Add the Command concept

src/SmartHomeDotNet.Package/SmartHome/Commands/CommandParser.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Linq;
+
+namespace SmartHomeDotNet.SmartHome.Commands
+{
+	/// <summary>
+	/// A default parser for common commands
+	/// </summary>
+	public sealed class CommandParser : ICommandParser
+	{
+		/// <summary>
+		/// Singleton instance of the parser
+		/// </summary>
+		public static ICommandParser Default { get; } = new CommandParser();
+
+		private CommandParser()
+		{
+		}
+
+		/// <inheritdoc />
+		public bool TryParse(string value, out ICommand command)
+		{
+			switch (value.ToLowerInvariant())
+			{
+				case "on":
+					command = new TurnOn();
+					return true;
+
+				case "off":
+					command = new TurnOff();
+					return true;
+
+				default:
+					command = default;
+					return false;
+			}
+		}
+	}
+}

src/SmartHomeDotNet.Package/SmartHome/Commands/ICommand.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Linq;
+using SmartHomeDotNet.SmartHome.Devices;
+using SmartHomeDotNet.Utils;
+
+namespace SmartHomeDotNet.SmartHome.Commands
+{
+	/// <summary>
+	/// Marker interface for commands on <see cref="IDevice"/>
+	/// </summary>
+	public interface ICommand
+	{
+	}
+
+	public static class CommandExtensions
+	{
+		public static AsyncContextOperation TurnOn<T>(this IDevice<T> device)
+			where T : ISupport<TurnOn>
+			=> device.Host.Execute(new TurnOn(), device);
+
+		public static AsyncContextOperation TurnOff<T>(this IDevice<T> device)
+			where T : ISupport<TurnOff>
+			=> device.Host.Execute(new TurnOff(), device);
+	}
+
+	public static class CommandParserExtensions
+	{
+		public static ICommand ParseOrDefault(this ICommandParser parser, string command)
+			=> parser.TryParse(command, out var c) ? c : default;
+	}
+}

src/SmartHomeDotNet.Package/SmartHome/Commands/ICommandParser.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Linq;
+
+namespace SmartHomeDotNet.SmartHome.Commands
+{
+	/// <summary>
+	/// A parser capable to create an instance of an <see cref="ICommand"/> from its string representation
+	/// </summary>
+	public interface ICommandParser
+	{
+		/// <summary>
+		/// Try to parse a command from it string representation
+		/// </summary>
+		/// <param name="value">The source string to parse</param>
+		/// <param name="command">The result command</param>
+		/// <returns>A bool which indicates if the parsing was successful or not</returns>
+		bool TryParse(string value, out ICommand command);
+	}
+}

src/SmartHomeDotNet.Package/SmartHome/Commands/ISupport.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Linq;
+using SmartHomeDotNet.SmartHome.Devices;
+
+namespace SmartHomeDotNet.SmartHome.Commands
+{
+	/// <summary>
+	/// Marker interface for an <see cref="IDevice"/> to indicates the supported <see cref="ICommand"/>
+	/// </summary>
+	/// <typeparam name="T">Type of the command that is supported by this device</typeparam>
+	public interface ISupport<T>
+		where T : ICommand
+	{
+	}
+}

src/SmartHomeDotNet.Package/SmartHome/Commands/Toggle.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Linq;
+
+namespace SmartHomeDotNet.SmartHome.Commands
+{
+	/// <summary>
+	/// A command to turn off a device
+	/// </summary>
+	public struct Toggle : ICommand
+	{
+		/// <summary>
+		/// The optional duration of the fade out for dimmable devices
+		/// </summary>
+		public TimeSpan? Duration { get; }
+	}
+}

src/SmartHomeDotNet.Package/SmartHome/Commands/TurnOff.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Linq;
+
+namespace SmartHomeDotNet.SmartHome.Commands
+{
+	/// <summary>
+	/// A command to turn off a device
+	/// </summary>
+	public struct TurnOff : ICommand
+	{
+		/// <summary>
+		/// The optional duration of the fade out for dimmable devices
+		/// </summary>
+		public TimeSpan? Duration { get; }
+	}
+}

src/SmartHomeDotNet.Package/SmartHome/Commands/TurnOn.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Drawing;
+using System.Linq;
+
+namespace SmartHomeDotNet.SmartHome.Commands
+{
+	/// <summary>
+	/// A command to turn on a device
+	/// </summary>
+	public struct TurnOn : ICommand
+	{
+		/// <summary>
+		/// The optional target color for light
+		/// </summary>
+		public Color? Color { get; set; }
+
+		/// <summary>
+		/// The optional target level for dimmable devices
+		/// </summary>
+		public double? Level { get; set; }
+
+		/// <summary>
+		/// The optional duration of the fade in for dimmable devices
+		/// </summary>
+		public TimeSpan? Duration { get; set; }
+	}
+}

src/SmartHomeDotNet.Package/SmartHomeDotNet.Package.csproj

@@ -6,6 +6,7 @@
 	<RootNamespace>SmartHomeDotNet</RootNamespace>
 	<PackageId>smarthomedotnet</PackageId>
 	<GeneratePackageOnBuild Condition="$(Configuration)=='Release'">true</GeneratePackageOnBuild>
+	<LangVersion>7.3</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>