Start date cannot be greater than end. Refs #8244.

Code/Mantid/MantidQt/MantidWidgets/inc/MantidQtMantidWidgets/ICatHelper.h

@@ -28,6 +28,8 @@ namespace MantidQt
       bool validSession();
       /// Open the login dialog if user not logged in.
       void openLoginDialog(QWidget* window);
+      /// Creates a time_t value from an input date ("23/06/2003") for comparison.
+      time_t getTimevalue(const std::string& inputDate);
 
     private:
       /// Creates an algorithm with the name provided.

Code/Mantid/MantidQt/MantidWidgets/inc/MantidQtMantidWidgets/ICatSearch2.h

@@ -83,6 +83,8 @@ namespace MantidQt
       void populateInvestigationTypeBox();
       /// Obtain the users' text input for each search field.
       std::map<std::string, std::string> getSearchFields();
+      /// Checks if start date is greater than end date.
+      bool validateDates();
 
       ///////////////////////////////////////////////////////////////////////////////
       // Methods for: "Search results"

Code/Mantid/MantidQt/MantidWidgets/src/ICatHelper.cpp

@@ -1,7 +1,9 @@
 #include "MantidQtMantidWidgets/ICatHelper.h"
 #include "MantidQtAPI/AlgorithmDialog.h"
 #include "MantidQtAPI/InterfaceManager.h"
+#include "MantidKernel/DateAndTime.h"
 
+#include <boost/algorithm/string/regex.hpp>
 #include <QCoreApplication>
 
 namespace MantidQt
@@ -193,6 +195,25 @@ namespace MantidQt
       }
     }
 
+    /**
+    * Creates a time_t value from an input date ("23/06/2003") for comparison.
+    * @param inputDate :: string containing the date.
+    * @return time_t value of date
+    */
+    time_t ICatHelper::getTimevalue(const std::string& inputDate)
+    {
+      // Prevent any possible errors.
+      if(inputDate.empty()) return 0;
+      // A container to hold the segments of the date.
+      std::vector<std::string> dateSegments;
+      // Split input by "/" prior to rearranging the date
+      boost::algorithm::split_regex(dateSegments, inputDate, boost::regex("/"));
+      // Reorganise the date to be ISO format.
+      std::string isoDate = dateSegments.at(2) + "-" + dateSegments.at(1) + "-" + dateSegments.at(0) + " 0:00:00.000";
+      // Return the date as time_t value.
+      return Mantid::Kernel::DateAndTime(isoDate).to_time_t();
+    }
+
     /**
      * Obtain the algorithm documentation for the given property.
      * @param properties :: A list of properties for a provided algorithm.

Code/Mantid/MantidQt/MantidWidgets/src/ICatSearch2.cpp

@@ -498,6 +498,32 @@ namespace MantidQt
       m_calendar->close();
     }
 
+    /**
+     * Checks if start date is greater than end date.
+     * @returns true if start date is greater than end date.
+     */
+    bool ICatSearch2::validateDates()
+    {
+      std::string startDateInput = m_icatUiForm.StartDate->text().toStdString();
+      std::string endDateInput   = m_icatUiForm.EndDate->text().toStdString();
+
+      // Return false if the user has not input any dates. This prevents any null errors occurring.
+      if (startDateInput.size() <= 2 || endDateInput.size() <= 2) return false;
+
+      // If startDate > endDate we want to throw an error and inform the user (red star(*)).
+      if (m_icatHelper->getTimevalue(startDateInput) > m_icatHelper->getTimevalue(endDateInput))
+      {
+        m_icatUiForm.StartDate_err->setToolTip(QString::fromStdString("<span style=\"color: white;\">Start date cannot be greater than end date.</span>"));
+        m_icatUiForm.StartDate_err->show();
+        return true;
+      }
+      else
+      {
+        m_icatUiForm.StartDate_err->hide();
+        return false;
+      }
+    }
+
     /**
      * Show or hide advanced options if "Advanced Search" checked.
      */
@@ -541,8 +567,10 @@ namespace MantidQt
         std::map<std::string, std::string> errors = m_icatHelper->validateProperties(inputFields);
 
         // Has any errors occurred?
-        if (!errors.empty())
+        if (!errors.empty() || validateDates())
         {
+          // Clear form to prevent previous search results showing if an error occurs.
+          clearSearchResultFrame();
           showErrorLabels(errors);
           m_icatUiForm.searchResultsLbl->setText("An error has occurred in the search form.");
           // Stop here to prevent the search being carried out below.