ErsatzTV/ErsatzTV.Application/Logs/Queries/GetRecentLogEntriesHandler.cs

using ErsatzTV.Core.Domain;
using ErsatzTV.Infrastructure.Data;
using Microsoft.EntityFrameworkCore;
using static ErsatzTV.Application.Logs.Mapper;

namespace ErsatzTV.Application.Logs;

public class GetRecentLogEntriesHandler : IRequestHandler<GetRecentLogEntries, PagedLogEntriesViewModel>
{
    private readonly IDbContextFactory<LogContext> _dbContextFactory;

    public GetRecentLogEntriesHandler(IDbContextFactory<LogContext> dbContextFactory) =>
        _dbContextFactory = dbContextFactory;

    public async Task<PagedLogEntriesViewModel> Handle(
        GetRecentLogEntries request,
        CancellationToken cancellationToken)
    {
        await using LogContext logContext = _dbContextFactory.CreateDbContext();
        int count = await logContext.LogEntries.CountAsync(cancellationToken);

        IOrderedQueryable<LogEntry> ordered = logContext.LogEntries
            .OrderByDescending(le => le.Id);

        foreach (bool descending in request.SortDescending)
        {
            ordered = descending
                ? logContext.LogEntries.OrderByDescending(request.SortExpression).ThenByDescending(le => le.Id)
                : logContext.LogEntries.OrderBy(request.SortExpression).ThenByDescending(le => le.Id);
        }

        List<LogEntryViewModel> page = await ordered
            .Skip(request.PageNum * request.PageSize)
            .Take(request.PageSize)
            .ToListAsync(cancellationToken)
            .Map(list => list.Map(ProjectToViewModel).ToList());

        return new PagedLogEntriesViewModel(count, page);
    }
}