using Dpz.Core.Service.Mediator.Features.Media.Contracts;
using Dpz.Core.Service.Mediator.Features.Media.Events;

namespace Dpz.Core.Service.Mediator.Features.Article.Events;

/// <summary>
/// 尝试为文章补充图片元信息。
/// </summary>
public class ArticleImageMetadataCollectedHandler(
    IRepository<global::Dpz.Core.Public.Entity.Article> repository,
    ILogger<ArticleImageMetadataCollectedHandler> logger
) : INotificationHandler<ImageMetadataCollectedNotification>
{
    /// <summary>
    /// 根据通知中的数据 ID 尝试更新文章集合。
    /// </summary>
    public async ValueTask Handle(
        ImageMetadataCollectedNotification notification,
        CancellationToken cancellationToken
    )
    {
        var article = await repository.TryGetAsync(notification.Id, cancellationToken);
        if (article == null)
        {
            return;
        }

        var images = ImageMetadataBackfillHelper.MergeByUrl(
            article.ImagesAddress,
            article.Images,
            notification.Images
        );
        var update = Builders<global::Dpz.Core.Public.Entity.Article>
            .Update.Set(x => x.MainImageMetadata, images.Count > 0 ? images[0] : null)
            .Set(x => x.Images, images);

        var result = await repository.UpdateAsync(
            x => x.Id == article.Id,
            update,
            cancellationToken
        );
        if (result.ModifiedCount > 0)
        {
            logger.LogInformation(
                "文章图片元信息已回填: Id={Id}, Count={Count}，Title={Title}",
                notification.Id,
                images.Count,
                article.Title
            );
        }
    }
}