/// <summary>
/// 获取指定事件的文券变动量
/// </summary>
/// <param name="event">文券事件</param>
/// <returns>变动量，可以为正数或者负数</returns>
public static int ToCouponChange(this CouponEvent @event)
{
switch (@event)
{
case CouponEvent.新注册:
return(10);
case CouponEvent.应邀注册:
return(5);
case CouponEvent.发布文章:
return(-3);
case CouponEvent.发出认可:
return(-1);
case CouponEvent.获得认可:
return(1);
case CouponEvent.每日访问:
return(1);
case CouponEvent.邀请注册:
return(3);
default:
throw new ArgumentOutOfRangeException(nameof(@event), @event, null);
}
}
/// <summary>
/// 增减用户的文券数量
/// </summary>
/// <param name="user">用户对象</param>
/// <param name="event">文券事件</param>
/// <param name="change">文券数量变化，正数为增加，负数为减少</param>
/// <param name="description">文券记录描述</param>
/// <param name="logTime">文券日志记录时间，如果为 null 则使用当前时间</param>
/// <exception cref="ArgumentNullException">user 参数为 null</exception>
public async Task UpdateAsync(KeylolUser user, CouponEvent @event, int change, object description = null,
DateTime?logTime = null)
{
if (user == null)
{
throw new ArgumentNullException(nameof(user));
}
var log = new CouponLog
{
Change = change,
Event = @event,
UserId = user.Id,
Description = JsonConvert.SerializeObject(description)
};
_dbContext.CouponLogs.Add(log);
bool saveFailed;
do
{
try
{
saveFailed = false;
user.Coupon += log.Change;
log.Balance = user.Coupon;
log.CreateTime = logTime ?? DateTime.Now;
await _dbContext.SaveChangesAsync();
NotificationProvider.Hub <CouponHub, ICouponHubClient>().User(user.Id)?
.OnCouponChanged(log.Event.ToString(), log.Change, log.Balance);
}
catch (DbUpdateConcurrencyException e)
{
saveFailed = true;
await e.Entries.Single().ReloadAsync();
}
} while (saveFailed);
}
/// <summary>
/// 根据文券事件更新用户的文券数量
/// </summary>
/// <param name="user">用户对象</param>
/// <param name="event">文券事件</param>
/// <param name="description">文券记录描述，会被序列化成 JSON 存储到数据库</param>
/// <param name="logTime">文券日志记录时间，如果为 null 则使用当前时间</param>
/// <exception cref="ArgumentNullException">user 参数为 null</exception>
public async Task UpdateAsync(KeylolUser user, CouponEvent @event, object description = null,
DateTime?logTime = null)
{
await UpdateAsync(user, @event, @event.ToCouponChange(), description, logTime);
}
/// <summary>
/// 判断指定用户是否有足够文券触发指定事件
/// </summary>
/// <param name="userId">用户 ID</param>
/// <param name="event">文券事件</param>
/// <returns>可以触发指定事件返回 true，不能则返回 false</returns>
public async Task <bool> CanTriggerEventAsync(string userId, CouponEvent @event)
{
var user = await _userManager.FindByIdAsync(userId);
return(user.Coupon + @event.ToCouponChange() >= 0);
}
