Fee preview consistency + rate view

CHANGELOG.md

@@ -3,6 +3,7 @@
 All notable changes to the Sharpy smart contract are documented here.
 
 ## [Unreleased]
+- feat(contract): `get_fee_bps()` rate view + preview-vs-invoice consistency proof (emitting vs silent share math, release untouched) — feat/fee-consistency (closes #195)
 - feat(contract): whitelist enforced uniformly in `pay`/`pay_with_tip`/`pool_pay` + `is_whitelisted_payer(id, payer)` view; `require!` message consistency — feat/whitelist-consistency (closes #194)
 - feat(contract): `get_tranche_remaining_bps(id)` view + cumulative-bps invariant (`released + remaining == 10000`) — feat/tranche-remaining (closes #193)
 - feat(contract): `resolve_route_chain(id, max_depth)` bounded follower + `get_route_chain_len(id)` cycle-safe depth view — feat/route-chain-depth (closes #192)

contracts/sharpy/src/lib.rs

@@ -1467,7 +1467,15 @@ impl SharpyContract {
         env.storage().instance().get(&fee_key())
     }
 
+    /// Current fee rate in bps (0 when unset). Pure view so dashboards can
+    /// render the rate without fetching the full `FeeConfig`.
+    pub fn get_fee_bps(env: Env) -> u32 {
+        env.storage().instance().get::<Symbol, FeeConfig>(&fee_key()).map(|c| c.fee_bps).unwrap_or(0)
+    }
+
     /// Preview the protocol fee owed on `amount` (pure query, no state change).
+    /// Emits `fprev` for indexer visibility; for a silent estimate on an invoice
+    /// total see `preview_fee_for_invoice` — both share `calc_protocol_fee` math.
     pub fn preview_fee(env: Env, amount: i128) -> i128 {
         let fee = calc_protocol_fee(&env, amount);
         events::fee_previewed(&env, amount, fee);

contracts/sharpy/src/test.rs

@@ -5760,3 +5760,126 @@ mod test_wl_consistency_c {
         assert!(client.is_whitelisted_payer(&id, &payer));
     }
 }
+
+#[cfg(test)]
+mod test_fee_consistency_a {
+    use soroban_sdk::{testutils::Address as _, Address, Env, Vec};
+    use crate::SharpyContractClient;
+    fn setup() -> (Env, SharpyContractClient<'static>) {
+        let env = Env::default();
+        env.mock_all_auths();
+        let cid = env.register(crate::SharpyContract, ());
+        let c = SharpyContractClient::new(&env, &cid);
+        let a = Address::generate(&env);
+        let t = Address::generate(&env);
+        c.initialize(&a, &t);
+        (env, c)
+    }
+    fn mk(env: &Env, client: &SharpyContractClient<'_>, creator: &Address, total: i128) -> u64 {
+        let r = Address::generate(env);
+        let tok = Address::generate(env);
+        let dl = env.ledger().timestamp() + 86400;
+        let opts = crate::types::InvoiceOptions { escrow_enabled: false, escrow_release_delay: None, split_rules: Vec::new(env), auto_resolve_rules: Vec::new(env), arbitrator: None };
+        client.create_invoice(creator, &Vec::from_array(env, [r]), &Vec::from_array(env, [total]), &Vec::from_array(env, [tok]), &dl, &opts)
+    }
+    #[test]
+    fn test_fee_bps_view_defaults_zero() {
+        let (env, client) = setup();
+        assert_eq!(client.get_fee_bps(), 0u32);
+        let collector = Address::generate(&env);
+        client.set_protocol_fee(&250u32, &collector);
+        assert_eq!(client.get_fee_bps(), 250u32);
+    }
+    #[test]
+    fn test_invoice_preview_matches_amount_preview() {
+        let (env, client) = setup();
+        let creator = Address::generate(&env);
+        let collector = Address::generate(&env);
+        client.set_protocol_fee(&500u32, &collector);
+        let id = mk(&env, &client, &creator, 10_000i128);
+        assert_eq!(client.preview_fee_for_invoice(&id), client.preview_fee(&10_000i128));
+    }
+}
+
+#[cfg(test)]
+mod test_fee_consistency_b {
+    use soroban_sdk::{testutils::Address as _, Address, Env, Vec};
+    use crate::SharpyContractClient;
+    fn setup() -> (Env, SharpyContractClient<'static>) {
+        let env = Env::default();
+        env.mock_all_auths();
+        let cid = env.register(crate::SharpyContract, ());
+        let c = SharpyContractClient::new(&env, &cid);
+        let a = Address::generate(&env);
+        let t = Address::generate(&env);
+        c.initialize(&a, &t);
+        (env, c)
+    }
+    fn mk2(env: &Env, client: &SharpyContractClient<'_>, creator: &Address) -> u64 {
+        let r1 = Address::generate(env);
+        let r2 = Address::generate(env);
+        let t1 = Address::generate(env);
+        let t2 = Address::generate(env);
+        let dl = env.ledger().timestamp() + 86400;
+        let opts = crate::types::InvoiceOptions { escrow_enabled: false, escrow_release_delay: None, split_rules: Vec::new(env), auto_resolve_rules: Vec::new(env), arbitrator: None };
+        client.create_invoice(creator, &Vec::from_array(env, [r1, r2]), &Vec::from_array(env, [6000i128, 4000i128]), &Vec::from_array(env, [t1, t2]), &dl, &opts)
+    }
+    #[test]
+    fn test_multi_recipient_total_preview_matches() {
+        let (env, client) = setup();
+        let creator = Address::generate(&env);
+        let collector = Address::generate(&env);
+        client.set_protocol_fee(&1000u32, &collector);
+        let id = mk2(&env, &client, &creator);
+        assert_eq!(client.preview_fee_for_invoice(&id), client.preview_fee(&10_000i128));
+        assert_eq!(client.preview_fee_for_invoice(&id), 1000i128);
+    }
+    #[test]
+    fn test_preview_is_pure_double_call() {
+        let (env, client) = setup();
+        let creator = Address::generate(&env);
+        let collector = Address::generate(&env);
+        client.set_protocol_fee(&250u32, &collector);
+        let r = Address::generate(&env);
+        let tok = Address::generate(&env);
+        let dl = env.ledger().timestamp() + 86400;
+        let opts = crate::types::InvoiceOptions { escrow_enabled: false, escrow_release_delay: None, split_rules: Vec::new(&env), auto_resolve_rules: Vec::new(&env), arbitrator: None };
+        let id = client.create_invoice(&creator, &Vec::from_array(&env, [r]), &Vec::from_array(&env, [8000i128]), &Vec::from_array(&env, [tok]), &dl, &opts);
+        let a = client.preview_fee_for_invoice(&id);
+        let b = client.preview_fee_for_invoice(&id);
+        assert_eq!(a, b);
+        assert_eq!(a, 200i128);
+    }
+}
+
+#[cfg(test)]
+mod test_fee_consistency_c {
+    use soroban_sdk::{testutils::Address as _, Address, Env};
+    use crate::SharpyContractClient;
+    fn setup() -> (Env, SharpyContractClient<'static>) {
+        let env = Env::default();
+        env.mock_all_auths();
+        let cid = env.register(crate::SharpyContract, ());
+        let c = SharpyContractClient::new(&env, &cid);
+        let a = Address::generate(&env);
+        let t = Address::generate(&env);
+        c.initialize(&a, &t);
+        (env, c)
+    }
+    #[test]
+    fn test_full_bps_equals_amount() {
+        let (env, client) = setup();
+        let collector = Address::generate(&env);
+        client.set_protocol_fee(&10_000u32, &collector);
+        assert_eq!(client.preview_fee(&12345i128), 12345i128);
+        assert_eq!(client.get_fee_bps(), 10_000u32);
+    }
+    #[test]
+    fn test_truncation_rounds_down() {
+        let (env, client) = setup();
+        let collector = Address::generate(&env);
+        client.set_protocol_fee(&100u32, &collector);
+        assert_eq!(client.preview_fee(&1i128), 0i128);
+        assert_eq!(client.preview_fee(&10_000i128), 100i128);
+    }
+}