<T: EthPoolTransaction>(
    transaction: &T,
    fork_tracker: &ForkTracker,
) -> Result<(), InvalidPoolTransactionError> {
    let spec_id = if fork_tracker.is_prague_activated() {
        SpecId::PRAGUE
    } else if fork_tracker.is_shanghai_activated() {
        SpecId::SHANGHAI
    } else {
        SpecId::MERGE
    };

    let gas_after_merge = validate_initial_tx_gas(
        spec_id,
        transaction.input(),
        transaction.kind().is_create(),
        transaction.access_list().map(|list| list.0.as_slice()).unwrap_or(&[]),
        transaction.authorization_count() as u64,
    );

    if transaction.gas_limit() < gas_after_merge {
        Err(InvalidPoolTransactionError::IntrinsicGasTooLow)
    } else {
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::{
        blobstore::InMemoryBlobStore, error::PoolErrorKind, CoinbaseTipOrdering,
        EthPooledTransaction, Pool, TransactionPool,
    };
    use alloy_primitives::{hex, U256};
    use reth_chainspec::MAINNET;
    use reth_primitives::PooledTransactionsElement;
    use reth_provider::test_utils::{ExtendedAccount, MockEthProvider};

    fn get_transaction() -> EthPooledTransaction {
        let raw = "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000000000000000000000000000c0000000000000000000000000d3fd4f95820a9aa848ce716d6c200eaefb9a2e4900000000000000000000000000000000000000000000000000000000000000640000000000000000000000000000000000000000000000000000000000000003543131000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000035431310000000000000000000000000000000000000000000000000000000000c001a04e551c75810ffdfe6caff57da9f5a8732449f42f0f4c57f935b05250a76db3b6a046cd47e6d01914270c1ec0d9ac7fae7dfb240ec9a8b6ec7898c4d6aa174388f2";

        let data = hex::decode(raw).unwrap();
        let tx = PooledTransactionsElement::decode_enveloped(&mut data.as_ref()).unwrap();

        tx.try_into_ecrecovered().unwrap().into()
    }

    // <https://github.com/paradigmxyz/reth/issues/5178>
    #[tokio::test]
    async fn validate_transaction() {
        let transaction = get_transaction();
        let mut fork_tracker =
            ForkTracker { shanghai: false.into(), cancun: false.into(), prague: false.into() };

        let res = ensure_intrinsic_gas(&transaction, &fork_tracker);
        assert!(res.is_ok());

        fork_tracker.shanghai = true.into();
        let res = ensure_intrinsic_gas(&transaction, &fork_tracker);
        assert!(res.is_ok());

        let provider = MockEthProvider::default();
        provider.add_account(
            transaction.sender(),
            ExtendedAccount::new(transaction.nonce(), U256::MAX),
        );
        let blob_store = InMemoryBlobStore::default();
        let validator = EthTransactionValidatorBuilder::new(MAINNET.clone())
            .build(provider, blob_store.clone());

        let outcome = validator.validate_one(TransactionOrigin::External, transaction.clone());

        assert!(outcome.is_valid());

        let pool =
            Pool::new(validator, CoinbaseTipOrdering::default(), blob_store, Default::default());

        let res = pool.add_external_transaction(transaction.clone()).await;
        assert!(res.is_ok());
        let tx = pool.get(transaction.hash());
        assert!(tx.is_some());
    }

    // <https://github.com/paradigmxyz/reth/issues/8550>
    #[tokio::test]
    async fn invalid_on_gas_limit_too_high() {
        let transaction = get_transaction();

        let provider = MockEthProvider::default();
        provider.add_account(
            transaction.sender(),
            ExtendedAccount::new(transaction.nonce(), U256::MAX),
        );

        let blob_store = InMemoryBlobStore::default();
        let validator = EthTransactionValidatorBuilder::new(MAINNET.clone())
            .set_block_gas_limit(1_000_000) // tx gas limit is 1_015_288
            .build(provider, blob_store.clone());

        let outcome = validator.validate_one(TransactionOrigin::External, transaction.clone());

        assert!(outcome.is_invalid());

        let pool =
            Pool::new(validator, CoinbaseTipOrdering::default(), blob_store, Default::default());

        let res = pool.add_external_transaction(transaction.clone()).await;
        assert!(res.is_err());
        assert!(matches!(
            res.unwrap_err().kind,
            PoolErrorKind::InvalidTransaction(InvalidPoolTransactionError::ExceedsGasLimit(
                1_015_288, 1_000_000
            ))
        ));
        let tx = pool.get(transaction.hash());
        assert!(tx.is_none());
    }
}