From 4c8e1cb5f0ca1cd494c107be6df6c74b2b6b0eda Mon Sep 17 00:00:00 2001
From: Pepe Rivera <joseartrivera@gmail.com>
Date: Mon, 15 Jun 2020 14:13:56 -0700
Subject: [PATCH] Check for valid input in min/max/step fields (#1270)

---
 .../GraphingCalculator/VariableViewModel.h        | 15 +++++++++++++++
 .../GraphingCalculator/EquationInputArea.xaml.cpp |  8 ++++++++
 2 files changed, 23 insertions(+)

diff --git a/src/CalcViewModel/GraphingCalculator/VariableViewModel.h b/src/CalcViewModel/GraphingCalculator/VariableViewModel.h
index cd5ffce..151499e 100644
--- a/src/CalcViewModel/GraphingCalculator/VariableViewModel.h
+++ b/src/CalcViewModel/GraphingCalculator/VariableViewModel.h
@@ -9,6 +9,9 @@
 
 namespace CalculatorApp::ViewModel
 {
+
+inline constexpr int DefaultMinMaxRange = 10;
+
 public
     value struct VariableChangedEventArgs sealed
     {
@@ -40,6 +43,12 @@ public
             {
                 if (m_variable->Min != value)
                 {
+                    if (value >= m_variable->Max)
+                    {
+                        m_variable->Max = value + DefaultMinMaxRange;
+                        RaisePropertyChanged("Max");
+                    }
+
                     m_variable->Min = value;
                     RaisePropertyChanged("Min");
                 }
@@ -72,6 +81,12 @@ public
             {
                 if (m_variable->Max != value)
                 {
+                    if (value <= m_variable->Min)
+                    {
+                        m_variable->Min = value - DefaultMinMaxRange;
+                        RaisePropertyChanged("Min");
+                    }
+
                     m_variable->Max = value;
                     RaisePropertyChanged("Max");
                 }
diff --git a/src/Calculator/Views/GraphingCalculator/EquationInputArea.xaml.cpp b/src/Calculator/Views/GraphingCalculator/EquationInputArea.xaml.cpp
index 37dd900..3d3650c 100644
--- a/src/Calculator/Views/GraphingCalculator/EquationInputArea.xaml.cpp
+++ b/src/Calculator/Views/GraphingCalculator/EquationInputArea.xaml.cpp
@@ -402,6 +402,7 @@ void EquationInputArea::SubmitTextbox(TextBox ^ sender)
     else if (sender->Name == "MinTextBox")
     {
         val = validateDouble(sender->Text, variableViewModel->Min);
+
         variableViewModel->Min = val;
         TraceLogger::GetInstance()->LogVariableSettingsChanged(L"MinTextBox");
     }
@@ -414,6 +415,13 @@ void EquationInputArea::SubmitTextbox(TextBox ^ sender)
     else if (sender->Name == "StepTextBox")
     {
         val = validateDouble(sender->Text, variableViewModel->Step);
+
+        // Don't allow a value less than or equal to 0 as the step
+        if (val <= 0)
+        {
+            val = variableViewModel->Step;
+        }
+
         variableViewModel->Step = val;
         TraceLogger::GetInstance()->LogVariableSettingsChanged(L"StepTextBox");
     }