/// <summary>
/// 获取指定据点的评分
/// </summary>
/// <param name="pointId">据点 ID</param>
/// <exception cref="ArgumentNullException"><paramref name="pointId"/> 为 null</exception>
/// <returns>据点评分</returns>
public async Task <PointRatingsDto> GetRatingsAsync([NotNull] string pointId)
{
if (pointId == null)
{
throw new ArgumentNullException(nameof(pointId));
}
var cacheKey = RatingCacheKey(pointId);
var redisDb = _redis.GetDatabase();
var cacheResult = await redisDb.StringGetAsync(cacheKey);
if (cacheResult.HasValue)
{
return(RedisProvider.Deserialize <PointRatingsDto>(cacheResult));
}
var ratings = new PointRatingsDto();
var userRatings = new Dictionary <string, UserRating>();
foreach (var ratingEntry in await _dbContext.Articles
.Where(a => a.TargetPointId == pointId && a.Rating != null &&
a.Archived == ArchivedState.None && a.Rejected == false)
.Select(a => new { a.AuthorId, a.Rating })
.Union(_dbContext.Activities
.Where(a => a.TargetPointId == pointId && a.Rating != null)
.Select(a => new { a.AuthorId, a.Rating }))
.ToListAsync())
{
switch (ratingEntry.Rating.Value)
{
case 1:
ratings.OneStarCount++;
break;
case 2:
ratings.TwoStarCount++;
break;
case 3:
ratings.ThreeStarCount++;
break;
case 4:
ratings.FourStarCount++;
break;
case 5:
ratings.FiveStarCount++;
break;
default:
continue;
}
UserRating userRating;
if (!userRatings.TryGetValue(ratingEntry.AuthorId, out userRating))
{
userRatings[ratingEntry.AuthorId] = userRating = new UserRating();
}
userRating.Count++;
userRating.Total += ratingEntry.Rating.Value;
}
ratings.AverageRating = userRatings.Count < 3
? (double?)null
: Math.Round(userRatings.Values.Sum(r => r.Total * 2 / (double)r.Count) / userRatings.Count, 1);
await redisDb.StringSetAsync(cacheKey, RedisProvider.Serialize(ratings), RatingUpdatePeriod);
return(ratings);
}
