From ad75b438cb99f29157760e8250d70bf37f4877b1 Mon Sep 17 00:00:00 2001
From: Rob Emery <kde@mintsoft.net>
Date: Sun, 1 Oct 2023 10:39:59 +0000
Subject: [PATCH] Implementing link priorities

Now that devices can potentially be connected via both network and bluetooth simultaneously we should prioritise connections over the highest performing link (probably wifi/network). To this end the
m_deviceLinks are now sorted based on priority with the fastest links first; this means that when Device::sendPacket is scheduling to send a packet, it should always use the fastest link first.
---
 core/backends/bluetooth/bluetoothlinkprovider.h | 5 +++++
 core/backends/devicelink.cpp                    | 1 +
 core/backends/devicelink.h                      | 8 ++++++++
 core/backends/lan/lanlinkprovider.h             | 5 +++++
 core/backends/linkprovider.h                    | 1 +
 core/backends/loopback/loopbacklinkprovider.h   | 4 ++++
 core/daemon.cpp                                 | 2 +-
 core/device.cpp                                 | 4 ++++
 8 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/core/backends/bluetooth/bluetoothlinkprovider.h b/core/backends/bluetooth/bluetoothlinkprovider.h
index 91103b6b7..b831c926b 100644
--- a/core/backends/bluetooth/bluetoothlinkprovider.h
+++ b/core/backends/bluetooth/bluetoothlinkprovider.h
@@ -37,6 +37,11 @@ public:
         return QStringLiteral("BluetoothLinkProvider");
     }
 
+    int priority() override
+    {
+        return 10;
+    }
+
 public Q_SLOTS:
     virtual void onNetworkChange() override;
     virtual void onStart() override;
diff --git a/core/backends/devicelink.cpp b/core/backends/devicelink.cpp
index 7fa5b2571..8d7126438 100644
--- a/core/backends/devicelink.cpp
+++ b/core/backends/devicelink.cpp
@@ -14,6 +14,7 @@ DeviceLink::DeviceLink(const QString &deviceId, LinkProvider *parent)
     connect(this, &QObject::destroyed, [this, deviceId, parent]() {
         parent->onLinkDestroyed(deviceId, this);
     });
+    this->priorityFromProvider = parent->priority();
 }
 
 #include "moc_devicelink.cpp"
diff --git a/core/backends/devicelink.h b/core/backends/devicelink.h
index f01ec5a8f..3eb2596e9 100644
--- a/core/backends/devicelink.h
+++ b/core/backends/devicelink.h
@@ -25,10 +25,18 @@ public:
         return deviceInfo().id;
     }
 
+    int priority() const
+    {
+        return priorityFromProvider;
+    }
+
     virtual bool sendPacket(NetworkPacket &np) = 0;
 
     virtual DeviceInfo deviceInfo() const = 0;
 
+private:
+    int priorityFromProvider;
+
 Q_SIGNALS:
     void receivedPacket(const NetworkPacket &np);
 };
diff --git a/core/backends/lan/lanlinkprovider.h b/core/backends/lan/lanlinkprovider.h
index aae13eb10..08b3b07bc 100644
--- a/core/backends/lan/lanlinkprovider.h
+++ b/core/backends/lan/lanlinkprovider.h
@@ -43,6 +43,11 @@ public:
         return QStringLiteral("LanLinkProvider");
     }
 
+    int priority() override
+    {
+        return 20;
+    }
+
     void sendUdpIdentityPacket(const QList<QHostAddress> &addresses);
 
     static void configureSslSocket(QSslSocket *socket, const QString &deviceId, bool isDeviceTrusted);
diff --git a/core/backends/linkprovider.h b/core/backends/linkprovider.h
index 9f407ad46..eeddd1d07 100644
--- a/core/backends/linkprovider.h
+++ b/core/backends/linkprovider.h
@@ -22,6 +22,7 @@ public:
     LinkProvider();
 
     virtual QString name() = 0;
+    virtual int priority() = 0;
 
 public Q_SLOTS:
     virtual void onStart() = 0;
diff --git a/core/backends/loopback/loopbacklinkprovider.h b/core/backends/loopback/loopbacklinkprovider.h
index b33e657e5..d6e82b888 100644
--- a/core/backends/loopback/loopbacklinkprovider.h
+++ b/core/backends/loopback/loopbacklinkprovider.h
@@ -22,6 +22,10 @@ public:
     {
         return QStringLiteral("LoopbackLinkProvider");
     }
+    int priority() override
+    {
+        return 0;
+    }
 
     void onStart() override;
     void onStop() override;
diff --git a/core/daemon.cpp b/core/daemon.cpp
index 94a92f98c..fb6b3d3a7 100644
--- a/core/daemon.cpp
+++ b/core/daemon.cpp
@@ -158,7 +158,7 @@ void Daemon::onNewDeviceLink(DeviceLink *link)
 {
     QString id = link->deviceId();
 
-    // qCDebug(KDECONNECT_CORE) << "Device discovered" << id << "via" << dl->name();
+    qCDebug(KDECONNECT_CORE) << "Device discovered" << id << "via link with priority" << link->priority();
 
     if (d->m_devices.contains(id)) {
         qCDebug(KDECONNECT_CORE) << "It is a known device" << link->deviceInfo().name;
diff --git a/core/device.cpp b/core/device.cpp
index a11ca659b..c9bb1fa3b 100644
--- a/core/device.cpp
+++ b/core/device.cpp
@@ -276,6 +276,10 @@ void Device::addLink(DeviceLink *link)
 
     d->m_deviceLinks.append(link);
 
+    std::sort(d->m_deviceLinks.begin(), d->m_deviceLinks.end(), [](DeviceLink *a, DeviceLink *b) {
+        return a->priority() > b->priority();
+    });
+
     connect(link, &QObject::destroyed, this, &Device::linkDestroyed);
     connect(link, &DeviceLink::receivedPacket, this, &Device::privateReceivedPacket);