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, src/node/interfaces.cpp
and src/validation.h and src/validation.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.

Author: D33r-Gee

Diff for: 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, std::function<void(double)> progress_callback) = 0;
+
     //! Set RPC timer interface if unset.
     virtual void rpcSetTimerInterfaceIfUnset(RPCTimerInterface* iface) = 0;
 

Diff for: 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);

Diff for: 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 +396,65 @@ class NodeImpl : public Node
     {
         m_context = context;
     }
+    bool snapshotLoad(const std::string& path_string, std::function<void(double)> progress_callback) override
+    {
+        const fs::path path = fs::u8path(path_string);
+        if (!fs::exists(path)) {
+            LogPrintf("[loadsnapshot] Snapshot file %s does not exist\n", path.u8string());
+            return false;
+        }
+
+        AutoFile afile{fsbridge::fopen(path, "rb")};
+        if (afile.IsNull()) {
+            LogPrintf("[loadsnapshot] Failed to open snapshot file %s\n", path.u8string());
+            return false;
+        }
+
+        SnapshotMetadata metadata;
+        try {
+            afile >> metadata;
+        } catch (const std::exception& e) {
+            LogPrintf("[loadsnapshot] Failed to read snapshot metadata: %s\n", e.what());
+            return false;
+        }
+
+        const uint256& base_blockhash = metadata.m_base_blockhash;
+        LogPrintf("[loadsnapshot] Waiting for blockheader %s in headers chain before snapshot activation\n",
+            base_blockhash.ToString());
+
+        if (!m_context->chainman) {
+            LogPrintf("[loadsnapshot] Chainman is null\n");
+            return false;
+        }
+
+        ChainstateManager& chainman = *m_context->chainman;
+        CBlockIndex* snapshot_start_block = nullptr;
+
+        // Wait for the block to appear in the block index
+        constexpr int max_wait_seconds = 600; // 10 minutes
+        for (int i = 0; i < max_wait_seconds; ++i) {
+            snapshot_start_block = WITH_LOCK(::cs_main, return chainman.m_blockman.LookupBlockIndex(base_blockhash));
+            if (snapshot_start_block) break;
+            std::this_thread::sleep_for(std::chrono::seconds(1));
+        }
+
+        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, progress_callback)) {
+            LogPrintf("[loadsnapshot] Unable to load UTXO snapshot %s\n", path.u8string());
+            return false;
+        }
+
+        CBlockIndex* new_tip = WITH_LOCK(::cs_main, return chainman.ActiveTip());
+        LogPrintf("[loadsnapshot] 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};
@@ -808,4 +868,4 @@ class ChainImpl : public Chain
 namespace interfaces {
 std::unique_ptr<Node> MakeNode(node::NodeContext& context) { return std::make_unique<node::NodeImpl>(context); }
 std::unique_ptr<Chain> MakeChain(node::NodeContext& context) { return std::make_unique<node::ChainImpl>(context); }
-} // namespace interfaces
+} // namespace interfaces

Diff for: src/qml/bitcoin.cpp

@@ -311,6 +311,8 @@ int QmlGuiMain(int argc, char* argv[])
     engine.rootContext()->setContextProperty("optionsModel", &options_model);
     engine.rootContext()->setContextProperty("needOnboarding", need_onboarding);
 
+    QObject::connect(&node_model, &NodeModel::snapshotLoaded, &options_model, &OptionsQmlModel::setSnapshotLoadCompleted);
+
     AppMode app_mode = SetupAppMode();
 
     qmlRegisterSingletonInstance<AppMode>("org.bitcoincore.qt", 1, 0, "AppMode", &app_mode);

Diff for: src/qml/components/ConnectionSettings.qml

@@ -8,36 +8,59 @@ import QtQuick.Layouts 1.15
 import "../controls"
 
 ColumnLayout {
-    property bool snapshotImported: false
+    // TODO: Remove this once storing the snapshot path is implemented
+    property bool isOnboarding: false
+    property bool snapshotImported: optionsModel.snapshotLoadCompleted
+
+    Component.onCompleted: {
+        snapshotImported = optionsModel.snapshotLoadCompleted
+    }
+
     function setSnapshotImported(imported) {
         snapshotImported = imported
+        optionsModel.setSnapshotLoadCompleted(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")

Diff for: src/qml/components/SnapshotSettings.qml

@@ -5,20 +5,22 @@
 import QtQuick 2.15
 import QtQuick.Controls 2.15
 import QtQuick.Layouts 1.15
+import QtQuick.Dialogs 1.3
+
 
 import "../controls"
 
 ColumnLayout {
     signal snapshotImportCompleted()
     property int snapshotVerificationCycles: 0
     property real snapshotVerificationProgress: 0
-    property bool snapshotVerified: false
+    property bool snapshotVerified: optionsModel.snapshotLoadCompleted
 
     id: 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
@@ -42,7 +44,7 @@ ColumnLayout {
 
     StackLayout {
         id: settingsStack
-        currentIndex: 0
+        currentIndex: optionsModel.snapshotLoadCompleted ? 2 : 0
 
         ColumnLayout {
             Layout.alignment: Qt.AlignHCenter
@@ -78,8 +80,26 @@ 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)
+                        settingsStack.currentIndex = 1
+                    }
                 }
             }
         }
@@ -109,10 +129,27 @@ ColumnLayout {
                 Layout.topMargin: 20
                 width: 200
                 height: 20
-                progress: snapshotVerificationProgress
+                progress: nodeModel.snapshotProgress
                 Layout.alignment: Qt.AlignCenter
                 progressColor: Theme.color.blue
             }
+
+            Connections {
+                target: nodeModel
+                function onSnapshotProgressChanged() {
+                    progressIndicator.progress = nodeModel.snapshotProgress
+                }
+                function onSnapshotLoaded(success) {
+                    if (success) {
+                        progressIndicator.progress = 1
+                        settingsStack.currentIndex = 2  // Move to the "Snapshot Loaded" page
+                    } else {
+                        // Handle snapshot loading failure
+                        console.error("Snapshot loading failed")
+                        // You might want to show an error message or take other actions here
+                    }
+                }
+            }
         }
 
         ColumnLayout {

Diff for: 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 +171,35 @@ 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, [this](double progress) {
+                setSnapshotProgress(progress);
+            });
+            Q_EMIT snapshotLoaded(result);
+        };
+
+        connect(snapshot_thread, &QThread::started, lambda);
+        connect(snapshot_thread, &QThread::finished, snapshot_thread, &QThread::deleteLater);
+
+        snapshot_thread->start();
+    }
+}
+
+void NodeModel::setSnapshotProgress(double new_snapshot_progress)
+{
+    if (new_snapshot_progress != m_snapshot_progress) {
+        m_snapshot_progress = new_snapshot_progress;
+        Q_EMIT snapshotProgressChanged();
+    }
+}

Diff for: src/qml/models/nodemodel.h

@@ -34,6 +34,7 @@ class NodeModel : public QObject
     Q_PROPERTY(double verificationProgress READ verificationProgress NOTIFY verificationProgressChanged)
     Q_PROPERTY(bool pause READ pause WRITE setPause NOTIFY pauseChanged)
     Q_PROPERTY(bool faulted READ errorState WRITE setErrorState NOTIFY errorStateChanged)
+    Q_PROPERTY(double snapshotProgress READ snapshotProgress NOTIFY snapshotProgressChanged)
 
 public:
     explicit NodeModel(interfaces::Node& node);
@@ -52,13 +53,19 @@ class NodeModel : public QObject
     void setPause(bool new_pause);
     bool errorState() const { return m_faulted; }
     void setErrorState(bool new_error);
+    double snapshotProgress() const { return m_snapshot_progress; }
+    void setSnapshotProgress(double new_snapshot_progress);
+    bool isSnapshotLoaded() const;
 
     Q_INVOKABLE float getTotalBytesReceived() const { return (float)m_node.getTotalBytesRecv(); }
     Q_INVOKABLE float getTotalBytesSent() const { return (float)m_node.getTotalBytesSent(); }
 
     Q_INVOKABLE void startNodeInitializionThread();
     Q_INVOKABLE void requestShutdown();
 
+    Q_INVOKABLE void initializeSnapshot(bool initLoadSnapshot, QString path_file);
+    Q_INVOKABLE bool snapshotLoad(QString path_file, std::function<void(double)> progress_callback) const { return m_node.snapshotLoad(path_file.toStdString(), progress_callback); }
+
     void startShutdownPolling();
     void stopShutdownPolling();
 
@@ -77,6 +84,9 @@ public Q_SLOTS:
 
     void setTimeRatioList(int new_time);
     void setTimeRatioListInitial();
+    void initializationFinished();
+    void snapshotLoaded(bool result);
+    void snapshotProgressChanged();
 
 protected:
     void timerEvent(QTimerEvent* event) override;
@@ -90,7 +100,7 @@ public Q_SLOTS:
     double m_verification_progress{0.0};
     bool m_pause{false};
     bool m_faulted{false};
-
+    double m_snapshot_progress{0.0};
     int m_shutdown_polling_timer_id{0};
 
     QVector<QPair<int, double>> m_block_process_time;