backend/Services/BlogPostService.cs

using backend.Models;
using Microsoft.Extensions.Options;
using MongoDB.Driver;

namespace backend.Services;

public class BlogPostService
{
    private readonly IMongoCollection<BlogPost> _posts;
    
    public BlogPostService(IOptions<BlogDatabaseSettings> settings)
    {
        var client = new MongoClient(settings.Value.ConnectionString);
        var database = client.GetDatabase(settings.Value.DatabaseName);

        _posts = database.GetCollection<BlogPost>(settings.Value.PostsCollectionName);
    }
    
    public async Task<BlogPost?> GetPostAsync(string id)
    {
        var post = await _posts.Find(p => p.Id == id).FirstOrDefaultAsync();
        return post;
    }

    public async Task<List<BlogPost>> GetLastNPostsAsync(int n)
    {
        var posts = await _posts.Find(p => true).SortByDescending(p => p.CreatedAt).Limit(n).ToListAsync();
        return posts;
    }
    
    public async Task<List<BlogPost>> GetAllPostsAsync()
    {
        var posts = await _posts.Find(p => true).ToListAsync();
        return posts;
    }
    
    public async Task CreatePostAsync(BlogPost post)
    {
        post.CreatedAt = DateTime.UtcNow;
        await _posts.InsertOneAsync(post);
    }
    
    public async Task UpdatePostAsync(string id, BlogPost postIn)
    {
        var oldPost = await _posts.Find(p => p.Id == id).FirstOrDefaultAsync();
        //Set timestamps
        postIn.CreatedAt = oldPost.CreatedAt;
        postIn.UpdatedAt = DateTime.UtcNow;
        await _posts.ReplaceOneAsync(p => p.Id == id, postIn);
    }
    
    public async Task DeletePostAsync(string id)
    {
        await _posts.DeleteOneAsync(p => p.Id == id);
    }
    
}