use crate::{
    ens, erc, maybe,
    pubsub::{PubsubClient, SubscriptionStream},
    stream::{FilterWatcher, DEFAULT_POLL_INTERVAL},
    FromErr, Http as HttpProvider, JsonRpcClient, JsonRpcClientWrapper, MockProvider,
    PendingTransaction, QuorumProvider, SyncingStatus,
};

#[cfg(feature = "celo")]
use crate::CeloMiddleware;
use crate::Middleware;
use async_trait::async_trait;

use ethers_core::{
    abi::{self, Detokenize, ParamType},
    types::{
        transaction::{eip2718::TypedTransaction, eip2930::AccessListWithGasUsed},
        Address, Block, BlockId, BlockNumber, BlockTrace, Bytes, EIP1186ProofResponse, FeeHistory,
        Filter, Log, NameOrAddress, Selector, Signature, Trace, TraceFilter, TraceType,
        Transaction, TransactionReceipt, TransactionRequest, TxHash, TxpoolContent, TxpoolInspect,
        TxpoolStatus, H256, U256, U64,
    },
    utils,
};
use hex::FromHex;
use serde::{de::DeserializeOwned, Deserialize, Serialize};
use thiserror::Error;
use url::{ParseError, Url};

use futures_util::{lock::Mutex, try_join};
use std::{convert::TryFrom, fmt::Debug, str::FromStr, sync::Arc, time::Duration};
use tracing::trace;
use tracing_futures::Instrument;

#[derive(Copy, Clone)]
pub enum NodeClient {
    Geth,
    Erigon,
    OpenEthereum,
    Nethermind,
    Besu,
}

impl FromStr for NodeClient {
    type Err = ProviderError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.split('/').next().unwrap().to_lowercase().as_str() {
            "geth" => Ok(NodeClient::Geth),
            "erigon" => Ok(NodeClient::Erigon),
            "openethereum" => Ok(NodeClient::OpenEthereum),
            "nethermind" => Ok(NodeClient::Nethermind),
            "besu" => Ok(NodeClient::Besu),
            _ => Err(ProviderError::UnsupportedNodeClient),
        }
    }
}

/// An abstract provider for interacting with the [Ethereum JSON RPC
/// API](https://github.com/ethereum/wiki/wiki/JSON-RPC). Must be instantiated
/// with a data transport which implements the [`JsonRpcClient`](trait@crate::JsonRpcClient) trait
/// (e.g. [HTTP](crate::Http), Websockets etc.)
///
/// # Example
///
/// ```no_run
/// # async fn foo() -> Result<(), Box<dyn std::error::Error>> {
/// use ethers_providers::{Middleware, Provider, Http};
/// use std::convert::TryFrom;
///
/// let provider = Provider::<Http>::try_from(
///     "https://mainnet.infura.io/v3/c60b0bb42f8a4c6481ecd229eddaca27"
/// ).expect("could not instantiate HTTP Provider");
///
/// let block = provider.get_block(100u64).await?;
/// println!("Got block: {}", serde_json::to_string(&block)?);
/// # Ok(())
/// # }
/// ```
#[derive(Clone, Debug)]
pub struct Provider<P> {
    inner: P,
    ens: Option<Address>,
    interval: Option<Duration>,
    from: Option<Address>,
    /// Node client hasn't been checked yet = `None`
    /// Unsupported node client = `Some(None)`
    /// Supported node client = `Some(Some(NodeClient))`
    _node_client: Arc<Mutex<Option<NodeClient>>>,
}

impl<P> AsRef<P> for Provider<P> {
    fn as_ref(&self) -> &P {
        &self.inner
    }
}

impl FromErr<ProviderError> for ProviderError {
    fn from(src: ProviderError) -> Self {
        src
    }
}

#[derive(Debug, Error)]
/// An error thrown when making a call to the provider
pub enum ProviderError {
    /// An internal error in the JSON RPC Client
    #[error(transparent)]
    JsonRpcClientError(#[from] Box<dyn std::error::Error + Send + Sync>),

    /// An error during ENS name resolution
    #[error("ens name not found: {0}")]
    EnsError(String),

    #[error(transparent)]
    SerdeJson(#[from] serde_json::Error),

    #[error(transparent)]
    HexError(#[from] hex::FromHexError),

    #[error(transparent)]
    HTTPError(#[from] reqwest::Error),

    #[error("custom error: {0}")]
    CustomError(String),

    #[error("unsupported RPC")]
    UnsupportedRPC,

    #[error("unsupported node client")]
    UnsupportedNodeClient,

    #[error("Attempted to sign a transaction with no available signer. Hint: did you mean to use a SignerMiddleware?")]
    SignerUnavailable,
}

/// Types of filters supported by the JSON-RPC.
#[derive(Clone, Debug)]
pub enum FilterKind<'a> {
    /// `eth_newBlockFilter`
    Logs(&'a Filter),

    /// `eth_newBlockFilter` filter
    NewBlocks,

    /// `eth_newPendingTransactionFilter` filter
    PendingTransactions,
}

// JSON RPC bindings
impl<P: JsonRpcClient> Provider<P> {
    /// Instantiate a new provider with a backend.
    pub fn new(provider: P) -> Self {
        Self {
            inner: provider,
            ens: None,
            interval: None,
            from: None,
            _node_client: Arc::new(Mutex::new(None)),
        }
    }

    /// Returns the type of node we're connected to, while also caching the value for use
    /// in other node-specific API calls, such as the get_block_receipts call.
    pub async fn node_client(&self) -> Result<NodeClient, ProviderError> {
        let mut node_client = self._node_client.lock().await;

        if let Some(node_client) = *node_client {
            Ok(node_client)
        } else {
            let client_version = self.client_version().await?;
            let client_version = match client_version.parse::<NodeClient>() {
                Ok(res) => res,
                Err(_) => return Err(ProviderError::UnsupportedNodeClient),
            };
            *node_client = Some(client_version);
            Ok(client_version)
        }
    }

    #[must_use]
    pub fn with_sender(mut self, address: impl Into<Address>) -> Self {
        self.from = Some(address.into());
        self
    }

    pub async fn request<T, R>(&self, method: &str, params: T) -> Result<R, ProviderError>
    where
        T: Debug + Serialize + Send + Sync,
        R: Serialize + DeserializeOwned + Debug,
    {
        let span =
            tracing::trace_span!("rpc", method = method, params = ?serde_json::to_string(&params)?);
        // https://docs.rs/tracing/0.1.22/tracing/span/struct.Span.html#in-asynchronous-code
        let res = async move {
            trace!("tx");
            let res: R = self.inner.request(method, params).await.map_err(Into::into)?;
            trace!(rx = ?serde_json::to_string(&res)?);
            Ok::<_, ProviderError>(res)
        }
        .instrument(span)
        .await?;
        Ok(res)
    }

    async fn get_block_gen<Tx: Default + Serialize + DeserializeOwned + Debug>(
        &self,
        id: BlockId,
        include_txs: bool,
    ) -> Result<Option<Block<Tx>>, ProviderError> {
        let include_txs = utils::serialize(&include_txs);

        Ok(match id {
            BlockId::Hash(hash) => {
                let hash = utils::serialize(&hash);
                self.request("eth_getBlockByHash", [hash, include_txs]).await?
            }
            BlockId::Number(num) => {
                let num = utils::serialize(&num);
                self.request("eth_getBlockByNumber", [num, include_txs]).await?
            }
        })
    }
}

#[cfg(feature = "celo")]
#[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
#[cfg_attr(not(target_arch = "wasm32"), async_trait)]
impl<P: JsonRpcClient> CeloMiddleware for Provider<P> {
    async fn get_validators_bls_public_keys<T: Into<BlockId> + Send + Sync>(
        &self,
        block_id: T,
    ) -> Result<Vec<String>, ProviderError> {
        let block_id = utils::serialize(&block_id.into());
        self.request("istanbul_getValidatorsBLSPublicKeys", [block_id]).await
    }
}

#[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
#[cfg_attr(not(target_arch = "wasm32"), async_trait)]
impl<P: JsonRpcClient> Middleware for Provider<P> {
    type Error = ProviderError;
    type Provider = P;
    type Inner = Self;

    fn inner(&self) -> &Self::Inner {
        unreachable!("There is no inner provider here")
    }

    fn provider(&self) -> &Provider<Self::Provider> {
        self
    }

    fn default_sender(&self) -> Option<Address> {
        self.from
    }

    ////// Blockchain Status
    //
    // Functions for querying the state of the blockchain

    /// Returns the current client version using the `web3_clientVersion` RPC.
    async fn client_version(&self) -> Result<String, Self::Error> {
        self.request("web3_clientVersion", ()).await
    }

    async fn fill_transaction(
        &self,
        tx: &mut TypedTransaction,
        block: Option<BlockId>,
    ) -> Result<(), Self::Error> {
        if let Some(default_sender) = self.default_sender() {
            if tx.from().is_none() {
                tx.set_from(default_sender);
            }
        }

        // TODO: Join the name resolution and gas price future

        // set the ENS name
        if let Some(NameOrAddress::Name(ref ens_name)) = tx.to() {
            let addr = self.resolve_name(ens_name).await?;
            tx.set_to(addr);
        }

        // fill gas price
        match tx {
            TypedTransaction::Eip2930(_) | TypedTransaction::Legacy(_) => {
                let gas_price = maybe(tx.gas_price(), self.get_gas_price()).await?;
                tx.set_gas_price(gas_price);
            }
            TypedTransaction::Eip1559(ref mut inner) => {
                if inner.max_fee_per_gas.is_none() || inner.max_priority_fee_per_gas.is_none() {
                    let (max_fee_per_gas, max_priority_fee_per_gas) =
                        self.estimate_eip1559_fees(None).await?;
                    inner.max_fee_per_gas = Some(max_fee_per_gas);
                    inner.max_priority_fee_per_gas = Some(max_priority_fee_per_gas);
                };
            }
        }

        // If the tx has an access list but it is empty, it is an Eip1559 or Eip2930 tx,
        // and we attempt to populate the acccess list. This may require `eth_estimateGas`,
        // in which case we save the result in maybe_gas_res for later
        let mut maybe_gas = None;
        if let Some(starting_al) = tx.access_list() {
            if starting_al.0.is_empty() {
                let (gas_res, al_res) = futures_util::join!(
                    maybe(tx.gas().cloned(), self.estimate_gas(tx)),
                    self.create_access_list(tx, block)
                );
                let mut gas = gas_res?;

                if let Ok(al_with_gas) = al_res {
                    // Set access list if it saves gas over the estimated (or previously set) value
                    if al_with_gas.gas_used < gas {
                        // Update the gas estimate with the lower amount
                        gas = al_with_gas.gas_used;
                        tx.set_access_list(al_with_gas.access_list);
                    }
                }
                maybe_gas = Some(gas);
            }
        }

        // Set gas to estimated value only if it was not set by the caller,
        // even if the access list has been populated and saves gas
        if tx.gas().is_none() {
            let gas_estimate = maybe(maybe_gas, self.estimate_gas(tx)).await?;
            tx.set_gas(gas_estimate);
        }

        Ok(())
    }

    /// Gets the latest block number via the `eth_BlockNumber` API
    async fn get_block_number(&self) -> Result<U64, ProviderError> {
        self.request("eth_blockNumber", ()).await
    }

    /// Gets the block at `block_hash_or_number` (transaction hashes only)
    async fn get_block<T: Into<BlockId> + Send + Sync>(
        &self,
        block_hash_or_number: T,
    ) -> Result<Option<Block<TxHash>>, Self::Error> {
        self.get_block_gen(block_hash_or_number.into(), false).await
    }

    /// Gets the block at `block_hash_or_number` (full transactions included)
    async fn get_block_with_txs<T: Into<BlockId> + Send + Sync>(
        &self,
        block_hash_or_number: T,
    ) -> Result<Option<Block<Transaction>>, ProviderError> {
        self.get_block_gen(block_hash_or_number.into(), true).await
    }

    /// Gets the block uncle count at `block_hash_or_number`
    async fn get_uncle_count<T: Into<BlockId> + Send + Sync>(
        &self,
        block_hash_or_number: T,
    ) -> Result<U256, Self::Error> {
        let id = block_hash_or_number.into();
        Ok(match id {
            BlockId::Hash(hash) => {
                let hash = utils::serialize(&hash);
                self.request("eth_getUncleCountByBlockHash", [hash]).await?
            }
            BlockId::Number(num) => {
                let num = utils::serialize(&num);
                self.request("eth_getUncleCountByBlockNumber", [num]).await?
            }
        })
    }

    /// Gets the block uncle at `block_hash_or_number` and `idx`
    async fn get_uncle<T: Into<BlockId> + Send + Sync>(
        &self,
        block_hash_or_number: T,
        idx: U64,
    ) -> Result<Option<Block<H256>>, ProviderError> {
        let blk_id = block_hash_or_number.into();
        let idx = utils::serialize(&idx);
        Ok(match blk_id {
            BlockId::Hash(hash) => {
                let hash = utils::serialize(&hash);
                self.request("eth_getUncleByBlockHashAndIndex", [hash, idx]).await?
            }
            BlockId::Number(num) => {
                let num = utils::serialize(&num);
                self.request("eth_getUncleByBlockNumberAndIndex", [num, idx]).await?
            }
        })
    }

    /// Gets the transaction with `transaction_hash`
    async fn get_transaction<T: Send + Sync + Into<TxHash>>(
        &self,
        transaction_hash: T,
    ) -> Result<Option<Transaction>, ProviderError> {
        let hash = transaction_hash.into();
        self.request("eth_getTransactionByHash", [hash]).await
    }

    /// Gets the transaction receipt with `transaction_hash`
    async fn get_transaction_receipt<T: Send + Sync + Into<TxHash>>(
        &self,
        transaction_hash: T,
    ) -> Result<Option<TransactionReceipt>, ProviderError> {
        let hash = transaction_hash.into();
        self.request("eth_getTransactionReceipt", [hash]).await
    }

    /// Returns all receipts for a block.
    ///
    /// Note that this uses the `eth_getBlockReceipts` RPC, which is
    /// non-standard and currently supported by Erigon.
    async fn get_block_receipts<T: Into<BlockNumber> + Send + Sync>(
        &self,
        block: T,
    ) -> Result<Vec<TransactionReceipt>, Self::Error> {
        self.request("eth_getBlockReceipts", [block.into()]).await
    }

    /// Returns all receipts for that block. Must be done on a parity node.
    async fn parity_block_receipts<T: Into<BlockNumber> + Send + Sync>(
        &self,
        block: T,
    ) -> Result<Vec<TransactionReceipt>, Self::Error> {
        self.request("parity_getBlockReceipts", vec![block.into()]).await
    }

    /// Gets the current gas price as estimated by the node
    async fn get_gas_price(&self) -> Result<U256, ProviderError> {
        self.request("eth_gasPrice", ()).await
    }

    /// Gets a heuristic recommendation of max fee per gas and max priority fee per gas for
    /// EIP-1559 compatible transactions.
    async fn estimate_eip1559_fees(
        &self,
        estimator: Option<fn(U256, Vec<Vec<U256>>) -> (U256, U256)>,
    ) -> Result<(U256, U256), Self::Error> {
        let base_fee_per_gas = self
            .get_block(BlockNumber::Latest)
            .await?
            .ok_or_else(|| ProviderError::CustomError("Latest block not found".into()))?
            .base_fee_per_gas
            .ok_or_else(|| ProviderError::CustomError("EIP-1559 not activated".into()))?;

        let fee_history = self
            .fee_history(
                utils::EIP1559_FEE_ESTIMATION_PAST_BLOCKS,
                BlockNumber::Latest,
                &[utils::EIP1559_FEE_ESTIMATION_REWARD_PERCENTILE],
            )
            .await?;

        // use the provided fee estimator function, or fallback to the default implementation.
        let (max_fee_per_gas, max_priority_fee_per_gas) = if let Some(es) = estimator {
            es(base_fee_per_gas, fee_history.reward)
        } else {
            utils::eip1559_default_estimator(base_fee_per_gas, fee_history.reward)
        };

        Ok((max_fee_per_gas, max_priority_fee_per_gas))
    }

    /// Gets the accounts on the node
    async fn get_accounts(&self) -> Result<Vec<Address>, ProviderError> {
        self.request("eth_accounts", ()).await
    }

    /// Returns the nonce of the address
    async fn get_transaction_count<T: Into<NameOrAddress> + Send + Sync>(
        &self,
        from: T,
        block: Option<BlockId>,
    ) -> Result<U256, ProviderError> {
        let from = match from.into() {
            NameOrAddress::Name(ens_name) => self.resolve_name(&ens_name).await?,
            NameOrAddress::Address(addr) => addr,
        };

        let from = utils::serialize(&from);
        let block = utils::serialize(&block.unwrap_or_else(|| BlockNumber::Latest.into()));
        self.request("eth_getTransactionCount", [from, block]).await
    }

    /// Returns the account's balance
    async fn get_balance<T: Into<NameOrAddress> + Send + Sync>(
        &self,
        from: T,
        block: Option<BlockId>,
    ) -> Result<U256, ProviderError> {
        let from = match from.into() {
            NameOrAddress::Name(ens_name) => self.resolve_name(&ens_name).await?,
            NameOrAddress::Address(addr) => addr,
        };

        let from = utils::serialize(&from);
        let block = utils::serialize(&block.unwrap_or_else(|| BlockNumber::Latest.into()));
        self.request("eth_getBalance", [from, block]).await
    }

    /// Returns the currently configured chain id, a value used in replay-protected
    /// transaction signing as introduced by EIP-155.
    async fn get_chainid(&self) -> Result<U256, ProviderError> {
        self.request("eth_chainId", ()).await
    }

    /// Return current client syncing status. If IsFalse sync is over.
    async fn syncing(&self) -> Result<SyncingStatus, Self::Error> {
        #[derive(Debug, Serialize, Deserialize)]
        #[serde(untagged)]
        pub enum SyncingStatusIntermediate {
            /// When client is synced to highest block, eth_syncing with return string "false"
            IsFalse(bool),
            /// When client is still syncing past blocks we get IsSyncing information.
            IsSyncing { starting_block: U256, current_block: U256, highest_block: U256 },
        }
        let intermediate: SyncingStatusIntermediate = self.request("eth_syncing", ()).await?;
        match intermediate {
            SyncingStatusIntermediate::IsFalse(false) => Ok(SyncingStatus::IsFalse),
            SyncingStatusIntermediate::IsFalse(true) => Err(ProviderError::CustomError(
                "eth_syncing returned `true` that is undefined value.".to_owned(),
            )),
            SyncingStatusIntermediate::IsSyncing {
                starting_block,
                current_block,
                highest_block,
            } => Ok(SyncingStatus::IsSyncing { starting_block, current_block, highest_block }),
        }
    }

    /// Returns the network version.
    async fn get_net_version(&self) -> Result<U64, ProviderError> {
        self.request("net_version", ()).await
    }

    ////// Contract Execution
    //
    // These are relatively low-level calls. The Contracts API should usually be used instead.

    /// Sends the read-only (constant) transaction to a single Ethereum node and return the result
    /// (as bytes) of executing it. This is free, since it does not change any state on the
    /// blockchain.
    async fn call(
        &self,
        tx: &TypedTransaction,
        block: Option<BlockId>,
    ) -> Result<Bytes, ProviderError> {
        let tx = utils::serialize(tx);
        let block = utils::serialize(&block.unwrap_or_else(|| BlockNumber::Latest.into()));
        self.request("eth_call", [tx, block]).await
    }

    /// Sends a transaction to a single Ethereum node and return the estimated amount of gas
    /// required (as a U256) to send it This is free, but only an estimate. Providing too little
    /// gas will result in a transaction being rejected (while still consuming all provided
    /// gas).
    async fn estimate_gas(&self, tx: &TypedTransaction) -> Result<U256, ProviderError> {
        self.request("eth_estimateGas", [tx]).await
    }

    async fn create_access_list(
        &self,
        tx: &TypedTransaction,
        block: Option<BlockId>,
    ) -> Result<AccessListWithGasUsed, ProviderError> {
        let tx = utils::serialize(tx);
        let block = utils::serialize(&block.unwrap_or_else(|| BlockNumber::Latest.into()));
        self.request("eth_createAccessList", [tx, block]).await
    }

    /// Sends the transaction to the entire Ethereum network and returns the transaction's hash
    /// This will consume gas from the account that signed the transaction.
    async fn send_transaction<T: Into<TypedTransaction> + Send + Sync>(
        &self,
        tx: T,
        block: Option<BlockId>,
    ) -> Result<PendingTransaction<'_, P>, ProviderError> {
        let mut tx = tx.into();
        self.fill_transaction(&mut tx, block).await?;
        let tx_hash = self.request("eth_sendTransaction", [tx]).await?;

        Ok(PendingTransaction::new(tx_hash, self).interval(self.get_interval()))
    }

    /// Send the raw RLP encoded transaction to the entire Ethereum network and returns the
    /// transaction's hash This will consume gas from the account that signed the transaction.
    async fn send_raw_transaction<'a>(
        &'a self,
        tx: Bytes,
    ) -> Result<PendingTransaction<'a, P>, ProviderError> {
        let rlp = utils::serialize(&tx);
        let tx_hash = self.request("eth_sendRawTransaction", [rlp]).await?;
        Ok(PendingTransaction::new(tx_hash, self).interval(self.get_interval()))
    }

    /// The JSON-RPC provider is at the bottom-most position in the middleware stack. Here we check
    /// if it has the key for the sender address unlocked, as well as supports the `eth_sign` call.
    async fn is_signer(&self) -> bool {
        match self.from {
            Some(sender) => self.sign(vec![], &sender).await.is_ok(),
            None => false,
        }
    }

    /// Signs data using a specific account. This account needs to be unlocked.
    async fn sign<T: Into<Bytes> + Send + Sync>(
        &self,
        data: T,
        from: &Address,
    ) -> Result<Signature, ProviderError> {
        let data = utils::serialize(&data.into());
        let from = utils::serialize(from);

        // get the response from `eth_sign` call and trim the 0x-prefix if present.
        let sig: String = self.request("eth_sign", [from, data]).await?;
        let sig = sig.strip_prefix("0x").unwrap_or(&sig);

        // decode the signature.
        let sig = hex::decode(sig)?;
        Ok(Signature::try_from(sig.as_slice())
            .map_err(|e| ProviderError::CustomError(e.to_string()))?)
    }

    /// Sign a transaction via RPC call
    async fn sign_transaction(
        &self,
        _tx: &TypedTransaction,
        _from: Address,
    ) -> Result<Signature, Self::Error> {
        Err(ProviderError::SignerUnavailable).map_err(FromErr::from)
    }

    ////// Contract state

    /// Returns an array (possibly empty) of logs that match the filter
    async fn get_logs(&self, filter: &Filter) -> Result<Vec<Log>, ProviderError> {
        self.request("eth_getLogs", [filter]).await
    }

    /// Streams matching filter logs
    async fn watch<'a>(
        &'a self,
        filter: &Filter,
    ) -> Result<FilterWatcher<'a, P, Log>, ProviderError> {
        let id = self.new_filter(FilterKind::Logs(filter)).await?;
        let filter = FilterWatcher::new(id, self).interval(self.get_interval());
        Ok(filter)
    }

    /// Streams new block hashes
    async fn watch_blocks(&self) -> Result<FilterWatcher<'_, P, H256>, ProviderError> {
        let id = self.new_filter(FilterKind::NewBlocks).await?;
        let filter = FilterWatcher::new(id, self).interval(self.get_interval());
        Ok(filter)
    }

    /// Streams pending transactions
    async fn watch_pending_transactions(
        &self,
    ) -> Result<FilterWatcher<'_, P, H256>, ProviderError> {
        let id = self.new_filter(FilterKind::PendingTransactions).await?;
        let filter = FilterWatcher::new(id, self).interval(self.get_interval());
        Ok(filter)
    }

    /// Creates a filter object, based on filter options, to notify when the state changes (logs).
    /// To check if the state has changed, call `get_filter_changes` with the filter id.
    async fn new_filter(&self, filter: FilterKind<'_>) -> Result<U256, ProviderError> {
        let (method, args) = match filter {
            FilterKind::NewBlocks => ("eth_newBlockFilter", vec![]),
            FilterKind::PendingTransactions => ("eth_newPendingTransactionFilter", vec![]),
            FilterKind::Logs(filter) => ("eth_newFilter", vec![utils::serialize(&filter)]),
        };

        self.request(method, args).await
    }

    /// Uninstalls a filter
    async fn uninstall_filter<T: Into<U256> + Send + Sync>(
        &self,
        id: T,
    ) -> Result<bool, ProviderError> {
        let id = utils::serialize(&id.into());
        self.request("eth_uninstallFilter", [id]).await
    }

    /// Polling method for a filter, which returns an array of logs which occurred since last poll.
    ///
    /// This method must be called with one of the following return types, depending on the filter
    /// type:
    /// - `eth_newBlockFilter`: [`H256`], returns block hashes
    /// - `eth_newPendingTransactionFilter`: [`H256`], returns transaction hashes
    /// - `eth_newFilter`: [`Log`], returns raw logs
    ///
    /// If one of these types is not used, decoding will fail and the method will
    /// return an error.
    ///
    /// [`H256`]: ethers_core::types::H256
    /// [`Log`]: ethers_core::types::Log
    async fn get_filter_changes<T, R>(&self, id: T) -> Result<Vec<R>, ProviderError>
    where
        T: Into<U256> + Send + Sync,
        R: Serialize + DeserializeOwned + Send + Sync + Debug,
    {
        let id = utils::serialize(&id.into());
        self.request("eth_getFilterChanges", [id]).await
    }

    /// Get the storage of an address for a particular slot location
    async fn get_storage_at<T: Into<NameOrAddress> + Send + Sync>(
        &self,
        from: T,
        location: H256,
        block: Option<BlockId>,
    ) -> Result<H256, ProviderError> {
        let from = match from.into() {
            NameOrAddress::Name(ens_name) => self.resolve_name(&ens_name).await?,
            NameOrAddress::Address(addr) => addr,
        };

        let from = utils::serialize(&from);
        let location = utils::serialize(&location);
        let block = utils::serialize(&block.unwrap_or_else(|| BlockNumber::Latest.into()));

        // get the hex encoded value.
        let value: String = self.request("eth_getStorageAt", [from, location, block]).await?;
        // get rid of the 0x prefix and left pad it with zeroes.
        let value = format!("{:0>64}", value.replace("0x", ""));
        Ok(H256::from_slice(&Vec::from_hex(value)?))
    }

    /// Returns the deployed code at a given address
    async fn get_code<T: Into<NameOrAddress> + Send + Sync>(
        &self,
        at: T,
        block: Option<BlockId>,
    ) -> Result<Bytes, ProviderError> {
        let at = match at.into() {
            NameOrAddress::Name(ens_name) => self.resolve_name(&ens_name).await?,
            NameOrAddress::Address(addr) => addr,
        };

        let at = utils::serialize(&at);
        let block = utils::serialize(&block.unwrap_or_else(|| BlockNumber::Latest.into()));
        self.request("eth_getCode", [at, block]).await
    }

    /// Returns the EIP-1186 proof response
    /// https://github.com/ethereum/EIPs/issues/1186
    async fn get_proof<T: Into<NameOrAddress> + Send + Sync>(
        &self,
        from: T,
        locations: Vec<H256>,
        block: Option<BlockId>,
    ) -> Result<EIP1186ProofResponse, ProviderError> {
        let from = match from.into() {
            NameOrAddress::Name(ens_name) => self.resolve_name(&ens_name).await?,
            NameOrAddress::Address(addr) => addr,
        };

        let from = utils::serialize(&from);
        let locations = locations.iter().map(|location| utils::serialize(&location)).collect();
        let block = utils::serialize(&block.unwrap_or_else(|| BlockNumber::Latest.into()));

        self.request("eth_getProof", [from, locations, block]).await
    }

    ////// Ethereum Naming Service
    // The Ethereum Naming Service (ENS) allows easy to remember and use names to
    // be assigned to Ethereum addresses. Any provider operation which takes an address
    // may also take an ENS name.
    //
    // ENS also provides the ability for a reverse lookup, which determines the name for an address
    // if it has been configured.

    /// Returns the address that the `ens_name` resolves to (or None if not configured).
    ///
    /// # Panics
    ///
    /// If the bytes returned from the ENS registrar/resolver cannot be interpreted as
    /// an address. This should theoretically never happen.
    async fn resolve_name(&self, ens_name: &str) -> Result<Address, ProviderError> {
        self.query_resolver(ParamType::Address, ens_name, ens::ADDR_SELECTOR).await
    }

    /// Returns the ENS name the `address` resolves to (or None if not configured).
    /// # Panics
    ///
    /// If the bytes returned from the ENS registrar/resolver cannot be interpreted as
    /// a string. This should theoretically never happen.
    async fn lookup_address(&self, address: Address) -> Result<String, ProviderError> {
        let ens_name = ens::reverse_address(address);
        self.query_resolver(ParamType::String, &ens_name, ens::NAME_SELECTOR).await
    }

    /// Returns the avatar HTTP link of the avatar that the `ens_name` resolves to (or None
    /// if not configured)
    ///
    /// # Example
    /// ```no_run
    /// # use ethers_providers::{Provider, Http as HttpProvider, Middleware};
    /// # use std::convert::TryFrom;
    /// # #[tokio::main(flavor = "current_thread")]
    /// # async fn main() {
    /// # let provider = Provider::<HttpProvider>::try_from("https://mainnet.infura.io/v3/c60b0bb42f8a4c6481ecd229eddaca27").unwrap();
    /// let avatar = provider.resolve_avatar("parishilton.eth").await.unwrap();
    /// assert_eq!(avatar.to_string(), "https://i.imgur.com/YW3Hzph.jpg");
    /// # }
    /// ```
    ///
    /// # Panics
    ///
    /// If the bytes returned from the ENS registrar/resolver cannot be interpreted as
    /// a string. This should theoretically never happen.
    async fn resolve_avatar(&self, ens_name: &str) -> Result<Url, ProviderError> {
        let (field, owner) =
            try_join!(self.resolve_field(ens_name, "avatar"), self.resolve_name(ens_name))?;
        let url = Url::from_str(&field).map_err(|e| ProviderError::CustomError(e.to_string()))?;
        match url.scheme() {
            "https" | "data" => Ok(url),
            "ipfs" => erc::http_link_ipfs(url).map_err(ProviderError::CustomError),
            "eip155" => {
                let token =
                    erc::ERCNFT::from_str(url.path()).map_err(ProviderError::CustomError)?;
                match token.type_ {
                    erc::ERCNFTType::ERC721 => {
                        let tx = TransactionRequest {
                            data: Some(
                                [&erc::ERC721_OWNER_SELECTOR[..], &token.id].concat().into(),
                            ),
                            to: Some(NameOrAddress::Address(token.contract)),
                            ..Default::default()
                        };
                        let data = self.call(&tx.into(), None).await?;
                        if decode_bytes::<Address>(ParamType::Address, data) != owner {
                            return Err(ProviderError::CustomError("Incorrect owner.".to_string()))
                        }
                    }
                    erc::ERCNFTType::ERC1155 => {
                        let tx = TransactionRequest {
                            data: Some(
                                [
                                    &erc::ERC1155_BALANCE_SELECTOR[..],
                                    &[0x0; 12],
                                    &owner.0,
                                    &token.id,
                                ]
                                .concat()
                                .into(),
                            ),
                            to: Some(NameOrAddress::Address(token.contract)),
                            ..Default::default()
                        };
                        let data = self.call(&tx.into(), None).await?;
                        if decode_bytes::<u64>(ParamType::Uint(64), data) == 0 {
                            return Err(ProviderError::CustomError("Incorrect balance.".to_string()))
                        }
                    }
                }

                let image_url = self.resolve_nft(token).await?;
                match image_url.scheme() {
                    "https" | "data" => Ok(image_url),
                    "ipfs" => erc::http_link_ipfs(image_url).map_err(ProviderError::CustomError),
                    _ => Err(ProviderError::CustomError(
                        "Unsupported scheme for the image".to_string(),
                    )),
                }
            }
            _ => Err(ProviderError::CustomError("Unsupported scheme".to_string())),
        }
    }

    /// Returns the URL (not necesserily HTTP) of the image behind a token.
    ///
    /// # Example
    /// ```no_run
    /// # use ethers_providers::{Provider, Http as HttpProvider, Middleware};
    /// # use std::{str::FromStr, convert::TryFrom};
    /// # #[tokio::main(flavor = "current_thread")]
    /// # async fn main() {
    /// # let provider = Provider::<HttpProvider>::try_from("https://mainnet.infura.io/v3/c60b0bb42f8a4c6481ecd229eddaca27").unwrap();
    /// let token = ethers_providers::erc::ERCNFT::from_str("erc721:0xc92ceddfb8dd984a89fb494c376f9a48b999aafc/9018").unwrap();
    /// let token_image = provider.resolve_nft(token).await.unwrap();
    /// assert_eq!(token_image.to_string(), "https://creature.mypinata.cloud/ipfs/QmNwj3aUzXfG4twV3no7hJRYxLLAWNPk6RrfQaqJ6nVJFa/9018.jpg");
    /// # }
    /// ```
    ///
    /// # Panics
    ///
    /// If the bytes returned from the ENS registrar/resolver cannot be interpreted as
    /// a string. This should theoretically never happen.
    async fn resolve_nft(&self, token: erc::ERCNFT) -> Result<Url, ProviderError> {
        let selector = token.type_.resolution_selector();
        let tx = TransactionRequest {
            data: Some([&selector[..], &token.id].concat().into()),
            to: Some(NameOrAddress::Address(token.contract)),
            ..Default::default()
        };
        let data = self.call(&tx.into(), None).await?;
        let mut metadata_url = Url::parse(&decode_bytes::<String>(ParamType::String, data))
            .map_err(|e| ProviderError::CustomError(format!("Invalid metadata url: {}", e)))?;

        if token.type_ == erc::ERCNFTType::ERC1155 {
            metadata_url
                .set_path(&metadata_url.path().replace("%7Bid%7D", &hex::encode(&token.id)));
        }
        if metadata_url.scheme() == "ipfs" {
            metadata_url = erc::http_link_ipfs(metadata_url).map_err(ProviderError::CustomError)?;
        }
        let metadata: erc::Metadata = reqwest::get(metadata_url).await?.json().await?;
        Url::parse(&metadata.image).map_err(|e| ProviderError::CustomError(e.to_string()))
    }

    /// Fetch a field for the `ens_name` (no None if not configured).
    ///
    /// # Panics
    ///
    /// If the bytes returned from the ENS registrar/resolver cannot be interpreted as
    /// a string. This should theoretically never happen.
    async fn resolve_field(&self, ens_name: &str, field: &str) -> Result<String, ProviderError> {
        let field: String = self
            .query_resolver_parameters(
                ParamType::String,
                ens_name,
                ens::FIELD_SELECTOR,
                Some(&ens::parameterhash(field)),
            )
            .await?;
        Ok(field)
    }

    /// Returns the details of all transactions currently pending for inclusion in the next
    /// block(s), as well as the ones that are being scheduled for future execution only.
    /// Ref: [Here](https://geth.ethereum.org/docs/rpc/ns-txpool#txpool_content)
    async fn txpool_content(&self) -> Result<TxpoolContent, ProviderError> {
        self.request("txpool_content", ()).await
    }

    /// Returns a summary of all the transactions currently pending for inclusion in the next
    /// block(s), as well as the ones that are being scheduled for future execution only.
    /// Ref: [Here](https://geth.ethereum.org/docs/rpc/ns-txpool#txpool_inspect)
    async fn txpool_inspect(&self) -> Result<TxpoolInspect, ProviderError> {
        self.request("txpool_inspect", ()).await
    }

    /// Returns the number of transactions currently pending for inclusion in the next block(s), as
    /// well as the ones that are being scheduled for future execution only.
    /// Ref: [Here](https://geth.ethereum.org/docs/rpc/ns-txpool#txpool_status)
    async fn txpool_status(&self) -> Result<TxpoolStatus, ProviderError> {
        self.request("txpool_status", ()).await
    }

    /// Executes the given call and returns a number of possible traces for it
    async fn trace_call<T: Into<TypedTransaction> + Send + Sync>(
        &self,
        req: T,
        trace_type: Vec<TraceType>,
        block: Option<BlockNumber>,
    ) -> Result<BlockTrace, ProviderError> {
        let req = req.into();
        let req = utils::serialize(&req);
        let block = utils::serialize(&block.unwrap_or(BlockNumber::Latest));
        let trace_type = utils::serialize(&trace_type);
        self.request("trace_call", [req, trace_type, block]).await
    }

    /// Executes given calls and returns a number of possible traces for each call
    async fn trace_call_many<T: Into<TypedTransaction> + Send + Sync>(
        &self,
        req: Vec<(T, Vec<TraceType>)>,
        block: Option<BlockNumber>,
    ) -> Result<Vec<BlockTrace>, ProviderError> {
        let req: Vec<(TypedTransaction, Vec<TraceType>)> =
            req.into_iter().map(|(tx, trace_type)| (tx.into(), trace_type)).collect();
        let req = utils::serialize(&req);
        let block = utils::serialize(&block.unwrap_or(BlockNumber::Latest));
        self.request("trace_callMany", [req, block]).await
    }

    /// Traces a call to `eth_sendRawTransaction` without making the call, returning the traces
    async fn trace_raw_transaction(
        &self,
        data: Bytes,
        trace_type: Vec<TraceType>,
    ) -> Result<BlockTrace, ProviderError> {
        let data = utils::serialize(&data);
        let trace_type = utils::serialize(&trace_type);
        self.request("trace_rawTransaction", [data, trace_type]).await
    }

    /// Replays a transaction, returning the traces
    async fn trace_replay_transaction(
        &self,
        hash: H256,
        trace_type: Vec<TraceType>,
    ) -> Result<BlockTrace, ProviderError> {
        let hash = utils::serialize(&hash);
        let trace_type = utils::serialize(&trace_type);
        self.request("trace_replayTransaction", [hash, trace_type]).await
    }

    /// Replays all transactions in a block returning the requested traces for each transaction
    async fn trace_replay_block_transactions(
        &self,
        block: BlockNumber,
        trace_type: Vec<TraceType>,
    ) -> Result<Vec<BlockTrace>, ProviderError> {
        let block = utils::serialize(&block);
        let trace_type = utils::serialize(&trace_type);
        self.request("trace_replayBlockTransactions", [block, trace_type]).await
    }

    /// Returns traces created at given block
    async fn trace_block(&self, block: BlockNumber) -> Result<Vec<Trace>, ProviderError> {
        let block = utils::serialize(&block);
        self.request("trace_block", [block]).await
    }

    /// Return traces matching the given filter
    async fn trace_filter(&self, filter: TraceFilter) -> Result<Vec<Trace>, ProviderError> {
        let filter = utils::serialize(&filter);
        self.request("trace_filter", vec![filter]).await
    }

    /// Returns trace at the given position
    async fn trace_get<T: Into<U64> + Send + Sync>(
        &self,
        hash: H256,
        index: Vec<T>,
    ) -> Result<Trace, ProviderError> {
        let hash = utils::serialize(&hash);
        let index: Vec<U64> = index.into_iter().map(|i| i.into()).collect();
        let index = utils::serialize(&index);
        self.request("trace_get", vec![hash, index]).await
    }

    /// Returns all traces of a given transaction
    async fn trace_transaction(&self, hash: H256) -> Result<Vec<Trace>, ProviderError> {
        let hash = utils::serialize(&hash);
        self.request("trace_transaction", vec![hash]).await
    }

    async fn subscribe<T, R>(
        &self,
        params: T,
    ) -> Result<SubscriptionStream<'_, P, R>, ProviderError>
    where
        T: Debug + Serialize + Send + Sync,
        R: DeserializeOwned + Send + Sync,
        P: PubsubClient,
    {
        let id: U256 = self.request("eth_subscribe", params).await?;
        SubscriptionStream::new(id, self).map_err(Into::into)
    }

    async fn unsubscribe<T>(&self, id: T) -> Result<bool, ProviderError>
    where
        T: Into<U256> + Send + Sync,
        P: PubsubClient,
    {
        self.request("eth_unsubscribe", [id.into()]).await
    }

    async fn subscribe_blocks(
        &self,
    ) -> Result<SubscriptionStream<'_, P, Block<TxHash>>, ProviderError>
    where
        P: PubsubClient,
    {
        self.subscribe(["newHeads"]).await
    }

    async fn subscribe_pending_txs(
        &self,
    ) -> Result<SubscriptionStream<'_, P, TxHash>, ProviderError>
    where
        P: PubsubClient,
    {
        self.subscribe(["newPendingTransactions"]).await
    }

    async fn subscribe_logs<'a>(
        &'a self,
        filter: &Filter,
    ) -> Result<SubscriptionStream<'a, P, Log>, ProviderError>
    where
        P: PubsubClient,
    {
        let logs = utils::serialize(&"logs"); // TODO: Make this a static
        let filter = utils::serialize(filter);
        self.subscribe([logs, filter]).await
    }

    async fn fee_history<T: Into<U256> + Send + Sync>(
        &self,
        block_count: T,
        last_block: BlockNumber,
        reward_percentiles: &[f64],
    ) -> Result<FeeHistory, Self::Error> {
        let block_count = block_count.into();
        let last_block = utils::serialize(&last_block);
        let reward_percentiles = utils::serialize(&reward_percentiles);

        // The blockCount param is expected to be an unsigned integer up to geth v1.10.6.
        // Geth v1.10.7 onwards, this has been updated to a hex encoded form. Failure to
        // decode the param from client side would fallback to the old API spec.
        self.request(
            "eth_feeHistory",
            [utils::serialize(&block_count), last_block.clone(), reward_percentiles.clone()],
        )
        .await
        .or(self
            .request(
                "eth_feeHistory",
                [utils::serialize(&block_count.as_u64()), last_block, reward_percentiles],
            )
            .await)
    }
}

impl<P: JsonRpcClient> Provider<P> {
    async fn query_resolver<T: Detokenize>(
        &self,
        param: ParamType,
        ens_name: &str,
        selector: Selector,
    ) -> Result<T, ProviderError> {
        self.query_resolver_parameters(param, ens_name, selector, None).await
    }

    async fn query_resolver_parameters<T: Detokenize>(
        &self,
        param: ParamType,
        ens_name: &str,
        selector: Selector,
        parameters: Option<&[u8]>,
    ) -> Result<T, ProviderError> {
        // Get the ENS address, prioritize the local override variable
        let ens_addr = self.ens.unwrap_or(ens::ENS_ADDRESS);

        // first get the resolver responsible for this name
        // the call will return a Bytes array which we convert to an address
        let data = self.call(&ens::get_resolver(ens_addr, ens_name).into(), None).await?;

        // otherwise, decode_bytes panics
        if data.0.is_empty() {
            return Err(ProviderError::EnsError(ens_name.to_owned()))
        }

        let resolver_address: Address = decode_bytes(ParamType::Address, data);
        if resolver_address == Address::zero() {
            return Err(ProviderError::EnsError(ens_name.to_owned()))
        }

        // resolve
        let data = self
            .call(&ens::resolve(resolver_address, selector, ens_name, parameters).into(), None)
            .await?;

        Ok(decode_bytes(param, data))
    }

    #[cfg(test)]
    /// ganache-only function for mining empty blocks
    pub async fn mine(&self, num_blocks: usize) -> Result<(), ProviderError> {
        for _ in 0..num_blocks {
            self.inner.request::<_, U256>("evm_mine", None::<()>).await.map_err(Into::into)?;
        }
        Ok(())
    }

    /// Sets the ENS Address (default: mainnet)
    #[must_use]
    pub fn ens<T: Into<Address>>(mut self, ens: T) -> Self {
        self.ens = Some(ens.into());
        self
    }

    /// Sets the default polling interval for event filters and pending transactions
    /// (default: 7 seconds)
    #[must_use]
    pub fn interval<T: Into<Duration>>(mut self, interval: T) -> Self {
        self.interval = Some(interval.into());
        self
    }

    /// Gets the polling interval which the provider currently uses for event filters
    /// and pending transactions (default: 7 seconds)
    pub fn get_interval(&self) -> Duration {
        self.interval.unwrap_or(DEFAULT_POLL_INTERVAL)
    }
}

#[cfg(feature = "ws")]
impl Provider<crate::Ws> {
    /// Direct connection to a websocket endpoint
    #[cfg(not(target_arch = "wasm32"))]
    pub async fn connect(
        url: impl tokio_tungstenite::tungstenite::client::IntoClientRequest + Unpin,
    ) -> Result<Self, ProviderError> {
        let ws = crate::Ws::connect(url).await?;
        Ok(Self::new(ws))
    }

    /// Direct connection to a websocket endpoint
    #[cfg(target_arch = "wasm32")]
    pub async fn connect(url: &str) -> Result<Self, ProviderError> {
        let ws = crate::Ws::connect(url).await?;
        Ok(Self::new(ws))
    }
}

#[cfg(all(target_family = "unix", feature = "ipc"))]
impl Provider<crate::Ipc> {
    /// Direct connection to an IPC socket.
    pub async fn connect_ipc(path: impl AsRef<std::path::Path>) -> Result<Self, ProviderError> {
        let ipc = crate::Ipc::connect(path).await?;
        Ok(Self::new(ipc))
    }
}

impl<T: JsonRpcClientWrapper> Provider<QuorumProvider<T>> {
    /// Provider that uses a quorum
    pub fn quorum(inner: QuorumProvider<T>) -> Self {
        Self::new(inner)
    }
}

impl Provider<MockProvider> {
    /// Returns a `Provider` instantiated with an internal "mock" transport.
    ///
    /// # Example
    ///
    /// ```
    /// # async fn foo() -> Result<(), Box<dyn std::error::Error>> {
    /// use ethers_core::types::U64;
    /// use ethers_providers::{Middleware, Provider};
    /// // Instantiate the provider
    /// let (provider, mock) = Provider::mocked();
    /// // Push the mock response
    /// mock.push(U64::from(12))?;
    /// // Make the call
    /// let blk = provider.get_block_number().await.unwrap();
    /// // The response matches
    /// assert_eq!(blk.as_u64(), 12);
    /// // and the request as well!
    /// mock.assert_request("eth_blockNumber", ()).unwrap();
    /// # Ok(())
    /// # }
    /// ```
    pub fn mocked() -> (Self, MockProvider) {
        let mock = MockProvider::new();
        let mock_clone = mock.clone();
        (Self::new(mock), mock_clone)
    }
}

/// infallible conversion of Bytes to Address/String
///
/// # Panics
///
/// If the provided bytes were not an interpretation of an address
fn decode_bytes<T: Detokenize>(param: ParamType, bytes: Bytes) -> T {
    let tokens = abi::decode(&[param], bytes.as_ref())
        .expect("could not abi-decode bytes to address tokens");
    T::from_tokens(tokens).expect("could not parse tokens as address")
}

impl TryFrom<&str> for Provider<HttpProvider> {
    type Error = ParseError;

    fn try_from(src: &str) -> Result<Self, Self::Error> {
        Ok(Provider::new(HttpProvider::new(Url::parse(src)?)))
    }
}

impl TryFrom<String> for Provider<HttpProvider> {
    type Error = ParseError;

    fn try_from(src: String) -> Result<Self, Self::Error> {
        Provider::try_from(src.as_str())
    }
}

/// A middleware supporting development-specific JSON RPC methods
///
/// # Example
///
///```
/// use ethers_providers::{Provider, Http, Middleware, DevRpcMiddleware};
/// use ethers_core::types::TransactionRequest;
/// use ethers_core::utils::Ganache;
/// use std::convert::TryFrom;
///
/// # #[tokio::main(flavor = "current_thread")]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// let ganache = Ganache::new().spawn();
/// let provider = Provider::<Http>::try_from(ganache.endpoint()).unwrap();
/// let client = DevRpcMiddleware::new(provider);
///
/// // snapshot the initial state
/// let block0 = client.get_block_number().await.unwrap();
/// let snap_id = client.snapshot().await.unwrap();
///
/// // send a transaction
/// let accounts = client.get_accounts().await?;
/// let from = accounts[0];
/// let to = accounts[1];
/// let balance_before = client.get_balance(to, None).await?;
/// let tx = TransactionRequest::new().to(to).value(1000).from(from);
/// client.send_transaction(tx, None).await?.await?;
/// let balance_after = client.get_balance(to, None).await?;
/// assert_eq!(balance_after, balance_before + 1000);
///
/// // revert to snapshot
/// client.revert_to_snapshot(snap_id).await.unwrap();
/// let balance_after_revert = client.get_balance(to, None).await?;
/// assert_eq!(balance_after_revert, balance_before);
/// # Ok(())
/// # }
/// ```
#[cfg(feature = "dev-rpc")]
pub mod dev_rpc {
    use crate::{FromErr, Middleware, ProviderError};
    use async_trait::async_trait;
    use ethers_core::types::U256;
    use thiserror::Error;

    use std::fmt::Debug;

    #[derive(Clone, Debug)]
    pub struct DevRpcMiddleware<M>(M);

    #[derive(Error, Debug)]
    pub enum DevRpcMiddlewareError<M: Middleware> {
        #[error("{0}")]
        MiddlewareError(M::Error),

        #[error("{0}")]
        ProviderError(ProviderError),

        #[error("Could not revert to snapshot")]
        NoSnapshot,
    }

    #[async_trait]
    impl<M: Middleware> Middleware for DevRpcMiddleware<M> {
        type Error = DevRpcMiddlewareError<M>;
        type Provider = M::Provider;
        type Inner = M;

        fn inner(&self) -> &M {
            &self.0
        }
    }

    impl<M: Middleware> FromErr<M::Error> for DevRpcMiddlewareError<M> {
        fn from(src: M::Error) -> DevRpcMiddlewareError<M> {
            DevRpcMiddlewareError::MiddlewareError(src)
        }
    }

    impl<M> From<ProviderError> for DevRpcMiddlewareError<M>
    where
        M: Middleware,
    {
        fn from(src: ProviderError) -> Self {
            Self::ProviderError(src)
        }
    }

    impl<M: Middleware> DevRpcMiddleware<M> {
        pub fn new(inner: M) -> Self {
            Self(inner)
        }

        // both ganache and hardhat increment snapshot id even if no state has changed
        pub async fn snapshot(&self) -> Result<U256, DevRpcMiddlewareError<M>> {
            self.provider().request::<(), U256>("evm_snapshot", ()).await.map_err(From::from)
        }

        pub async fn revert_to_snapshot(&self, id: U256) -> Result<(), DevRpcMiddlewareError<M>> {
            let ok = self
                .provider()
                .request::<[U256; 1], bool>("evm_revert", [id])
                .await
                .map_err(DevRpcMiddlewareError::ProviderError)?;
            if ok {
                Ok(())
            } else {
                Err(DevRpcMiddlewareError::NoSnapshot)
            }
        }
    }
    #[cfg(test)]
    // Celo blocks can not get parsed when used with Ganache
    #[cfg(not(feature = "celo"))]
    mod tests {
        use super::*;
        use crate::{Http, Provider};
        use ethers_core::utils::Ganache;
        use std::convert::TryFrom;

        #[tokio::test]
        async fn test_snapshot() {
            // launch ganache
            let ganache = Ganache::new().spawn();
            let provider = Provider::<Http>::try_from(ganache.endpoint()).unwrap();
            let client = DevRpcMiddleware::new(provider);

            // snapshot initial state
            let block0 = client.get_block_number().await.unwrap();
            let time0 = client.get_block(block0).await.unwrap().unwrap().timestamp;
            let snap_id0 = client.snapshot().await.unwrap();

            // mine a new block
            client.provider().mine(1).await.unwrap();

            // snapshot state
            let block1 = client.get_block_number().await.unwrap();
            let time1 = client.get_block(block1).await.unwrap().unwrap().timestamp;
            let snap_id1 = client.snapshot().await.unwrap();

            // mine some blocks
            client.provider().mine(5).await.unwrap();

            // snapshot state
            let block2 = client.get_block_number().await.unwrap();
            let time2 = client.get_block(block2).await.unwrap().unwrap().timestamp;
            let snap_id2 = client.snapshot().await.unwrap();

            // mine some blocks
            client.provider().mine(5).await.unwrap();

            // revert_to_snapshot should reset state to snap id
            client.revert_to_snapshot(snap_id2).await.unwrap();
            let block = client.get_block_number().await.unwrap();
            let time = client.get_block(block).await.unwrap().unwrap().timestamp;
            assert_eq!(block, block2);
            assert_eq!(time, time2);

            client.revert_to_snapshot(snap_id1).await.unwrap();
            let block = client.get_block_number().await.unwrap();
            let time = client.get_block(block).await.unwrap().unwrap().timestamp;
            assert_eq!(block, block1);
            assert_eq!(time, time1);

            // revert_to_snapshot should throw given non-existent or
            // previously used snapshot
            let result = client.revert_to_snapshot(snap_id1).await;
            assert!(result.is_err());

            client.revert_to_snapshot(snap_id0).await.unwrap();
            let block = client.get_block_number().await.unwrap();
            let time = client.get_block(block).await.unwrap().unwrap().timestamp;
            assert_eq!(block, block0);
            assert_eq!(time, time0);
        }
    }
}

#[cfg(test)]
#[cfg(not(target_arch = "wasm32"))]
mod tests {
    use super::*;
    use crate::Http;
    use ethers_core::{
        types::{
            transaction::eip2930::AccessList, Eip1559TransactionRequest, TransactionRequest, H256,
        },
        utils::Geth,
    };
    use futures_util::StreamExt;

    const INFURA: &str = "https://mainnet.infura.io/v3/c60b0bb42f8a4c6481ecd229eddaca27";

    #[tokio::test]
    // Test vector from: https://docs.ethers.io/ethers.js/v5-beta/api-providers.html#id2
    async fn mainnet_resolve_name() {
        let provider = Provider::<HttpProvider>::try_from(INFURA).unwrap();

        let addr = provider.resolve_name("registrar.firefly.eth").await.unwrap();
        assert_eq!(addr, "6fC21092DA55B392b045eD78F4732bff3C580e2c".parse().unwrap());

        // registrar not found
        provider.resolve_name("asdfasdffads").await.unwrap_err();

        // name not found
        provider.resolve_name("asdfasdf.registrar.firefly.eth").await.unwrap_err();
    }

    #[tokio::test]
    // Test vector from: https://docs.ethers.io/ethers.js/v5-beta/api-providers.html#id2
    async fn mainnet_lookup_address() {
        let provider = Provider::<HttpProvider>::try_from(INFURA).unwrap();

        let name = provider
            .lookup_address("6fC21092DA55B392b045eD78F4732bff3C580e2c".parse().unwrap())
            .await
            .unwrap();

        assert_eq!(name, "registrar.firefly.eth");

        provider
            .lookup_address("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA".parse().unwrap())
            .await
            .unwrap_err();
    }

    #[tokio::test]
    async fn mainnet_resolve_avatar() {
        let provider = Provider::<HttpProvider>::try_from(INFURA).unwrap();

        for (ens_name, res) in &[
            // HTTPS
            ("alisha.eth", "https://ipfs.io/ipfs/QmeQm91kAdPGnUKsE74WvkqYKUeHvc2oHd2FW11V3TrqkQ"),
            // ERC-1155
            ("nick.eth", "https://lh3.googleusercontent.com/hKHZTZSTmcznonu8I6xcVZio1IF76fq0XmcxnvUykC-FGuVJ75UPdLDlKJsfgVXH9wOSmkyHw0C39VAYtsGyxT7WNybjQ6s3fM3macE"),
            // HTTPS
            ("parishilton.eth", "https://i.imgur.com/YW3Hzph.jpg"),
            // ERC-721 with IPFS link
            ("ikehaya-nft.eth", "https://ipfs.io/ipfs/QmdKkwCE8uVhgYd7tWBfhtHdQZDnbNukWJ8bvQmR6nZKsk"),
            // ERC-1155 with IPFS link
            ("vitalik.eth", "https://ipfs.io/ipfs/QmSP4nq9fnN9dAiCj42ug9Wa79rqmQerZXZch82VqpiH7U/image.gif"),
            // IPFS
            ("cdixon.eth", "https://ipfs.io/ipfs/QmYA6ZpEARgHvRHZQdFPynMMX8NtdL2JCadvyuyG2oA88u"),
            ("0age.eth", "data:image/svg+xml;base64,PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0iVVRGLTgiPz48c3ZnIHN0eWxlPSJiYWNrZ3JvdW5kLWNvbG9yOmJsYWNrIiB2aWV3Qm94PSIwIDAgNTAwIDUwMCIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48cmVjdCB4PSIxNTUiIHk9IjYwIiB3aWR0aD0iMTkwIiBoZWlnaHQ9IjM5MCIgZmlsbD0iIzY5ZmYzNyIvPjwvc3ZnPg==")
        ] {
        println!("Resolving: {}", ens_name);
        assert_eq!(provider.resolve_avatar(ens_name).await.unwrap(), Url::parse(res).unwrap());
    }
    }

    #[tokio::test]
    #[cfg_attr(feature = "celo", ignore)]
    async fn test_new_block_filter() {
        let num_blocks = 3;
        let geth = Geth::new().block_time(2u64).spawn();
        let provider = Provider::<Http>::try_from(geth.endpoint())
            .unwrap()
            .interval(Duration::from_millis(1000));

        let start_block = provider.get_block_number().await.unwrap();

        let stream = provider.watch_blocks().await.unwrap().stream();

        let hashes: Vec<H256> = stream.take(num_blocks).collect::<Vec<H256>>().await;
        for (i, hash) in hashes.iter().enumerate() {
            let block = provider.get_block(start_block + i as u64 + 1).await.unwrap().unwrap();
            assert_eq!(*hash, block.hash.unwrap());
        }
    }

    #[tokio::test]
    #[cfg_attr(feature = "celo", ignore)]
    async fn test_is_signer() {
        use ethers_core::utils::Ganache;
        use std::str::FromStr;

        let ganache = Ganache::new().spawn();
        let provider = Provider::<Http>::try_from(ganache.endpoint())
            .unwrap()
            .with_sender(ganache.addresses()[0]);
        assert!(provider.is_signer().await);

        let provider = Provider::<Http>::try_from(ganache.endpoint()).unwrap();
        assert!(!provider.is_signer().await);

        let sender = Address::from_str("635B4764D1939DfAcD3a8014726159abC277BecC")
            .expect("should be able to parse hex address");
        let provider = Provider::<Http>::try_from(
            "https://ropsten.infura.io/v3/fd8b88b56aa84f6da87b60f5441d6778",
        )
        .unwrap()
        .with_sender(sender);
        assert!(!provider.is_signer().await);
    }

    #[tokio::test]
    async fn test_new_pending_txs_filter() {
        let num_txs = 5;

        let geth = Geth::new().block_time(2u64).spawn();
        let provider = Provider::<Http>::try_from(geth.endpoint())
            .unwrap()
            .interval(Duration::from_millis(1000));
        let accounts = provider.get_accounts().await.unwrap();

        let stream = provider.watch_pending_transactions().await.unwrap().stream();

        let mut tx_hashes = Vec::new();
        let tx = TransactionRequest::new().from(accounts[0]).to(accounts[0]).value(1e18 as u64);

        for _ in 0..num_txs {
            tx_hashes.push(provider.send_transaction(tx.clone(), None).await.unwrap());
        }

        let hashes: Vec<H256> = stream.take(num_txs).collect::<Vec<H256>>().await;
        assert_eq!(tx_hashes, hashes);
    }

    #[tokio::test]
    async fn receipt_on_unmined_tx() {
        use ethers_core::{
            types::TransactionRequest,
            utils::{parse_ether, Ganache},
        };
        let ganache = Ganache::new().block_time(2u64).spawn();
        let provider = Provider::<Http>::try_from(ganache.endpoint()).unwrap();

        let accounts = provider.get_accounts().await.unwrap();
        let tx = TransactionRequest::pay(accounts[0], parse_ether(1u64).unwrap()).from(accounts[0]);
        let pending_tx = provider.send_transaction(tx, None).await.unwrap();

        assert!(provider.get_transaction_receipt(*pending_tx).await.unwrap().is_none());

        let hash = *pending_tx;
        let receipt = pending_tx.await.unwrap().unwrap();
        assert_eq!(receipt.transaction_hash, hash);
    }

    #[tokio::test]
    async fn parity_block_receipts() {
        let url = match std::env::var("PARITY") {
            Ok(inner) => inner,
            _ => return,
        };
        let provider = Provider::<Http>::try_from(url.as_str()).unwrap();
        let receipts = provider.parity_block_receipts(10657200).await.unwrap();
        assert!(!receipts.is_empty());
    }

    #[tokio::test]
    // Celo blocks can not get parsed when used with Ganache
    #[cfg(not(feature = "celo"))]
    async fn block_subscribe() {
        use ethers_core::utils::Ganache;
        use futures_util::StreamExt;
        let ganache = Ganache::new().block_time(2u64).spawn();
        let provider = Provider::connect(ganache.ws_endpoint()).await.unwrap();

        let stream = provider.subscribe_blocks().await.unwrap();
        let blocks = stream.take(3).map(|x| x.number.unwrap().as_u64()).collect::<Vec<_>>().await;
        assert_eq!(blocks, vec![1, 2, 3]);
    }

    #[tokio::test]
    #[cfg_attr(feature = "celo", ignore)]
    async fn fee_history() {
        let provider = Provider::<Http>::try_from(
            "https://goerli.infura.io/v3/fd8b88b56aa84f6da87b60f5441d6778",
        )
        .unwrap();

        let history =
            provider.fee_history(10u64, BlockNumber::Latest, &[10.0, 40.0]).await.unwrap();
        dbg!(&history);
    }

    #[tokio::test]
    #[ignore]
    #[cfg(feature = "ws")]
    async fn test_trace_call_many() {
        use ethers_core::types::H160;

        // TODO: Implement ErigonInstance, so it'd be possible to test this.
        let provider = Provider::new(crate::Ws::connect("ws://127.0.0.1:8545").await.unwrap());
        let traces = provider
            .trace_call_many(
                vec![
                    (
                        TransactionRequest::new()
                            .from(Address::zero())
                            .to("0x0000000000000000000000000000000000000001"
                                .parse::<H160>()
                                .unwrap())
                            .value(U256::from(10000000000000000u128)),
                        vec![TraceType::StateDiff],
                    ),
                    (
                        TransactionRequest::new()
                            .from(
                                "0x0000000000000000000000000000000000000001"
                                    .parse::<H160>()
                                    .unwrap(),
                            )
                            .to("0x0000000000000000000000000000000000000002"
                                .parse::<H160>()
                                .unwrap())
                            .value(U256::from(10000000000000000u128)),
                        vec![TraceType::StateDiff],
                    ),
                ],
                None,
            )
            .await
            .unwrap();
        dbg!(traces);
    }

    #[tokio::test]
    async fn test_fill_transaction_1559() {
        let (mut provider, mock) = Provider::mocked();
        provider.from = Some("0x6fC21092DA55B392b045eD78F4732bff3C580e2c".parse().unwrap());

        let gas = U256::from(21000_usize);
        let basefee = U256::from(25_usize);
        let prio_fee = U256::from(25_usize);
        let access_list: AccessList = vec![Default::default()].into();

        // --- leaves a filled 1559 transaction unchanged, making no requests
        let from: Address = "0x0000000000000000000000000000000000000001".parse().unwrap();
        let to: Address = "0x0000000000000000000000000000000000000002".parse().unwrap();
        let mut tx = Eip1559TransactionRequest::new()
            .from(from)
            .to(to)
            .gas(gas)
            .max_fee_per_gas(basefee)
            .max_priority_fee_per_gas(prio_fee)
            .access_list(access_list.clone())
            .into();
        provider.fill_transaction(&mut tx, None).await.unwrap();

        assert_eq!(tx.from(), Some(&from));
        assert_eq!(tx.to(), Some(&to.into()));
        assert_eq!(tx.gas(), Some(&gas));
        assert_eq!(tx.gas_price(), Some(basefee + prio_fee));
        assert_eq!(tx.access_list(), Some(&access_list));

        // --- fills a 1559 transaction, leaving the existing gas limit unchanged, but including
        // access list if cheaper
        let gas_with_al = gas - 1;
        let mut tx = Eip1559TransactionRequest::new()
            .gas(gas)
            .max_fee_per_gas(basefee)
            .max_priority_fee_per_gas(prio_fee)
            .into();

        mock.push(AccessListWithGasUsed {
            access_list: access_list.clone(),
            gas_used: gas_with_al,
        })
        .unwrap();

        provider.fill_transaction(&mut tx, None).await.unwrap();

        assert_eq!(tx.from(), provider.from.as_ref());
        assert!(tx.to().is_none());
        assert_eq!(tx.gas(), Some(&gas));
        assert_eq!(tx.access_list(), Some(&access_list));

        // --- fills a 1559 transaction, ignoring access list if more expensive
        let gas_with_al = gas + 1;
        let mut tx = Eip1559TransactionRequest::new()
            .max_fee_per_gas(basefee)
            .max_priority_fee_per_gas(prio_fee)
            .into();

        mock.push(AccessListWithGasUsed {
            access_list: access_list.clone(),
            gas_used: gas_with_al,
        })
        .unwrap();
        mock.push(gas).unwrap();

        provider.fill_transaction(&mut tx, None).await.unwrap();

        assert_eq!(tx.from(), provider.from.as_ref());
        assert!(tx.to().is_none());
        assert_eq!(tx.gas(), Some(&gas));
        assert_eq!(tx.access_list(), Some(&Default::default()));

        // --- fills a 1559 transaction, using estimated gas if create_access_list() errors
        let mut tx = Eip1559TransactionRequest::new()
            .max_fee_per_gas(basefee)
            .max_priority_fee_per_gas(prio_fee)
            .into();

        // bad mock value causes error response for eth_createAccessList
        mock.push(b'b').unwrap();
        mock.push(gas).unwrap();

        provider.fill_transaction(&mut tx, None).await.unwrap();

        assert_eq!(tx.from(), provider.from.as_ref());
        assert!(tx.to().is_none());
        assert_eq!(tx.gas(), Some(&gas));
        assert_eq!(tx.access_list(), Some(&Default::default()));

        // --- propogates estimate_gas() error
        let mut tx = Eip1559TransactionRequest::new()
            .max_fee_per_gas(basefee)
            .max_priority_fee_per_gas(prio_fee)
            .into();

        // bad mock value causes error response for eth_estimateGas
        mock.push(b'b').unwrap();

        let res = provider.fill_transaction(&mut tx, None).await;

        assert!(matches!(res, Err(ProviderError::JsonRpcClientError(_))));
    }

    #[tokio::test]
    async fn test_fill_transaction_legacy() {
        let (mut provider, mock) = Provider::mocked();
        provider.from = Some("0x6fC21092DA55B392b045eD78F4732bff3C580e2c".parse().unwrap());

        let gas = U256::from(21000_usize);
        let gas_price = U256::from(50_usize);

        // --- leaves a filled legacy transaction unchanged, making no requests
        let from: Address = "0x0000000000000000000000000000000000000001".parse().unwrap();
        let to: Address = "0x0000000000000000000000000000000000000002".parse().unwrap();
        let mut tx =
            TransactionRequest::new().from(from).to(to).gas(gas).gas_price(gas_price).into();
        provider.fill_transaction(&mut tx, None).await.unwrap();

        assert_eq!(tx.from(), Some(&from));
        assert_eq!(tx.to(), Some(&to.into()));
        assert_eq!(tx.gas(), Some(&gas));
        assert_eq!(tx.gas_price(), Some(gas_price));
        assert!(tx.access_list().is_none());

        // --- fills an empty legacy transaction
        let mut tx = TransactionRequest::new().into();
        mock.push(gas).unwrap();
        mock.push(gas_price).unwrap();
        provider.fill_transaction(&mut tx, None).await.unwrap();

        assert_eq!(tx.from(), provider.from.as_ref());
        assert!(tx.to().is_none());
        assert_eq!(tx.gas(), Some(&gas));
        assert_eq!(tx.gas_price(), Some(gas_price));
        assert!(tx.access_list().is_none());
    }
}