AuthorBuddy/Services/ChatService.cs

using AuthorBuddy.Web.Data;
using LiteDB;

namespace AuthorBuddy.Web.Services;

public class ChatService : IChatService
{
    private readonly ILiteDatabase _db;

    public ChatService(ILiteDatabase db)
    {
        _db = db;
    }

    public Task<List<ChatEntity>> GetHistoryAsync(int userId)
    {
        var col = _db.GetCollection<ChatEntity>("chats");
        return Task.FromResult(col.Find(c => c.UserId == userId)
            .OrderByDescending(c => c.Timestamp)
            .Take(100)
            .Reverse()
            .ToList());
    }

    public Task AddMessageAsync(ChatEntity message)
    {
        var col = _db.GetCollection<ChatEntity>("chats");
        col.Insert(message);
        return Task.CompletedTask;
    }

    public Task ClearHistoryAsync(int userId)
    {
        var col = _db.GetCollection<ChatEntity>("chats");
        col.DeleteMany(c => c.UserId == userId);
        return Task.CompletedTask;
    }
}