Settlement Logic | SplitPay Docs

The settlement function transforms a pending payment into finalized token transfers and immutable distribution records.

Settlement Mechanics

Settlement can only be invoked once per payment. Re-executing causes Error::PaymentAlreadySettled.

Source Code Walkthrough

rustcontracts/splitpay/src/contract.rs

// 1. Authenticate payer
let mut payment = get_payment(&env, payment_id)?;
payment.payer.require_auth();
// 2. Validate active pool & 10,000 BPS
let members = get_pool_members(&env, payment.pool_id)?;
let mut total_shares: u32 = 0;
for m in members.iter() {
    total_shares = total_shares.checked_add(m.share_bps).ok_or(Error::ArithmeticOverflow)?;
}
if total_shares != MAX_BPS {
    return Err(Error::InvalidTotalShares);
}
// 3. Compute allocations & assign remainder to index 0
let mut allocations = Vec::new(&env);
let mut allocated_sum: i128 = 0;
for m in members.iter() {
    let alloc = payment.amount.checked_mul(m.share_bps as i128)?
        .checked_div(BPS_DENOMINATOR)?;
    allocated_sum = allocated_sum.checked_add(alloc)?;
    allocations.push_back(alloc);
}
let remainder = payment.amount.checked_sub(allocated_sum)?;
if remainder > 0 && !allocations.is_empty() {
    let first = allocations.get(0).unwrap().checked_add(remainder)?;
    allocations.set(0, first);
}

Two-Step Token Transfer

The contract uses a clean two-step transfer model:

Step 1: Total payment amount is transferred from payment.payer to contract_address.
Step 2: Contract loops through members and transfers their calculated alloc directly to their address.