From d1c4ca5eaeb2aa6e1246bd970fdbf9402381b623 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Sun, 12 Jul 2020 13:19:26 -0700
Subject: [PATCH] Use uniform_int_distribution for generating PINs

---
 app/gui/PcView.qml        |  2 +-
 app/gui/computermodel.cpp | 12 ++++++++++++
 app/gui/computermodel.h   |  2 ++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/app/gui/PcView.qml b/app/gui/PcView.qml
index e653ddce..6c42b2e1 100644
--- a/app/gui/PcView.qml
+++ b/app/gui/PcView.qml
@@ -187,7 +187,7 @@ CenteredGridView {
                 }
                 else {
                     if (!model.busy) {
-                        var pin = ("0000" + Math.floor(Math.random() * 10000)).slice(-4)
+                        var pin = computerModel.generatePinString()
 
                         // Kick off pairing in the background
                         computerModel.pairComputer(index, pin)
diff --git a/app/gui/computermodel.cpp b/app/gui/computermodel.cpp
index 141070ca..6a44e936 100644
--- a/app/gui/computermodel.cpp
+++ b/app/gui/computermodel.cpp
@@ -2,6 +2,8 @@
 
 #include <QThreadPool>
 
+#include <random>
+
 ComputerModel::ComputerModel(QObject* object)
     : QAbstractListModel(object) {}
 
@@ -135,6 +137,16 @@ void ComputerModel::renameComputer(int computerIndex, QString name)
     m_ComputerManager->renameHost(m_Computers[computerIndex], name);
 }
 
+// TODO: Use QRandomGenerator when we drop Qt 5.9 support
+QString ComputerModel::generatePinString()
+{
+    std::uniform_int_distribution<int> dist(0, 9999);
+    std::random_device rd;
+    std::mt19937 engine(rd());
+
+    return QString::asprintf("%04u", dist(engine));
+}
+
 void ComputerModel::pairComputer(int computerIndex, QString pin)
 {
     Q_ASSERT(computerIndex < m_Computers.count());
diff --git a/app/gui/computermodel.h b/app/gui/computermodel.h
index a0fd5def..7224d51e 100644
--- a/app/gui/computermodel.h
+++ b/app/gui/computermodel.h
@@ -31,6 +31,8 @@ public:
 
     Q_INVOKABLE void deleteComputer(int computerIndex);
 
+    Q_INVOKABLE QString generatePinString();
+
     Q_INVOKABLE void pairComputer(int computerIndex, QString pin);
 
     Q_INVOKABLE void wakeComputer(int computerIndex);