FileConventions: fix WrapText function

Split paragraph based on codeblock positions so that codeblocks
with two lines, are not broken into multiple paragraphs.

Fixes nblockchain#117

src/FileConventions/Library.fs

@@ -244,11 +244,55 @@ let private WrapParagraph (text: string) (maxCharsPerLine: int) : string =
 
     processWords String.Empty String.Empty words
 
+let rec ExtractParagraphs (text: string) : List<string> =
+    let codeBlockParagraphRegex = "(\s*)(```[\s\S]*```)(\s*)"
+    let matchedRegex = Regex.Match(text, codeBlockParagraphRegex)
+    let twoNewLines = $"{Environment.NewLine}{Environment.NewLine}"
+
+    if matchedRegex.Success then
+        let preWhiteSpaceGroup = matchedRegex.Groups[1]
+        let postWhiteSpaceGroup = matchedRegex.Groups[3]
+
+        let beforeMatch = text.Substring(0, matchedRegex.Index)
+        let afterMatch = text.Substring(matchedRegex.Index + matchedRegex.Length)
+
+        let paragraphsBeforeMatch = ExtractParagraphs beforeMatch
+        let paragraphsAfterMatch = ExtractParagraphs afterMatch
+
+        if preWhiteSpaceGroup.Value.Contains(twoNewLines) && postWhiteSpaceGroup.Value.Contains(twoNewLines) then
+            paragraphsBeforeMatch @ (List.singleton matchedRegex.Value) @ paragraphsAfterMatch
+        elif preWhiteSpaceGroup.Value.Contains(twoNewLines) then
+            match paragraphsAfterMatch with
+            | [] ->
+                paragraphsBeforeMatch @ (List.singleton matchedRegex.Value)
+            | head::tail ->
+                paragraphsBeforeMatch @ List.singleton (matchedRegex.Value + postWhiteSpaceGroup.Value + head) @ tail
+        elif postWhiteSpaceGroup.Value.Contains(twoNewLines) then
+            match List.rev paragraphsBeforeMatch with
+            | [] ->
+                (List.singleton matchedRegex.Value) @ paragraphsAfterMatch
+            | head::tail ->
+                List.rev tail @ List.singleton (head + preWhiteSpaceGroup.Value + matchedRegex.Value) @ paragraphsAfterMatch
+        else
+            match List.rev paragraphsBeforeMatch, paragraphsAfterMatch with
+            | [], [] ->
+                List.singleton matchedRegex.Value
+            | headPre::tailPre, [] ->
+                List.rev tailPre @ List.singleton (headPre + preWhiteSpaceGroup.Value + matchedRegex.Value)
+            | [], headPost::tailPost ->
+                List.singleton (matchedRegex.Value + postWhiteSpaceGroup.Value + headPost) @ tailPost
+            | headPre::tailPre, headPost::tailPost ->
+                List.rev tailPre @ List.singleton (headPre + preWhiteSpaceGroup.Value + matchedRegex.Value + postWhiteSpaceGroup.Value + headPost) @ tailPost
+    elif String.IsNullOrEmpty(text) then
+        List.Empty
+    else
+        text.Split $"{Environment.NewLine}{Environment.NewLine}"
+        |> Seq.toList
+
 let WrapText (text: string) (maxCharsPerLine: int) : string =
     let wrappedParagraphs =
-        text.Split $"{Environment.NewLine}{Environment.NewLine}"
+        ExtractParagraphs text
         |> Seq.map(fun paragraph -> WrapParagraph paragraph maxCharsPerLine)
-
     String.Join(
         $"{Environment.NewLine}{Environment.NewLine}",
         wrappedParagraphs