add fiat<->sat conversion methods and hook up UI

electrum/gui/qml/components/Send.qml

@@ -8,10 +8,10 @@ Pane {
 
     GridLayout {
         width: parent.width
-        columns: 4
+        columns: 6
 
         BalanceSummary {
-            Layout.columnSpan: 4
+            Layout.columnSpan: 6
             Layout.alignment: Qt.AlignHCenter
         }
 
@@ -21,7 +21,7 @@ Pane {
 
         TextField {
             id: address
-            Layout.columnSpan: 2
+            Layout.columnSpan: 4
             Layout.fillWidth: true
             font.family: FixedFont
             placeholderText: qsTr('Paste address or invoice')
@@ -46,11 +46,26 @@ Pane {
         }
 
         Label {
-            text: Config.baseUnit
+            text: Config.baseUnit + '  ' // add spaces for easy right margin
             color: Material.accentColor
-            Layout.fillWidth: true
         }
 
+        TextField {
+            id: amountFiat
+            visible: Config.fiatCurrency != ''
+            font.family: FixedFont
+            placeholderText: qsTr('Amount')
+            inputMethodHints: Qt.ImhPreferNumbers
+        }
+
+        Label {
+            visible: Config.fiatCurrency != ''
+            text: Config.fiatCurrency
+            color: Material.accentColor
+        }
+
+        Item { visible: Config.fiatCurrency == ''; height: 1; Layout.columnSpan: 2; Layout.fillWidth: true }
+
         Item { width: 1; height: 1 } // workaround colspan on baseunit messing up row above
 
         Label {
@@ -61,11 +76,11 @@ Pane {
             id: fee
             font.family: FixedFont
             placeholderText: qsTr('sat/vB')
-            Layout.columnSpan: 3
+            Layout.columnSpan: 5
         }
 
         RowLayout {
-            Layout.columnSpan: 4
+            Layout.columnSpan: 6
             Layout.alignment: Qt.AlignHCenter
             spacing: 10
 
@@ -94,6 +109,31 @@ Pane {
         }
     }
 
+    Connections {
+        target: amount
+        function onTextChanged() {
+            if (amountFiat.activeFocus)
+                return
+            var a = Config.unitsToSats(amount.text)
+            amountFiat.text = Daemon.fiatValue(a)
+        }
+    }
+    Connections {
+        target: amountFiat
+        function onTextChanged() {
+            if (amountFiat.activeFocus) {
+                amount.text = Daemon.satoshiValue(amountFiat.text)
+            }
+        }
+    }
+    Connections {
+        target: Network
+        function onFiatUpdated() {
+            var a = Config.unitsToSats(amount.text)
+            amountFiat.text = Daemon.fiatValue(a)
+        }
+    }
+
     // make clicking the dialog background move the scope away from textedit fields
     // so the keyboard goes away
     MouseArea {