TBMM/GCMM/MainForm.cs

using GCMM.Properties;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Net;
using System.Reflection;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace GCMM
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();
        }

        private readonly Dictionary<string, ModInfo> mods = new Dictionary<string, ModInfo>();
        private readonly ModInfo gcipa = new ModInfo { Author = "modtainers", Name = "GCIPA" };
        private readonly ModInfo gcmm = new ModInfo { Author = "NorbiPeti", Name = "GCMM" };
        private const string defaultInfo = @"
Gamecraft Mod Manager

If you click on a mod it will show some info about it. The install instructions there are usually for manual installs.
To get started, click on a mod and select Install mod. Most mods need GamecraftModdingAPI as well.
Then, simply click Play. This will first download and run the patcher (GCIPA) if needed.
If all goes well, after some time a modded Gamecraft should launch.

After a Gamecraft update there's a good chance that mods will break. If this happens you may get errors when trying to start Gamecraft.
Until updated versions are released, use the ""Disable mods"" checkbox at the bottom to launch the game without mods.

You don't have to use the mod manager to run the game each time, though it will tell you about mod updates when they come.
However, you need to run it and click ""Patch & Play"" each time there's a Gamecraft update.

Disclaimer:
This mod manager and the mods in the list are made by the ExMods developers. We are not associated with Freejam or Gamecraft. Modify Gamecraft at your own risk.

If you encounter an issue while any mods are installed, report it to us. If you think it's an issue with the game, test again with the ""Disable mods"" option checked before reporting to Freejam.
You may also want to verify the game's files by right clicking the game in Steam and choosing Properties, going to Local files and clicking Verify integrity of game files.
";

        private void Form1_Load(object sender, EventArgs e)
        {
            if (Settings.Default.NeedsUpdate)
            {
                Settings.Default.Upgrade();
                Settings.Default.NeedsUpdate = false;
                Settings.Default.Save();
            }
            modlist.Items.Clear();
            UpdateButton(installbtn, false);
            modinfobox.Text = defaultInfo;
            if (string.IsNullOrWhiteSpace(Settings.Default.GamePath) || GetExe() == null)
            {
                Settings.Default.GamePath = GetGameFolder();
                if (string.IsNullOrWhiteSpace(Settings.Default.GamePath))
                    Settings.Default.GamePath = SelectGameFolder();
                else
                    MessageBox.Show("Found game at " + Settings.Default.GamePath);
                Settings.Default.Save();
            }
            if(string.IsNullOrWhiteSpace(Settings.Default.GamePath))
            {
                status.Text = "Status: Game not found";
                return;
            }
            DeleteEmptyPluginsDir(out bool pexists, out bool dexists);
            if (!pexists && dexists)
                unpatched.Checked = true; //It will call the event but that won't do anything
            refreshbtn_Click(refreshbtn, null);
        }

        private async void playbtn_Click(object sender, EventArgs e)
        {
            if (playbtn.ForeColor == Color.Green) return; //Disabled
            await UpdateAPI();
            await PatchStartGame(); //It will call EndWork();
        }

        private void settingsbtn_Click(object sender, EventArgs e)
        {
            if (settingsbtn.ForeColor == Color.Green) return; //Disabled
            var sf = new SettingsForm();
            sf.ShowDialog(this);
        }

        private void modlist_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (working) return;
            modinfobox.Clear();
            switch (modlist.SelectedItems.Count)
            {
                case 0:
                    modinfobox.Text = defaultInfo;
                    UpdateButton(installbtn, false);
                    UpdateButton(uninstallbtn, false);
                    break;
                case 1:
                default:
                    installbtn.Text = "Install mod";
                    UpdateButton(installbtn, false);
                    UpdateButton(uninstallbtn, false);
                    bool install = false, update = false;
                    foreach (ListViewItem item in modlist.SelectedItems)
                    {
                        var mod = mods[item.Name];
                        if (modlist.SelectedItems.Count == 1)
                        {
                            bool up = mod.Updatable;
                            modinfobox.Text = ((up ? "New version available! " + mod.UpdateDetails + "\n\n"
                                : "") + mod.Description).Replace("\n", Environment.NewLine);
                            if(up)
                            {
                                modinfobox.Select(0, "New version available!".Length);
                                modinfobox.SelectionColor = Color.Aqua;
                                modinfobox.DeselectAll();
                                modinfobox.SelectionColor = modinfobox.ForeColor;
                            }
                        }
                        else
                            modinfobox.Text = modlist.SelectedItems.Count + " mods selected";
                        if (mod.DownloadURL != null && !(mod.LatestVersion <= mod.Version))
                        {
                            UpdateButton(installbtn, true);
                            if (mod.Version != null)
                                update = true;
                            else
                                install = true;
                        }
                        if (mod.Version != null)
                            UpdateButton(uninstallbtn, true);
                    }
                    if (install && update)
                        installbtn.Text = "Install and update mod";
                    else if (update)
                        installbtn.Text = "Update mod";
                    else
                        installbtn.Text = "Install mod";
                    break;
            }
            if (unpatched.Checked)
            { //Don't allow (un)installing mods if mods are disabled
                UpdateButton(installbtn, false);
                UpdateButton(uninstallbtn, false);
                modlist.Enabled = false;
            }
            else
                modlist.Enabled = true;
        }

        private async void installbtn_Click(object sender, EventArgs e)
        {
            if (installbtn.ForeColor == Color.Green) return; //Disabled
            if (!BeginWork()) return;
            foreach (ListViewItem item in modlist.SelectedItems)
            {
                var mod = mods[item.Name];
                if (item.Group.Name == "installed" && (mod.DownloadURL == null || mod.LatestVersion <= mod.Version)) continue;
                await InstallMod(mod);
            }
            EndWork();
        }

        private void uninstallbtn_Click(object sender, EventArgs e)
        {
            if (uninstallbtn.ForeColor == Color.Green) return; //Disabled
            foreach (ListViewItem item in modlist.SelectedItems)
            {
                if (item.Group.Name != "installed") continue;
                UninstallMod(mods[item.Name]);
            }
            EndWork(); //Update button states
        }

        private void findlog_Click(object sender, EventArgs e)
        {
            if (Environment.OSVersion.Platform == PlatformID.Win32NT)
            {
                if (CheckNoExe(out string exe))
                    return;
                Process.Start("explorer.exe", $@"/select,{Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData)}Low\Freejam\{exe.Replace(".exe", "")}\Player.log");
            }
        }

        private void unpatched_CheckedChanged(object sender, EventArgs e)
        { //Not using the patcher's revert option because sometimes it restores the wrong files - the game can be patched without mods
            if (CheckNoExe())
                return;
            CheckIfPatched();
            modlist_SelectedIndexChanged(modlist, null);
            string plugins = GamePath("\\Plugins");
            string disabled = GamePath("\\Plugins_Disabled");
            DeleteEmptyPluginsDir(out bool pexists, out bool dexists);
            if (unpatched.Checked)
            {
                if (pexists)
                {
                    if (dexists)
                        Directory.Delete(disabled, true); //Resolving conflicts would be complicated so delete the other mods - this shouldn't happen normally
                    Directory.Move(plugins, disabled);
                }
            }
            else
            {
                if (dexists)
                {
                    if (pexists)
                        Directory.Delete(plugins, true);
                    Directory.Move(disabled, plugins);
                }
            }
        }
        
        private void DeleteEmptyPluginsDir(out bool pexists, out bool dexists)
        {
            string plugins = GamePath("\\Plugins");
            string disabled = GamePath("\\Plugins_Disabled");
            pexists = Directory.Exists(plugins);
            dexists = Directory.Exists(disabled);
            if (pexists && !Directory.EnumerateFiles(plugins).Any())
            {
                Directory.Delete(plugins);
                pexists = false;
            }
            if (dexists && !Directory.EnumerateFiles(disabled).Any())
            {
                Directory.Delete(disabled);
                dexists = false;
            }
        }

        private async void refreshbtn_Click(object sender, EventArgs e)
        {
            CheckIfPatched(); //Set from placeholder
            var mods = GetInstalledMods();
            await GetAvailableMods();
            CheckUninstalledMods(mods);
            CheckIfPatched(); //Check after getting the available mods to show GCIPA updates
        }

        private void validatebtn_Click(object sender, EventArgs e)
        {
            if (CheckNoExe())
                return;
            if (MessageBox.Show("Validating the game's files is useful if the game doesn't start even without mods. Make sure to click Refresh once Steam finished verifying the game. The Steam window that shows the progress might open in the background. Note that you will need to patch the game again using the Play button in order to use mods.\n\nContinue?", "Verify game files", MessageBoxButtons.OKCancel) == DialogResult.Cancel)
                return;
            string exe = GetExe();
            File.Delete(GamePath($@"\{exe.Replace(".exe", "")}_Data\Managed\IllusionInjector.dll")); //Used to check if game is patched
            if (Environment.OSVersion.Platform == PlatformID.Win32NT)
                Process.Start("steam://validate/1078000/");
            else
                Process.Start("xdg-open", "steam://validate/1078000/");
        }
    }
}