using System;

// ElementaryExtensions API:
using ElementaryExtensions;

namespace MiscellaneousDemo {

//**************************************************************************************************
static partial class Program {
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

/// <summary>
/// Fatal Error and Unbreakable Region tests.
/// </summary>
static bool FatalErrorURTest()
{
   int nDialogItemIdx=
      ЄConsole.NumberedListDialog
      (
         "Fatal Error Simulation and Unbreakable Region Test:",
         new string[]
         {
            "Raise directly",
            "Unhandled exception",
            "Unhandled exception chain",
            "Unhandled exception chains (two concatenated chains)",
            "Implicit exception in unbreakable code region",
            "Safe throwing from UR (will not cause fatal error)"
         },
         ЄConsoleDialogListNumeration.EndWithZero,
         "Cancel"
      );
   if (nDialogItemIdx<0)
      return false;
   ЄConsole.Print();
   switch (nDialogItemIdx)
   {
   case 0:
      ЄConsole.PrintOperation("Simulating fatal error (raising directly)");
      ЄFatalError.Raise("Simulated error.");
      break;
   case 1:
      ЄConsole.PrintOperation("Simulating fatal error (throwing exception)");
      throw new ApplicationException("Simulated error.");
   case 2:
      ЄConsole.PrintOperation("Simulating fatal error (throwing exception chain)");
      try
         { throw new ApplicationException("Simulated error #1."); }
      catch (ApplicationException e)
         { throw new ApplicationException("Simulated error #2.",e); }
   case 3:
      ЄConsole.PrintOperation("Simulating fatal error (throwing two concatenated exception chains)");
      // We need to wrap the throwing this way. (Else we will not see the both chains,
      // because unhandled exception handler will report the error prior to "finally" block
      // in "ThrowConcatenatedChains" method.)
      try
         { ThrowConcatenatedChains(); }
      catch
         { throw; }
      break;
   case 4:
   case 5:
      try
      {
         URExceptionTest(nDialogItemIdx==5);
      }
      catch (Exception e)
      {
         Sound.Play(SoundSignal.Error);
         ЄConsole.PrintError(
            ЄException.ComposeChainedMessage(
               e, ЄExceptionMessageChainingOptions.ConsoleStyle ));
      }
      break;
   default:
      throw new ЄDeadCodeBranchException();
   }
   return true;
}

/// <summary>
/// Throwing two concatenated exception chains.
/// </summary>
static void ThrowConcatenatedChains()
{
   // Variable for saving of primary exception (chain):
   Exception
      exception=null;
   try
   {
   // Throwing primary exception chain:
      try
         { throw new ApplicationException("Simulated error #1."); }
      catch (ApplicationException e)
         { throw new ApplicationException("Simulated error #2.",e); }
   }
   catch (Exception e)
   {
   // Saving and rethrowing primary exception:
      exception=e; throw;
   }
   finally
   {
   // Throwing secondary exception chain (from finalization phase of the primary exception):
      try
      {
      // Throwing secondary exception chain:
         try
            { throw new InvalidOperationException("Simulated error #3."); }
         catch (InvalidOperationException e)
            { throw new InvalidOperationException("Simulated error #4.",e); }
      }
      catch (Exception e)
      {
      // Throwing concatenated chains (e+exception):
         throw ЄException.ConcatenatePreviousChain(e,exception);
      }
   }
}

/// <summary>
/// Testing exception throwing from UR-region.
/// </summary>
static void URExceptionTest(bool bSafeThrowing)
{
   ЄConsole.PrintOperation(
      bSafeThrowing ?
      "Performing safe exception throwing from unbreakable region" :
      "Performing unsafe exception throwing from unbreakable region" );

   // Fully unbreakable region formed as extended user's callback:
   ЄUnbreakableRegion.ExecuteX
   (
      delegate (ЄUnbreakableRegion ur)
      {
      // Unbreakable code block:
         if (bSafeThrowing)
         // Safe exception throwing (will not cause fatal error):
            throw ur.PrepareForSafeThrowing(
               new ApplicationException("Simulated error.") );
         else
         // Unsafe exception throwing (will cause fatal error):
            throw new ApplicationException("Simulated error.");
      }
   );
}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
} // Program
//**************************************************************************************************

} // MiscellaneousDemo