using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
using FirebirdSql.Data.FirebirdClient;
using FirebirdSql.Data.Isql;

namespace Test.Server
{
    [ServiceContract(Namespace = "Test.Server")]
    public interface IUser
    {
        [OperationContract]
        bool AddUser(string user, string pass);
    }

    public class UserService : IUser
    {
        String constring = "server type=Embedded;User=SYSDBA;Pooling=false;Password=masterkey;Database=c:\\Chorus\\data.fdb";

    // add new user to the database
        public bool AddUser(string user, string pass)
        {
            using (FbConnection con = new FbConnection(constring))
            {
                con.Open();
                if (CheckUser(user, pass, con) == 0)
                {
                    FbCommand cmd = new FbCommand("INSERT INTO users (name, pass) VALUES ('" + user + "','" + pass + "')", con);
                    cmd.ExecuteNonQuery();
                    return true;
                }
                else
                {
                    return false;
                }
            }
        }

    // check if user exists
        private int CheckUser(string user, string pass, FbConnection con)
        {
        // this is where the exception might be occurring.
        // if i comment out both the lines below and return a dummy value, the problem seems to go away.
        // could this have something to do with integer overflows corrupting the stack?
            FbCommand cmd = new FbCommand("SELECT count(*) FROM users WHERE name='" + user + "' AND pass='" + pass +"'", con);
            return Convert.ToInt32(cmd.ExecuteScalar());
        }
    }
}