From b05f3ff13748b86de2f9c5141b4d23b3e8af1994 Mon Sep 17 00:00:00 2001
From: Jonas Arnold <jonas.arnold@live.de>
Date: Mon, 10 Apr 2023 11:32:57 +0200
Subject: [PATCH] implemented abstract CommunicationProtocol and enhanced
 ICommunicationProtocol

---
 MultiTerm.Protocols/CommunicationProtocol.cs  | 96 +++++++++++++++++++
 MultiTerm.Protocols/ICommunicationProtocol.cs | 43 +++++++++
 .../MultiTerm.Protocols.csproj                |  4 +
 MultiTerm.Protocols/ReceivedDataEventArgs.cs  | 13 +++
 MultiTerm.Protocols/SentDataEventArgs.cs      | 13 +++
 5 files changed, 169 insertions(+)
 create mode 100644 MultiTerm.Protocols/CommunicationProtocol.cs
 create mode 100644 MultiTerm.Protocols/ICommunicationProtocol.cs
 create mode 100644 MultiTerm.Protocols/ReceivedDataEventArgs.cs
 create mode 100644 MultiTerm.Protocols/SentDataEventArgs.cs

diff --git a/MultiTerm.Protocols/CommunicationProtocol.cs b/MultiTerm.Protocols/CommunicationProtocol.cs
new file mode 100644
index 0000000..14aab03
--- /dev/null
+++ b/MultiTerm.Protocols/CommunicationProtocol.cs
@@ -0,0 +1,96 @@
+using Common.Logging;
+
+namespace MultiTerm.Protocols;
+
+public abstract class CommunicationProtocol : ICommunicationProtocol
+{
+    public string NewlineSequenceOnSend { get; set; }
+
+    public string NewlineOnReceivedSequence { get; set; }
+
+    protected ILogger logger;
+    private CancellationTokenSource cancellationTokenSource;
+    private Thread? readingThread;
+
+    public event EventHandler<ReceivedDataEventArgs>? ReceivedDataEvent;
+    public event EventHandler<SentDataEventArgs>? SentDataEvent;
+
+
+    public CommunicationProtocol(ILogger logger)
+    {
+        // initialize with empty string, must be correctly initalized by factory
+        this.NewlineSequenceOnSend = string.Empty;
+        this.NewlineOnReceivedSequence = string.Empty;
+
+        // initialize other
+        this.cancellationTokenSource = new CancellationTokenSource();
+        this.logger = logger;
+    }
+
+    /// <summary>
+    /// To be called when data was received from the connected device.
+    /// </summary>
+    /// <param name="e"><see cref="ReceivedDataEventArgs"/></param>
+    protected void OnReceivedData(ReceivedDataEventArgs e) { this.ReceivedDataEvent?.Invoke(this, e); }
+
+    /// <summary>
+    /// To be called when data was sent to the connected device.
+    /// </summary>
+    /// <param name="e"><see cref="SentDataEventArgs"/></param>
+    protected void OnSentData(SentDataEventArgs e) { this.SentDataEvent?.Invoke(this, e); }
+
+    /// <summary>
+    /// Allows to send bytes using the implemented protocol.
+    /// </summary>
+    /// <param name="bytes">data as bytes</param>
+    protected abstract void InternalSendBytes(byte[] bytes);
+
+    public void SendBytes(byte[] bytes)
+    {
+        this.InternalSendBytes(bytes);
+    }
+
+    /// <summary>
+    /// Allows to connect to the selected device using the implemented protocol.
+    /// </summary>
+    /// <returns>true on success</returns>
+    protected abstract bool InternalConnect();
+
+    /// <summary>
+    /// Reads from the connected device in an endless loop.
+    /// The endless loop must be ended when the <paramref name="ct"/> has <see cref="CancellationToken.IsCancellationRequested"/> set.
+    /// </summary>
+    /// <param name="ct">cancellation token</param>
+    protected abstract void InternalRead(CancellationToken ct);
+
+    public void Connect()
+    {
+        if (this.InternalConnect())
+        {
+            // renew token source
+            this.cancellationTokenSource = new CancellationTokenSource();
+            // start internal reading thread
+            this.readingThread = new Thread(() => this.InternalRead(this.cancellationTokenSource.Token));
+            this.readingThread.Start();
+        }
+        else
+        {
+            this.logger.LogWarn($"'{nameof(Connect)}()' failed to connect to protocol, did not start reading thread.", nameof(CommunicationProtocol));
+        }
+    }
+
+    /// <summary>
+    /// Allows to disconnect from the connected device.
+    /// </summary>
+    protected abstract void InternalDisconnect();
+    public void Disconnect()
+    {
+        // if reading thread exists and is running => cancel it and wait 
+        if (this.readingThread != null && this.readingThread.IsAlive)
+        {
+            this.cancellationTokenSource.Cancel();
+            this.readingThread.Join();
+        }
+        this.InternalDisconnect();
+    }
+}
diff --git a/MultiTerm.Protocols/ICommunicationProtocol.cs b/MultiTerm.Protocols/ICommunicationProtocol.cs
new file mode 100644
index 0000000..cd02870
--- /dev/null
+++ b/MultiTerm.Protocols/ICommunicationProtocol.cs
@@ -0,0 +1,43 @@
+namespace MultiTerm.Protocols;
+
+/// <summary>
+/// Interface to interact with a Communication protocol.
+/// </summary>
+public interface ICommunicationProtocol
+{
+    /// <summary>
+    /// Newline sequence to add on the end when sending a message using <see cref="SendBytes(byte[])"/>.
+    /// </summary>
+    string NewlineSequenceOnSend { get; }
+
+    /// <summary>
+    /// When this sequence is detected while reading, a new line is introduced.
+    /// </summary>
+    string NewlineOnReceivedSequence { get; }
+
+    /// <summary>
+    /// New data received from connected device.
+    /// </summary>
+    event EventHandler<ReceivedDataEventArgs>? ReceivedDataEvent;
+
+    /// <summary>
+    /// New data sent to the connected device.
+    /// </summary>
+    event EventHandler<SentDataEventArgs>? SentDataEvent;
+
+    /// <summary>
+    /// Connect to the device.
+    /// </summary>
+    void Connect();
+
+    /// <summary>
+    /// Disconnect from the device. Ends all internal activities.
+    /// </summary>
+    void Disconnect();
+
+    /// <summary>
+    /// Send data to the connected device. 
+    /// </summary>
+    /// <param name="bytes">data to send, as an array of bytes</param>
+    void SendBytes(byte[] bytes);
+}
diff --git a/MultiTerm.Protocols/MultiTerm.Protocols.csproj b/MultiTerm.Protocols/MultiTerm.Protocols.csproj
index 132c02c..56e7d3b 100644
--- a/MultiTerm.Protocols/MultiTerm.Protocols.csproj
+++ b/MultiTerm.Protocols/MultiTerm.Protocols.csproj
@@ -6,4 +6,8 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\Common\Common.csproj" />
+  </ItemGroup>
+
 </Project>
diff --git a/MultiTerm.Protocols/ReceivedDataEventArgs.cs b/MultiTerm.Protocols/ReceivedDataEventArgs.cs
new file mode 100644
index 0000000..856185b
--- /dev/null
+++ b/MultiTerm.Protocols/ReceivedDataEventArgs.cs
@@ -0,0 +1,13 @@
+using MultiTerm.Protocols.Model;
+
+namespace MultiTerm.Protocols;
+
+public class ReceivedDataEventArgs : EventArgs
+{
+    public IEnumerable<ExtendedChar> ReceivedCharacters { get; private set; }
+
+    public ReceivedDataEventArgs(IEnumerable<ExtendedChar> receivedCharacters)
+    {
+        this.ReceivedCharacters = receivedCharacters;
+    }
+}
diff --git a/MultiTerm.Protocols/SentDataEventArgs.cs b/MultiTerm.Protocols/SentDataEventArgs.cs
new file mode 100644
index 0000000..ffa3c77
--- /dev/null
+++ b/MultiTerm.Protocols/SentDataEventArgs.cs
@@ -0,0 +1,13 @@
+using MultiTerm.Protocols.Model;
+
+namespace MultiTerm.Protocols;
+
+public class SentDataEventArgs : EventArgs
+{
+    public IEnumerable<ExtendedChar> SentCharacters { get; private set; }
+
+    public SentDataEventArgs(IEnumerable<ExtendedChar> sentCharacters)
+    {
+        this.SentCharacters = sentCharacters;
+    }
+}
\ No newline at end of file