Initial test to define the task of the parser

Terminal.Gui/ConsoleDrivers/AnsiResponseParser.cs

@@ -0,0 +1,20 @@
+#nullable enable
+
+namespace Terminal.Gui;
+class AnsiResponseParser
+{
+
+    public bool ConsumeInput (char character, out string? released)
+    {
+        // if character is escape
+
+        // start consuming till we see terminator
+
+        released = null;
+        return false;
+    }
+
+    public void ExpectResponse (char terminator, Action<string> response)
+    {
+    }
+}

UnitTests/ConsoleDrivers/AnsiResponseParserTests.cs

@@ -0,0 +1,76 @@
+namespace UnitTests.ConsoleDrivers;
+public class AnsiResponseParserTests
+{
+    AnsiResponseParser _parser = new AnsiResponseParser ();
+
+    [Fact]
+    public void TestInputProcessing ()
+    {
+        string ansiStream = "\x1B[<0;10;20M" +   // ANSI escape for mouse move at (10, 20)
+                            "Hello" +             // User types "Hello"
+                            "\x1B[0c";            // Device Attributes response (e.g., terminal identification i.e. DAR)
+
+
+        string? response = null;
+
+        int i = 0;
+
+        // Imagine that we are expecting a DAR
+        _parser.ExpectResponse ('c',(s)=> response = s);
+
+        // First char is Escape which we must consume incase what follows is the DAR
+        AssertConsumed (ansiStream, ref i); // Esc
+
+        for (int c = 0; c < "[<0;10;20".Length; c++)
+        {
+            AssertConsumed (ansiStream, ref i);
+        }
+
+        // We see the M terminator
+        AssertReleased (ansiStream, ref i, "\x1B[<0;10;20M");
+
+        // Regular user typing
+        for (int c = 0; c < "Hello".Length; c++)
+        {
+            AssertIgnored (ansiStream, ref i);
+        }
+
+        // Now we have entered the actual DAR we should be consuming these
+        for (int c = 0; c < "\x1B [0".Length; c++)
+        {
+            AssertConsumed (ansiStream, ref i);
+        }
+
+        // Consume the terminator 'c' and expect this to call the above event
+        Assert.Null (response);
+        AssertConsumed (ansiStream, ref i);
+        Assert.NotNull (response);
+        Assert.Equal ("\u001b[0c", response);
+    }
+
+    private void AssertIgnored (string ansiStream, ref int i)
+    {
+        // Parser does not grab this key (i.e. driver can continue with regular operations)
+        Assert.False (_parser.ConsumeInput (NextChar (ansiStream, ref i), out var released));
+        Assert.Null (released);
+    }
+    private void AssertConsumed (string ansiStream, ref int i)
+    {
+        // Parser grabs this key
+        Assert.True (_parser.ConsumeInput( NextChar (ansiStream, ref i), out var released));
+        Assert.Null (released);
+    }
+    private void AssertReleased (string ansiStream, ref int i, string expectedRelease)
+    {
+        // Parser realizes it has grabbed content that does not belong to an outstanding request
+        // Parser returns false to indicate to continue
+        Assert.False(_parser.ConsumeInput (NextChar (ansiStream,ref i), out var released));
+
+        // Parser releases all the grabbed content back to the driver
+        Assert.Equal ( released,expectedRelease);
+    }
+    private char NextChar (string ansiStream, ref int i)
+    {
+        return ansiStream [i++];
+    }
+}