From 761a30e8d5db9384d7bbaa9a5b83e6a7e8fd5443 Mon Sep 17 00:00:00 2001
From: gaebel <gaebel.dev@icloud.com>
Date: Fri, 20 Aug 2021 16:56:21 +0200
Subject: [PATCH] Fix mixing elements and inheriting attributes, fixes #97

---
 .../Common/Elements/Bold/MarkdownBold.swift   | 22 +++++++----------
 .../Elements/Italic/MarkdownItalic.swift      | 24 +++++++------------
 .../Strikethrough/MarkdownStrikethrough.swift | 12 ++++------
 .../Sources/Common/MarkdownParser.swift       |  2 +-
 MarkdownKit/Tests/MarkdownParserTests.swift   | 23 ++++++++++++++++++
 5 files changed, 45 insertions(+), 38 deletions(-)

diff --git a/MarkdownKit/Sources/Common/Elements/Bold/MarkdownBold.swift b/MarkdownKit/Sources/Common/Elements/Bold/MarkdownBold.swift
index bd42d86..2d5c4fc 100644
--- a/MarkdownKit/Sources/Common/Elements/Bold/MarkdownBold.swift
+++ b/MarkdownKit/Sources/Common/Elements/Bold/MarkdownBold.swift
@@ -26,20 +26,14 @@ open class MarkdownBold: MarkdownCommonElement {
   public func match(_ match: NSTextCheckingResult, attributedString: NSMutableAttributedString) {
     attributedString.deleteCharacters(in: match.range(at: 4))
 
-    let currentAttributes = attributedString.attributes(
-      at: match.range(at: 3).location,
-      longestEffectiveRange: nil,
-      in: match.range(at: 3)
-    )
-
-    addAttributes(attributedString, range: match.range(at: 3))
-
-    if let font = currentAttributes[.font] as? MarkdownFont {
-      attributedString.addAttribute(
-        NSAttributedString.Key.font,
-        value: font.bold(),
-        range: match.range(at: 3)
-      )
+    attributedString.enumerateAttribute(.font, in: match.range(at: 3)) { value, range, stop in
+      if let font = value as? MarkdownFont {
+        attributedString.addAttribute(
+          NSAttributedString.Key.font,
+          value: font.bold(),
+          range: range
+        )
+      }
     }
 
     attributedString.deleteCharacters(in: match.range(at: 2))
diff --git a/MarkdownKit/Sources/Common/Elements/Italic/MarkdownItalic.swift b/MarkdownKit/Sources/Common/Elements/Italic/MarkdownItalic.swift
index 708cfdd..b8cc71d 100644
--- a/MarkdownKit/Sources/Common/Elements/Italic/MarkdownItalic.swift
+++ b/MarkdownKit/Sources/Common/Elements/Italic/MarkdownItalic.swift
@@ -9,7 +9,7 @@ import Foundation
 
 open class MarkdownItalic: MarkdownCommonElement {
   
-  fileprivate static let regex = "(\\s|^)(\\*|_)(?![\\*_\\s])(.+?)(?<![\\*_\\s])(\\2)"
+  fileprivate static let regex = "(.?|^)(\\*|_)(?=\\S)(.+?)(?<![\\*_\\s])(\\2)"
 
   open var font: MarkdownFont?
   open var color: MarkdownColor?
@@ -26,20 +26,14 @@ open class MarkdownItalic: MarkdownCommonElement {
   public func match(_ match: NSTextCheckingResult, attributedString: NSMutableAttributedString) {
     attributedString.deleteCharacters(in: match.range(at: 4))
 
-    let currentAttributes = attributedString.attributes(
-      at: match.range(at: 3).location,
-      longestEffectiveRange: nil,
-      in: match.range(at: 3)
-    )
-
-    addAttributes(attributedString, range: match.range(at: 3))
-
-    if let font = currentAttributes[.font] as? MarkdownFont {
-      attributedString.addAttribute(
-        NSAttributedString.Key.font,
-        value: font.italic(),
-        range: match.range(at: 3)
-      )
+    attributedString.enumerateAttribute(.font, in: match.range(at: 3)) { value, range, stop in
+      if let font = value as? MarkdownFont {
+        attributedString.addAttribute(
+          NSAttributedString.Key.font,
+          value: font.italic(),
+          range: range
+        )
+      }
     }
 
     attributedString.deleteCharacters(in: match.range(at: 2))
diff --git a/MarkdownKit/Sources/Common/Elements/Strikethrough/MarkdownStrikethrough.swift b/MarkdownKit/Sources/Common/Elements/Strikethrough/MarkdownStrikethrough.swift
index 6187d90..9243e7a 100644
--- a/MarkdownKit/Sources/Common/Elements/Strikethrough/MarkdownStrikethrough.swift
+++ b/MarkdownKit/Sources/Common/Elements/Strikethrough/MarkdownStrikethrough.swift
@@ -25,16 +25,12 @@ open class MarkdownStrikethrough: MarkdownCommonElement {
   public func match(_ match: NSTextCheckingResult, attributedString: NSMutableAttributedString) {
     attributedString.deleteCharacters(in: match.range(at: 4))
 
-    var attributes = attributedString.attributes(
-      at: match.range(at: 3).location,
-      longestEffectiveRange: nil,
-      in: match.range(at: 3)
+    attributedString.addAttribute(
+      NSAttributedString.Key.strikethroughStyle,
+      value: NSNumber.init(value: NSUnderlineStyle.single.rawValue),
+      range: match.range(at: 3)
     )
 
-    attributes[NSAttributedString.Key.strikethroughStyle] = NSNumber.init(value: NSUnderlineStyle.single.rawValue)
-
-    attributedString.addAttributes(attributes, range: match.range(at: 3))
-
     attributedString.deleteCharacters(in: match.range(at: 2))
   }
 }
diff --git a/MarkdownKit/Sources/Common/MarkdownParser.swift b/MarkdownKit/Sources/Common/MarkdownParser.swift
index 1224a3c..c0892a5 100644
--- a/MarkdownKit/Sources/Common/MarkdownParser.swift
+++ b/MarkdownKit/Sources/Common/MarkdownParser.swift
@@ -156,9 +156,9 @@ open class MarkdownParser {
       (.header, header),
       (.list, list),
       (.quote, quote),
-      (.strikethrough, strikethrough),
       (.bold, bold),
       (.italic, italic),
+      (.strikethrough, strikethrough),
       (.link, link),
       (.automaticLink, automaticLink),
       (.code, code),
diff --git a/MarkdownKit/Tests/MarkdownParserTests.swift b/MarkdownKit/Tests/MarkdownParserTests.swift
index 4f98930..56c4d32 100644
--- a/MarkdownKit/Tests/MarkdownParserTests.swift
+++ b/MarkdownKit/Tests/MarkdownParserTests.swift
@@ -16,6 +16,29 @@ class Tests: XCTestCase {
         sut = MarkdownParser()
     }
 
+    func testShouldNotParseWithWhitespace() {
+        let variations = [
+            "__ Bold __",
+            "_ Italic _",
+            "** Bold **",
+            "X * Italic *",
+            "~~ Strikethrough ~~"
+        ]
+
+        variations.forEach {
+            let attributedString = sut.parse($0)
+            let attributes = attributedString.attributes(at: 0, effectiveRange: nil)
+            guard let font = attributes[NSAttributedString.Key.font] as? MarkdownFont else {
+                XCTFail("Font attributes missing")
+                return
+            }
+
+            XCTAssertFalse(font.contains(attribute: .bold))
+            XCTAssertFalse(font.contains(attribute: .italic))
+            XCTAssertNil(attributes[NSAttributedString.Key.strikethroughStyle])
+        }
+    }
+
     func testParseBoldItalicStrikethrough() throws {
         let combinations = [
             "___~~Bold-Italic-Strikethrough~~___",