1 files changed, 103 insertions, 0 deletions
diff --git a/src/SMAPI.Installer/Framework/InstallerContext.cs b/src/SMAPI.Installer/Framework/InstallerContext.cs
new file mode 100644
index 00000000..7531eaee
--- /dev/null
+++ b/src/SMAPI.Installer/Framework/InstallerContext.cs
@@ -0,0 +1,103 @@
+using System;
+using System.IO;
+using Microsoft.Win32;
+using StardewModdingAPI.Toolkit;
+using StardewModdingAPI.Toolkit.Framework.GameScanning;
+using StardewModdingAPI.Toolkit.Utilities;
+
+namespace StardewModdingAPI.Installer.Framework
+{
+    /// <summary>The installer context.</summary>
+    internal class InstallerContext
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>The <see cref="Environment.OSVersion"/> value that represents Windows 7.</summary>
+        private readonly Version Windows7Version = new Version(6, 1);
+
+        /// <summary>The underlying toolkit game scanner.</summary>
+        private readonly GameScanner GameScanner = new GameScanner();
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The current OS.</summary>
+        public Platform Platform { get; }
+
+        /// <summary>The human-readable OS name and version.</summary>
+        public string PlatformName { get; }
+
+        /// <summary>The name of the Stardew Valley executable.</summary>
+        public string ExecutableName { get; }
+
+        /// <summary>Whether the installer is running on Windows.</summary>
+        public bool IsWindows => this.Platform == Platform.Windows;
+
+        /// <summary>Whether the installer is running on a Unix OS (including Linux or MacOS).</summary>
+        public bool IsUnix => !this.IsWindows;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        public InstallerContext()
+        {
+            this.Platform = EnvironmentUtility.DetectPlatform();
+            this.PlatformName = EnvironmentUtility.GetFriendlyPlatformName(this.Platform);
+            this.ExecutableName = EnvironmentUtility.GetExecutableName(this.Platform);
+        }
+
+        /// <summary>Get the installer's version number.</summary>
+        public ISemanticVersion GetInstallerVersion()
+        {
+            var raw = this.GetType().Assembly.GetName().Version;
+            return new SemanticVersion(raw);
+        }
+
+        /// <summary>Get whether the current system has .NET Framework 4.5 or later installed. This only applies on Windows.</summary>
+        /// <exception cref="NotSupportedException">The current platform is not Windows.</exception>
+        public bool HasNetFramework45()
+        {
+            switch (this.Platform)
+            {
+                case Platform.Windows:
+                    using (RegistryKey versionKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full"))
+                        return versionKey?.GetValue("Release") != null; // .NET Framework 4.5+
+
+                default:
+                    throw new NotSupportedException("The installed .NET Framework version can only be checked on Windows.");
+            }
+        }
+
+        /// <summary>Get whether the current system has XNA Framework installed. This only applies on Windows.</summary>
+        /// <exception cref="NotSupportedException">The current platform is not Windows.</exception>
+        public bool HasXna()
+        {
+            switch (this.Platform)
+            {
+                case Platform.Windows:
+                    using (RegistryKey key = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey(@"SOFTWARE\Microsoft\XNA\Framework"))
+                        return key != null; // XNA Framework 4.0+
+
+                default:
+                    throw new NotSupportedException("The installed XNA Framework version can only be checked on Windows.");
+            }
+        }
+
+        /// <summary>Whether the current OS supports newer versions of .NET Framework.</summary>
+        public bool CanInstallLatestNetFramework()
+        {
+            return Environment.OSVersion.Version >= this.Windows7Version; // Windows 7+
+        }
+
+        /// <summary>Get whether a folder seems to contain the game files.</summary>
+        /// <param name="dir">The folder to check.</param>
+        public bool LooksLikeGameFolder(DirectoryInfo dir)
+        {
+            return this.GameScanner.LooksLikeGameFolder(dir);
+        }
+    }
+}