/// <summary>
/// 借书
/// </summary>
/// <param name="readerId"></param>
/// <param name="comment"></param>
/// <returns></returns>
public Result Lend(int readerId, string comment)
{
if (this.RegistrationStatus == RegistrationStatus.Lend)
{
return(Result.FromError("该书已被借出"));
}
this.RegistrationStatus = RegistrationStatus.Lend;
ShouldReturnDate = DateTime.Now.AddDays(10);
//持久化？？
//todo: 这个应该放在这里还是读者的领域服务？
//应该是放在这里，因为借书必然产生借书记录，而且如果放在外面，会造成遗漏，比如很多地方调用借书这个方法，有可能会有地方忘记写这个借书记录
var history = new BookHistory(readerId, this.Id, RegistrationStatus.Lend, comment);
return(Result.Ok());
}
/// <summary>
/// 借书
/// </summary>
/// <param name="readerId"></param>
/// <returns></returns>
public Result Return(int readerId)
{
if (this.RegistrationStatus == RegistrationStatus.Lend)
{
return(Result.FromError("该书已被借出"));
}
this.RegistrationStatus = RegistrationStatus.Normal;
if (DateTime.Today > ShouldReturnDate)
{
//todo: 扣款
}
//还书不一定有留言
var history = new BookHistory(readerId, this.Id, RegistrationStatus.Normal, string.Empty);
return(Result.Ok());
}