Feature/multi investor factoring payer role

contracts/invoice-escrow/src/errors.rs

@@ -35,4 +35,6 @@ pub enum Error {
     Overflow = 13,
     /// Escrow has been cancelled by the seller.
     EscrowCancelled = 14,
+    /// Payer is not the authorized debtor for this invoice.
+    InvalidPayer = 15,
 }

contracts/invoice-escrow/src/events.rs

@@ -7,22 +7,40 @@ pub fn escrow_created(
     env: &Env,
     inv_id: Symbol,
     seller: &Address,
-    amount: i128,
+    debtor: &Address,
+    face_value: i128,
+    purchase_price: i128,
     due_dt: u64,
     token: &Address,
     inv_token: &Address,
 ) {
     env.events().publish(
         (Symbol::new(env, "escrow_created"),),
-        (inv_id.clone(), seller, amount, due_dt, token, inv_token),
+        (
+            inv_id.clone(),
+            seller,
+            debtor,
+            face_value,
+            purchase_price,
+            due_dt,
+            token,
+            inv_token,
+        ),
     );
 }
 
-/// Publish escrow_funded event.
-pub fn escrow_funded(env: &Env, inv_id: Symbol, funder: &Address, amount: i128) {
+/// Publish escrow_funded event with partial funding info.
+pub fn escrow_funded(
+    env: &Env,
+    inv_id: Symbol,
+    funder: &Address,
+    amount: i128,
+    funded_amt: i128,
+    purchase_price: i128,
+) {
     env.events().publish(
         (Symbol::new(env, "escrow_funded"),),
-        (inv_id, funder, amount),
+        (inv_id, funder, amount, funded_amt, purchase_price),
     );
 }
 
@@ -41,19 +59,15 @@ pub fn payment_settled(
 }
 
 /// Publish refund event.
-pub fn escrow_refunded(env: &Env, inv_id: Symbol, funder: &Address, amount: i128) {
-    env.events().publish(
-        (Symbol::new(env, "escrow_refunded"),),
-        (inv_id, funder, amount),
-    );
+pub fn escrow_refunded(env: &Env, inv_id: Symbol, amount: i128) {
+    env.events()
+        .publish((Symbol::new(env, "escrow_refunded"),), (inv_id, amount));
 }
 
 /// Publish escrow_cancelled event (invoice_id, seller).
 pub fn escrow_cancelled(env: &Env, inv_id: Symbol, seller: &Address) {
-    env.events().publish(
-        (Symbol::new(env, "escrow_cancelled"),),
-        (inv_id, seller),
-    );
+    env.events()
+        .publish((Symbol::new(env, "escrow_cancelled"),), (inv_id, seller));
 }
 
 /// Publish platform fee update event with old and new basis points.

contracts/invoice-escrow/src/integration_test.rs

@@ -56,14 +56,16 @@ fn test_integration_escrow_lifecycle_happy_path() {
     escrow_client.create_escrow(
         &invoice_id,
         &seller,
+        &payer,
+        &amount,
         &amount,
         &due_date,
         &payment_token_id.address(),
         &inv_token_id,
     );
 
     // 8. Fund Escrow (Buyer buys the invoice)
-    escrow_client.fund_escrow(&invoice_id, &buyer);
+    escrow_client.fund_escrow(&invoice_id, &buyer, &amount);
 
     // Verify buyer received invoice tokens and paid payment tokens
     assert_eq!(inv_token_client.balance(&buyer), amount);
@@ -141,13 +143,15 @@ fn test_integration_refund_lifecycle() {
     escrow_client.create_escrow(
         &invoice_id,
         &seller,
+        &seller,
+        &amount,
         &amount,
         &due_date,
         &payment_token_id.address(),
         &inv_token_id,
     );
 
-    escrow_client.fund_escrow(&invoice_id, &buyer);
+    escrow_client.fund_escrow(&invoice_id, &buyer, &amount);
 
     // Attempt refund before due date (should fail)
     let res = escrow_client.try_refund(&invoice_id);
@@ -178,6 +182,7 @@ fn test_integration_token_locked_during_active_escrow() {
     let admin = Address::generate(&env);
     let seller = Address::generate(&env);
     let buyer = Address::generate(&env);
+    let payer = Address::generate(&env);
 
     let escrow_id = env.register(InvoiceEscrow, ());
     let escrow_client = InvoiceEscrowClient::new(&env, &escrow_id);
@@ -208,6 +213,8 @@ fn test_integration_token_locked_during_active_escrow() {
     escrow_client.create_escrow(
         &invoice_id,
         &seller,
+        &payer,
+        &amount,
         &amount,
         &due_date,
         &payment_token_id.address(),
@@ -217,7 +224,7 @@ fn test_integration_token_locked_during_active_escrow() {
     // Token is locked even before funding (initialized locked)
     assert!(inv_token_client.transfer_locked());
 
-    escrow_client.fund_escrow(&invoice_id, &buyer);
+    escrow_client.fund_escrow(&invoice_id, &buyer, &amount);
 
     // Token is still locked after funding — transfers are blocked while invoice is active
     assert!(inv_token_client.transfer_locked());
@@ -226,7 +233,6 @@ fn test_integration_token_locked_during_active_escrow() {
     assert!(result.is_err());
 
     // After settlement, token unlocks
-    let payer = Address::generate(&env);
     payment_token_asset.mint(&payer, &amount);
     escrow_client.record_payment(&invoice_id, &payer, &amount);