/
SaverChangeSet.cs
25 lines (22 loc) · 1.11 KB
/
SaverChangeSet.cs
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using System.Collections.ObjectModel;
namespace tbm.Crawler.Tieba.Crawl.Saver;
public class SaverChangeSet<T> where T : class, IPost
{
public ReadOnlyCollection<(T Before, T After)> Existing { get; }
public ReadOnlyCollection<T> NewlyAdded { get; }
public ReadOnlyCollection<T> AllAfter { get; }
public SaverChangeSet(ICollection<T> existingBefore, ICollection<T> existingAfterAndNewlyAdded, Func<T, PostId> postIdSelector)
{
var existingAfter = existingAfterAndNewlyAdded
.IntersectBy(existingBefore.Select(postIdSelector), postIdSelector)
.OrderBy(postIdSelector).ToList();
if (existingAfter.Count != existingBefore.Count) throw new(
"Length of existingAfter is not match with existingBefore.");
Existing = new(existingBefore
.OrderBy(postIdSelector)
.Zip(existingAfter, (before, after) => (before, after)).ToList());
NewlyAdded = new(existingAfterAndNewlyAdded
.ExceptBy(existingBefore.Select(postIdSelector), postIdSelector).ToList());
AllAfter = new(existingAfterAndNewlyAdded.ToList());
}
}