qml, control: new IPAddressValueInput

Adding a new improved ValueInput control to handle both IP address and port values
combined in the same field with the correct visual formatting (255.255.255.255:65535).

In this iteration, validation for this control is implemented using both a function
within the control itself focused solely on ensuring correct formatting and a simple regex
validator for the valid input characters.
Future versions will see integration with network model classes, enabling parsing of IP
addresses and ports and additional checks, such as those outlined in doc/p2p-bad-ports.md.

src/qml/bitcoin_qml.qrc

@@ -26,6 +26,7 @@
         <file>controls/Header.qml</file>
         <file>controls/Icon.qml</file>
         <file>controls/InformationPage.qml</file>
+        <file>controls/IPAddressValueInput.qml</file>
         <file>controls/NavButton.qml</file>
         <file>controls/PageIndicator.qml</file>
         <file>controls/NavigationBar.qml</file>

src/qml/components/ProxySettings.qml

@@ -44,14 +44,16 @@ ColumnLayout {
         header: qsTr("IP and Port")
         errorText: qsTr("Invalid IP address or port format. Please use the format '255.255.255.255:65535'.")
         state: !defaultProxyEnable.loadedItem.checked ? "DISABLED" : "FILLED"
-        actionItem: ValueInput {
+        showErrorText: !defaultProxy.loadedItem.validInput && state==="FILLED"
+        actionItem: IPAddressValueInput {
             parentState: defaultProxy.state
             description: "127.0.0.1:9050"
-            onEditingFinished: {
-                defaultProxy.forceActiveFocus()
-            }
+            activeFocusOnTab: true
+        }
+        onClicked: {
+            loadedItem.filled = true
+            loadedItem.forceActiveFocus()
         }
-        onClicked: loadedItem.forceActiveFocus()
     }
     Separator { Layout.fillWidth: true }
     Header {
@@ -90,14 +92,16 @@ ColumnLayout {
         header: qsTr("IP and Port")
         errorText: qsTr("Invalid IP address or port format. Please use the format '255.255.255.255:65535'.")
         state: !torProxyEnable.loadedItem.checked ? "DISABLED" : "FILLED"
-        actionItem: ValueInput {
+        showErrorText: !torProxy.loadedItem.validInput && state==="FILLED"
+        actionItem: IPAddressValueInput {
             parentState: torProxy.state
             description: "127.0.0.1:9050"
-            onEditingFinished: {
-                torProxy.forceActiveFocus()
-            }
+            activeFocusOnTab: true
+        }
+        onClicked: {
+            loadedItem.filled = true
+            loadedItem.forceActiveFocus()
         }
-        onClicked: loadedItem.forceActiveFocus()
     }
     Separator { Layout.fillWidth: true }
 }

src/qml/controls/IPAddressValueInput.qml

@@ -0,0 +1,82 @@
+// Copyright (c) 2024 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+import QtQuick 2.15
+import QtQuick.Controls 2.15
+
+TextInput {
+    id: root
+    required property string parentState
+    property string description: ""
+    property bool filled: false
+    property int descriptionSize: 18
+    property color textColor: root.filled ? Theme.color.neutral9 : Theme.color.neutral5
+    // Expose a property to indicate validity, initial value will be true (no error message displayed)
+    property bool validInput: true
+    enabled: true
+    state: root.parentState
+    validator: RegExpValidator { regExp: /[0-9.:]*/ } // Allow only digits, dots, and colons
+
+    maximumLength: 21
+
+    states: [
+        State {
+            name: "ACTIVE"
+            PropertyChanges { target: root; textColor: Theme.color.orange }
+        },
+        State {
+            name: "HOVER"
+            PropertyChanges {
+                target: root
+                textColor: root.filled ? Theme.color.orangeLight1 : Theme.color.neutral5
+            }
+        },
+        State {
+            name: "DISABLED"
+            PropertyChanges {
+                target: root
+                enabled: false
+                textColor: Theme.color.neutral4
+            }
+        }
+    ]
+
+    font.family: "Inter"
+    font.styleName: "Regular"
+    font.pixelSize: root.descriptionSize
+    color: root.textColor
+    text: root.description
+    horizontalAlignment: Text.AlignRight
+    wrapMode: Text.WordWrap
+
+    Behavior on color {
+        ColorAnimation { duration: 150 }
+    }
+
+    function isValidIPPort(input)
+    {
+        var parts = input.split(":");
+        if (parts.length !== 2) return false;
+        if (parts[1].length === 0) return false; // port part is empty
+        var ipAddress = parts[0];
+        var ipAddressParts = ipAddress.split(".");
+        if (ipAddressParts.length !== 4) return false;
+        for (var i = 0; (i < ipAddressParts.length); i++) {
+            if (ipAddressParts[i].length === 0) return false; // ip group number part is empty
+            if (parseInt(ipAddressParts[i]) > 255) return false;
+        }
+        var port = parseInt(parts[1]);
+        if (port < 1 || port > 65535) return false;
+        return true;
+    }
+
+    // Connections element to ensure validation on editing finished
+    Connections {
+        target: root
+        function onEditingFinished() {
+            // Validate the input whenever editing is finished
+            validInput = isValidIPPort(root.text);
+        }
+    }
+}