simulator_client/

builders.rs

use std::collections::{BTreeMap, BTreeSet};

use base64::{Engine as _, engine::general_purpose::STANDARD as BASE64};
use bon::Builder;
use simulator_api::{
    AccountData, AccountModifications, AgentParams, BinaryEncoding, ContinueParams,
    CreateBacktestSessionRequest, CreateBacktestSessionRequestV1, CreateSessionParams,
    DiscoveryFilter, ScheduledAction,
};
use solana_address::Address;
use solana_client::rpc_client::SerializableTransaction;
use thiserror::Error;

use crate::BacktestClientError;

/// Error serializing a transaction for injection.
#[derive(Debug, Error)]
pub enum SerializeEncodeError {
    #[error("bincode serialization error: {0}")]
    Bincode(#[from] bincode::error::EncodeError),
}

fn serialize_to_base64(value: &impl serde::Serialize) -> Result<String, SerializeEncodeError> {
    let bytes = bincode::serde::encode_to_vec(
        value,
        bincode::config::standard()
            .with_fixed_int_encoding()
            .with_little_endian(),
    )?;
    Ok(BASE64.encode(&bytes))
}

/// Builder for `CreateBacktestSession`.
///
/// Set either `end_slot` or `slot_count` (not both). Use the helper methods to
/// add account filters.
#[derive(Debug, Clone, Builder)]
pub struct CreateSession {
    pub start_slot: u64,

    pub end_slot: Option<u64>,

    pub slot_count: Option<u64>,

    #[builder(default)]
    pub signer_filter: BTreeSet<Address>,

    /// When true, include a session summary with transaction statistics in the Completed response.
    #[builder(default)]
    pub send_summary: bool,

    /// When true, ask manager to create all available sessions in the target epoch.
    #[builder(default)]
    pub parallel: bool,

    pub capacity_wait_timeout_secs: Option<u16>,

    pub disconnect_timeout_secs: Option<u16>,

    /// Extra compute units to add to each transaction's SetComputeUnitLimit budget.
    pub extra_compute_units: Option<u32>,

    #[builder(default)]
    pub agents: Vec<AgentParams>,

    /// Batch discovery filters registered at session creation. For each
    /// filter, the server emits [`BacktestResponse::DiscoveryBatch`] ahead
    /// of every matching batch so the caller can pause via
    /// [`BacktestSession::advance_to_discovery`] before it executes.
    #[builder(default)]
    pub discoveries: Vec<DiscoveryFilter>,

    /// Transactions the server runs automatically during the session, with
    /// results streamed over `actionSubscribe`.
    #[builder(default)]
    pub actions: Vec<ScheduledAction>,
}

impl CreateSession {
    /// Add an account to the signer filter.
    pub fn add_signer_filter(mut self, address: Address) -> Self {
        self.signer_filter.insert(address);
        self
    }

    /// Convert the builder into API parameters, validating slot options.
    pub fn into_params(self) -> Result<CreateSessionParams, BacktestClientError> {
        let end_slot = match (self.end_slot, self.slot_count) {
            (Some(_), Some(_)) => {
                return Err(BacktestClientError::InvalidParams {
                    message: "CreateSession: set only one of end_slot or slot_count".to_string(),
                });
            }
            (Some(end_slot), None) => end_slot,
            (None, Some(slot_count)) => {
                self.start_slot.checked_add(slot_count).ok_or_else(|| {
                    BacktestClientError::InvalidParams {
                        message: "CreateSession: start_slot + slot_count overflow".to_string(),
                    }
                })?
            }
            (None, None) => {
                return Err(BacktestClientError::InvalidParams {
                    message: "CreateSession: must set end_slot or slot_count".to_string(),
                });
            }
        };

        if end_slot < self.start_slot {
            return Err(BacktestClientError::InvalidParams {
                message: format!(
                    "CreateSession: end_slot ({end_slot}) must be >= start_slot ({})",
                    self.start_slot
                ),
            });
        }

        Ok(CreateSessionParams::builder()
            .start_slot(self.start_slot)
            .end_slot(end_slot)
            .signer_filter(self.signer_filter)
            .send_summary(self.send_summary)
            .maybe_capacity_wait_timeout_secs(self.capacity_wait_timeout_secs)
            .maybe_disconnect_timeout_secs(self.disconnect_timeout_secs)
            .maybe_extra_compute_units(self.extra_compute_units)
            .agents(self.agents)
            .discoveries(self.discoveries)
            .actions(self.actions)
            .build())
    }

    /// Convert the builder into versioned create request payload.
    pub fn into_request(self) -> Result<CreateBacktestSessionRequest, BacktestClientError> {
        let parallel = self.parallel;
        let request = self.into_params()?;
        if parallel {
            Ok(CreateBacktestSessionRequestV1 { request, parallel }.into())
        } else {
            Ok(request.into())
        }
    }
}

/// Builder for `Continue` requests.
///
/// Use this to advance the simulation, inject transactions, or patch accounts.
#[derive(Debug, Builder)]
pub struct Continue {
    #[builder(default = ContinueParams::default_advance_count())]
    pub advance_count: u64,

    #[builder(default)]
    pub transactions: Vec<String>,

    #[builder(default)]
    pub modify_accounts: BTreeMap<Address, AccountData>,
}

impl Continue {
    /// Append a base64-encoded transaction payload.
    pub fn push_transaction_base64(mut self, data: impl Into<String>) -> Self {
        self.transactions.push(data.into());
        self
    }

    /// Append a raw transaction payload encoded as base64.
    pub fn push_transaction_bytes(mut self, bytes: &[u8]) -> Self {
        self.transactions.push(BinaryEncoding::Base64.encode(bytes));
        self
    }

    /// Append a serializable transaction encoded as base64.
    pub fn push_transaction(
        mut self,
        transaction: &impl SerializableTransaction,
    ) -> Result<Self, SerializeEncodeError> {
        self.transactions.push(serialize_to_base64(&transaction)?);
        Ok(self)
    }

    /// Modify an account state prior to execution.
    pub fn modify_account(mut self, address: Address, account: AccountData) -> Self {
        self.modify_accounts.insert(address, account);
        self
    }

    /// Convert the builder into API parameters.
    pub fn into_params(self) -> ContinueParams {
        ContinueParams {
            advance_count: self.advance_count,
            transactions: self.transactions,
            modify_account_states: AccountModifications(self.modify_accounts),
        }
    }
}