Add regular bsv-20 coupon bond.

src/contracts/bsv20CouponBond.ts

@@ -0,0 +1,274 @@
+import { BSV20V2 } from 'scrypt-ord'
+import {
+    assert,
+    ByteString,
+    byteString2Int,
+    fill,
+    FixedArray,
+    hash256,
+    method,
+    prop,
+    PubKey,
+    pubKey2Addr,
+    Sig,
+    slice,
+    toByteString,
+    Utils,
+} from 'scrypt-ts'
+import { RabinPubKey, RabinSig, RabinVerifier } from 'scrypt-ts-lib'
+
+export type Investor = {
+    emptySlot: boolean
+    pubKey: PubKey
+    forSale: boolean
+    price: bigint
+}
+
+export class Bsv20CouponBond extends BSV20V2 {
+    static readonly N_INVESTORS = 10
+
+    @prop()
+    issuer: PubKey
+
+    @prop(true)
+    investors: FixedArray<Investor, typeof Bsv20CouponBond.N_INVESTORS>
+
+    @prop()
+    faceValue: bigint
+
+    @prop()
+    interestRate: bigint // 1n == 1%
+
+    @prop()
+    matureTime: bigint
+
+    @prop()
+    oraclePubKey: RabinPubKey
+
+    constructor(
+        id: ByteString,
+        sym: ByteString,
+        max: bigint,
+        dec: bigint,
+        issuer: PubKey,
+        faceValue: bigint,
+        interestRate: bigint,
+        matureTime: bigint,
+        oraclePubKey: RabinPubKey
+    ) {
+        super(id, sym, max, dec)
+        this.init(...arguments)
+
+        this.issuer = issuer
+        this.investors = fill(
+            {
+                emptySlot: true,
+                pubKey: PubKey(
+                    toByteString(
+                        '000000000000000000000000000000000000000000000000'
+                    )
+                ),
+                forSale: false,
+                price: 0n,
+            } as Investor,
+            10
+        )
+        this.faceValue = faceValue
+        this.interestRate = interestRate
+        this.matureTime = matureTime
+        this.oraclePubKey = oraclePubKey
+    }
+
+    @method()
+    public invest(
+        slotIdx: bigint,
+        investorPubKey: PubKey,
+        investorSig: Sig,
+        oracleMsg: ByteString,
+        oracleSig: RabinSig
+    ) {
+        // Check investor sig.
+        assert(
+            this.checkSig(investorSig, investorPubKey),
+            'invalid sig investor'
+        )
+
+        // 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))
+
+        // Ensure token amount is equal to the face value.
+        assert(utxoTokenAmt == this.faceValue, 'utxo token amount insufficient')
+
+        // Check slot index is empty.
+        const investor = this.investors[Number(slotIdx)]
+        assert(investor.emptySlot == true, 'slot is not empty')
+
+        // Add to investors array.
+        this.investors[Number(slotIdx)] = {
+            emptySlot: false,
+            pubKey: investorPubKey,
+            forSale: false,
+            price: 0n,
+        }
+
+        // Ensure that investor pays issuer face value
+        // and propagate contract.
+        let outputs = this.buildStateOutput(this.ctx.utxo.value)
+        outputs += BSV20V2.buildTransferOutput(
+            pubKey2Addr(this.issuer),
+            this.id,
+            this.faceValue
+        )
+        outputs += this.buildChangeOutput()
+        assert(hash256(outputs) == this.ctx.hashOutputs, 'hashOutputs mismatch')
+    }
+
+    @method()
+    public makePayment(
+        issuerSig: Sig,
+        oracleMsg: ByteString,
+        oracleSig: RabinSig
+    ) {
+        // Check issuer sig.
+        assert(this.checkSig(issuerSig, this.issuer), 'invalid sig issuer')
+
+        // 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'
+        )
+
+        // For each investor add an output that pays them interest.
+        const interest = (this.faceValue * this.interestRate) / 100n
+        let outputs = toByteString('')
+        let totalAmt = 0n
+        for (let i = 0; i < Bsv20CouponBond.N_INVESTORS; i++) {
+            const investor = this.investors[i]
+            if (!investor.emptySlot) {
+                outputs += BSV20V2.buildTransferOutput(
+                    pubKey2Addr(investor.pubKey),
+                    this.id,
+                    interest
+                )
+                totalAmt += interest
+            }
+        }
+
+        // Get token amount held by the UTXO from oracle message.
+        const utxoTokenAmt = byteString2Int(slice(oracleMsg, 36n, 44n))
+
+        // Ensure utxo token amount covers output token amount.
+        assert(utxoTokenAmt >= totalAmt, 'utxo token amount insufficient')
+
+        // Enforce outputs.
+        outputs += this.buildChangeOutput()
+        assert(hash256(outputs) == this.ctx.hashOutputs, 'hashOutputs mismatch')
+    }
+
+    @method()
+    public mature(issuerSig: Sig, oracleMsg: ByteString, oracleSig: RabinSig) {
+        // Check issuer sig.
+        assert(this.checkSig(issuerSig, this.issuer), 'invalid sig issuer')
+
+        // Check mature time.
+        assert(this.timeLock(this.matureTime), 'not matured yet')
+
+        // 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'
+        )
+
+        // For each investor add an output that pays them the face value token amount.
+        let outputs = toByteString('')
+        let totalAmt = 0n
+        for (let i = 0; i < Bsv20CouponBond.N_INVESTORS; i++) {
+            const investor = this.investors[i]
+            if (!investor.emptySlot) {
+                outputs += BSV20V2.buildTransferOutput(
+                    pubKey2Addr(investor.pubKey),
+                    this.id,
+                    this.faceValue
+                )
+                totalAmt += this.faceValue
+            }
+        }
+
+        // Get token amount held by the UTXO from oracle message.
+        const utxoTokenAmt = byteString2Int(slice(oracleMsg, 36n, 44n))
+
+        // Ensure utxo token amount covers output token amount.
+        assert(utxoTokenAmt >= totalAmt, 'utxo token amount insufficient')
+
+        // Enforce outputs.
+        outputs += this.buildChangeOutput()
+        assert(hash256(outputs) == this.ctx.hashOutputs, 'hashOutputs mismatch')
+    }
+
+    @method()
+    public listForSale(slotIdx: bigint, price: bigint, investorSig: Sig) {
+        const investor = this.investors[Number(slotIdx)]
+
+        // Check investor sig.
+        assert(
+            this.checkSig(investorSig, investor.pubKey),
+            'invalid sig investor'
+        )
+
+        // Toggle forSale flag and set price.
+        this.investors[Number(slotIdx)].forSale = true
+        this.investors[Number(slotIdx)].price = price
+
+        // Propagate contract.
+        let outputs = this.buildStateOutput(this.ctx.utxo.value)
+        outputs += this.buildChangeOutput()
+        assert(hash256(outputs) == this.ctx.hashOutputs, 'hashOutputs mismatch')
+    }
+
+    @method()
+    public buy(slotIdx: bigint, newOwner: PubKey, newOwnerSig: Sig) {
+        const investor = this.investors[Number(slotIdx)]
+
+        // Check new owner sig.
+        assert(this.checkSig(newOwnerSig, newOwner), 'invalid sig investor')
+
+        // Check bond is for sale.
+        assert(investor.forSale, 'bond not for sale')
+
+        // Toggle forSale flag.
+        this.investors[Number(slotIdx)].forSale = false
+
+        // Propagate contract and ensure new owner pays seller of the bond.
+        let outputs = this.buildStateOutput(this.ctx.utxo.value)
+        outputs += Utils.buildAddressOutput(
+            pubKey2Addr(investor.pubKey),
+            investor.price
+        )
+        outputs += this.buildChangeOutput()
+        assert(hash256(outputs) == this.ctx.hashOutputs, 'hashOutputs mismatch')
+    }
+}