// DwarfMgr.cs

using System.Data;
using System.Data.SqlClient;
using System.Runtime.CompilerServices;
using System.EnterpriseServices;
using System.Reflection;
using Database;
using Dwarf;

//Registration details.
//COM+ application name as it appears in the COM+ catalog.
[assembly: ApplicationName("DwarfMgr")]
[assembly: ApplicationActivation(ActivationOption.Library)]
//Strong name for assembly.
[assembly: AssemblyKeyFileAttribute("components/DwarfMgr.snk")]
[assembly: AssemblyVersion("1.0.0.0")]

namespace DwarfMgr {
  [Transaction(TransactionOption.Required)]
  public class DwarfMgr :  ServicedComponent {
    // yes, marriage could be a method on Dwarf,
    // and could be done easier with a smaller update
    // but we are trying to demonstrate transaction composition
    [AutoComplete]
    public void Marry(int groom_id, int bride_id){
      Dwarf.Dwarf dw = new Dwarf.Dwarf();

      if(groom_id == bride_id){
        throw new System.Exception("You can't marry yourself!");
      }

      // is this a "select for update / select holdlock", or do we have a race condition???
      DataSet gds = dw.Get(groom_id);
      DataSet bds = dw.Get(bride_id);

      if(gds.Tables[0].Rows[0]["spouse_id"] != System.DBNull.Value){
        throw new System.Exception("Groom already married!");
      }

      if(bds.Tables[0].Rows[0]["spouse_id"] != System.DBNull.Value){
        throw new System.Exception("Bride already married!");
      }

      int gHome;
      int bHome;

      if(gds.Tables[0].Rows[0]["home_id"] == System.DBNull.Value){
        gHome = 0;
      }else{
        gHome = System.Int32.Parse(gds.Tables[0].Rows[0]["home_id"].ToString());
      }

      if(bds.Tables[0].Rows[0]["home_id"] == System.DBNull.Value){
        bHome = 0;
      }else{
        bHome = System.Int32.Parse(bds.Tables[0].Rows[0]["home_id"].ToString());
      }

      dw.Update(groom_id,
                   gds.Tables[0].Rows[0]["dwarf_name"].ToString(),
                   System.Int32.Parse(gds.Tables[0].Rows[0]["born"].ToString()),
                   gHome,
                   bride_id);

      // uncomment next two lines to verify ACID transaction
      // int zero = 0;
      // int divide_by = 5 / zero;

      dw.Update(bride_id,
                   bds.Tables[0].Rows[0]["dwarf_name"].ToString(),
                   System.Int32.Parse(bds.Tables[0].Rows[0]["born"].ToString()),
                   gHome,
                   groom_id);
    }
  }
}