Freshness.cs

/////////////////////////////////////////////////////////////////////////////////
// CodeLab for Paint.NET
// Portions Copyright ©2007-2020 BoltBait. All Rights Reserved.
// Portions Copyright ©Microsoft Corporation. All Rights Reserved.
//
// THE CODELAB DEVELOPERS MAKE NO WARRANTY OF ANY KIND REGARDING THE CODE. THEY
// SPECIFICALLY DISCLAIM ANY WARRANTY OF FITNESS FOR ANY PARTICULAR PURPOSE OR
// ANY OTHER WARRANTY.  THE CODELAB DEVELOPERS DISCLAIM ALL LIABILITY RELATING
// TO THE USE OF THIS CODE.  NO LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR
// OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED HEREIN.
//
// Latest distribution: https://www.BoltBait.com/pdn/codelab
/////////////////////////////////////////////////////////////////////////////////

using System;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace PdnCodeLab
{
    internal static class Freshness
    {
        private const string ThisVersion = CodeLab.Version;
        private const string WebUpdateFile = "https://www.boltbait.com/versions.txt"; // The web site to check for updates
        private const string ThisApplication = "1"; // in the WebUpadteFile, CodeLab is application #1
        // format of the versions.txt file:  application number;current version;URL to download current version
        // for example: 1;2.13;https://boltbait.com/pdn/CodeLab/CodeLab213.zip
        // each application on its own line

        private static string updateURL;
        private static string updateVER;
        private static bool needToShowNotification = false;
        private static readonly HttpClient httpClient = new HttpClient();

        internal static void DisplayUpdateNotification()
        {
            if (needToShowNotification)
            {
                needToShowNotification = false;

                if (FlexibleMessageBox.Show("An update to CodeLab is available.\n\nWould you like to download CodeLab v" + updateVER + "?\n\n(This will not close your current CodeLab session.)", "CodeLab Updater", MessageBoxButtons.YesNo, MessageBoxIcon.Exclamation) == DialogResult.Yes)
                {
                    UIUtil.LaunchUrl(null, updateURL);
                }
            }
        }

        internal static async Task GoCheckForUpdates(bool silentMode, bool force)
        {
            updateURL = string.Empty;
            updateVER = string.Empty;
            needToShowNotification = false;

            if (!force)
            {
                // only check for updates every 7 days
                if (Math.Abs((Settings.LatestUpdateCheck - DateTime.Today).TotalDays) < 7)
                {
                    return; // not time yet
                }
            }

            UpdateStatus updateStatus = UpdateStatus.Unknown;

            HttpResponseMessage response = null;
            Random r = new Random(); // defeat any cache by appending a random number to the URL

            try
            {
                response = await httpClient.GetAsync($"{WebUpdateFile}?r={r.Next(int.MaxValue)}");
            }
            catch
            {
            }

            if (response != null && response.IsSuccessStatusCode)
            {
                Settings.LatestUpdateCheck = DateTime.Now;

                string content = await response.Content.ReadAsStringAsync();

                foreach (string line in content.Split('\n', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries))
                {
                    string[] data = line.Split(';', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
                    if (data.Length >= 2 && data[0] == ThisApplication)
                    {
                        if (Version.TryParse(data[1], out Version remoteVersion) &&
                            Version.TryParse(ThisVersion, out Version localVersion))
                        {
                            if (remoteVersion > localVersion)
                            {
                                updateStatus = UpdateStatus.UpdateAvailable;
                                updateVER = data[1];
                                updateURL = data[2];
                            }
                            else
                            {
                                updateStatus = UpdateStatus.UpToDate;
                            }
                        }

                        break;
                    }
                }
            }

            response?.Dispose();

            if (silentMode)
            {
                needToShowNotification = updateStatus == UpdateStatus.UpdateAvailable;
            }
            else
            {
                switch (updateStatus)
                {
                    case UpdateStatus.Unknown:
                        FlexibleMessageBox.Show("I'm not sure if you are up-to-date.\n\nI was not able to reach the update website.\n\nTry again later.", "CodeLab Updater", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                        break;
                    case UpdateStatus.UpToDate:
                        FlexibleMessageBox.Show("You are up-to-date!", "CodeLab Updater", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        break;
                    case UpdateStatus.UpdateAvailable:
                        if (FlexibleMessageBox.Show("An update to CodeLab is available.\n\nWould you like to download CodeLab v" + updateVER + "?\n\n(This will not close your current CodeLab session.)", "CodeLab Updater", MessageBoxButtons.YesNo, MessageBoxIcon.Exclamation) == DialogResult.Yes)
                        {
                            UIUtil.LaunchUrl(null, updateURL);
                        }
                        break;
                }
            }
        }

        private enum UpdateStatus
        {
            Unknown,
            UpToDate,
            UpdateAvailable
        }
    }
}