Add basic plugin version checking functionality

GamecraftModdingAPI/Utility/Dependency.cs

@@ -1,10 +1,79 @@
 using System;
-namespace GamecraftModdingAPI
+
+using IllusionInjector;
+using IllusionPlugin;
+
+namespace GamecraftModdingAPI.Utility
 {
-    public class Dependency
+    /// <summary>
+    /// Simple plugin interaction operations
+    /// </summary>
+    public static class Dependency
     {
-        public Dependency()
-        {
-        }
+        /// <summary>
+        /// Find a plugin by name
+        /// </summary>
+        /// <returns>The plugin.</returns>
+        /// <param name="name">The plugin's name.</param>
+        public static IPlugin GetPlugin(string name)
+		{
+			foreach(IPlugin plugin in PluginManager.Plugins)
+			{
+                if (plugin.Name == name)
+				{
+					return plugin;
+				}
+			}
+			return null;
+		}
+
+        /// <summary>
+        /// Gets the plugin version.
+		/// This gives priority to the plugin's Version string but falls back to the Assembly's version
+        /// </summary>
+        /// <returns>The plugin's version.</returns>
+        /// <param name="name">The plugin's name.</param>
+        public static Version GetPluginVersion(string name)
+		{
+			IPlugin plugin = GetPlugin(name);
+			if (plugin != null) {
+				try
+				{
+					return new Version(plugin.Version);
+				} catch (Exception e) when (
+				    e is ArgumentException
+					|| e is ArgumentNullException
+				    || e is ArgumentOutOfRangeException
+					|| e is FormatException
+				    || e is OverflowException) {}
+				return plugin.GetType().Assembly.GetName().Version;
+			}
+			return null;
+		}
+        
+        // (I'm leaving the auto-generated version)
+        // <summary>
+        // Hell the specified name and version.
+        // </summary>
+        // <returns>The hell.</returns>
+        // <param name="name">Name.</param>
+        // <param name="version">Version.</param>
+        /// <summary>
+        /// Detect if you're in dependency hell with respect to the plugin.
+		/// ie Check if the plugin doesn't exist or is out of date.
+		/// When version is null, this only checks if the plugin exists.
+		/// The version is retrieved using GetPluginVersion(string name).
+        /// </summary>
+        /// <returns>Are you in dependency hell?</returns>
+        /// <param name="name">The plugin's name'</param>
+        /// <param name="version">The target version.</param>
+		public static bool Hell(string name, Version version = null)
+		{
+			Version pluginVersion = GetPluginVersion(name);
+			if (version == null) {
+				return pluginVersion == null;
+			}
+			return (pluginVersion == null || pluginVersion < version);
+		}
     }
 }