fix: simple transaction do not have any 4 inputs limitation (#158)

src/CONSTANTS.js

@@ -27,8 +27,8 @@ const CONSTANTS = {
   UTXO_SELECTION_MAX_FEE_VS_SINGLE_UTXO_FEE_FACTOR: 5,
   MAX_STANDARD_TX_SIZE: 100000,
   MAX_P2SH_SIGOPS: 15,
-  MAX_INPUTS_FOR_AUTO_IX: 4,
-  UTXO_MAX_INPUTS_PER_TX: 25,
+  // limit to how many times an unconfirmed input in a new tx can be respent
+  UTXO_CHAINED_SPENDING_LIMIT_FOR_TX: 25,
   FEES: {
     DUST_RELAY_TX_FEE: 1000,
     ZERO: 0,

src/types/Account/Account.js

@@ -5,7 +5,7 @@ const { WALLET_TYPES } = require('../../CONSTANTS');
 const { is } = require('../../utils');
 const EVENTS = require('../../EVENTS');
 const Wallet = require('../Wallet/Wallet.js');
-const { simpleTransactionOptimizedAccumulator } = require('../../utils/coinSelections/strategies');
+const { simpleDescendingAccumulator } = require('../../utils/coinSelections/strategies');
 
 function getNextUnusedAccountIndexForWallet(wallet) {
   if (wallet && wallet.accounts) {
@@ -35,7 +35,7 @@ const defaultOptions = {
   plugins: [],
   injectDefaultPlugins: true,
   debug: false,
-  strategy: simpleTransactionOptimizedAccumulator,
+  strategy: simpleDescendingAccumulator,
 };
 
 /* eslint-disable no-underscore-dangle */

src/utils/coinSelection.spec.js

@@ -3,6 +3,7 @@ const {Transaction, Address, Script} = require('@dashevo/dashcore-lib');
 const coinSelection = require('./coinSelection');
 const {utxosList} = require('../../fixtures/crackspice');
 const STRATEGIES = require('./coinSelections/strategies');
+const TransactionEstimator = require('./coinSelections/TransactionEstimator')
 
 const utxosListAsUnspentOutput = utxosList.map((utxo)=> Transaction.UnspentOutput(utxo));
 const outputs = {
@@ -56,7 +57,6 @@ describe('Utils - coinSelection', function suite() {
   it('should require a outputsList with at least one output', () => {
     expect(() => coinSelection(utxosList, [])).to.throw('outputsList must contains at least 1 output');
   });
-
   it('should require a outputsList with valid outputs', () => {
     expect(() => coinSelection(utxosListAsUnspentOutput, [{toto: true}])).to.throw('data parameter supplied is not a string.');
   });
@@ -317,6 +317,51 @@ describe('Utils - coinSelection', function suite() {
 
     expect(result).to.deep.equal(expectedResult);
   });
+  it('should handle externally crafted strategy', function () {
+    // A dummy strategy that takes a random selection of utxo
+    const externalStrategy = (utxosList, outputsList, deductFee = false, feeCategory = 'normal') => {
+      const copiedUtxos = [...utxosList];
+      const txEstimator = new TransactionEstimator(feeCategory);
+
+      txEstimator.addOutputs(outputsList);
+
+      let inputValue = 0;
+      let outputValue = txEstimator.getOutValue();
+      const randomlySelectedUtxos = [];
+
+      while(inputValue<outputValue){
+        if(copiedUtxos.length === 0){
+          throw new Error('Not enought UTXOs');
+        }
+        // Take a random item and add it to selection
+        const utxo = copiedUtxos.splice(Math.floor(Math.random() * copiedUtxos.length),1)[0];
+        inputValue+=utxo.satoshis;
+        randomlySelectedUtxos.push(utxo);
+      }
+
+      txEstimator.addInputs(randomlySelectedUtxos);
+
+      return {
+        utxos: txEstimator.getInputs(),
+        outputs: txEstimator.getOutputs(),
+        feeCategory,
+        estimatedFee: txEstimator.getFeeEstimate(),
+        utxosValue: txEstimator.getInValue(),
+      };
+    }
+    const result = coinSelection(
+        utxosListAsUnspentOutput,
+        [outputs.FOURTY_FIVE_DASH],
+        false,
+        'normal',
+        externalStrategy);
+
+    expect(result).to.exist;
+    expect(result.feeCategory).to.equal('normal');
+    expect(result.utxosValue).to.gte(4500000000);
+    expect(result.outputs).to.deep.equal([outputs.FOURTY_FIVE_DASH]);
+    expect(result.utxos.length).to.gte(0);
+  });
   // Note : Removed, kept in case of fallback needed
   // it('should return an error in not any utxo has been found', () => {
   //   const utxo = utxosList[15];

src/utils/coinSelections/index.js

@@ -4,7 +4,7 @@ const InvalidUTXO = require('../../errors/InvalidUTXO');
 const InvalidOutput = require('../../errors/InvalidOutput');
 const CoinSelectionUnsufficientUTXOS = require('../../errors/CoinSelectionUnsufficientUTXOS');
 
-module.exports = function coinSelection(utxosList, outputsList, deductFee = false, feeCategory = 'normal', strategy = STRATEGIES.simpleTransactionOptimizedAccumulator) {
+module.exports = function coinSelection(utxosList, outputsList, deductFee = false, feeCategory = 'normal', strategy = STRATEGIES.simpleDescendingAccumulator) {
   if (!utxosList) { throw new Error('A utxosList is required'); }
   if (utxosList.constructor.name !== Array.name) { throw new Error('UtxosList is expected to be an array of utxos'); }
   if (utxosList.length < 1) { throw new Error('utxosList must contain at least 1 utxo'); }

src/utils/coinSelections/strategies/index.js

@@ -1,10 +1,8 @@
 const simpleAscendingAccumulator = require('./simpleAscendingAccumulator');
 const simpleDescendingAccumulator = require('./simpleDescendingAccumulator');
-const simpleTransactionOptimizedAccumulator = require('./simpleTransactionOptimizedAccumulator');
 
 const STRATEGIES = {
   simpleDescendingAccumulator,
   simpleAscendingAccumulator,
-  simpleTransactionOptimizedAccumulator,
 };
 module.exports = STRATEGIES;