fix: block ZEC and XMR from being installed simultaneously

fix: improve error message and organize some code

lib/blockchain/install.js

@@ -138,19 +138,34 @@ function getBlockchainSyncStatus (cryptoList) {
     })
 }
 
+function isInstalled (crypto) {
+  if (crypto.cryptoCode === 'XMR') return true
+  return isInstalledSoftware(crypto) && isInstalledVolume(crypto)
+}
+
+function isDisabled (crypto) {
+  switch (crypto.cryptoCode) {
+    case 'ETH':
+      return 'Use admin\'s Infura plugin'
+    case 'ZEC':
+      return isInstalled(crypto) && 'Installed' || isInstalled(_.find(it => it.code === 'monero', cryptos)) && 'Insufficient resources. Contact support.'
+    case 'XMR':
+      return isInstalled(crypto) && 'Installed' || isInstalled(_.find(it => it.code === 'zcash', cryptos)) && 'Insufficient resources. Contact support.'
+    default:
+      return isInstalled(crypto) && 'Installed'
+  }
+}
+
 function run () {  
   const choices = _.flow([
     _.filter(c => c.type !== 'erc-20'),
     _.map(c => {
-      const checked = isInstalledSoftware(c) && isInstalledVolume(c)
       const name = c.code === 'ethereum' ? 'Ethereum and/or USDT' : c.display
       return {
         name,
         value: c.code,
-        checked,
+        checked: isInstalled(c),
-        disabled: c.cryptoCode === 'ETH'
+        disabled: isDisabled(c)
-          ? 'Use admin\'s Infura plugin'
-          : checked && 'Installed'
       }
     }),
   ])(cryptos)
@@ -159,6 +174,15 @@ function run () {
 
   const validateAnswers = async (answers) => {
     if (_.size(answers) > 2) return { message: `Please insert a maximum of two coins to install.`, isValid: false }
+
+    if (
+      _.isEmpty(_.difference(['monero', 'zcash'], answers)) ||
+      (_.includes('monero', answers) && isInstalled(_.find(it => it.code === 'zcash', cryptos))) ||
+      (_.includes('zcash', answers) && isInstalled(_.find(it => it.code === 'monero', cryptos)))
+    ) {
+      return { message: `Zcash and Monero installations are temporarily mutually exclusive, given the space needed for their blockchains. Contact support for more information.`, isValid: false }
+    }
+
     return getBlockchainSyncStatus(cryptos)
       .then(blockchainStatuses => {
         const result = _.reduce((acc, value) => ({ ...acc, [value]: _.isNil(acc[value]) ? 1 : acc[value] + 1 }), {}, _.values(blockchainStatuses))