FIX: properly locked payments

class/Paym.js

@@ -2,14 +2,15 @@ var crypto = require('crypto');
 var lightningPayReq = require('bolt11');
 import { BigNumber } from 'bignumber.js';
 
-export class Paym {
+export class Payment {
   constructor(redis, bitcoindrpc, lightning) {
     this._redis = redis;
     this._bitcoindrpc = bitcoindrpc;
     this._lightning = lightning;
+    this._decoded = false;
   }
 
-  async decodePayReq(invoice) {
+  async decodePayReqViaRpc(invoice) {
     return new Promise(function(resolve, reject) {
       this._lightning.decodePayReq({ pay_req: invoice }, function(err, info) {
         if (err) return reject(err);
@@ -17,4 +18,8 @@ export class Paym {
       });
     });
   }
+
+  decodePayReq(payReq) {
+    this._decoded = lightningPayReq.decode(payReq);
+  }
 }

class/User.js

@@ -153,6 +153,13 @@ export class User {
         calculatedBalance -= +tx.value;
       }
     }
+
+    let lockedPayments = await this.getLockedPayments();
+    for (let paym of lockedPayments) {
+      // TODO: check if payment in determined state and actually evict it from this list
+      calculatedBalance -= +paym.amount;
+    }
+
     return calculatedBalance;
   }
 
@@ -386,6 +393,59 @@ export class User {
     }
   }
 
+  /**
+   * Adds invoice to a list of user's locked payments.
+   * Used to calculate balance till the lock is lifted (payment is in
+   * determined state - succeded or failed).
+   *
+   * @param {String} pay_req
+   * @param {Object} decodedInvoice
+   * @returns {Promise<void>}
+   */
+  async lockFunds(pay_req, decodedInvoice) {
+    let doc = {
+      pay_req,
+      amount: +decodedInvoice.num_satoshis,
+      timestamp: Math.floor(+new Date() / 1000),
+    };
+
+    return this._redis.rpush('locked_payments_for_' + this._userid, JSON.stringify(doc));
+  }
+
+  /**
+   * Strips specific payreq from the list of locked payments
+   * @param pay_req
+   * @returns {Promise<void>}
+   */
+  async unlockFunds(pay_req) {
+    let payments = await this.getLockedPayments();
+    let saveBack = [];
+    for (let paym of payments) {
+      if (paym.pay_req !== pay_req) {
+        saveBack.push(paym);
+      }
+    }
+
+    await this._redis.del('locked_payments_for_' + this._userid);
+    for (let doc of saveBack) {
+      await this._redis.rpush('locked_payments_for_' + this._userid, JSON.stringify(doc));
+    }
+  }
+
+  async getLockedPayments() {
+    let payments = await this._redis.lrange('locked_payments_for_' + this._userid, 0, -1);
+    let result = [];
+    for (let paym of payments) {
+      let json;
+      try {
+        json = JSON.parse(paym);
+        result.push(json);
+      } catch (_) {}
+    }
+
+    return result;
+  }
+
   _hash(string) {
     return crypto
       .createHash('sha256')

controllers/api.js

@@ -185,6 +185,7 @@ router.post('/payinvoice', async function(req, res) {
       var call = lightning.sendPayment();
       call.on('data', async function(payment) {
         // payment callback
+        await u.unlockFunds(req.body.invoice);
         if (payment && payment.payment_route && payment.payment_route.total_amt_msat) {
           userBalance -= +payment.payment_route.total_fees + +payment.payment_route.total_amt;
           u.saveBalance(userBalance);
@@ -206,6 +207,7 @@ router.post('/payinvoice', async function(req, res) {
       }
       let inv = { payment_request: req.body.invoice, amt: info.num_satoshis }; // amt is used only for 'tip' invoices
       try {
+        await u.lockFunds(req.body.invoice, info);
         call.write(inv);
       } catch (Err) {
         await lock.releaseLock();

doc/schema.md

@@ -20,6 +20,8 @@ User storage schema
 * bitcoin_address_for_{userid} = {address}
 * balance_for_{userid} = {int}
 * txs_for_{userid} = [] `serialized paid lnd invoices in a list`
+* locked_invoices_for_{userod} = [] `serialized attempts to pay invoice. used in calculating user's balance`
+    : {pay_req:..., amount:666, timestamp:666}
 * imported_txids_for_{userid} = [] `list of txids processed for this user`
 * metadata_for_{userid}= {serialized json}
 * userinvoices_for_{userid} = []