Allow existing triggers to be merged in with new trigger definitions

Removed unused using statement

Code cleanup

Cleaning up tests

Deal with possible existing simple compound event triggers

It's possible for triggers to take the form "showMessage,doStuff" so be sure to split these triggers into multiple triggers.

src/Htmx/HtmxResponseHeaders.cs

@@ -183,7 +183,7 @@ public HtmxResponseHeaders WithTrigger(string eventName, object? detail = null,
         }
         else
         {
-            _triggers[timing].Add(eventName, detail ?? string.Empty);
+            _triggers[timing].TryAdd(eventName, detail ?? string.Empty);
         }
 
         return this;
@@ -194,38 +194,64 @@ public HtmxResponseHeaders WithTrigger(string eventName, object? detail = null,
     /// </summary>
     internal HtmxResponseHeaders Process()
     {
-        if (_triggers.ContainsKey(HtmxTriggerTiming.Default))
-        {
-            if (_headers.ContainsKey(Keys.Trigger))
-            {
-                throw new Exception("You must use either WithTrigger(..) or Trigger(..), but not both.");
-            }
+	    if (_triggers.ContainsKey(HtmxTriggerTiming.Default))
+	    {
+		    ParsePossibleExistingTriggers(Keys.Trigger, HtmxTriggerTiming.Default);
 
-            _headers[Keys.Trigger] = BuildTriggerHeader(HtmxTriggerTiming.Default);
-        }
+		    _headers[Keys.Trigger] = BuildTriggerHeader(HtmxTriggerTiming.Default);
+	    }
 
-        if (_triggers.ContainsKey(HtmxTriggerTiming.AfterSettle))
-        {
-            if (_headers.ContainsKey(Keys.TriggerAfterSettle))
-            {
-                throw new Exception("You must use either WithTrigger(..) or TriggerAfterSettle(..), but not both.");
-            }
+	    if (_triggers.ContainsKey(HtmxTriggerTiming.AfterSettle))
+	    {
+		    ParsePossibleExistingTriggers(Keys.TriggerAfterSettle, HtmxTriggerTiming.AfterSettle);
 
-            _headers[Keys.TriggerAfterSettle] = BuildTriggerHeader(HtmxTriggerTiming.AfterSettle);
-        }
+		    _headers[Keys.TriggerAfterSettle] = BuildTriggerHeader(HtmxTriggerTiming.AfterSettle);
+	    }
 
-        // ReSharper disable once InvertIf
-        if (_triggers.ContainsKey(HtmxTriggerTiming.AfterSwap))
-        {
-            if (_headers.ContainsKey(Keys.TriggerAfterSwap))
-            {
-                throw new Exception("You must use either WithTrigger(..) or TriggerAfterSwap(..), but not both.");
-            }
+	    // ReSharper disable once InvertIf
+	    if (_triggers.ContainsKey(HtmxTriggerTiming.AfterSwap))
+	    {
+		    ParsePossibleExistingTriggers(Keys.TriggerAfterSwap, HtmxTriggerTiming.AfterSwap);
 
-            _headers[Keys.TriggerAfterSwap] = BuildTriggerHeader(HtmxTriggerTiming.AfterSwap);
-        }
+		    _headers[Keys.TriggerAfterSwap] = BuildTriggerHeader(HtmxTriggerTiming.AfterSwap);
+	    }
 
-        return this;
+	    return this;
+    }
+
+    /// <summary>
+    /// Checks to see if the response has an existing header defined by headerKey.  If it does the
+    /// header loads all of the triggers locally so they aren't overwritten by Htmx.
+    /// </summary>
+    /// <param name="headerKey"></param>
+    /// <param name="timing"></param>
+    private void ParsePossibleExistingTriggers(string headerKey, HtmxTriggerTiming timing)
+    {
+	    if (!_headers.ContainsKey(headerKey))
+		    return;
+
+	    // Attempt to parse existing header as Json, if fails it is a simplified event key
+	    try
+	    {
+		    var existingTriggers = JsonSerializer.Deserialize<Dictionary<string, object?>>(_headers[headerKey]) ??
+		                           new Dictionary<string, object?>();
+
+		    // Load any existing triggers
+		    foreach (var eventName in existingTriggers.Keys)
+			    WithTrigger(eventName, existingTriggers[eventName], timing);
+	    }
+	    catch (System.Text.Json.JsonException)
+	    {
+		    foreach (var headerValue in _headers[headerKey])
+		    {
+			    if (headerValue is null) continue;
+
+                var eventNames = headerValue.Split(',');
+
+                foreach (var eventName in eventNames)
+				    WithTrigger(eventName, null, timing);
+			}
+		}
     }
 
     private string BuildTriggerHeader(HtmxTriggerTiming timing)

test/Htmx.Tests/HtmxHttpResponseExtensionsTests.cs

@@ -122,24 +122,47 @@ public void Can_add_multiple_triggers_with_detail()
     }
 
     [Fact]
-    public void Cant_use_legacy_trigger_and_with_trigger()
+    public void Can_use_existing_trigger_with_trigger()
     {
-        Response.Htmx(h => h.Trigger("cool"));
-        Assert.Throws<Exception>(() => Response.Htmx(h => h.WithTrigger("neat")));
+	    const string expected = @"{""neat"":"""",""cool"":""""}";
+
+	    Response.Htmx(h => h.WithTrigger("cool"));
+	    Response.Htmx(h => h.WithTrigger("neat"));
+
+	    Assert.True(Headers.ContainsKey(Keys.Trigger));
+	    Assert.Equal(expected, Headers[Keys.Trigger]);
     }
-        
+
     [Fact]
-    public void Cant_use_legacy_triggeraftersettle_and_with_trigger()
+    public void Can_use_existing_trigger_with_multiple_triggers_with_detail()
     {
-        Response.Htmx(h => h.TriggerAfterSettle("cool"));
-        Assert.Throws<Exception>(() => Response.Htmx(h => h.WithTrigger("neat", timing: HtmxTriggerTiming.AfterSettle)));
+	    const string expected = @"{""cool"":{""magic"":""something""},""neat"":{""moremagic"":false},""wow"":""""}";
+
+	    Response.Htmx(h => h.WithTrigger("wow"));
+	    Response.Htmx(h =>
+	    {
+		    h.WithTrigger("cool", new { magic = "something" });
+		    h.WithTrigger("neat", new { moremagic = false });
+	    });
+
+	    Assert.True(Headers.ContainsKey(Keys.Trigger));
+	    Assert.Equal(expected, Headers[Keys.Trigger]);
     }
-        
+
     [Fact]
-    public void Cant_use_legacy_triggerafterswap_and_with_trigger()
+    public void Can_use_existing_trigger_with_detail_with_multiple_triggers_with_detail()
     {
-        Response.Htmx(h => h.TriggerAfterSwap("cool"));
-        Assert.Throws<Exception>(() => Response.Htmx(h => h.WithTrigger("neat", timing: HtmxTriggerTiming.AfterSwap)));
+	    const string expected = @"{""cool"":{""magic"":""something""},""neat"":{""moremagic"":false},""wow"":{""display"":true}}";
+
+	    Response.Htmx(h => h.WithTrigger("wow", new { display = true }));
+	    Response.Htmx(h =>
+	    {
+		    h.WithTrigger("cool", new { magic = "something" });
+		    h.WithTrigger("neat", new { moremagic = false });
+	    });
+
+	    Assert.True(Headers.ContainsKey(Keys.Trigger));
+	    Assert.Equal(expected, Headers[Keys.Trigger]);
     }
 
     [Fact]