cdk 0.16.0-rc.2

Core Cashu Development Kit library implementing the Cashu protocol
Documentation 
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use cdk_common::SpendingConditionVerification;
#[cfg(feature = "prometheus")]
use cdk_prometheus::METRICS;
use swap_saga::SwapSaga;
use tracing::instrument;

use super::{Mint, SwapRequest, SwapResponse};
use crate::Error;

pub mod swap_saga;

#[cfg(test)]
mod tests;

impl Mint {
    /// Process Swap
    #[instrument(skip_all)]
    pub async fn process_swap_request(
        &self,
        swap_request: SwapRequest,
    ) -> Result<SwapResponse, Error> {
        #[cfg(feature = "prometheus")]
        METRICS.inc_in_flight_requests("process_swap_request");

        swap_request.input_amount()?;
        swap_request.output_amount()?;

        let input_proofs = swap_request.inputs();

        if input_proofs.is_empty() {
            return Err(Error::TransactionUnbalanced(
                0,
                swap_request.output_amount()?.to_u64(),
                0,
            ));
        }

        // Verify inputs (cryptographic verification, no DB needed)
        let input_verification = self.verify_inputs(input_proofs).await.map_err(|err| {
            #[cfg(feature = "prometheus")]
            self.record_swap_failure("process_swap_request");

            tracing::debug!("Input verification failed: {:?}", err);
            err
        })?;

        // Verify spending conditions (NUT-10/NUT-11/NUT-14), i.e. P2PK
        // and HTLC (including SIGALL)
        swap_request.verify_spending_conditions()?;

        // Step 1: Initialize the swap saga
        let init_saga = SwapSaga::new(self, self.localstore.clone(), self.pubsub_manager.clone());

        // Step 2: TX1 - Setup swap (verify balance + add inputs as pending + add output blinded messages)
        let setup_saga = init_saga
            .setup_swap(
                swap_request.inputs(),
                swap_request.outputs(),
                None,
                input_verification,
            )
            .await?;

        // Step 3: Blind sign outputs (no DB transaction)
        let signed_saga = setup_saga.sign_outputs().await?;

        // Step 4: TX2 - Finalize swap (add signatures + mark inputs spent)
        let response = signed_saga.finalize().await?;

        #[cfg(feature = "prometheus")]
        {
            METRICS.dec_in_flight_requests("process_swap_request");
            METRICS.record_mint_operation("process_swap_request", true);
        }

        Ok(response)
    }

    #[cfg(feature = "prometheus")]
    fn record_swap_failure(&self, operation: &str) {
        METRICS.dec_in_flight_requests(operation);
        METRICS.record_mint_operation(operation, false);
        METRICS.record_error();
    }
}