wip: Add initial support for loading signet UTXO snapshots

Adds wiring to connect QML GUI to loading a signet UTXO snapshot via
the connection settings. Modifies src/interfaces/node.h and src/node/interfaces.cpp
to implement snapshot loading functionality.

Current limitations:
- Not integrated with onboarding process
- Requires manual navigation to connection settings after initial startup

Testing:
1. Start the node
2. Complete onboarding
3. Navigate to connection settings
4. Load snapshot from provided interface

Note: This is a work in progress. Do not merge until fully implemented and tested.

src/interfaces/node.h

@@ -199,6 +199,9 @@ class Node
     //! List rpc commands.
     virtual std::vector<std::string> listRpcCommands() = 0;
 
+    //! Load UTXO Snapshot.
+    virtual bool snapshotLoad(const std::string& path_string) = 0;
+
     //! Set RPC timer interface if unset.
     virtual void rpcSetTimerInterfaceIfUnset(RPCTimerInterface* iface) = 0;
 

src/kernel/chainparams.cpp

@@ -371,6 +371,13 @@ class SigNetParams : public CChainParams {
 
         vFixedSeeds.clear();
 
+        m_assumeutxo_data = MapAssumeutxo{
+            {
+                160000,
+                {AssumeutxoHash{uint256S("0x5225141cb62dee63ab3be95f9b03d60801f264010b1816d4bd00618b2736e7be")}, 1278002},
+            },
+        };
+
         base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,111);
         base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,196);
         base58Prefixes[SECRET_KEY] =     std::vector<unsigned char>(1,239);

src/node/interfaces.cpp

@@ -29,6 +29,7 @@
 #include <node/context.h>
 #include <node/interface_ui.h>
 #include <node/transaction.h>
+#include <node/utxo_snapshot.h>
 #include <policy/feerate.h>
 #include <policy/fees.h>
 #include <policy/policy.h>
@@ -395,6 +396,73 @@ class NodeImpl : public Node
     {
         m_context = context;
     }
+    bool snapshotLoad(const std::string& path_string) override
+    {
+        fs::path path(fs::u8path(path_string));
+        if (!fs::exists(path)) {
+            LogPrintf("[loadsnapshot] snapshot file %s does not exist\n", path.u8string());
+            return false;
+        }
+
+        FILE* file{fsbridge::fopen(path, "rb")};
+
+        AutoFile afile{file};
+        if (afile.IsNull()) {
+            LogPrintf("[loadsnapshot] failed to open snapshot file %s\n", path_string);
+            return false;
+        }
+
+        // Read the snapshot metadata.
+        SnapshotMetadata metadata;
+        afile >> metadata;
+
+        // Get the base blockhash and look up the corresponding CBlockIndex object.
+        uint256 base_blockhash = metadata.m_base_blockhash;
+        int max_secs_to_wait_for_headers = 60 * 10;
+        CBlockIndex* snapshot_start_block = nullptr;
+
+        LogPrintf("[loadsnapshot] waiting to see blockheader %s in headers chain before snapshot activation\n",
+            base_blockhash.ToString());
+
+        if (m_context->chainman == nullptr) {
+            LogPrintf("[loadsnapshot] m_context->chainman is null\n");
+            return false;
+        }
+
+        ChainstateManager& chainman = *m_context->chainman;
+
+        while (max_secs_to_wait_for_headers > 0) {
+            LogPrintf("[loadsnapshot] base_blockhash = %s\n", base_blockhash.ToString());
+            snapshot_start_block = WITH_LOCK(::cs_main,
+                return chainman.m_blockman.LookupBlockIndex(base_blockhash));
+            max_secs_to_wait_for_headers -= 1;
+
+            if (!snapshot_start_block) {
+                std::this_thread::sleep_for(std::chrono::seconds(1));
+            } else {
+                break;
+            }
+        }
+
+        if (!snapshot_start_block) {
+            LogPrintf("[loadsnapshot] timed out waiting for snapshot start blockheader %s\n",
+                base_blockhash.ToString());
+            return false;
+        }
+
+        // Activate the snapshot.
+        if (!chainman.ActivateSnapshot(afile, metadata, false)) {
+            LogPrintf("[loadsnapshot] Unable to load UTXO snapshot %s\n", path.u8string());
+            return false;
+        }
+
+        // Get the new tip and print a log message.
+        CBlockIndex* new_tip{WITH_LOCK(::cs_main, return chainman.ActiveTip())};
+        LogPrintf("[loadsnashot] Loaded %d coins from snapshot %s at height %d\n",
+                    metadata.m_coins_count, new_tip->GetBlockHash().ToString(), new_tip->nHeight);
+
+        return true;
+    }
     ArgsManager& args() { return *Assert(Assert(m_context)->args); }
     ChainstateManager& chainman() { return *Assert(m_context->chainman); }
     NodeContext* m_context{nullptr};

src/qml/components/ConnectionSettings.qml

@@ -8,36 +8,53 @@ import QtQuick.Layouts 1.15
 import "../controls"
 
 ColumnLayout {
+    // TODO: Remove this once storing the snapshot path is implemented
+    property bool isOnboarding: false
     property bool snapshotImported: false
     function setSnapshotImported(imported) {
         snapshotImported = imported
     }
     spacing: 4
-    Setting {
-        id: gotoSnapshot
+    Item {
+        // TODO: Remove this once storing the snapshot path is implemented
+        visible: !isOnboarding
+        height: visible ? implicitHeight : 0
         Layout.fillWidth: true
-        header: qsTr("Load snapshot")
-        description: qsTr("Instant use with background sync")
-        actionItem: Item {
-            width: 26
-            height: 26
-            CaretRightIcon {
-                anchors.centerIn: parent
-                visible: !snapshotImported
-                color: gotoSnapshot.stateColor
+        Layout.preferredHeight: gotoSnapshot.height
+
+        Setting {
+            id: gotoSnapshot
+            visible: parent.visible
+            Layout.fillWidth: true
+            header: qsTr("Load snapshot")
+            description: qsTr("Instant use with background sync")
+            actionItem: Item {
+                width: 26
+                height: 26
+                CaretRightIcon {
+                    // TODO: aligment will be fixed once Onboarding snapshot works
+                    anchors.right: parent.right
+                    anchors.verticalCenter: parent.verticalCenter
+                    visible: !snapshotImported
+                    color: gotoSnapshot.stateColor
+                }
+                GreenCheckIcon {
+                    anchors.centerIn: parent
+                    visible: snapshotImported
+                    color: Theme.color.transparent
+                }
             }
-            GreenCheckIcon {
-                anchors.centerIn: parent
-                visible: snapshotImported
-                color: Theme.color.transparent
+            onClicked: {
+                connectionSwipe.incrementCurrentIndex()
+                connectionSwipe.incrementCurrentIndex()
             }
         }
-        onClicked: {
-            connectionSwipe.incrementCurrentIndex()
-            connectionSwipe.incrementCurrentIndex()
-        }
     }
-    Separator { Layout.fillWidth: true }
+    Separator {
+        Layout.fillWidth: true
+        // TODO: Remove this once storing the snapshot path is implemented
+        visible: !isOnboarding
+    }
     Setting {
         Layout.fillWidth: true
         header: qsTr("Enable listening")

src/qml/components/SnapshotSettings.qml

@@ -5,6 +5,8 @@
 import QtQuick 2.15
 import QtQuick.Controls 2.15
 import QtQuick.Layouts 1.15
+import QtQuick.Dialogs 1.3
+
 
 import "../controls"
 
@@ -18,7 +20,7 @@ ColumnLayout {
     width: Math.min(parent.width, 450)
     anchors.horizontalCenter: parent.horizontalCenter
 
-
+    // TODO: Remove simulation timer before release
     Timer {
         id: snapshotSimulationTimer
         interval: 50 // Update every 50ms
@@ -78,8 +80,25 @@ ColumnLayout {
                 Layout.alignment: Qt.AlignCenter
                 text: qsTr("Choose snapshot file")
                 onClicked: {
-                    settingsStack.currentIndex = 1
-                    snapshotSimulationTimer.start()
+                    // TODO: Connect this to snapshot loading
+                    // settingsStack.currentIndex = 1
+                    fileDialog.open()
+                }
+            }
+
+            FileDialog {
+                id: fileDialog
+                folder: shortcuts.home
+                selectMultiple: false
+                onAccepted: {
+                    console.log("File chosen:", fileDialog.fileUrls)
+                    var snapshotFileName = fileDialog.fileUrl.toString()
+                    console.log("Snapshot file name:", snapshotFileName)
+                    if (snapshotFileName.endsWith(".dat")) {
+                        // optionsModel.setSnapshotDirectory(snapshotFileName)
+                        // console.log("Snapshot directory set:", optionsModel.getSnapshotDirectory())
+                        nodeModel.initializeSnapshot(true, snapshotFileName)
+                    }
                 }
             }
         }

src/qml/models/nodemodel.cpp

@@ -16,6 +16,9 @@
 #include <QMetaObject>
 #include <QTimerEvent>
 #include <QString>
+#include <QThread>
+#include <QUrl>
+#include <QDebug>
 
 NodeModel::NodeModel(interfaces::Node& node)
     : m_node{node}
@@ -121,6 +124,8 @@ void NodeModel::initializeResult(bool success, interfaces::BlockAndHeaderTipInfo
     setVerificationProgress(tip_info.verification_progress);
 
     Q_EMIT setTimeRatioListInitial();
+    // TODO: fix this so that it works once storing the snapshot path is implemented
+    Q_EMIT initializationFinished();
 }
 
 void NodeModel::startShutdownPolling()
@@ -166,3 +171,25 @@ void NodeModel::ConnectToNumConnectionsChangedSignal()
             setNumOutboundPeers(new_num_peers.outbound_full_relay + new_num_peers.block_relay);
         });
 }
+
+// Loads a snapshot from a given path using FileDialog
+void NodeModel::initializeSnapshot(bool initLoadSnapshot, QString path_file) {
+    if (initLoadSnapshot) {
+        // TODO: this is to deal with FileDialog returning a QUrl
+        path_file = QUrl(path_file).toLocalFile();
+        // TODO: Remove this before release
+        // qDebug() << "path_file: " << path_file;
+        QThread* snapshot_thread = new QThread();
+
+        // Capture path_file by value
+        auto lambda = [this, path_file]() {
+            bool result = this->snapshotLoad(path_file);
+            Q_EMIT snapshotLoaded(result);
+        };
+
+        connect(snapshot_thread, &QThread::started, lambda);
+        connect(snapshot_thread, &QThread::finished, snapshot_thread, &QThread::deleteLater);
+
+        snapshot_thread->start();
+    }
+}

src/qml/models/nodemodel.h

@@ -59,6 +59,9 @@ class NodeModel : public QObject
     Q_INVOKABLE void startNodeInitializionThread();
     Q_INVOKABLE void requestShutdown();
 
+    Q_INVOKABLE void initializeSnapshot(bool initLoadSnapshot, QString path_file);
+    Q_INVOKABLE bool snapshotLoad(QString path_file) const { return m_node.snapshotLoad(path_file.toStdString()); }
+
     void startShutdownPolling();
     void stopShutdownPolling();
 
@@ -77,6 +80,8 @@ public Q_SLOTS:
 
     void setTimeRatioList(int new_time);
     void setTimeRatioListInitial();
+    void initializationFinished();
+    void snapshotLoaded(bool result);
 
 protected:
     void timerEvent(QTimerEvent* event) override;

src/qml/pages/node/NodeRunner.qml

@@ -22,11 +22,27 @@ Page {
         }
     }
 
-    Component.onCompleted: nodeModel.startNodeInitializionThread();
+    Component.onCompleted: {
+        nodeModel.startNodeInitializionThread();
+        // TODO: Fix this so that it works once storing the snapshot path is implemented
+        // nodeModel.initializationFinished.connect(onInitializationFinished);
+        nodeModel.initializationFinished.connect(function() {
+            console.log("Initialization finished, initializing snapshot...")
+        });
+    }
 
     BlockClock {
         parentWidth: parent.width - 40
         parentHeight: parent.height
         anchors.centerIn: parent
     }
+
+    function onInitializationFinished() {
+        // TODO: Fix this so that it works once storing the snapshot path is implemented
+        console.log("Initialization finished, initializing snapshot...")
+        // if (optionsModel.getLoadUtxo() && !optionsModel.getSnapshotLoaded()) {
+        // nodeModel.initializeSnapshot(true, optionsModel.getSnapshotDirectory());
+        // optionsModel.setSnapshotLoaded(true);
+        // }
+    }
 }

src/qml/pages/onboarding/OnboardingConnection.qml

@@ -17,6 +17,8 @@ Page {
         anchors.fill: parent
         interactive: false
         orientation: Qt.Vertical
+        // TODO: Remove this once storing the snapshot path is implemented
+        property bool isOnboarding: true
         InformationPage {
             navLeftDetail: NavButton {
                 iconSource: "image://images/caret-left"
@@ -49,6 +51,8 @@ Page {
             buttonMargin: 20
         }
         SettingsConnection {
+            // TODO: Remove this once storing the snapshot path is implemented
+            isOnboarding: connections.isOnboarding
             navRightDetail: NavButton {
                 text: qsTr("Done")
                 onClicked: {

src/qml/pages/settings/SettingsConnection.qml

@@ -14,12 +14,17 @@ Item {
     property alias navLeftDetail: connectionSwipe.navLeftDetail
     property alias showHeader: connectionSwipe.showHeader
 
+    // TODO: Remove this once storing the snapshot path is implemented
+    property bool isOnboarding: false
+
     function setSnapshotImported(imported) {
         connection_settings.loadedDetailItem.setSnapshotImported(imported)
     }
 
     SwipeView {
         id: connectionSwipe
+        // TODO: Remove this once storing the snapshot path is implemented
+        property bool isOnboarding: parent.isOnboarding
         property alias navRightDetail: connection_settings.navRightDetail
         property alias navMiddleDetail: connection_settings.navMiddleDetail
         property alias navLeftDetail: connection_settings.navLeftDetail
@@ -36,7 +41,9 @@ Item {
             headerText: qsTr("Connection settings")
             headerMargin: 0
             detailActive: true
-            detailItem: ConnectionSettings {}
+            detailItem: ConnectionSettings {
+                isOnboarding: connectionSwipe.isOnboarding
+            }
         }
         SettingsProxy {
             onBackClicked: {