Add oracle to bsv-20 loan.

sCrypt-Inc · Nov 24, 2023 · b9db604 · b9db604
1 parent 4e1956f
commit b9db604
Showing 1 changed file with 31 additions and 9 deletions.
diff --git a/src/contracts/bsv20Loan.ts b/src/contracts/bsv20Loan.ts
@@ -2,18 +2,17 @@ import { BSV20V2 } from 'scrypt-ord'
 import {
     assert,
     ByteString,
+    byteString2Int,
     hash256,
     method,
     prop,
     PubKey,
     pubKey2Addr,
-    sha256,
-    Sha256,
     Sig,
-    SmartContract,
-    toByteString,
+    slice,
     Utils,
 } from 'scrypt-ts'
+import { RabinPubKey, RabinSig, RabinVerifier } from 'scrypt-ts-lib'
 
 export class Bsv20Loan extends BSV20V2 {
     @prop()
@@ -26,7 +25,7 @@ export class Bsv20Loan extends BSV20V2 {
     @prop()
     tokenAmt: bigint
 
-    // Fixed interest rate of the load.
+    // Fixed interest rate of the loan.
     // 1 = 1%
     @prop()
     interestRate: bigint
@@ -44,6 +43,9 @@ export class Bsv20Loan extends BSV20V2 {
     @prop(true)
     taken: boolean
 
+    @prop()
+    oraclePubKey: RabinPubKey
+
     constructor(
         id: ByteString,
         sym: ByteString,
@@ -54,7 +56,8 @@ export class Bsv20Loan extends BSV20V2 {
         tokenAmt: bigint,
         interestRate: bigint,
         collateral: bigint,
-        deadline: bigint
+        deadline: bigint,
+        oraclePubKey: RabinPubKey
     ) {
         super(id, sym, max, dec)
         this.init(...arguments)
@@ -66,10 +69,11 @@ export class Bsv20Loan extends BSV20V2 {
         this.collateral = collateral
         this.deadline = deadline
         this.taken = false
+        this.oraclePubKey = oraclePubKey
     }
 
     @method()
-    public takeLoan() {
+    public borrow() {
         // Check loan isn't taken yet.
         assert(this.taken == false, 'loan already taken')
         this.taken = true
@@ -88,12 +92,30 @@ export class Bsv20Loan extends BSV20V2 {
     }
 
     @method()
-    public repay() {
+    public repay(oracleMsg: ByteString, oracleSig: RabinSig) {
         // Check loan is already taken.
         assert(this.taken == true, 'loan not taken yet')
 
-        // Pay lender back the principal token amount plus interest.
+        // Check oracle signature.
+        assert(
+            RabinVerifier.verifySig(oracleMsg, oracleSig, this.oraclePubKey),
+            'oracle sig verify failed'
+        )
+
+        // Check that we're unlocking the UTXO specified in the oracles message.
+        assert(
+            slice(this.prevouts, 0n, 36n) == slice(oracleMsg, 0n, 36n),
+            'first input is not spending specified ordinal UTXO'
+        )
+
+        // Get token amount held by the UTXO from oracle message.
+        const utxoTokenAmt = byteString2Int(slice(oracleMsg, 36n, 44n))
+
+        // Check token amount is correct.
         const interest = (this.tokenAmt * this.interestRate) / 100n
+        assert(utxoTokenAmt == this.tokenAmt + interest, 'invalid token amount')
+
+        // Pay lender back the principal token amount plus interest.
         let outputs = BSV20V2.buildTransferOutput(
             pubKey2Addr(this.lender),
             this.id,