ErsatzTV/ErsatzTV.Application/Libraries/Commands/LocalLibraryHandlerBase.cs

using ErsatzTV.Core;
using ErsatzTV.Core.Domain;
using ErsatzTV.Infrastructure.Data;
using Microsoft.EntityFrameworkCore;

namespace ErsatzTV.Application.Libraries;

public abstract class LocalLibraryHandlerBase
{
    protected static Task<Validation<BaseError, LocalLibrary>> NameMustBeValid(
        ILocalLibraryRequest request,
        LocalLibrary localLibrary) =>
        request.NotEmpty(c => c.Name)
            .Bind(_ => request.NotLongerThan(50)(c => c.Name))
            .Map(_ => localLibrary).AsTask();

    protected static async Task<Validation<BaseError, LocalLibrary>> PathsMustBeValid(
        TvContext dbContext,
        LocalLibrary localLibrary,
        int? existingLibraryId = null)
    {
        List<string> allPaths = await dbContext.LocalLibraries
            .Include(ll => ll.Paths)
            .Filter(ll => existingLibraryId == null || ll.Id != existingLibraryId)
            .ToListAsync()
            .Map(list => list.SelectMany(ll => ll.Paths).Map(lp => lp.Path).ToList());

        return Optional(localLibrary.Paths.Count(folder => allPaths.Any(f => AreSubPaths(f, folder.Path))))
            .Where(length => length == 0)
            .Map(_ => localLibrary)
            .ToValidation<BaseError>("Path must not belong to another library path");
    }

    private static bool AreSubPaths(string path1, string path2)
    {
        string one = path1 + Path.DirectorySeparatorChar;
        string two = path2 + Path.DirectorySeparatorChar;
        return one == two || one.StartsWith(two, StringComparison.OrdinalIgnoreCase) ||
               two.StartsWith(one, StringComparison.OrdinalIgnoreCase);
    }
}