freenet_stdlib/client_api/
client_events.rs

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use flatbuffers::WIPOffset;
use std::fmt::Display;

use serde::{de::DeserializeOwned, Deserialize, Deserializer, Serialize};

use crate::client_api::TryFromFbs;
use crate::client_request_generated::client_request::{
    root_as_client_request, ClientRequestType, ContractRequest as FbsContractRequest,
    ContractRequestType, DelegateRequest as FbsDelegateRequest, DelegateRequestType,
};

use crate::common_generated::common::{
    ApplicationMessage as FbsApplicationMessage, ApplicationMessageArgs, ContractCode,
    ContractCodeArgs, ContractContainer as FbsContractContainer, ContractContainerArgs,
    ContractInstanceId, ContractInstanceIdArgs, ContractKey as FbsContractKey, ContractKeyArgs,
    ContractType, DeltaUpdate, DeltaUpdateArgs, GetSecretRequest as FbsGetSecretRequest,
    GetSecretRequestArgs, GetSecretResponse as FbsGetSecretResponse, GetSecretResponseArgs,
    RelatedDeltaUpdate, RelatedDeltaUpdateArgs, RelatedStateAndDeltaUpdate,
    RelatedStateAndDeltaUpdateArgs, RelatedStateUpdate, RelatedStateUpdateArgs,
    SecretsId as FbsSecretsId, SecretsIdArgs, StateAndDeltaUpdate, StateAndDeltaUpdateArgs,
    StateUpdate, StateUpdateArgs, UpdateData as FbsUpdateData, UpdateDataArgs, UpdateDataType,
    WasmContractV1, WasmContractV1Args,
};
use crate::delegate_interface::DelegateContext;
use crate::host_response_generated::host_response::{
    finish_host_response_buffer, ClientResponse as FbsClientResponse, ClientResponseArgs,
    ContextUpdated as FbsContextUpdated, ContextUpdatedArgs,
    ContractResponse as FbsContractResponse, ContractResponseArgs, ContractResponseType,
    DelegateKey as FbsDelegateKey, DelegateKeyArgs, DelegateResponse as FbsDelegateResponse,
    DelegateResponseArgs, GetResponse as FbsGetResponse, GetResponseArgs,
    HostResponse as FbsHostResponse, HostResponseArgs, HostResponseType, Ok as FbsOk, OkArgs,
    OutboundDelegateMsg as FbsOutboundDelegateMsg, OutboundDelegateMsgArgs,
    OutboundDelegateMsgType, PutResponse as FbsPutResponse, PutResponseArgs,
    RequestUserInput as FbsRequestUserInput, RequestUserInputArgs,
    SetSecretRequest as FbsSetSecretRequest, SetSecretRequestArgs,
    UpdateNotification as FbsUpdateNotification, UpdateNotificationArgs,
    UpdateResponse as FbsUpdateResponse, UpdateResponseArgs,
};
use crate::prelude::ContractContainer::Wasm;
use crate::prelude::ContractWasmAPIVersion::V1;
use crate::prelude::UpdateData::{
    Delta, RelatedDelta, RelatedState, RelatedStateAndDelta, State, StateAndDelta,
};
use crate::{
    delegate_interface::{DelegateKey, InboundDelegateMsg, OutboundDelegateMsg},
    prelude::{
        ContractKey, DelegateContainer, GetSecretRequest, Parameters, RelatedContracts, SecretsId,
        StateSummary, UpdateData, WrappedState,
    },
    versioning::ContractContainer,
};

use super::WsApiError;

#[derive(Debug, Serialize, Deserialize)]
pub struct ClientError {
    kind: Box<ErrorKind>,
}

impl ClientError {
    pub fn into_fbs_bytes(self) -> Result<Vec<u8>, Box<ClientError>> {
        use crate::host_response_generated::host_response::{Error, ErrorArgs};
        let mut builder = flatbuffers::FlatBufferBuilder::new();
        let msg_offset = builder.create_string(&self.to_string());
        let err_offset = Error::create(
            &mut builder,
            &ErrorArgs {
                msg: Some(msg_offset),
            },
        );
        let host_response_offset = FbsHostResponse::create(
            &mut builder,
            &HostResponseArgs {
                response_type: HostResponseType::Ok,
                response: Some(err_offset.as_union_value()),
            },
        );
        finish_host_response_buffer(&mut builder, host_response_offset);
        Ok(builder.finished_data().to_vec())
    }

    pub fn kind(&self) -> ErrorKind {
        (*self.kind).clone()
    }
}

impl From<ErrorKind> for ClientError {
    fn from(kind: ErrorKind) -> Self {
        ClientError {
            kind: Box::new(kind),
        }
    }
}

impl From<String> for ClientError {
    fn from(cause: String) -> Self {
        ClientError {
            kind: Box::new(ErrorKind::Unhandled { cause }),
        }
    }
}

#[derive(thiserror::Error, Debug, Serialize, Deserialize, Clone)]
#[non_exhaustive]
pub enum ErrorKind {
    #[error("comm channel between client/host closed")]
    ChannelClosed,
    #[error("error while deserializing: {cause}")]
    DeserializationError { cause: String },
    #[error("client disconnected")]
    Disconnect,
    #[error("failed while trying to unpack state for {0}")]
    IncorrectState(ContractKey),
    #[error("node not available")]
    NodeUnavailable,
    #[error("lost the connection with the protocol hanling connections")]
    TransportProtocolDisconnect,
    #[error("unhandled error: {cause}")]
    Unhandled { cause: String },
    #[error("unknown client id: {0}")]
    UnknownClient(usize),
    #[error(transparent)]
    RequestError(#[from] RequestError),
}

impl Display for ClientError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "client error: {}", self.kind)
    }
}

impl std::error::Error for ClientError {}

#[derive(Debug, thiserror::Error, Serialize, Deserialize, Clone)]
#[non_exhaustive]
pub enum RequestError {
    #[error(transparent)]
    ContractError(#[from] ContractError),
    #[error(transparent)]
    DelegateError(#[from] DelegateError),
    #[error("client disconnect")]
    Disconnect,
    #[error("operation timed out")]
    Timeout,
}

/// Errors that may happen while interacting with delegates.
#[derive(Debug, thiserror::Error, Serialize, Deserialize, Clone)]
#[non_exhaustive]
pub enum DelegateError {
    #[error("error while registering delegate {0}")]
    RegisterError(DelegateKey),
    #[error("execution error, cause {0}")]
    ExecutionError(String),
    #[error("missing delegate {0}")]
    Missing(DelegateKey),
    #[error("missing secret `{secret}` for delegate {key}")]
    MissingSecret { key: DelegateKey, secret: SecretsId },
    #[error("forbidden access to secret: {0}")]
    ForbiddenSecretAccess(SecretsId),
}

/// Errors that may happen while interacting with contracts.
#[derive(Debug, thiserror::Error, Serialize, Deserialize, Clone)]
#[non_exhaustive]
pub enum ContractError {
    #[error("failed to get contract {key}, reason: {cause}")]
    Get { key: ContractKey, cause: String },
    #[error("put error for contract {key}, reason: {cause}")]
    Put { key: ContractKey, cause: String },
    #[error("update error for contract {key}, reason: {cause}")]
    Update { key: ContractKey, cause: String },
    #[error("failed to subscribe for contract {key}, reason: {cause}")]
    Subscribe { key: ContractKey, cause: String },
    #[error("missing related contract: {key}")]
    MissingRelated {
        key: crate::contract_interface::ContractInstanceId,
    },
    // todo: actually build a stack of the involved keys
    #[error("dependency contract stack overflow : {key}")]
    ContractStackOverflow {
        key: crate::contract_interface::ContractInstanceId,
    },
}

/// A request from a client application to the host.
#[derive(Serialize, Deserialize, Debug, Clone)]
#[non_exhaustive]
// #[cfg_attr(test, derive(arbitrary::Arbitrary))]
pub enum ClientRequest<'a> {
    DelegateOp(#[serde(borrow)] DelegateRequest<'a>),
    ContractOp(#[serde(borrow)] ContractRequest<'a>),
    Disconnect { cause: Option<String> },
    Authenticate { token: String },
}

impl ClientRequest<'_> {
    pub fn into_owned(self) -> ClientRequest<'static> {
        match self {
            ClientRequest::ContractOp(op) => {
                let owned = match op {
                    ContractRequest::Put {
                        contract,
                        state,
                        related_contracts,
                    } => {
                        let related_contracts = related_contracts.into_owned();
                        ContractRequest::Put {
                            contract,
                            state,
                            related_contracts,
                        }
                    }
                    ContractRequest::Update { key, data } => {
                        let data = data.into_owned();
                        ContractRequest::Update { key, data }
                    }
                    ContractRequest::Get {
                        key,
                        fetch_contract,
                    } => ContractRequest::Get {
                        key,
                        fetch_contract,
                    },
                    ContractRequest::Subscribe { key, summary } => ContractRequest::Subscribe {
                        key,
                        summary: summary.map(StateSummary::into_owned),
                    },
                };
                owned.into()
            }
            ClientRequest::DelegateOp(op) => {
                let op = op.into_owned();
                ClientRequest::DelegateOp(op)
            }
            ClientRequest::Disconnect { cause } => ClientRequest::Disconnect { cause },
            ClientRequest::Authenticate { token } => ClientRequest::Authenticate { token },
        }
    }

    pub fn is_disconnect(&self) -> bool {
        matches!(self, Self::Disconnect { .. })
    }

    pub fn try_decode_fbs(msg: &[u8]) -> Result<ClientRequest, WsApiError> {
        let req = {
            match root_as_client_request(msg) {
                Ok(client_request) => match client_request.client_request_type() {
                    ClientRequestType::ContractRequest => {
                        let contract_request =
                            client_request.client_request_as_contract_request().unwrap();
                        ContractRequest::try_decode_fbs(&contract_request)?.into()
                    }
                    ClientRequestType::DelegateRequest => {
                        let delegate_request =
                            client_request.client_request_as_delegate_request().unwrap();
                        DelegateRequest::try_decode_fbs(&delegate_request)?.into()
                    }
                    ClientRequestType::Disconnect => {
                        let delegate_request =
                            client_request.client_request_as_disconnect().unwrap();
                        let cause = delegate_request
                            .cause()
                            .map(|cuase_msg| cuase_msg.to_string());
                        ClientRequest::Disconnect { cause }
                    }
                    ClientRequestType::Authenticate => {
                        let auth_req = client_request.client_request_as_authenticate().unwrap();
                        let token = auth_req.token();
                        ClientRequest::Authenticate {
                            token: token.to_owned(),
                        }
                    }
                    _ => unreachable!(),
                },
                Err(e) => {
                    let cause = format!("{e}");
                    return Err(WsApiError::deserialization(cause));
                }
            }
        };

        Ok(req)
    }
}

#[derive(Clone, Serialize, Deserialize, Debug, PartialEq, Eq)]
#[non_exhaustive]
pub enum ContractRequest<'a> {
    /// Insert a new value in a contract corresponding with the provided key.
    Put {
        contract: ContractContainer,
        /// Value to upsert in the contract.
        state: WrappedState,
        /// Related contracts.
        #[serde(borrow)]
        related_contracts: RelatedContracts<'a>,
    },
    /// Update an existing contract corresponding with the provided key.
    Update {
        key: ContractKey,
        #[serde(borrow)]
        data: UpdateData<'a>,
    },
    /// Fetch the current state from a contract corresponding to the provided key.
    Get {
        /// Key of the contract.
        key: ContractKey,
        /// If this flag is set then fetch also the contract itself.
        fetch_contract: bool,
    },
    /// Subscribe to the changes in a given contract. Implicitly starts a get operation
    /// if the contract is not present yet.
    Subscribe {
        key: ContractKey,
        summary: Option<StateSummary<'a>>,
    },
}

impl ContractRequest<'_> {
    pub fn into_owned(self) -> ContractRequest<'static> {
        match self {
            Self::Put {
                contract,
                state,
                related_contracts,
            } => ContractRequest::Put {
                contract,
                state,
                related_contracts: related_contracts.into_owned(),
            },
            Self::Update { key, data } => ContractRequest::Update {
                key,
                data: data.into_owned(),
            },
            Self::Get {
                key,
                fetch_contract,
            } => ContractRequest::Get {
                key,
                fetch_contract,
            },
            Self::Subscribe { key, summary } => ContractRequest::Subscribe {
                key,
                summary: summary.map(StateSummary::into_owned),
            },
        }
    }
}

impl<'a> From<ContractRequest<'a>> for ClientRequest<'a> {
    fn from(op: ContractRequest<'a>) -> Self {
        ClientRequest::ContractOp(op)
    }
}

/// Deserializes a `ContractRequest` from a Flatbuffers message.
impl<'a> TryFromFbs<&FbsContractRequest<'a>> for ContractRequest<'a> {
    fn try_decode_fbs(request: &FbsContractRequest<'a>) -> Result<Self, WsApiError> {
        let req = {
            match request.contract_request_type() {
                ContractRequestType::Get => {
                    let get = request.contract_request_as_get().unwrap();
                    let key = ContractKey::try_decode_fbs(&get.key())?;
                    let fetch_contract = get.fetch_contract();
                    ContractRequest::Get {
                        key,
                        fetch_contract,
                    }
                }
                ContractRequestType::Put => {
                    let put = request.contract_request_as_put().unwrap();
                    let contract = ContractContainer::try_decode_fbs(&put.container())?;
                    let state = WrappedState::new(put.wrapped_state().bytes().to_vec());
                    let related_contracts =
                        RelatedContracts::try_decode_fbs(&put.related_contracts())?.into_owned();
                    ContractRequest::Put {
                        contract,
                        state,
                        related_contracts,
                    }
                }
                ContractRequestType::Update => {
                    let update = request.contract_request_as_update().unwrap();
                    let key = ContractKey::try_decode_fbs(&update.key())?;
                    let data = UpdateData::try_decode_fbs(&update.data())?.into_owned();
                    ContractRequest::Update { key, data }
                }
                ContractRequestType::Subscribe => {
                    let subscribe = request.contract_request_as_subscribe().unwrap();
                    let key = ContractKey::try_decode_fbs(&subscribe.key())?;
                    let summary = subscribe
                        .summary()
                        .map(|summary_data| StateSummary::from(summary_data.bytes()));
                    ContractRequest::Subscribe { key, summary }
                }
                _ => unreachable!(),
            }
        };

        Ok(req)
    }
}

impl<'a> From<DelegateRequest<'a>> for ClientRequest<'a> {
    fn from(op: DelegateRequest<'a>) -> Self {
        ClientRequest::DelegateOp(op)
    }
}

#[derive(Serialize, Deserialize, Debug, Clone)]
#[non_exhaustive]
pub enum DelegateRequest<'a> {
    ApplicationMessages {
        key: DelegateKey,
        #[serde(deserialize_with = "DelegateRequest::deser_params")]
        params: Parameters<'a>,
        #[serde(borrow)]
        inbound: Vec<InboundDelegateMsg<'a>>,
    },
    GetSecretRequest {
        key: DelegateKey,
        #[serde(borrow)]
        params: Parameters<'a>,
        get_request: GetSecretRequest,
    },
    RegisterDelegate {
        delegate: DelegateContainer,
        cipher: [u8; 32],
        nonce: [u8; 24],
    },
    UnregisterDelegate(DelegateKey),
}

impl DelegateRequest<'_> {
    pub const DEFAULT_CIPHER: [u8; 32] = [
        0, 24, 22, 150, 112, 207, 24, 65, 182, 161, 169, 227, 66, 182, 237, 215, 206, 164, 58, 161,
        64, 108, 157, 195, 0, 0, 0, 0, 0, 0, 0, 0,
    ];

    pub const DEFAULT_NONCE: [u8; 24] = [
        57, 18, 79, 116, 63, 134, 93, 39, 208, 161, 156, 229, 222, 247, 111, 79, 210, 126, 127, 55,
        224, 150, 139, 80,
    ];

    pub fn into_owned(self) -> DelegateRequest<'static> {
        match self {
            DelegateRequest::ApplicationMessages {
                key,
                inbound,
                params,
            } => DelegateRequest::ApplicationMessages {
                key,
                params: params.into_owned(),
                inbound: inbound.into_iter().map(|e| e.into_owned()).collect(),
            },
            DelegateRequest::GetSecretRequest {
                key,
                get_request,
                params,
            } => DelegateRequest::GetSecretRequest {
                key,
                get_request,
                params: params.into_owned(),
            },
            DelegateRequest::RegisterDelegate {
                delegate,
                cipher,
                nonce,
            } => DelegateRequest::RegisterDelegate {
                delegate,
                cipher,
                nonce,
            },
            DelegateRequest::UnregisterDelegate(key) => DelegateRequest::UnregisterDelegate(key),
        }
    }

    pub fn key(&self) -> &DelegateKey {
        match self {
            DelegateRequest::ApplicationMessages { key, .. } => key,
            DelegateRequest::GetSecretRequest { key, .. } => key,
            DelegateRequest::RegisterDelegate { delegate, .. } => delegate.key(),
            DelegateRequest::UnregisterDelegate(key) => key,
        }
    }

    fn deser_params<'de, 'a, D>(deser: D) -> Result<Parameters<'a>, D::Error>
    where
        D: Deserializer<'de>,
    {
        let bytes_vec: Vec<u8> = Deserialize::deserialize(deser)?;
        Ok(Parameters::from(bytes_vec))
    }
}

impl Display for ClientRequest<'_> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            ClientRequest::ContractOp(op) => match op {
                ContractRequest::Put {
                    contract, state, ..
                } => {
                    write!(
                        f,
                        "put request for contract `{contract}` with state {state}"
                    )
                }
                ContractRequest::Update { key, .. } => write!(f, "update request for {key}"),
                ContractRequest::Get {
                    key,
                    fetch_contract: contract,
                    ..
                } => {
                    write!(
                        f,
                        "get request for `{key}` (fetch full contract: {contract})"
                    )
                }
                ContractRequest::Subscribe { key, .. } => {
                    write!(f, "subscribe request for `{key}`")
                }
            },
            ClientRequest::DelegateOp(op) => match op {
                DelegateRequest::ApplicationMessages { key, inbound, .. } => {
                    write!(
                        f,
                        "delegate app request for `{key}` with {} messages",
                        inbound.len()
                    )
                }
                DelegateRequest::GetSecretRequest {
                    get_request: GetSecretRequest { key: secret_id, .. },
                    key,
                    ..
                } => {
                    write!(f, "get delegate secret `{secret_id}` for `{key}`")
                }
                DelegateRequest::RegisterDelegate { delegate, .. } => {
                    write!(f, "delegate register request for `{}`", delegate.key())
                }
                DelegateRequest::UnregisterDelegate(key) => {
                    write!(f, "delegate unregister request for `{key}`")
                }
            },
            ClientRequest::Disconnect { .. } => write!(f, "client disconnected"),
            ClientRequest::Authenticate { .. } => write!(f, "authenticate"),
        }
    }
}

/// Deserializes a `DelegateRequest` from a Flatbuffers message.
impl<'a> TryFromFbs<&FbsDelegateRequest<'a>> for DelegateRequest<'a> {
    fn try_decode_fbs(request: &FbsDelegateRequest<'a>) -> Result<Self, WsApiError> {
        let req = {
            match request.delegate_request_type() {
                DelegateRequestType::ApplicationMessages => {
                    let app_msg = request.delegate_request_as_application_messages().unwrap();
                    let key = DelegateKey::try_decode_fbs(&app_msg.key())?;
                    let params = Parameters::from(app_msg.params().bytes());
                    let inbound = app_msg
                        .inbound()
                        .iter()
                        .map(|msg| InboundDelegateMsg::try_decode_fbs(&msg))
                        .collect::<Result<Vec<_>, _>>()?;
                    DelegateRequest::ApplicationMessages {
                        key,
                        params,
                        inbound,
                    }
                }
                DelegateRequestType::GetSecretRequestType => {
                    let get_secret = request
                        .delegate_request_as_get_secret_request_type()
                        .unwrap();
                    let key = DelegateKey::try_decode_fbs(&get_secret.key())?;
                    let params = Parameters::from(get_secret.params().bytes().to_vec());
                    let get_request = GetSecretRequest {
                        key: SecretsId::try_decode_fbs(&get_secret.get_request().key())?,
                        context: DelegateContext::new(
                            get_secret.get_request().delegate_context().bytes().to_vec(),
                        ),
                        processed: get_secret.get_request().processed(),
                    };
                    DelegateRequest::GetSecretRequest {
                        key,
                        params,
                        get_request,
                    }
                }
                DelegateRequestType::RegisterDelegate => {
                    let register = request.delegate_request_as_register_delegate().unwrap();
                    let delegate = DelegateContainer::try_decode_fbs(&register.delegate())?;
                    let cipher =
                        <[u8; 32]>::try_from(register.cipher().bytes().to_vec().as_slice())
                            .unwrap();
                    let nonce =
                        <[u8; 24]>::try_from(register.nonce().bytes().to_vec().as_slice()).unwrap();
                    DelegateRequest::RegisterDelegate {
                        delegate,
                        cipher,
                        nonce,
                    }
                }
                DelegateRequestType::UnregisterDelegate => {
                    let unregister = request.delegate_request_as_unregister_delegate().unwrap();
                    let key = DelegateKey::try_decode_fbs(&unregister.key())?;
                    DelegateRequest::UnregisterDelegate(key)
                }
                _ => unreachable!(),
            }
        };

        Ok(req)
    }
}

/// A response to a previous [`ClientRequest`]
#[derive(Serialize, Deserialize, Debug)]
#[non_exhaustive]
pub enum HostResponse<T = WrappedState> {
    ContractResponse(#[serde(bound(deserialize = "T: DeserializeOwned"))] ContractResponse<T>),
    DelegateResponse {
        key: DelegateKey,
        values: Vec<OutboundDelegateMsg>,
    },
    /// A requested action which doesn't require an answer was performed successfully.
    Ok,
}

impl HostResponse {
    pub fn unwrap_put(self) -> ContractKey {
        if let Self::ContractResponse(ContractResponse::PutResponse { key }) = self {
            key
        } else {
            panic!("called `HostResponse::unwrap_put()` on other than `PutResponse` value")
        }
    }

    pub fn unwrap_get(self) -> (WrappedState, Option<ContractContainer>) {
        if let Self::ContractResponse(ContractResponse::GetResponse {
            contract, state, ..
        }) = self
        {
            (state, contract)
        } else {
            panic!("called `HostResponse::unwrap_put()` on other than `PutResponse` value")
        }
    }

    pub fn into_fbs_bytes(self) -> Result<Vec<u8>, Box<ClientError>> {
        let mut builder = flatbuffers::FlatBufferBuilder::new();
        match self {
            HostResponse::ContractResponse(res) => match res {
                ContractResponse::PutResponse { key } => {
                    let instance_data = builder.create_vector(key.bytes());
                    let instance_offset = ContractInstanceId::create(
                        &mut builder,
                        &ContractInstanceIdArgs {
                            data: Some(instance_data),
                        },
                    );

                    let code = key
                        .code_hash()
                        .map(|code| builder.create_vector(code.0.as_ref()));
                    let key_offset = FbsContractKey::create(
                        &mut builder,
                        &ContractKeyArgs {
                            instance: Some(instance_offset),
                            code,
                        },
                    );

                    let put_offset = FbsPutResponse::create(
                        &mut builder,
                        &PutResponseArgs {
                            key: Some(key_offset),
                        },
                    );

                    let contract_response_offset = FbsContractResponse::create(
                        &mut builder,
                        &ContractResponseArgs {
                            contract_response: Some(put_offset.as_union_value()),
                            contract_response_type: ContractResponseType::PutResponse,
                        },
                    );

                    let response_offset = FbsHostResponse::create(
                        &mut builder,
                        &HostResponseArgs {
                            response: Some(contract_response_offset.as_union_value()),
                            response_type: HostResponseType::ContractResponse,
                        },
                    );

                    finish_host_response_buffer(&mut builder, response_offset);
                    Ok(builder.finished_data().to_vec())
                }
                ContractResponse::UpdateResponse { key, summary } => {
                    let instance_data = builder.create_vector(key.bytes());
                    let instance_offset = ContractInstanceId::create(
                        &mut builder,
                        &ContractInstanceIdArgs {
                            data: Some(instance_data),
                        },
                    );

                    let code = key
                        .code_hash()
                        .map(|code| builder.create_vector(code.0.as_ref()));

                    let key_offset = FbsContractKey::create(
                        &mut builder,
                        &ContractKeyArgs {
                            instance: Some(instance_offset),
                            code,
                        },
                    );

                    let summary_data = builder.create_vector(&summary.into_bytes());

                    let update_response_offset = FbsUpdateResponse::create(
                        &mut builder,
                        &UpdateResponseArgs {
                            key: Some(key_offset),
                            summary: Some(summary_data),
                        },
                    );

                    let contract_response_offset = FbsContractResponse::create(
                        &mut builder,
                        &ContractResponseArgs {
                            contract_response: Some(update_response_offset.as_union_value()),
                            contract_response_type: ContractResponseType::UpdateResponse,
                        },
                    );

                    let response_offset = FbsHostResponse::create(
                        &mut builder,
                        &HostResponseArgs {
                            response: Some(contract_response_offset.as_union_value()),
                            response_type: HostResponseType::ContractResponse,
                        },
                    );

                    finish_host_response_buffer(&mut builder, response_offset);
                    Ok(builder.finished_data().to_vec())
                }
                ContractResponse::GetResponse {
                    key,
                    contract: contract_container,
                    state,
                } => {
                    let instance_data = builder.create_vector(key.bytes());
                    let instance_offset = ContractInstanceId::create(
                        &mut builder,
                        &ContractInstanceIdArgs {
                            data: Some(instance_data),
                        },
                    );

                    let code = key.code_hash().map(|code| builder.create_vector(&code.0));
                    let key_offset = FbsContractKey::create(
                        &mut builder,
                        &ContractKeyArgs {
                            instance: Some(instance_offset),
                            code,
                        },
                    );

                    let container_offset = if let Some(contract) = contract_container {
                        let data = builder.create_vector(contract.key().bytes());

                        let instance_offset = ContractInstanceId::create(
                            &mut builder,
                            &ContractInstanceIdArgs { data: Some(data) },
                        );

                        let code = contract
                            .key()
                            .code_hash()
                            .map(|code| builder.create_vector(&code.0));
                        let contract_key_offset = FbsContractKey::create(
                            &mut builder,
                            &ContractKeyArgs {
                                instance: Some(instance_offset),
                                code,
                            },
                        );

                        let contract_data =
                            builder.create_vector(contract.clone().unwrap_v1().data.data());
                        let contract_code_hash =
                            builder.create_vector(&contract.clone().unwrap_v1().data.hash().0);

                        let contract_code_offset = ContractCode::create(
                            &mut builder,
                            &ContractCodeArgs {
                                data: Some(contract_data),
                                code_hash: Some(contract_code_hash),
                            },
                        );

                        let contract_params =
                            builder.create_vector(&contract.clone().params().into_bytes());

                        let contract_offset = match contract {
                            Wasm(V1(..)) => WasmContractV1::create(
                                &mut builder,
                                &WasmContractV1Args {
                                    key: Some(contract_key_offset),
                                    data: Some(contract_code_offset),
                                    parameters: Some(contract_params),
                                },
                            ),
                        };

                        Some(FbsContractContainer::create(
                            &mut builder,
                            &ContractContainerArgs {
                                contract_type: ContractType::WasmContractV1,
                                contract: Some(contract_offset.as_union_value()),
                            },
                        ))
                    } else {
                        None
                    };

                    let state_data = builder.create_vector(&state);

                    let get_offset = FbsGetResponse::create(
                        &mut builder,
                        &GetResponseArgs {
                            key: Some(key_offset),
                            contract: container_offset,
                            state: Some(state_data),
                        },
                    );

                    let contract_response_offset = FbsContractResponse::create(
                        &mut builder,
                        &ContractResponseArgs {
                            contract_response_type: ContractResponseType::GetResponse,
                            contract_response: Some(get_offset.as_union_value()),
                        },
                    );

                    let response_offset = FbsHostResponse::create(
                        &mut builder,
                        &HostResponseArgs {
                            response: Some(contract_response_offset.as_union_value()),
                            response_type: HostResponseType::ContractResponse,
                        },
                    );

                    finish_host_response_buffer(&mut builder, response_offset);
                    Ok(builder.finished_data().to_vec())
                }
                ContractResponse::UpdateNotification { key, update } => {
                    let instance_data = builder.create_vector(key.bytes());
                    let instance_offset = ContractInstanceId::create(
                        &mut builder,
                        &ContractInstanceIdArgs {
                            data: Some(instance_data),
                        },
                    );

                    let code = key
                        .code_hash()
                        .map(|code| builder.create_vector(code.0.as_ref()));
                    let key_offset = FbsContractKey::create(
                        &mut builder,
                        &ContractKeyArgs {
                            instance: Some(instance_offset),
                            code,
                        },
                    );

                    let update_data = match update {
                        State(state) => {
                            let state_data = builder.create_vector(&state.into_bytes());
                            let state_update_offset = StateUpdate::create(
                                &mut builder,
                                &StateUpdateArgs {
                                    state: Some(state_data),
                                },
                            );
                            FbsUpdateData::create(
                                &mut builder,
                                &UpdateDataArgs {
                                    update_data_type: UpdateDataType::StateUpdate,
                                    update_data: Some(state_update_offset.as_union_value()),
                                },
                            )
                        }
                        Delta(delta) => {
                            let delta_data = builder.create_vector(&delta.into_bytes());
                            let update_offset = DeltaUpdate::create(
                                &mut builder,
                                &DeltaUpdateArgs {
                                    delta: Some(delta_data),
                                },
                            );
                            FbsUpdateData::create(
                                &mut builder,
                                &UpdateDataArgs {
                                    update_data_type: UpdateDataType::DeltaUpdate,
                                    update_data: Some(update_offset.as_union_value()),
                                },
                            )
                        }
                        StateAndDelta { state, delta } => {
                            let state_data = builder.create_vector(&state.into_bytes());
                            let delta_data = builder.create_vector(&delta.into_bytes());

                            let update_offset = StateAndDeltaUpdate::create(
                                &mut builder,
                                &StateAndDeltaUpdateArgs {
                                    state: Some(state_data),
                                    delta: Some(delta_data),
                                },
                            );

                            FbsUpdateData::create(
                                &mut builder,
                                &UpdateDataArgs {
                                    update_data_type: UpdateDataType::StateAndDeltaUpdate,
                                    update_data: Some(update_offset.as_union_value()),
                                },
                            )
                        }
                        RelatedState { related_to, state } => {
                            let state_data = builder.create_vector(&state.into_bytes());
                            let instance_data =
                                builder.create_vector(related_to.encode().as_bytes());

                            let instance_offset = ContractInstanceId::create(
                                &mut builder,
                                &ContractInstanceIdArgs {
                                    data: Some(instance_data),
                                },
                            );

                            let update_offset = RelatedStateUpdate::create(
                                &mut builder,
                                &RelatedStateUpdateArgs {
                                    related_to: Some(instance_offset),
                                    state: Some(state_data),
                                },
                            );

                            FbsUpdateData::create(
                                &mut builder,
                                &UpdateDataArgs {
                                    update_data_type: UpdateDataType::RelatedStateUpdate,
                                    update_data: Some(update_offset.as_union_value()),
                                },
                            )
                        }
                        RelatedDelta { related_to, delta } => {
                            let instance_data =
                                builder.create_vector(related_to.encode().as_bytes());
                            let delta_data = builder.create_vector(&delta.into_bytes());

                            let instance_offset = ContractInstanceId::create(
                                &mut builder,
                                &ContractInstanceIdArgs {
                                    data: Some(instance_data),
                                },
                            );

                            let update_offset = RelatedDeltaUpdate::create(
                                &mut builder,
                                &RelatedDeltaUpdateArgs {
                                    related_to: Some(instance_offset),
                                    delta: Some(delta_data),
                                },
                            );

                            FbsUpdateData::create(
                                &mut builder,
                                &UpdateDataArgs {
                                    update_data_type: UpdateDataType::RelatedDeltaUpdate,
                                    update_data: Some(update_offset.as_union_value()),
                                },
                            )
                        }
                        RelatedStateAndDelta {
                            related_to,
                            state,
                            delta,
                        } => {
                            let instance_data =
                                builder.create_vector(related_to.encode().as_bytes());
                            let state_data = builder.create_vector(&state.into_bytes());
                            let delta_data = builder.create_vector(&delta.into_bytes());

                            let instance_offset = ContractInstanceId::create(
                                &mut builder,
                                &ContractInstanceIdArgs {
                                    data: Some(instance_data),
                                },
                            );

                            let update_offset = RelatedStateAndDeltaUpdate::create(
                                &mut builder,
                                &RelatedStateAndDeltaUpdateArgs {
                                    related_to: Some(instance_offset),
                                    state: Some(state_data),
                                    delta: Some(delta_data),
                                },
                            );

                            FbsUpdateData::create(
                                &mut builder,
                                &UpdateDataArgs {
                                    update_data_type: UpdateDataType::RelatedStateAndDeltaUpdate,
                                    update_data: Some(update_offset.as_union_value()),
                                },
                            )
                        }
                    };

                    let update_notification_offset = FbsUpdateNotification::create(
                        &mut builder,
                        &UpdateNotificationArgs {
                            key: Some(key_offset),
                            update: Some(update_data),
                        },
                    );

                    let put_response_offset = FbsContractResponse::create(
                        &mut builder,
                        &ContractResponseArgs {
                            contract_response_type: ContractResponseType::UpdateNotification,
                            contract_response: Some(update_notification_offset.as_union_value()),
                        },
                    );

                    let host_response_offset = FbsHostResponse::create(
                        &mut builder,
                        &HostResponseArgs {
                            response_type: HostResponseType::ContractResponse,
                            response: Some(put_response_offset.as_union_value()),
                        },
                    );

                    finish_host_response_buffer(&mut builder, host_response_offset);
                    Ok(builder.finished_data().to_vec())
                }
            },
            HostResponse::DelegateResponse { key, values } => {
                let key_data = builder.create_vector(key.bytes());
                let code_hash_data = builder.create_vector(&key.code_hash().0);
                let key_offset = FbsDelegateKey::create(
                    &mut builder,
                    &DelegateKeyArgs {
                        key: Some(key_data),
                        code_hash: Some(code_hash_data),
                    },
                );
                let mut messages: Vec<WIPOffset<FbsOutboundDelegateMsg>> = Vec::new();
                values.iter().for_each(|msg| match msg {
                    OutboundDelegateMsg::ApplicationMessage(app) => {
                        let instance_data = builder.create_vector(key.bytes());
                        let instance_offset = ContractInstanceId::create(
                            &mut builder,
                            &ContractInstanceIdArgs {
                                data: Some(instance_data),
                            },
                        );
                        let payload_data = builder.create_vector(&app.payload);
                        let delegate_context_data = builder.create_vector(app.context.as_ref());
                        let app_offset = FbsApplicationMessage::create(
                            &mut builder,
                            &ApplicationMessageArgs {
                                app: Some(instance_offset),
                                payload: Some(payload_data),
                                context: Some(delegate_context_data),
                                processed: app.processed,
                            },
                        );
                        let msg = FbsOutboundDelegateMsg::create(
                            &mut builder,
                            &OutboundDelegateMsgArgs {
                                inbound_type: OutboundDelegateMsgType::common_ApplicationMessage,
                                inbound: Some(app_offset.as_union_value()),
                            },
                        );
                        messages.push(msg);
                    }
                    OutboundDelegateMsg::RequestUserInput(input) => {
                        let message_data = builder.create_vector(input.message.bytes());
                        let mut responses: Vec<WIPOffset<FbsClientResponse>> = Vec::new();
                        input.responses.iter().for_each(|resp| {
                            let response_data = builder.create_vector(resp.bytes());
                            let response = FbsClientResponse::create(
                                &mut builder,
                                &ClientResponseArgs {
                                    data: Some(response_data),
                                },
                            );
                            responses.push(response)
                        });
                        let responses_offset = builder.create_vector(&responses);
                        let input_offset = FbsRequestUserInput::create(
                            &mut builder,
                            &RequestUserInputArgs {
                                request_id: input.request_id,
                                message: Some(message_data),
                                responses: Some(responses_offset),
                            },
                        );
                        let msg = FbsOutboundDelegateMsg::create(
                            &mut builder,
                            &OutboundDelegateMsgArgs {
                                inbound_type: OutboundDelegateMsgType::RequestUserInput,
                                inbound: Some(input_offset.as_union_value()),
                            },
                        );
                        messages.push(msg);
                    }
                    OutboundDelegateMsg::ContextUpdated(context) => {
                        let context_data = builder.create_vector(context.as_ref());
                        let context_offset = FbsContextUpdated::create(
                            &mut builder,
                            &ContextUpdatedArgs {
                                context: Some(context_data),
                            },
                        );
                        let msg = FbsOutboundDelegateMsg::create(
                            &mut builder,
                            &OutboundDelegateMsgArgs {
                                inbound_type: OutboundDelegateMsgType::ContextUpdated,
                                inbound: Some(context_offset.as_union_value()),
                            },
                        );
                        messages.push(msg);
                    }
                    OutboundDelegateMsg::GetSecretRequest(request) => {
                        let secret_key_data = builder.create_vector(request.key.key());
                        let secret_hash_data = builder.create_vector(request.key.hash());
                        let secret_id_offset = FbsSecretsId::create(
                            &mut builder,
                            &SecretsIdArgs {
                                key: Some(secret_key_data),
                                hash: Some(secret_hash_data),
                            },
                        );

                        let delegate_context_data = builder.create_vector(request.context.as_ref());
                        let request_offset = FbsGetSecretRequest::create(
                            &mut builder,
                            &GetSecretRequestArgs {
                                key: Some(secret_id_offset),
                                delegate_context: Some(delegate_context_data),
                                processed: request.processed,
                            },
                        );
                        let msg = FbsOutboundDelegateMsg::create(
                            &mut builder,
                            &OutboundDelegateMsgArgs {
                                inbound_type: OutboundDelegateMsgType::common_GetSecretRequest,
                                inbound: Some(request_offset.as_union_value()),
                            },
                        );
                        messages.push(msg);
                    }
                    OutboundDelegateMsg::SetSecretRequest(request) => {
                        let secret_key_data = builder.create_vector(request.key.key());
                        let secret_hash_data = builder.create_vector(request.key.hash());
                        let secret_id_offset = FbsSecretsId::create(
                            &mut builder,
                            &SecretsIdArgs {
                                key: Some(secret_key_data),
                                hash: Some(secret_hash_data),
                            },
                        );

                        let value_data = request
                            .value
                            .clone()
                            .map(|value| builder.create_vector(value.as_slice()));
                        let request_offset = FbsSetSecretRequest::create(
                            &mut builder,
                            &SetSecretRequestArgs {
                                key: Some(secret_id_offset),
                                value: value_data,
                            },
                        );
                        let msg = FbsOutboundDelegateMsg::create(
                            &mut builder,
                            &OutboundDelegateMsgArgs {
                                inbound_type: OutboundDelegateMsgType::SetSecretRequest,
                                inbound: Some(request_offset.as_union_value()),
                            },
                        );
                        messages.push(msg);
                    }
                    OutboundDelegateMsg::GetSecretResponse(response) => {
                        let secret_key_data = builder.create_vector(response.key.key());
                        let secret_hash_data = builder.create_vector(response.key.hash());
                        let secret_id_offset = FbsSecretsId::create(
                            &mut builder,
                            &SecretsIdArgs {
                                key: Some(secret_key_data),
                                hash: Some(secret_hash_data),
                            },
                        );

                        let value_data = response
                            .value
                            .clone()
                            .map(|value| builder.create_vector(value.as_slice()));

                        let delegate_context_data =
                            builder.create_vector(response.context.as_ref());
                        let response_offset = FbsGetSecretResponse::create(
                            &mut builder,
                            &GetSecretResponseArgs {
                                key: Some(secret_id_offset),
                                value: value_data,
                                delegate_context: Some(delegate_context_data),
                            },
                        );
                        let msg = FbsOutboundDelegateMsg::create(
                            &mut builder,
                            &OutboundDelegateMsgArgs {
                                inbound_type: OutboundDelegateMsgType::common_GetSecretResponse,
                                inbound: Some(response_offset.as_union_value()),
                            },
                        );
                        messages.push(msg);
                    }
                });
                let messages_offset = builder.create_vector(&messages);
                let delegate_response_offset = FbsDelegateResponse::create(
                    &mut builder,
                    &DelegateResponseArgs {
                        key: Some(key_offset),
                        values: Some(messages_offset),
                    },
                );
                let host_response_offset = FbsHostResponse::create(
                    &mut builder,
                    &HostResponseArgs {
                        response_type: HostResponseType::DelegateResponse,
                        response: Some(delegate_response_offset.as_union_value()),
                    },
                );
                finish_host_response_buffer(&mut builder, host_response_offset);
                Ok(builder.finished_data().to_vec())
            }
            HostResponse::Ok => {
                let ok_offset = FbsOk::create(&mut builder, &OkArgs { msg: None });
                let host_response_offset = FbsHostResponse::create(
                    &mut builder,
                    &HostResponseArgs {
                        response_type: HostResponseType::Ok,
                        response: Some(ok_offset.as_union_value()),
                    },
                );
                finish_host_response_buffer(&mut builder, host_response_offset);
                Ok(builder.finished_data().to_vec())
            }
        }
    }
}

impl std::fmt::Display for HostResponse {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            HostResponse::ContractResponse(res) => match res {
                ContractResponse::PutResponse { key } => {
                    f.write_fmt(format_args!("put response for `{key}`"))
                }
                ContractResponse::UpdateResponse { key, .. } => {
                    f.write_fmt(format_args!("update response for `{key}`"))
                }
                ContractResponse::GetResponse { key, .. } => {
                    f.write_fmt(format_args!("get response for `{key}`"))
                }
                ContractResponse::UpdateNotification { key, .. } => {
                    f.write_fmt(format_args!("update notification for `{key}`"))
                }
            },
            HostResponse::DelegateResponse { .. } => write!(f, "delegate responses"),
            HostResponse::Ok => write!(f, "ok response"),
        }
    }
}

// todo: add a `AsBytes` trait for state representations
#[derive(Clone, Serialize, Deserialize, Debug)]
#[non_exhaustive]
pub enum ContractResponse<T = WrappedState> {
    GetResponse {
        key: ContractKey,
        contract: Option<ContractContainer>,
        #[serde(bound(deserialize = "T: DeserializeOwned"))]
        state: T,
    },
    PutResponse {
        key: ContractKey,
    },
    /// Message sent when there is an update to a subscribed contract.
    UpdateNotification {
        key: ContractKey,
        #[serde(deserialize_with = "ContractResponse::<T>::deser_update_data")]
        update: UpdateData<'static>,
    },
    /// Successful update
    UpdateResponse {
        key: ContractKey,
        #[serde(deserialize_with = "ContractResponse::<T>::deser_state")]
        summary: StateSummary<'static>,
    },
}

impl<T> ContractResponse<T> {
    fn deser_update_data<'de, D>(deser: D) -> Result<UpdateData<'static>, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        let value = <UpdateData as Deserialize>::deserialize(deser)?;
        Ok(value.into_owned())
    }

    fn deser_state<'de, D>(deser: D) -> Result<StateSummary<'static>, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        let value = <StateSummary as Deserialize>::deserialize(deser)?;
        Ok(value.into_owned())
    }
}

impl<T> From<ContractResponse<T>> for HostResponse<T> {
    fn from(value: ContractResponse<T>) -> HostResponse<T> {
        HostResponse::ContractResponse(value)
    }
}

#[cfg(test)]
mod client_request_test {
    use crate::client_api::{ContractRequest, TryFromFbs};
    use crate::client_request_generated::client_request::root_as_client_request;
    use crate::contract_interface::UpdateData;

    const EXPECTED_ENCODED_CONTRACT_ID: &str = "6kVs66bKaQAC6ohr8b43SvJ95r36tc2hnG7HezmaJHF9";

    #[test]
    fn test_build_contract_put_op_from_fbs() -> Result<(), Box<dyn std::error::Error>> {
        let put_req_op = vec![
            4, 0, 0, 0, 244, 255, 255, 255, 16, 0, 0, 0, 0, 0, 0, 1, 8, 0, 12, 0, 11, 0, 4, 0, 8,
            0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 1, 198, 255, 255, 255, 12, 0, 0, 0, 20, 0, 0, 0, 36, 0,
            0, 0, 170, 255, 255, 255, 4, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8,
            8, 0, 10, 0, 9, 0, 4, 0, 8, 0, 0, 0, 16, 0, 0, 0, 0, 1, 10, 0, 16, 0, 12, 0, 8, 0, 4,
            0, 10, 0, 0, 0, 12, 0, 0, 0, 76, 0, 0, 0, 92, 0, 0, 0, 176, 255, 255, 255, 8, 0, 0, 0,
            16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 8, 0, 4, 0, 6, 0, 0, 0, 4, 0, 0, 0, 32, 0, 0, 0,
            85, 111, 11, 171, 40, 85, 240, 177, 207, 81, 106, 157, 173, 90, 234, 2, 250, 253, 75,
            210, 62, 7, 6, 34, 75, 26, 229, 230, 107, 167, 17, 108, 8, 0, 0, 0, 1, 2, 3, 4, 5, 6,
            7, 8, 8, 0, 12, 0, 8, 0, 4, 0, 8, 0, 0, 0, 8, 0, 0, 0, 16, 0, 0, 0, 8, 0, 0, 0, 1, 2,
            3, 4, 5, 6, 7, 8, 8, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8,
        ];
        let request = if let Ok(client_request) = root_as_client_request(&put_req_op) {
            let contract_request = client_request.client_request_as_contract_request().unwrap();
            ContractRequest::try_decode_fbs(&contract_request)?
        } else {
            panic!("failed to decode client request")
        };

        match request {
            ContractRequest::Put {
                contract,
                state,
                related_contracts: _,
            } => {
                assert_eq!(
                    contract.to_string(),
                    "wasm container version 0.0.1 of contract \
                Contract(D8fdVLbRyMLw5mZtPRpWMFcrXGN2z8Nq8UGcLGPFBg2W)"
                );
                assert_eq!(contract.unwrap_v1().data.data(), &[1, 2, 3, 4, 5, 6, 7, 8]);
                assert_eq!(state.to_vec(), &[1, 2, 3, 4, 5, 6, 7, 8]);
            }
            _ => panic!("wrong contract request type"),
        }

        Ok(())
    }

    #[test]
    fn test_build_contract_get_op_from_fbs() -> Result<(), Box<dyn std::error::Error>> {
        let get_req_op = vec![
            4, 0, 0, 0, 244, 255, 255, 255, 16, 0, 0, 0, 0, 0, 0, 1, 8, 0, 12, 0, 11, 0, 4, 0, 8,
            0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 3, 222, 255, 255, 255, 12, 0, 0, 0, 8, 0, 12, 0, 8, 0, 4,
            0, 8, 0, 0, 0, 8, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 8, 0, 4, 0, 6, 0, 0, 0,
            4, 0, 0, 0, 32, 0, 0, 0, 85, 111, 11, 171, 40, 85, 240, 177, 207, 81, 106, 157, 173,
            90, 234, 2, 250, 253, 75, 210, 62, 7, 6, 34, 75, 26, 229, 230, 107, 167, 17, 108,
        ];
        let request = if let Ok(client_request) = root_as_client_request(&get_req_op) {
            let contract_request = client_request.client_request_as_contract_request().unwrap();
            ContractRequest::try_decode_fbs(&contract_request)?
        } else {
            panic!("failed to decode client request")
        };

        match request {
            ContractRequest::Get {
                key,
                fetch_contract,
            } => {
                assert_eq!(key.encoded_contract_id(), EXPECTED_ENCODED_CONTRACT_ID);
                assert!(!fetch_contract);
            }
            _ => panic!("wrong contract request type"),
        }

        Ok(())
    }

    #[test]
    fn test_build_contract_update_op_from_fbs() -> Result<(), Box<dyn std::error::Error>> {
        let update_op = vec![
            4, 0, 0, 0, 220, 255, 255, 255, 8, 0, 0, 0, 0, 0, 0, 1, 232, 255, 255, 255, 8, 0, 0, 0,
            0, 0, 0, 2, 204, 255, 255, 255, 16, 0, 0, 0, 52, 0, 0, 0, 8, 0, 12, 0, 11, 0, 4, 0, 8,
            0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 2, 210, 255, 255, 255, 4, 0, 0, 0, 8, 0, 0, 0, 1, 2, 3,
            4, 5, 6, 7, 8, 8, 0, 12, 0, 8, 0, 4, 0, 8, 0, 0, 0, 8, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 6, 0, 8, 0, 4, 0, 6, 0, 0, 0, 4, 0, 0, 0, 32, 0, 0, 0, 85, 111, 11, 171, 40,
            85, 240, 177, 207, 81, 106, 157, 173, 90, 234, 2, 250, 253, 75, 210, 62, 7, 6, 34, 75,
            26, 229, 230, 107, 167, 17, 108,
        ];
        let request = if let Ok(client_request) = root_as_client_request(&update_op) {
            let contract_request = client_request.client_request_as_contract_request().unwrap();
            ContractRequest::try_decode_fbs(&contract_request)?
        } else {
            panic!("failed to decode client request")
        };

        match request {
            ContractRequest::Update { key, data } => {
                assert_eq!(
                    key.encoded_contract_id(),
                    "6kVs66bKaQAC6ohr8b43SvJ95r36tc2hnG7HezmaJHF9"
                );
                match data {
                    UpdateData::Delta(delta) => {
                        assert_eq!(delta.to_vec(), &[1, 2, 3, 4, 5, 6, 7, 8])
                    }
                    _ => panic!("wrong update data type"),
                }
            }
            _ => panic!("wrong contract request type"),
        }

        Ok(())
    }
}