using System.Data;

namespace brecal.model
{
    public class RoleAssignment : DbEntity
    {

        #region Properties

        public int? UserId { get; set; }

        public int? RoleId { get; set; }

        public Role? AssignedRole { get; set; }

        public User? AssignedUser { get; set; }

        #endregion

        #region public static methods

        public static async Task<List<RoleAssignment>> LoadForUser(User? u, IDBManager manager)
        {
            List<DbEntity> loadResultList = await manager.Load(SetLoadQuery, LoadElems, args: u);
            List<RoleAssignment> result = new();
            foreach (RoleAssignment ra in loadResultList.Cast<RoleAssignment>())
            {
                ra.AssignedUser = u;
                result.Add(ra);
            }
                
            return result;
        }

        public static void SetLoadQuery(IDbCommand cmd, params object?[] args)
        {
            cmd.CommandText = "SELECT id, user_id, role_id FROM user_role_map WHERE user_id = @UID";
            if (args.Length != 1 || !(args[0] is User))
                throw new ArgumentException("loader needs single user as argument");
            IDataParameter uid = cmd.CreateParameter();
            uid.ParameterName = "UID";
            if (args[0] is User u)
                uid.Value = u.Id;
            cmd.Parameters.Add(uid);
        }

        public static List<DbEntity> LoadElems(IDataReader reader)
        {
            List<DbEntity> result = new List<DbEntity>();
            while (reader.Read())
            {
                RoleAssignment ra = new();
                ra.Id = (uint)reader.GetInt32(0);
                if (!reader.IsDBNull(1)) ra.UserId = reader.GetInt32(1);
                if (!reader.IsDBNull(2)) ra.RoleId = reader.GetInt32(2);                
                result.Add(ra);
            }
            return result;
        }

        #endregion

        #region overrides

        public override void SetUpdate(IDbCommand cmd)
        {
            throw new NotImplementedException();
        }

        public override void SetCreate(IDbCommand cmd)
        {
            cmd.CommandText = "INSERT INTO user_role_map (user_id, role_id) VALUES (@USERID, @ROLEID)";

            IDbDataParameter userid = cmd.CreateParameter();
            userid.ParameterName = "USERID";
            userid.Value = this.UserId;
            cmd.Parameters.Add(userid);

            IDbDataParameter roleid = cmd.CreateParameter();
            roleid.ParameterName = "ROLEID";
            roleid.Value = this.RoleId;
            cmd.Parameters.Add(roleid);
        }

        public override void SetDelete(IDbCommand cmd)
        {
            cmd.CommandText = "DELETE FROM user_role_map WHERE id = @ID";

            IDataParameter idParam = cmd.CreateParameter();
            idParam.ParameterName = "ID";
            idParam.Value = this.Id;
            cmd.Parameters.Add(idParam);
        }

        public override string ToString()
        {
            if (this.AssignedRole == null)
            {
                return $"{Id}: <defunct role>";
            }
            else
            {
                return AssignedRole.Name ?? AssignedRole.Id.ToString();
            }
        }

        #endregion

    }
}