using ampl;
using System;
using System.Collections.Generic;

namespace Examples
{
  /// <summary>
  /// This example shows how to redirect AMPL output (normally directed to the console) and AMPL
  /// errors (by default, an error throws an exception and a warning is simply directed to the console.
  /// </summary>
  public class OutputAndErrorRedirectionExample
  {
    private static List<Tuple<DateTime, Kind, string>> outputs = new List<Tuple<DateTime, Kind, string>>();

    public static int Main(string[] args)
    {
      try
      {
        using (var ampl = new AMPL())
        {
          ampl.Eval("var x{1..3};");
          ampl.Eval("maximize z: sum{i in 1..3} x[i];");

          // *** Output redirection *** Enable output redirection
          ampl.EnableOutputRouting();
          // Assign handler: Method 1: using method
          ampl.Output += HandleOutput;
          ampl.Eval("display x;");
          ampl.Eval("let {i in 1..3} x[i] := i;");
          ampl.Eval("display x;");
          // Unassign output handler
          ampl.Output -= HandleOutput;
          // print all outputs
          foreach (var t in outputs)
            Console.Write("{0} - Kind: {1} - Msg:\n{2}", t.Item1,
              t.Item2, t.Item3);

          // Method 2: Using lambda expression
          ampl.Output += (kind, message) => Console.Write("Got AMPL message:\n{0}\n", message);
          // Test it
          ampl.Eval("display x,x;");

          // *** Error redirection *** Enable error and warnings redirection
          ampl.EnableErrorAndWarningRouting();
          // Register handlers
          ampl.Error += HandleError;
          ampl.Warning += HandleWarning;
          // Normally throws exception, will just be printed on screen
          ampl.Eval("var x;");
          // Create an obvious infeasibility
          ampl.Eval("c1: x[1]>=1; c2: x[1]<=0;");
          // Solve the model, issuing a warning
          ampl.Solve();
        }
      }
      catch (Exception ex)
      {
        Console.WriteLine(ex.Message);
        return 1;
      }
      return 0;
    }

    private static void HandleError(AMPLException obj)
    {
      Console.Write("Got error: {0}\n", obj.Message);
    }

    private static void HandleOutput(Kind arg1, string arg2)
    {
      outputs.Add(System.Tuple.Create(DateTime.Now, arg1, arg2));
    }

    private static void HandleWarning(AMPLException obj)
    {
      Console.Write("Got warning: {0}\n", obj.Message);
    }
  }
}