btcmortgage/scripts/btcMortgage.js
2023-07-22 02:00:06 +05:30

949 lines
48 KiB
JavaScript

(function (EXPORTS) {
const btcMortgage = EXPORTS;
//USERS: B: Borrower, L: Lender, C: Collateral provider, T: Trusted banker (us)
const APP_NAME = "BTCMortgage";
const APP_IDENTIFIER = "BTC Mortgage";
const BANKER_ID = "";
const BANKER_PUBKEY = "";
const CURRENCY = "USD";
const PERIOD_REGEX = /^\d{1,5}(Y|M|D)$/,
TXID_REGEX = /^[0-9a-f]{64}$/i,
VALUE_REGEX = /^\d+(.\d{1,8})?$/;
const
TYPE_LOAN_COLLATERAL_REQUEST = "type_loan_collateral_request",
TYPE_LOAN_REQUEST = "type_loan_request",
TYPE_LENDER_RESPONSE = "type_loan_response",
TYPE_COLLATERAL_LOCK_REQUEST = "type_collateral_lock_request",
TYPE_COLLATERAL_LOCK_ACK = "type_collateral_lock_ack",
TYPE_LOAN_CLOSED_ACK = "type_loan_closed_ack",
TYPE_UNLOCK_COLLATERAL_REQUEST = "type_unlock_collateral_request",
TYPE_UNLOCK_COLLATERAL_ACK = "type_unlock_collateral_ack";
const POLICIES = {}
const toFixedDecimal = value => parseFloat((value).toFixed(8));
function encodePeriod(str) {
if (typeof str != 'string')
throw "passed value must be string";
if (PERIOD_REGEX.test(str)) //already in format
return str;
let P = '', n = 0;
str.toLowerCase().replace(/,/g, '').split(" ").forEach(s => {
if (!isNaN(s))
n = parseInt(s);
else switch (s) {
case "year(s)": case "year": case "years": P += (n + 'Y'); n = 0; break;
case "month(s)": case "month": case "months": P += (n + 'M'); n = 0; break;
case "day(s)": case "day": case "days": P += (n + 'D'); n = 0; break;
}
});
if (!PERIOD_REGEX.test(P)) {//not in format: something wrong
console.error(`encodePeriod('${str}') failed`, P)
throw "Invalid period";
}
return P;
}
function decodePeriod(str) {
if (typeof str != 'string')
throw "passed value must be string";
else if (!PERIOD_REGEX.test(str)) //not in format
throw "Invalid period";
let n = parseInt(str);
let v = str[str.length - 1];
switch (v) {
case 'Y': return n + (n == 1 ? "year" : "years");
case 'M': return n + (n == 1 ? "month" : "months");
case "D": return n + (n == 1 ? "day" : "days");
}
}
const dateFormat = (date = null) => {
let d = (date ? new Date(date) : new Date()).toDateString();
return [d.substring(8, 10), d.substring(4, 7), d.substring(11, 15)].join(" ");
}
const yearDiff = (d1 = null, d2 = null) => {
d1 = d1 ? new Date(d1) : new Date();
d2 = d2 ? new Date(d2) : new Date();
let y = d1.getYear() - d2.getYear(),
m = d1.getMonth() - d2.getMonth(),
d = d1.getDate() - d2.getDate()
return y + m / 12 + d / 365;
}
const dateAdder = function (start_date, duration) {
let date = new Date(start_date);
let y = parseInt(duration.match(/\d+Y/)),
m = parseInt(duration.match(/\d+M/)),
d = parseInt(duration.match(/\d+D/));
if (!isNaN(y))
date.setFullYear(date.getFullYear() + y);
if (!isNaN(m))
date.setMonth(date.getMonth() + m);
if (!isNaN(d))
date.setDate(date.getDate() + d);
return date;
}
function calcAllowedLoan(collateralQuantity, security_percent) {
return collateralQuantity * security_percent;
}
function calcRequiredCollateral(loanEquivalent, security_percent) {
let inverse_security_percent = 1 / security_percent;
return loanEquivalent * inverse_security_percent;
}
function findLocker(coborrower_pubKey, lender_pubKey) {
return btcOperator.multiSigAddress([coborrower_pubKey, lender_pubKey, BANKER_PUBKEY], 2);
}
function extractPubKeyFromSign(sign) {
return sign.split('.')[0];
}
btcMortgage.util = {
toFixedDecimal,
encodePeriod, decodePeriod,
calcAllowedLoan, calcRequiredCollateral,
findLocker, extractPubKeyFromSign
}
//get BTC rates
const getRate = btcMortgage.getRate = {};
getRate["BTC"] = function () {
return new Promise((resolve, reject) => {
fetch('https://api.coinlore.net/api/ticker/?id=90').then(response => {
if (response.ok) {
response.json()
.then(result => resolve(result[0].price_usd))
.catch(error => reject(error));
} else
reject(response.status);
}).catch(error => reject(error));
});
}
//function to read all policy from blockchain
function readPoliciesFromBlockchain() {
return new Promise((resolve, reject) => {
const LASTTX_IDB_KEY = APP_NAME + ":" + BANKER_ID
compactIDB.readData("lastTx", LASTTX_IDB_KEY).then(lastTx => {
var query_options = { sentOnly: true, tx: true, filter: d => d.startsWith(APP_IDENTIFIER) };
if (typeof lastTx == 'number') //lastTx is tx count (*backward support)
query_options.ignoreOld = lastTx;
else if (typeof lastTx == 'string') //lastTx is txid of last tx
query_options.after = lastTx;
floBlockchainAPI.readData(BANKER_ID, query_options).then(result => {
let p = [];
for (var i = result.items.length - 1; i >= 0; i--) {
let t = result.items[i];
if (t.data.startsWith(LOAN_POLICY_IDENTIFIER)) {
let policy_id = t.txid,
policy_details = parsePolicyData(t.data, t.time);
p.push(compactIDB.addData("policies", policy_details, policy_id));
}
}
Promise.all(p).then(result => {
compactIDB.writeData("lastTx", result.lastItem, LASTTX_IDB_KEY);
compactIDB.readAllData("policies").then(result => {
for (let p in result)
POLICIES[p] = result[p];
resolve(POLICIES); //MAYBE: resolve a copy of it?
})
}).catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
//Policy details
const LOAN_POLICY_IDENTIFIER = APP_IDENTIFIER + ": Loan policy";
function stringifyPolicyData(duration, interest, pre_liquidation_threshold, loan_collateral_ratio) {
return [
LOAN_POLICY_IDENTIFIER,
"Duration:" + decodePeriod(duration),
"Interest per annum:" + interest,
"Pre-Liquidation threshold:" + pre_liquidation_threshold,
"Loan to Collateral ratio:" + loan_collateral_ratio
].join('|');
}
function parsePolicyData(str, tx_time) {
let splits = str.split('|');
if (splits[0] !== LOAN_POLICY_IDENTIFIER)
throw "Invalid Loan Policy data";
var details = { policy_creation_time: tx_time };
splits.forEach(s => {
let d = s.split(':');
switch (d[0]) {
case "Duration": details.duration = encodePeriod(d[1]); break;
case "Interest per annum": details.interest = parseFloat(d[1]); break;
case "Pre-Liquidation threshold": details.pre_liquidation_threshold = parseFloat(d[1]); break;
case "Loan to Collateral ratio": details.loan_collateral_ratio = parseFloat(d[1]); break;
}
});
return details;
}
//Loan details on FLO blockchain
const LOAN_DETAILS_IDENTIFIER = APP_IDENTIFIER + ": Loan details";
function stringifyLoanOpenData(
borrower, loan_amount, policy_id,
coborrower, collateral_value, collateral_lock_id,
lender, loan_transfer_id,
borrower_sign, coborrower_sign, lender_sign
) {
return [
LOAN_DETAILS_IDENTIFIER,
"Borrower:" + floCrypto.toFloID(borrower),
"Amount:" + loan_amount,
"Policy:" + policy_id,
"CoBorrower:" + floCrypto.toFloID(coborrower),
"CollateralValue:" + collateral_value + "BTC",
"CollateralLock:" + collateral_lock_id,
"Lender:" + floCrypto.toFloID(lender),
"TokenTransfer:" + loan_transfer_id,
"Signature-B:" + borrower_sign,
"Signature-C:" + coborrower_sign,
"Signature-L:" + lender_sign
].join('|');
/*MAYDO: Maybe make it a worded sentence?
BTC Mortgage:
L#${lender_floid} is lending ${loan_amount}USD (ref#${loan_transfer_id}) to B#${borrower_floid}
inaccoradance with policy#${policy_id}
as mortgage on collateral#${collateral_id} (${btc_amount}BTC) provided by C#${coborrower_floid}.
Signed by B'${borrower_sign} , C'{coborrower_sign} and L'${lender_sign}
*/
}
function parseLoanOpenData(str, tx_time) {
let splits = str.split('|');
if (splits[0] !== LOAN_DETAILS_IDENTIFIER)
throw "Invalid Loan blockchain data";
var details = { open_time: tx_time };
splits.forEach(s => {
let d = s.split(':');
switch (d[0]) {
case "Borrower": details.borrower = d[1]; break;
case "Amount": details.loan_amount = parseFloat(d[1]); break;
case "Policy": details.policy_id = d[1]; break;
case "CoBorrower": details.coborrower = d[1]; break;
case "CollateralValue": details.collateral_value = parseFloat(d[1]); break;
case "CollateralLock": details.collateral_lock_id = d[1]; break;
case "Lender": details.lender = d[1]; break;
case "TokenTransfer": details.loan_transfer_id = d[1]; break;
case "Signature-B": details.borrower_sign = d[1]; break;
case "Signature-C": details.coborrower_sign = d[1]; break;
case "Signature-L": details.lender_sign = d[1]; break;
}
});
return details;
}
const getLoanDetails = btcMortgage.getLoanDetails = function (loan_id) {
return new Promise((resolve, reject) => {
floBlockchainAPI.getTx(loan_id).then(tx => {
let parsed_loan_details = parseLoanOpenData(tx.floData, tx.time);
validateLoanDetails(parsed_loan_details)
.then(_ => resolve(parsed_loan_details))
.catch(error => reject(error))
}).catch(error => reject(error))
})
}
const validateLoanDetails = btcMortgage.validateLoanDetails = function (loan_details) {
return new Promise((resolve, reject) => {
//validate floIDs
if (!floCrypto.validateFloID(loan_details.borrower))
return reject("Invalid borrower floID");
if (!floCrypto.validateFloID(loan_details.coborrower))
return reject("Invalid coborrower floID");
if (!floCrypto.validateFloID(loan_details.lender))
return reject("Invalid lender floID");
//check policy
if (!(loan_details.policy_id in POLICIES))
return reject("Policy not found");
//verify signatures
if (!verify_borrowerSign(loan_details.borrower_sign, loan_details.borrower, loan_details.loan_amount, loan_details.policy_id, loan_details.coborrower, loan_details.lender))
return reject("Invalid borrower signature");
if (!verify_coborrowerSign(loan_details.coborrower_sign, loan_details.coborrower, loan_details.borrower_sign, loan_details.collateral_value, loan_details.collateral_lock_id))
return reject("Invalid coborrower signature");
if (!verify_lenderSign(loan_details.lender_sign, loan_details.lender, loan_details.coborrower_sign, loan_details.loan_transfer_id))
return reject("Invalid lender signature");
resolve(true)
})
}
const LOAN_CLOSING_IDENTIFIER = APP_IDENTIFIER + ": Loan closing";
function stringifyLoanCloseData(loan_id, borrower, closing_sign) {
return [
LOAN_CLOSING_IDENTIFIER,
"Borrower:" + floCrypto.toFloID(borrower),
"Loan ID:" + loan_id,
"Signature:" + closing_sign,
].join('|');
}
function parseLoanCloseData(str, tx_time) {
let splits = str.split('|');
if (splits[0] !== LOAN_CLOSING_IDENTIFIER)
throw "Invalid Loan closing data";
var details = { close_time: tx_time };
splits.forEach(s => {
let d = s.split(':');
switch (d[0]) {
case "Borrower": details.borrower = d[1]; break;
case "Loan ID": details.loan_id = d[1]; break;
case "Signature": details.closing_sign = d[1]; break;
}
});
return details;
}
const getLoanClosing = btcMortgage.getLoanClosing = function (loan_id, closing_txid) {
return new Promise((resolve, reject) => {
floBlockchainAPI.getTx(closing_txid).then(tx => {
let parsed_loan_closing = parseLoanCloseData(tx.floData, tx.time);
validateLoanClosing(parsed_loan_closing)
.then(_ => resolve(parsed_loan_closing))
.catch(error => reject(error))
}).catch(error => reject(error))
})
}
/*Signature and verification */
function sign_borrower(privKey, loan_amount, policy_id, coborrower, lender) {
let borrower_floID = floCrypto.toFloID(floDapps.user.id),
coborrower_floID = floCrypto.toFloID(coborrower),
lender_floID = floCrypto.toFloID(lender);
//validate values before signing
if (!floCrypto.verifyPrivKey(privKey, borrower_floID))
throw "Invalid Private key for borrower";
if (typeof loan_amount !== "number" || !VALUE_REGEX.test(loan_amount))
throw "Invalid loan amount";
if (!(policy_id in POLICIES))
throw "Invalid Policy";
if (!floCrypto.validateFloID(coborrower_floID, true))
throw "Invalid coborrower floID";
if (!floCrypto.validateFloID(lender_floID, true))
throw "Invalid lender floID";
//sign the value-data
let timestamp = Date.now();
let doc_array = [timestamp, borrower_floID, coborrower_floID, lender_floID, loan_amount, policy_id];
let sign_part = floCrypto.signData(doc_array.join("|"));
let pubKey = floCrypto.getPubKeyHex(privKey);
let borrower_sign = [pubKey, sign_part, timestamp].join(".")
return borrower_sign;
}
function verify_borrowerSign(borrower_sign, borrower, loan_amount, policy_id, coborrower, lender) {
//split the signature part
let sign_splits = borrower_sign.split('.');
let borrower_pubKey = sign_splits[0],
sign_part = sign_splits[1],
timestamp = sign_splits[2];
let borrower_floID = floCrypto.getFloID(borrower_pubKey),
coborrower_floID = floCrypto.toFloID(coborrower),
lender_floID = floCrypto.toFloID(lender);
//validate values
if (!floCrypto.verifyPubKey(borrower_pubKey, borrower))
throw "Invalid public key";
if (typeof loan_amount !== "number" || !VALUE_REGEX.test(loan_amount))
throw "Invalid loan amount";
if (!(policy_id in POLICIES))
throw "Invalid Policy";
if (!floCrypto.validateFloID(borrower_floID, true))
throw "Invalid borrower floID";
if (!floCrypto.validateFloID(coborrower_floID, true))
throw "Invalid coborrower floID";
if (!floCrypto.validateFloID(lender_floID, true))
throw "Invalid lender floID";
//verify the signature
let doc_array = [timestamp, borrower_floID, coborrower_floID, lender_floID, loan_amount, policy_id];
if (floCrypto.verifySign(doc_array.join("|"), sign_part, borrower_pubKey))
return timestamp;
else return false;
}
function sign_coborrower(privKey, borrower_sign, collateral_value, collateral_lock_id) {
let coborrower_floID = floCrypto.toFloID(floDapps.user.id);
//validate values before signing
if (!floCrypto.verifyPrivKey(privKey, coborrower_floID))
throw "Invalid Private key for coborrower";
if (typeof collateral_value !== "number" || !VALUE_REGEX.test(collateral_value))
throw "Invalid collateral amount";
if (typeof collateral_lock_id !== 'string' || !TXID_REGEX.test(collateral_lock_id))
throw "Invalid collateral lock id";
//sign the value-data
let timestamp = Date.now();
let doc_array = [timestamp, borrower_sign, collateral_value, collateral_lock_id];
let sign_part = floCrypto.signData(doc_array.join("|"));
let pubKey = floCrypto.getPubKeyHex(privKey);
let coborrower_sign = [pubKey, sign_part, timestamp].join(".")
return coborrower_sign;
}
function verify_coborrowerSign(coborrower_sign, coborrower, borrower_sign, collateral_value, collateral_lock_id) {
//split the signature part
let sign_splits = coborrower_sign.split('.');
let coborrower_pubKey = sign_splits[0],
sign_part = sign_splits[1],
timestamp = sign_splits[2];
//validate values
if (!floCrypto.verifyPubKey(coborrower_pubKey, coborrower))
throw "Invalid public key";
if (typeof collateral_value !== "number" || !VALUE_REGEX.test(collateral_value))
throw "Invalid collateral amount";
if (typeof collateral_lock_id !== 'string' || !TXID_REGEX.test(collateral_lock_id))
throw "Invalid collateral lock id";
//verify the signature
let doc_array = [timestamp, borrower_sign, collateral_value, collateral_lock_id];
if (floCrypto.verifySign(doc_array.join("|"), sign_part, coborrower_pubKey))
return timestamp;
else return false;
}
function sign_lender(privKey, coborrower_sign, loan_transfer_id) {
let lender_floID = floCrypto.toFloID(floDapps.user.id);
//validate values before signing
if (!floCrypto.verifyPrivKey(privKey, lender_floID))
throw "Invalid Private key for lender";
if (typeof loan_transfer_id !== 'string' || !TXID_REGEX.test(loan_transfer_id))
throw "Invalid token transfer id";
//sign the value-data
let timestamp = Date.now();
let doc_array = [timestamp, coborrower_sign, loan_transfer_id];
let sign_part = floCrypto.signData(doc_array.join("|"));
let pubKey = floCrypto.getPubKeyHex(privKey);
let lender_sign = [pubKey, sign_part, timestamp].join(".")
return lender_sign;
}
function verify_lenderSign(lender_sign, lender, coborrower_sign, loan_transfer_id) {
//split the signature part
let sign_splits = lender_sign.split('.');
let lender_pubKey = sign_splits[0],
sign_part = sign_splits[1],
timestamp = sign_splits[2];
//validate values
if (!floCrypto.verifyPubKey(lender_pubKey, lender))
throw "Invalid public key";
if (typeof loan_transfer_id !== 'string' || !TXID_REGEX.test(loan_transfer_id))
throw "Invalid token transfer id";
//verify the signature
let doc_array = [timestamp, coborrower_sign, loan_transfer_id];
if (floCrypto.verifySign(doc_array.join("|"), sign_part, lender_pubKey))
return timestamp;
else return false;
}
//Signed by borrower when closing the loan
const CLOSING_IDENTIFIER = "closing";
function sign_closing(privKey, loan_id, lender_sign) {
let borrower_floID = floCrypto.toFloID(floDapps.user.id)
//validate values before signing
if (!floCrypto.verifyPrivKey(privKey, borrower_floID))
throw "Invalid Private key for borrower";
if (typeof loan_id !== 'string' || !TXID_REGEX.test(loan_id))
throw "Invalid loan id";
//sign the value-data
let timestamp = Date.now();
let doc_array = [timestamp, CLOSING_IDENTIFIER, loan_id, lender_sign];
let sign_part = floCrypto.signData(doc_array.join("|"));
let pubKey = floCrypto.getPubKeyHex(privKey);
let closing_sign = [pubKey, sign_part, timestamp].join(".")
return closing_sign;
}
function verify_closingSign(closing_sign, borrower, loan_id, lender_sign) {
//split the signature part
let sign_splits = closing_sign.split('.');
let borrower_pubKey = sign_splits[0],
sign_part = sign_splits[1],
timestamp = sign_splits[2];
//validate values
if (!floCrypto.verifyPubKey(borrower_pubKey, borrower))
throw "Invalid public key";
//verify the signature
let doc_array = [timestamp, CLOSING_IDENTIFIER, loan_id, lender_sign];
if (floCrypto.verifySign(doc_array.join("|"), sign_part, borrower_pubKey))
return timestamp;
else return false;
}
btcMortgage.verify = {
borrower_sign: verify_borrowerSign,
coborrower_sign: verify_coborrowerSign,
lender_sign: verify_lenderSign,
closing_sign: verify_closingSign
}
const validateRequest = btcMortgage.validateRequest = {};
const RequestValidationError = (req_type, message) => { req_type, message };
/*Inbox / Board */
//list all loan requests
btcMortgage.listLoanRequests = function (callback = undefined) {
return new Promise((resolve, reject) => {
let options = {}
if (callback instanceof Function)
options.callback = callback;
floCloudAPI.requestApplicationData(TYPE_LOAN_REQUEST, options)
.then(result => resolve(result))
.catch(error => reject(error))
})
}
//view responses
btcMortgage.viewMyInbox = function () {
return new Promise((resolve, reject) => {
let options = { receiverID: floDapps.user.id }
if (callback instanceof Function)
options.callback = callback;
floCloudAPI.requestApplicationData(null, options) //view all inbox
.then(result => resolve(result))
.catch(error => reject(error))
})
}
/*Loan Opening*/
//1. B: requests collateral from coborrower
btcMortgage.requestLoanCollateral = function (loan_amount, policy_id, coborrower) {
return new Promise((resolve, reject) => {
const borrower = floDapps.user.id;
//Input validation
if (typeof loan_amount !== 'number' && loan_amount <= 0)
return reject("Invalid loan amount: " + loan_amount);
loan_amount = toFixedDecimal(loan_amount); //decimal allowed upto 8 decimal places
if (!(policy_id in POLICIES))
return reject("Invalid policy: " + policy_id);
if (!floCrypto.validateAddr(coborrower))
return reject("Invalid coborrower id")
//request collateral from coborrower
floCloudAPI.sendApplicationData({
borrower, coborrower,
loan_amount, policy_id
}, TYPE_LOAN_COLLATERAL_REQUEST, { receiverID: coborrower })
.then(result => resolve(result))
.catch(error => reject(error))
})
}
function validate_loanCollateral_request(loan_collateral_req_id, borrower, coborrower) {
return new Promise((resolve, reject) => {
floCloudAPI.requestApplicationData(TYPE_LOAN_COLLATERAL_REQUEST, { atVectorClock: loan_collateral_req_id }).then(loan_collateral_req => {
if (!loan_collateral_req.length)
return reject(RequestValidationError(TYPE_LOAN_REQUEST, "request not found"));
loan_collateral_req = loan_collateral_req[0];
if (!floCrypto.isSameAddr(loan_collateral_req.senderID, borrower))
return reject(RequestValidationError(TYPE_LOAN_COLLATERAL_REQUEST, "sender is not borrower"));
if (!floCrypto.isSameAddr(loan_collateral_req.receiverID, coborrower))
return reject(RequestValidationError(TYPE_LOAN_COLLATERAL_REQUEST, "receiver is not coborrower"));
let { loan_amount, policy_id } = loan_collateral_req.message;
if (typeof loan_amount !== 'number' && loan_amount <= 0 || VALUE_REGEX.test(loan_amount))
return reject(RequestValidationError(TYPE_LOAN_COLLATERAL_REQUEST, "Invalid loan amount"));
if (!(policy_id in POLICIES))
return reject(RequestValidationError(TYPE_LOAN_COLLATERAL_REQUEST, "Invalid policy"));
let result = { loan_amount, policy_id, borrower, coborrower };
result.borrower_pubKey = loan_collateral_req.pubKey;
resolve(result);
}).catch(error => reject(error))
})
}
//2. B: post loan request (with proof of collateral)
btcMortgage.requestLoan = function (loan_collateral_req_id, borrower) {
return new Promise((resolve, reject) => {
const coborrower = floDapps.user.id;
//validate request
validate_loanCollateral_request(loan_collateral_req_id, borrower, coborrower).then(({ loan_amount, policy_id }) => {
//calculate required collateral
getRate["BTC"].then(rate => {
let policy = POLICIES[policy_id];
let collateral_value = calcRequiredCollateral(loan_amount * rate, policy.security_percent)
//check if collateral is available
let coborrower_floID = floCrypto.toFloID(coborrower);
let coborrower_btcID = btcOperator.convert.legacy2bech(coborrower_floID);
btcOperator.getBalance(coborrower_btcID).then(coborrower_balance => {
if (coborrower_balance < collateral_value)
return reject("Insufficient collateral available");
//post request
floCloudAPI.sendApplicationData({
borrower, coborrower,
loan_amount, policy_id, loan_collateral_req_id,
collateral: {
btc_id: coborrower_btcID,
quantity: collateral_value
}
}, TYPE_LOAN_REQUEST)
.then(result => resolve(result))
.catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
function validate_loan_request(loan_req_id, borrower, coborrower) {
return new Promise((resolve, reject) => {
floCloudAPI.requestApplicationData(TYPE_LOAN_REQUEST, { atVectorClock: loan_req_id }).then(loan_req => {
if (!loan_req.length)
return reject(RequestValidationError(TYPE_LOAN_REQUEST, "request not found"));
loan_req = loan_req[0];
if (!floCrypto.isSameAddr(coborrower, loan_req.senderID))
return reject(RequestValidationError(TYPE_LOAN_REQUEST, "request not posted by coborrower"))
let { loan_collateral_req_id, loan_amount, policy_id, collateral } = loan_req.message;
if (!floCrypto.isSameAddr(collateral.btc_id, coborrower))
return reject(RequestValidationError(TYPE_LOAN_REQUEST, "collateral btc id is not coborrower"));
validate_loanCollateral_request(loan_collateral_req_id, borrower, coborrower).then(result => {
if (result.loan_amount !== loan_amount)
return reject(RequestValidationError(TYPE_LOAN_REQUEST, "loan amount mismatch"));
if (policy_id !== result.policy_id)
return reject(RequestValidationError(TYPE_LOAN_REQUEST, "policy id mismatch"));
getRate["BTC"].then(rate => {
let policy = POLICIES[policy_id];
let required_collateral = calcRequiredCollateral(loan_amount * rate, policy.security_percent)
if (required_collateral > collateral.quantity)
return reject(RequestValidationError(TYPE_LOAN_REQUEST, "Insufficient collateral value"));
//check if collateral is available
btcOperator.getBalance(collateral.btc_id).then(coborrower_balance => {
if (coborrower_balance < collateral.quantity)
return reject(RequestValidationError(TYPE_LOAN_REQUEST, "Insufficient collateral available"));
result.collateral = collateral;
result.coborrower_pubKey = loan_req.pubKey;
resolve(result)
}).catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
//3. L: respond to loan request
btcMortgage.respondLoan = function (loan_req_id, borrower, coborrower) {
return new Promise((resolve, reject) => {
const lender = floDapps.user.id;
validate_loan_request(loan_req_id, borrower, coborrower).then(({ loan_amount, borrower }) => {
//check if loan amount (token) is available to lend
let lender_floID = floCrypto.toFloID(lender);
floTokenAPI.getBalance(lender_floID).then(lender_tokenBalance => {
if (lender_tokenBalance < loan_amount)
return reject("Insufficient tokens to lend");
floCloudAPI.sendApplicationData({
lender, borrower, coborrower,
loan_req_id
}, TYPE_LENDER_RESPONSE, { receiverID: borrower })
.then(result => resolve(result))
.catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
function validate_lender_response(lender_res_id, borrower, coborrower, lender) {
return new Promise((resolve, reject) => {
floCloudAPI.requestApplicationData(TYPE_LENDER_RESPONSE, { atVectorClock: lender_res_id, receiverID: borrower }).then(lender_res => {
if (!lender_res.length)
return reject(RequestValidationError(TYPE_LENDER_RESPONSE, "response not found"));
lender_res = lender_res[0];
if (!floCrypto.isSameAddr(lender, lender_res.senderID))
return reject(RequestValidationError(TYPE_LENDER_RESPONSE, "response not sent by lender"))
let { loan_req_id } = lender_res.message;
validate_loan_request(loan_req_id, borrower, coborrower).then(result => {
let { loan_amount } = result;
//check if loan amount (token) is available to lend
let lender_floID = floCrypto.toFloID(lender);
floTokenAPI.getBalance(lender_floID).then(lender_tokenBalance => {
if (lender_tokenBalance < loan_amount)
return reject(RequestValidationError(TYPE_LENDER_RESPONSE, "lender doesnot have sufficient funds to lend"));
result.lender = lender;
result.lender_pubKey = lender_res.pubKey;
resolve(result);
}).catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
//4. B: requests C to lock the collateral
btcMortgage.requestCollateralLock = function (lender_res_id, coborrower, lender, privKey) {
return new Promise((resolve, reject) => {
const borrower = floDapps.user.id;
validate_lender_response(lender_res_id, borrower, coborrower, lender).then(({ loan_amount, policy_id }) => {
//send request to coborrower for locking the collateral asset
let borrower_sign = sign_borrower(privKey, loan_amount, policy_id, lender);
floCloudAPI.sendApplicationData({
lender, borrower, coborrower,
lender_res_id, borrower_sign
}, TYPE_COLLATERAL_LOCK_REQUEST, { receiverID: collateral.provider })
.then(result => resolve(result))
.catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
}
function validate_collateralLock_request(collateral_lock_req_id, borrower, coborrower, lender) {
return new Promise((resolve, reject) => {
floCloudAPI.requestApplicationData(TYPE_COLLATERAL_LOCK_REQUEST, { atVectorClock: collateral_lock_req_id, receiverID: coborrower }).then(collateral_lock_req => {
if (!collateral_lock_req.length)
return reject(RequestValidationError(TYPE_COLLATERAL_LOCK_REQUEST, "request not found"));
collateral_lock_req = collateral_lock_req[0];
if (!floCrypto.isSameAddr(borrower, collateral_lock_req.senderID))
return reject(RequestValidationError(TYPE_LENDER_RESPONSE, "request not sent by borrower"));
let { lender_res_id, borrower_sign } = collateral_lock_req.message;
validate_lender_response(lender_res_id, borrower, coborrower, lender).then(result => {
let { loan_amount, policy_id } = result;
//verify borrower_sign
let borrower_sign_time = verify_borrowerSign(borrower_sign, borrower, loan_amount, policy_id, lender)
if (!borrower_sign_time) //MAYDO: expire signatures?
return reject("Invalid borrower signature");
result.borrower_sign = borrower_sign;
resolve(result);
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
//5. C: locks required collateral in multisig (C, L, T)
btcMortgage.lockCollateral = function (collateral_lock_req_id, borrower, lender, privKey) {
return new Promise((resolve, reject) => {
const coborrower = floDapps.user.id;
validate_collateralLock_request(collateral_lock_req_id, borrower, coborrower, lender).then(({ borrower_sign, collateral, lender_pubKey }) => {
//lock collateral
lockCollateralInBlockchain(privKey, lender_pubKey, collateral.quantity).then(collateral_txid => {
//sign and request lender to finalize
let coborrower_sign = sign_coborrower(privKey, borrower_sign, collateral.quantity, collateral_txid)
floCloudAPI.sendApplicationData({
borrower, coborrower, lender,
collateral_lock_id: collateral_txid,
coborrower_sign, collateral_lock_req_id
}, TYPE_COLLATERAL_LOCK_ACK, { receiverID: lender })
.then(result => resolve(result))
.catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
function lockCollateralInBlockchain(privKey, lenderPubKey, collateral_value) {
return new Promise((resolve, reject) => {
const locker_id = findLocker(floDapps.user.public, lenderPubKey).address;
btcOperator.sendTx(floDapps.user.id, privKey, locker_id, collateral_value)
.then(txid => resolve(txid))
.catch(error => reject(error))
})
}
function validate_collateralLock_ack(collateral_lock_ack_id, borrower, coborrower, lender) {
return new Promise((resolve, reject) => {
floCloudAPI.requestApplicationData(TYPE_COLLATERAL_LOCK_ACK, { atVectorClock: collateral_lock_ack_id, receiverID: lender }).then(collateral_lock_ack => {
if (!collateral_lock_ack.length)
return reject(RequestValidationError(TYPE_COLLATERAL_LOCK_REQUEST, "request not found"));
collateral_lock_ack = collateral_lock_ack[0];
if (!floCrypto.isSameAddr(borrower, collateral_lock_ack.senderID))
return reject(RequestValidationError(TYPE_LENDER_RESPONSE, "request not sent by borrower"));
let { collateral_lock_req_id, coborrower_sign, collateral_lock_id } = collateral_lock_ack.message;
validate_collateralLock_request(collateral_lock_req_id, borrower, coborrower, lender).then(result => {
let { borrower_sign, collateral } = result;
let coborrower_sign_time = verify_coborrowerSign(coborrower_sign, coborrower, borrower_sign, collateral.quantity, collateral_lock_id)
if (!coborrower_sign_time) //MAYDO: expire signatures?
return reject(RequestValidationError(TYPE_COLLATERAL_LOCK_ACK, "Invalid coborrower signature"));
btcOperator.getTx(collateral_lock_id).then(collateral_tx => {
if (!collateral_tx.confirmations)
return reject(RequestValidationError(TYPE_COLLATERAL_LOCK_ACK, "Collateral lock transaction not confirmed yet"));
let locker_id = findLocker(finalize_request.pubKey, lender_response.pubKey).address;
let locked_amt = collateral_tx.outputs.filter(o => o.address == locker_id).reduce((a, o) => a += o.value, 0);
if (locked_amt < collateral.quantity)
return reject(RequestValidationError(TYPE_COLLATERAL_LOCK_ACK, "Insufficient Collateral locked"));
//TODO: make sure same collateral is not reused?
result.coborrower_sign = coborrower_sign;
result.collateral_lock_id = collateral_lock_id;
resolve(result);
}).catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
//6. L: sends loan amount (USD tokens) to B and writes loan details in flo blockchain
btcMortgage.sendLoanAmount = function (collateral_lock_ack_id, borrower, coborrower, privKey) {
return new Promise((resolve, reject) => {
const lender = floDapps.user.id;
validate_collateralLock_ack(collateral_lock_ack_id, borrower, coborrower, lender).then(result => {
let { loan_amount, policy_id, collateral, borrower_sign, coborrower_sign } = result;
//transfer tokens for loan amount
floTokenAPI.sendToken(privKey, loan_amount, borrower, "as loan", CURRENCY).then(token_txid => {
//construct the blockchain data
let lender_sign = sign_lender(privKey, coborrower_sign, token_txid);
let blockchainData = stringifyLoanOpenData(
borrower, loan_amount, policy_id,
coborrower, collateral.quantity, collateral_lock_id,
lender, token_txid,
borrower_sign, coborrower_sign, lender_sign
);
let receivers = [borrower, coborrower].map(addr => floCrypto.toFloID(addr));
//write loan details in blockchain
floBlockchainAPI.writeDataMultiple([privKey], blockchainData, receivers)
.then(result => resolve(result))
.catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
/*Loan Closing*/
//1. B: sends amount (PA + interest) to L (via USD tokens)
btcMortgage.repayLoan = function (loan_id, privKey) {
return new Promise((resolve, reject) => {
getLoanDetails(loan_id).then(loan_details => {
//calculate repayment amount
let policy = POLICIES[loan_details.policy_id],
current_time = Date.now(),
duration = yearDiff(current_time, loan_details.open_time);
let interest_amount = loan_details.loan_amount * policy.interest * duration;
let repay_amount = loan_details.loan_amount + interest_amount;
//repay and close the loan
let closing_sign = sign_closing(privKey, loan_id, loan_details.lender_sign);
var closing_data = stringifyLoanCloseData(loan_id, loan_details.borrower, closing_sign);
floTokenAPI.sendToken(privKey, repay_amount, loan_details.lender, closing_data, CURRENCY).then(closing_txid => {
//send message to coborrower as reminder to unlock collateral
floCloudAPI.sendApplicationData({ loan_id, closing_txid }, TYPE_LOAN_CLOSED_ACK, { receiverID: loan_details.coborrower })
.then(result => resolve(result))
.catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
//2. C: requests L or T to free collateral
btcMortgage.requestUnlockCollateral = function (loan_id, closing_txid, privKey) {
return new Promise((resolve, reject) => {
let coborrower_pubKey = floDapps.user.public;
validateLoanClosing(loan_id, closing_txid).then(loan_details => {
//find locker
let lender_pubKey = extractPubKeyFromSign(loan_details.lender_sign);
let locker = findLocker(coborrower_pubKey, lender_pubKey)
//create the tx hex and sign it
createUnlockCollateralTxHex(locker, loan_details.collateral_lock_id, privKey).then(unlock_tx_hex => {
floCloudAPI.sendApplicationData({
loan_id, closing_txid, unlock_tx_hex
}, TYPE_UNLOCK_COLLATERAL_REQUEST, { receiverID: loan_details.lender })
.then(result => resolve(result))
.catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
function createUnlockCollateralTxHex(locker, collateral_lock_id, privKey) {
return new Promise((resolve, reject) => {
btcOperator.getUTXOs(locker.address).then(utxos => {
let collateral_utxos = utxos.filter(u => u.txid == collateral_lock_id);
if (!collateral_utxos.length)
return reject("Collateral already unlocked");
btcOperator.getTx(collateral_lock_id).then(collateral_tx => {
if (collateral_tx.confirmations == 0)
return reject("Collateral not confirmed in blockchain"); //This should not happen, as loan will not be issued until collateral is locked with confirmations
let collateral_owner = collateral_tx.inputs[0].address; //this will be coborrower's BTC id
//create the tx
const tx = coinjs.transaction();
//estimate the fee
let estimate_tx_size = BASE_TX_SIZE;
estimate_tx_size += collateral_utxos.length * btcOperator.util.sizePerInput(locker.address, locker.redeemScript)
estimate_tx_size += btcOperator.util.sizePerOutput(collateral_owner);
btcOperator.util.get_fee_rate().then(fee_rate => {
let fee_estimate = fee_rate * estimate_tx_size;
//add inputs
let total_input_value = 0;
collateral_utxos.forEach(u => {
//locker is btc bech32 multisig
let s = coinjs.script();
s.writeBytes(Crypto.util.hexToBytes(rs));
s.writeOp(0);
s.writeBytes(coinjs.numToBytes(u.value.toFixed(0), 8));
script = Crypto.util.bytesToHex(s.buffer);
tx.addinput(u.txid, u.vout, script, 0xfffffffd /*sequence*/); //0xfffffffd for Replace-by-fee
total_input_value += u.value;
});
total_input_value = btcOperator.util.Sat_to_BTC; //convert from satoshi to BTC
//add output
let receiver_amount = total_input_value - fee_estimate;
console.debug("FEE calc", total_input_value, fee_estimate, receiver_amount);
tx.addoutput(collateral_owner, receiver_amount);
tx.sign(privKey, 1 /*sighashtype*/);
resolve(tx.serialize())
}).catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
//3. L: unlock collateral
btcMortgage.unlockCollateral = function (loan_id, closing_txid, unlock_tx_hex, privKey) {
let lender_pubKey = floDapps.user.public;
validateLoanClosing(loan_id, closing_txid).then(loan_details => {
//find locker
let coborrower_pubKey = extractPubKeyFromSign(loan_details.coborrower_sign);
let locker = findLocker(coborrower_pubKey, lender_pubKey)
//verify and sign the tx
signUnlockCollateralTxHex(locker, loan_details.collateral_lock_id, unlock_tx_hex, privKey).then(signed_tx_hex => {
btcOperator.broadcastTx(signed_tx_hex).then(txid => {
floCloudAPI.sendApplicationData({
loan_id, closing_txid, unlock_collateral_id: txid
}, TYPE_UNLOCK_COLLATERAL_ACK, { receiverID: loan_details.coborrower })
.then(result => resolve(result))
.catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
}).catch(error => reject(error))
}
function signUnlockCollateralTxHex(locker, collateral_lock_id, unlock_tx_hex, privKey) {
return new Promise((resolve, reject) => {
btcOperator.getUTXOs(locker.address).then(utxos => {
let collateral_utxos = utxos.filter(u => u.txid == collateral_lock_id);
if (!collateral_utxos.length)
return reject("Collateral already unlocked");
btcOperator.getTx(collateral_lock_id).then(collateral_tx => {
if (collateral_tx.confirmations == 0)
return reject("Collateral not confirmed in blockchain"); //This should not happen, as loan will not be issued until collateral is locked with confirmations
//create the tx
let tx = coinjs.transaction().deserialize(unlock_tx_hex);
//check inputs
if (tx.ins.some(i => i.outpoint.hash !== collateral_lock_id))//vin other than this collateral is present in tx, ABORT
return reject("Transaction Hex contains other/non collateral inputs");
//sign the tx hex
tx.sign(privKey, 1 /*sighashtype*/);
resolve(tx.serialize())
}).catch(error => reject(error))
}).catch(error => reject(error))
})
}
})(window.btcMortgage = {})