Fix anchor links for web-snippets

Author: flcdrg

readme.md

@@ -219,11 +219,11 @@ Files are downloaded to `%temp%MarkdownSnippets` with a maximum of 100 files kep
 Will render:
 
 	<!-- web-snippet: https://raw.githubusercontent.com/SimonCropp/MarkdownSnippets/main/src/Tests/DirectorySnippetExtractor/Case/code1.txt#snipPet -->
-	<a id='snippet-snipPet'></a>
+	<a id='snippet-https://raw.githubusercontent.com/SimonCropp/MarkdownSnippets/main/src/Tests/DirectorySnippetExtractor/Case/code1.txt%23snipPet'></a>
 	```txt
 	Some code
 	```
-	<sup><a href='#snippet-snipPet' title='Start of snippet'>anchor</a></sup>
+	<sup><a href='https://raw.githubusercontent.com/SimonCropp/MarkdownSnippets/main/src/Tests/DirectorySnippetExtractor/Case/code1.txt#snipPet' title='Snippet source file'>anchor</a></sup>
 	<!-- endSnippet -->
 
 ### Including a full file
@@ -347,7 +347,7 @@ switch (linkFormat)
         throw new($"Unknown LinkFormat: {linkFormat}");
 }
 ```
-<sup><a href='/src/MarkdownSnippets/Processing/SnippetMarkdownHandling.cs#L103-L124' title='Snippet source file'>snippet source</a> | <a href='#snippet-BuildLink' title='Start of snippet'>anchor</a></sup>
+<sup><a href='/src/MarkdownSnippets/Processing/SnippetMarkdownHandling.cs#L121-L142' title='Snippet source file'>snippet source</a> | <a href='#snippet-BuildLink' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 

src/MarkdownSnippets/Processing/SnippetMarkdownHandling.cs

@@ -50,7 +50,19 @@ void WriteSnippet(Action<string> appendLine, Snippet snippet, uint index)
 
     static string GetAnchorText(Snippet snippet, uint index)
     {
-        var id = $"snippet-{snippet.Key}";
+        string id;
+        var pathStr = snippet.Path;
+        if (pathStr != null && pathStr.StartsWith("http", StringComparison.OrdinalIgnoreCase))
+        {
+            // For web-snippets, include the full URL and the snippet key, with '#' encoded
+            var combined = $"snippet-{pathStr}#{snippet.Key}";
+            id = combined.Replace("#", "%23");
+        }
+        else
+        {
+            id = $"snippet-{snippet.Key}";
+        }
+
         if (index == 0)
         {
             return id;
@@ -62,12 +74,18 @@ static string GetAnchorText(Snippet snippet, uint index)
     string GetSupText(Snippet snippet, string anchor)
     {
         var linkForAnchor = $"<a href='#{anchor}' title='Start of snippet'>anchor</a>";
-        if (snippet.Path == null || linkFormat == LinkFormat.None)
+        var pathLocal = snippet.Path;
+        if (pathLocal == null || linkFormat == LinkFormat.None)
         {
             return linkForAnchor;
         }
 
-        var path = snippet.Path.Replace('\\', '/');
+        var path = pathLocal.Replace('\\', '/');
+        if (path.StartsWith("http", StringComparison.OrdinalIgnoreCase))
+        {
+            // For web-snippets: link back to the original URL with the snippet key as a hash
+            return $"<a href='{path}#{snippet.Key}' title='Snippet source file'>anchor</a>";
+        }
         if (!path.StartsWith(targetDirectory))
         {
             // if file is not in the targetDirectory then the url wont work

src/Tests/SnippetMarkdownHandlingTests.AppendWebSnippet.verified.txt

@@ -0,0 +1,5 @@
+<a id='snippet-http://example.com/file.cs%23mysnippet'></a>
+```cs
+theValue
+```
+<sup><a href='http://example.com/file.cs#mysnippet' title='Snippet source file'>anchor</a></sup>

src/Tests/SnippetMarkdownHandlingTests.cs

@@ -70,6 +70,27 @@ public Task AppendHashed()
         return Verify(builder.ToString());
     }
 
+    [Fact]
+    public Task AppendWebSnippet()
+    {
+        var builder = new StringBuilder();
+        var webSnippet = Snippet.Build(
+            startLine: 1,
+            endLine: 2,
+            value: "theValue",
+            key: "mysnippet",
+            language: "cs",
+            path: "http://example.com/file.cs",
+            expressiveCode: null);
+        var markdownHandling = new SnippetMarkdownHandling(Environment.CurrentDirectory, LinkFormat.GitHub, false);
+        using (var writer = new StringWriter(builder))
+        {
+            markdownHandling.Append("key1", new List<Snippet> { webSnippet }, writer.WriteLine);
+        }
+
+        return Verify(builder.ToString());
+    }
+
     static List<Snippet> Snippets() =>
         [Snippet.Build(1, 2, "theValue", "thekey", "thelanguage", Environment.CurrentDirectory, expressiveCode: null)];
 }