Migrate currency converter endpoints (#524)

We are migrating the REST endpoint that Currency Converter uses. The REST endpoint is not licensed for your use. To continue to enable community participation in the development of the feature, developer builds will use an alternate REST endpoint that serves mock data (clearly identifiable as it references planets instead of countries).

src/CalcViewModel/CalcViewModel.vcxproj

@@ -408,6 +408,23 @@
       <Project>{311e866d-8b93-4609-a691-265941fee101}</Project>
     </ProjectReference>
   </ItemGroup>
+  <ItemDefinitionGroup Condition="!Exists('DataLoaders\DataLoaderConstants.h')">
+    <ClCompile>
+      <AdditionalOptions>/DUSE_MOCK_DATA %(AdditionalOptions)</AdditionalOptions>
+    </ClCompile>
+  </ItemDefinitionGroup>
+  <Choose>
+	<When Condition="Exists('DataLoaders\DataLoaderConstants.h')">
+	  <ItemGroup>
+		<ClInclude Include="DataLoaders\DataLoaderConstants.h" />
+	  </ItemGroup>
+	</When>
+	<Otherwise>
+	  <ItemGroup>
+		<ClInclude Include="DataLoaders\DataLoaderMockConstants.h" />
+	  </ItemGroup>
+	</Otherwise>
+  </Choose>
   <ItemGroup>
     <None Include="DataLoaders\DefaultFromToCurrency.json" />
     <None Include="packages.config" />

src/CalcViewModel/CalcViewModel.vcxproj.filters

@@ -213,6 +213,12 @@
     <ClInclude Include="Common\TraceActivity.h">
       <Filter>Common</Filter>
     </ClInclude>
+    <ClInclude Include="DataLoaders\DataLoaderMockConstants.h">
+      <Filter>DataLoaders</Filter>
+    </ClInclude>
+    <ClInclude Include="DataLoaders\DataLoaderConstants.h">
+      <Filter>DataLoaders</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include="DataLoaders\DefaultFromToCurrency.json">

src/CalcViewModel/DataLoaders/CurrencyDataLoader.cpp

@@ -644,6 +644,23 @@ void CurrencyDataLoader::GuaranteeSelectedUnits()
             isConversionTargetSet = true;
         }
     }
+
+    // If still not set for either source or target, just select the first currency in the list
+
+    if (!m_currencyUnits.empty())
+    {
+        if (!isConversionSourceSet)
+        {
+            m_currencyUnits[0].isConversionSource = true;
+            isConversionSourceSet = true;
+        }
+
+        if (!isConversionTargetSet)
+        {
+            m_currencyUnits[0].isConversionTarget = true;
+            isConversionTargetSet = true;
+        }
+    }
 }
 
 void CurrencyDataLoader::NotifyDataLoadFinished(bool didLoad)

src/CalcViewModel/DataLoaders/CurrencyHttpClient.cpp

@@ -1,18 +1,21 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
 #include "pch.h"
 #include "CurrencyHttpClient.h"
 
+#ifdef USE_MOCK_DATA
+#include "DataLoaderMockConstants.h"
+#else
+#include "DataLoaderConstants.h"
+#endif
+
 using namespace CalculatorApp::DataLoaders;
 using namespace Platform;
 using namespace std;
 using namespace Windows::Foundation;
 using namespace Windows::Web::Http;
 
-static constexpr auto sc_MetadataUriLocalizeFor = L"https://go.microsoft.com/fwlink/?linkid=2041093&localizeFor=";
-static constexpr auto sc_RatiosUriRelativeTo = L"https://go.microsoft.com/fwlink/?linkid=2041339&localCurrency=";
-
 CurrencyHttpClient::CurrencyHttpClient()
     : m_client(ref new HttpClient())
     , m_responseLanguage(L"en-US")

src/CalcViewModel/DataLoaders/DataLoaderMockConstants.h

@@ -0,0 +1,13 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+#pragma once
+
+namespace CalculatorApp
+{
+    namespace DataLoaders
+    {
+        static constexpr auto sc_MetadataUriLocalizeFor = L"https://go.microsoft.com/fwlink/?linkid=2091028&localizeFor=";
+        static constexpr auto sc_RatiosUriRelativeTo = L"https://go.microsoft.com/fwlink/?linkid=2091307&localCurrency=";
+    }
+}