feat: add protobuf message concept (#21)

Author: tylerkron

src/Daqifi.Core.Tests/Communication/Producers/ScpiMessageProducerTests.cs

@@ -289,7 +289,7 @@ public void ForceBootloader_ReturnsCorrectMessage()
         Assert.Equal("SYSTem:FORceBoot", message.Data);
     }
 
-    private static void AssertMessageFormat(IMessage message)
+    private static void AssertMessageFormat(IOutboundMessage<string> message)
     {
         var bytes = message.GetBytes();
         var expectedBytes = Encoding.ASCII.GetBytes($"{message.Data}\r\n");

src/Daqifi.Core/Communication/Messages/DaqifiOutMessage.cs

@@ -0,0 +1,13 @@
+namespace Daqifi.Core.Communication.Messages;
+
+/// <summary>
+/// Represents a message containing data received from the DAQiFi device (Inbound).
+/// </summary>
+/// <typeparam name="T">The type of the data payload.</typeparam>
+public interface IInboundMessage<out T> // Using 'out' for covariance
+{
+    /// <summary>
+    /// Gets the payload data received from the device.
+    /// </summary>
+    T Data { get; }
+} 

src/Daqifi.Core/Communication/Messages/IInboundMessage.cs

@@ -0,0 +1,20 @@
+namespace Daqifi.Core.Communication.Messages;
+
+/// <summary>
+/// Represents a message to be sent to the DAQiFi device (Outbound).
+/// Defines the contract for serializing the message data into bytes.
+/// </summary>
+/// <typeparam name="T">The type of the data payload.</typeparam>
+public interface IOutboundMessage<T>
+{
+    /// <summary>
+    /// Gets or sets the payload data to be sent.
+    /// </summary>
+    T Data { get; set;}
+
+    /// <summary>
+    /// Converts the message data into a byte array suitable for transmission.
+    /// </summary>
+    /// <returns>A byte array representing the message.</returns>
+    byte[] GetBytes();
+} 

src/Daqifi.Core/Communication/Messages/IMessage.cs

@@ -0,0 +1,26 @@
+namespace Daqifi.Core.Communication.Messages;
+
+/// <summary>
+/// Represents a message containing incoming data from the DAQiFi device,
+/// formatted using Google Protocol Buffers (Protobuf).
+/// The name DaqifiOutMessage signifies data coming "out" from the device.
+/// Implements IInboundMessage.
+/// </summary>
+public class ProtobufMessage : IInboundMessage<DaqifiOutMessage>
+{
+    /// <summary>
+    /// Gets the data associated with the message, which is a DaqifiOutMessage
+    /// received from the device.
+    /// </summary>
+    public DaqifiOutMessage Data { get; }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ProtobufMessage"/> class
+    /// to wrap incoming device data.
+    /// </summary>
+    /// <param name="message">The DaqifiOutMessage received from the device.</param>
+    public ProtobufMessage(DaqifiOutMessage message)
+    {
+        Data = message;
+    }
+}

src/Daqifi.Core/Communication/Messages/IOutboundMessage.cs

@@ -2,12 +2,26 @@
 
 namespace Daqifi.Core.Communication.Messages;
 
-public class ScpiMessage(string command) : IMessage
+/// <summary>
+/// Represents a Standard Commands for Programmable Instruments (SCPI) message
+/// to be sent to the device (Outbound).
+/// Implements IOutboundMessage.
+/// </summary>
+/// <param name="command">The SCPI command string.</param>
+public class ScpiMessage(string command) : IOutboundMessage<string>
 {
-    public object Data { get; set; } = command;
+    /// <summary>
+    /// Gets or sets the data associated with the message, which is the SCPI command string.
+    /// </summary>
+    public string Data { get; set; } = command;
 
+    /// <summary>
+    /// Converts the SCPI command string to a byte array suitable for transmission,
+    /// appending the required carriage return and newline characters.
+    /// </summary>
+    /// <returns>A byte array representing the SCPI message.</returns>
     public byte[] GetBytes()
     {
-        return Encoding.ASCII.GetBytes((string)Data + "\r\n");
+        return Encoding.ASCII.GetBytes(Data + "\r\n");
     }
 }