jacobh2
06f48ef9e9
Cargo workspace (kvitt-domain, kvitt-server, kvitt-import), Rust 1.99.1 pinned. kvitt-domain passes every Rust vector and adds next_occurrence_date (D-015). kvitt-server: config, SQLite pool (WAL, §8.9 pragmas), migration 0001 identical to the contract schema, error type for all 25 codes, auth extractor and protocol layer, all 33 routes (E-1/E-2 implemented, the rest 501), utoipa document equal to contracts/openapi.yaml, seams for M3/M4/M9, serve/migrate/healthcheck. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
87 lines
2.9 KiB
Rust
87 lines
2.9 KiB
Rust
//! Balances (SPEC §9.3, §14.5.2).
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use std::collections::BTreeMap;
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use serde::{Deserialize, Serialize};
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/// A non-deleted expense as far as balances are concerned.
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#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
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pub struct BalanceExpense {
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pub account_id: String,
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pub amount_ore: i64,
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pub payer_user_id: String,
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/// user id → share in öre.
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pub shares: BTreeMap<String, i64>,
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}
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/// A non-deleted settlement as far as balances are concerned.
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#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
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pub struct BalanceSettlement {
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pub from_user_id: String,
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pub to_user_id: String,
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/// account id → öre.
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pub allocations: BTreeMap<String, i64>,
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}
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/// Net per account and user, and the global net per user.
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#[derive(Debug, Clone, PartialEq, Eq, Default, Serialize, Deserialize)]
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pub struct Balances {
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/// account id → user id → net öre.
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pub per_account: BTreeMap<String, BTreeMap<String, i64>>,
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/// user id → net öre over every account.
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pub global: BTreeMap<String, i64>,
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}
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/// Computes `net(u)` per account and globally (SPEC §9.3). Inputs hold only non-deleted rows.
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///
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/// `per_account` has an entry for every id of `account_ids` (zeros included) and for any other account id the rows
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/// reference; each inner map has every id of `user_ids`. Arithmetic saturates instead of overflowing; real data is
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/// many orders of magnitude below `i64::MAX`.
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pub fn compute_balances(
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user_ids: &[String],
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account_ids: &[String],
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expenses: &[BalanceExpense],
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settlements: &[BalanceSettlement],
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) -> Balances {
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let zeros: BTreeMap<String, i64> = user_ids.iter().map(|u| (u.clone(), 0)).collect();
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let mut per_account: BTreeMap<String, BTreeMap<String, i64>> = BTreeMap::new();
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for account in account_ids {
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per_account
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.entry(account.clone())
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.or_insert_with(|| zeros.clone());
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}
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for expense in expenses {
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let nets = per_account
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.entry(expense.account_id.clone())
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.or_insert_with(|| zeros.clone());
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add(nets, &expense.payer_user_id, expense.amount_ore);
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for (user, share) in &expense.shares {
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add(nets, user, share.saturating_neg());
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}
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}
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for settlement in settlements {
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for (account, amount) in &settlement.allocations {
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let nets = per_account
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.entry(account.clone())
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.or_insert_with(|| zeros.clone());
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add(nets, &settlement.from_user_id, *amount);
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add(nets, &settlement.to_user_id, amount.saturating_neg());
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}
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}
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let mut global = zeros;
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for nets in per_account.values() {
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for (user, net) in nets {
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add(&mut global, user, *net);
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}
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}
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Balances {
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per_account,
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global,
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}
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}
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fn add(nets: &mut BTreeMap<String, i64>, user: &str, delta: i64) {
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let net = nets.entry(user.to_owned()).or_insert(0);
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*net = net.saturating_add(delta);
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}
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