modernkeepass/ModernKeePass.Application/Database/Commands/SaveDatabase/SaveDatabaseCommand.cs

using MediatR;
using System.Threading.Tasks;
using ModernKeePass.Application.Common.Interfaces;
using ModernKeePass.Domain.Exceptions;

namespace ModernKeePass.Application.Database.Commands.SaveDatabase
{
    public class SaveDatabaseCommand : IRequest
    {
        public string FilePath { get; set; }

        public class SaveDatabaseCommandHandler : IAsyncRequestHandler<SaveDatabaseCommand>
        {
            private readonly IDatabaseProxy _database;
            private readonly IFileProxy _file;

            public SaveDatabaseCommandHandler(IDatabaseProxy database, IFileProxy file)
            {
                _database = database;
                _file = file;
            }

            public async Task Handle(SaveDatabaseCommand message)
            {
                if (!_database.IsOpen) throw new DatabaseClosedException();

                byte[] contents;
                if (string.IsNullOrEmpty(message.FilePath))
                {
                    contents = await _database.SaveDatabase();
                    await _file.WriteBinaryContentsToFile(_database.FileAccessToken, contents);
                }
                else
                {
                    var newFileContents = await _file.OpenBinaryFile(message.FilePath);
                    contents = await _database.SaveDatabase(newFileContents);
                    await _file.WriteBinaryContentsToFile(message.FilePath, contents);

                    _file.ReleaseFile(_database.FileAccessToken);
                    _database.FileAccessToken = message.FilePath;
                }

            }
        }
    }
}