Notes/Notes.Data/Models/Note.cs

using System;
using System.Collections.Generic;
using System.Linq;
using Utils;

namespace Notes.Models;

public class Note
{
    public const string Extension = ".notes.txt";
    public string Filename { get; set; }
    public string Text { get; set; }
    public DateTime Date { get; set; }

    public string ShortName => Filename.Replace(Extension, string.Empty);

    public static string AppDataDirectory
    {
        get
        {
            var appDataDirectory = FileSystem.Combine(AppContext.BaseDirectory, "Data");
            IOUtils.EnsureDirectory(appDataDirectory,false);
            return appDataDirectory;
        }
    }
    public Note()
    {
        Filename = $"{FileSystem.GetRandomFileName()}{Extension}";
        Date = DateTime.Now;
        Text = "";
    }

    public void Save() =>
        FileSystem.WriteAllText(FileSystem.Combine(AppDataDirectory, Filename), Text);

    public void Delete() =>
        FileSystem.Delete(FileSystem.Combine(AppDataDirectory, Filename));

    public static Note Load(string filename)
    {
        filename = FileSystem.Combine(AppDataDirectory, filename);

        if (!FileSystem.ExistsFile(filename))
            throw new InvalidOperationException($"Unable to find file '{filename}' on local storage.");

        return
            new()
            {
                Filename = FileSystem.GetFileName(filename),
                Text = FileSystem.ReadAllText(filename),
                Date = FileSystem.GetLastWriteTime(filename)
            };
    }

    public static IEnumerable<Note> LoadAll()
    {
        // Get the folder where the notes are stored.
        string appDataPath = AppDataDirectory;

        // Use Linq extensions to load the *.notes.txt files.
        return FileSystem

            // Select the file names from the directory
            .EnumerateFiles(appDataPath, "*.notes.txt")

            // Each file name is used to load a note
            .Select(filename => Load(FileSystem.GetFileName(filename)))

            // With the final collection of notes, order them by date
            .OrderByDescending(note => note.Date);
    }
}