add fiat balance to wallet (#2157)

also fixed payments table fiat denomination for consistency

lnbits/static/js/wallet.js

@@ -241,6 +241,7 @@ new Vue({
         location: window.location
       },
       balance: 0,
+      fiatBalance: 0,
       credit: 0,
       update: {
         name: null,
@@ -256,6 +257,14 @@ new Vue({
         return LNbits.utils.formatSat(this.balance || this.g.wallet.sat)
       }
     },
+    formattedFiatBalance() {
+      if (this.fiatBalance) {
+        return LNbits.utils.formatCurrency(
+          this.fiatBalance.toFixed(2),
+          this.g.wallet.currency
+        )
+      }
+    },
     filteredPayments: function () {
       var q = this.paymentsTable.filter
       if (!q || q === '') return this.payments
@@ -797,6 +806,24 @@ new Vue({
           this.balance
         ])
       })
+      if (this.g.wallet.currency) {
+        this.updateFiatBalance()
+      }
+    },
+    updateFiatBalance() {
+      if (!this.g.wallet.currency) return 0
+      LNbits.api
+        .request('POST', `/api/v1/conversion`, null, {
+          amount: this.balance || this.g.wallet.sat,
+          to: this.g.wallet.currency
+        })
+        .then(response => {
+          this.fiatBalance = response.data[this.g.wallet.currency]
+        })
+        .catch(e => console.error(e))
+    },
+    formatFiat(currency, amount) {
+      return LNbits.utils.formatCurrency(amount, currency)
     },
     exportCSV: function () {
       // status is important for export but it is not in paymentsTable