Add support for shortening GitHub issues links (#531)

* Add support for shortening GitHub issues links

Relates to #411

* Added Tests

Classes/Issues/Comments/Markdown/CommentModelsFromMarkdown.swift

@@ -357,6 +357,53 @@ func updateIssueShorthand(
     return mutableAttributedString
 }
 
+private let issueURLRegex = try! NSRegularExpression(pattern: "https?:\\/\\/.*github.com\\/(\\w*)\\/([^/]*?)\\/issues\\/([0-9]+)", options: [])
+func shortenGitHubLinks(attributedString: NSAttributedString,
+                        options: GitHubMarkdownOptions) -> NSAttributedString {
+    
+    guard options.flavors.contains(.issueShorthand) else { return attributedString }
+    
+    let string = attributedString.string
+    let mutableAttributedString = NSMutableAttributedString(attributedString: attributedString)
+    let matches = issueURLRegex.matches(in: string, options: [], range: string.nsrange)
+    
+    for match in matches.reversed() {
+        let ownerRange = match.range(at: 1)
+        let repoRange = match.range(at: 2)
+        let numberRange = match.range(at: 3)
+        
+        guard let ownerSubstring = string.substring(with: ownerRange),
+              let repoSubstring = string.substring(with: repoRange),
+              let numberSubstring = string.substring(with: numberRange) else { continue }
+        
+        var attributes = attributedString.attributes(at: match.range.location, effectiveRange: nil)
+        
+        // manually disable link shortening for some text (namely code)
+        guard attributes[MarkdownAttribute.linkShorteningDisabled] == nil else { continue }
+        
+        attributes[.foregroundColor] = Styles.Colors.Blue.medium.color
+        attributes[MarkdownAttribute.issue] = IssueDetailsModel(
+            owner: ownerSubstring,
+            repo: repoSubstring,
+            number: (numberSubstring as NSString).integerValue
+        )
+        attributes[MarkdownAttribute.url] = nil
+        
+        var shortenedText: String
+        
+        if ownerSubstring == options.owner && repoSubstring == options.repo {
+            shortenedText = "#\(numberSubstring)"
+        } else {
+            shortenedText = "\(ownerSubstring)/\(repoSubstring)#\(numberSubstring)"
+        }
+        
+        let linkAttributedString = NSAttributedString(string: shortenedText, attributes: attributes)
+        mutableAttributedString.replaceCharacters(in: match.range, with: linkAttributedString)
+    }
+    
+    return mutableAttributedString
+}
+
 func createTextModelUpdatingGitHubFeatures(
     attributedString: NSAttributedString,
     width: CGFloat,
@@ -366,10 +413,11 @@ func createTextModelUpdatingGitHubFeatures(
 
     let usernames = updateUsernames(attributedString: attributedString, options: options)
     let issues = updateIssueShorthand(attributedString: usernames, options: options)
+    let shorten = shortenGitHubLinks(attributedString: issues, options: options)
 
     return NSAttributedStringSizing(
         containerWidth: width,
-        attributedText: issues,
+        attributedText: shorten,
         inset: inset
     )
 }

Classes/Issues/Comments/Markdown/MMElement+Attributes.swift

@@ -42,6 +42,7 @@ func PushAttributes(
         NSAttributedStringKey.backgroundColor: Styles.Colors.Gray.lighter.color,
         .foregroundColor: Styles.Colors.Gray.dark.color,
         MarkdownAttribute.usernameDisabled: true,
+        MarkdownAttribute.linkShorteningDisabled: true,
         ]
     case .link: newAttributes = [
         .foregroundColor: Styles.Colors.Blue.medium.color,

Classes/Issues/Comments/Markdown/MarkdownAttribute.swift

@@ -13,5 +13,6 @@ enum MarkdownAttribute {
     static let email = NSAttributedStringKey(rawValue: "com.freetime.Markdown.email-name")
     static let username = NSAttributedStringKey(rawValue: "com.freetime.Markdown.username-name")
     static let usernameDisabled = NSAttributedStringKey(rawValue: "com.freetime.Markdown.username-disabled-name")
+    static let linkShorteningDisabled = NSAttributedStringKey(rawValue: "com.freetime.Markdown.link-shortening-disabled-name")
     static let issue = NSAttributedStringKey(rawValue: "com.freetime.Markdown.issue")
 }

FreetimeTests/MMMarkdownASTTests.swift

@@ -124,5 +124,33 @@ final class MMMarkdownASTTests: XCTestCase {
         XCTAssertEqual(comboDetails.repo, "bar")
         XCTAssertEqual(comboDetails.number, 456)
     }
+    
+    func test_shortenLinks() {
+        let options = GitHubMarkdownOptions(owner: "owner", repo: "repo", flavors: [.issueShorthand])
+        
+        // Test Same Repository
+        let testOne = "https://github.com/owner/repo/issues/123"
+        let resultOne = CreateCommentModels(markdown: testOne, width: 300, options: options)
+        let textOne = resultOne.first as! NSAttributedStringSizing
+        XCTAssertEqual(textOne.attributedText.string, "#123")
+        XCTAssertNotNil(textOne.attributedText.attributes(at: 1, effectiveRange: nil)[MarkdownAttribute.issue])
+        
+        let detailsOne = textOne.attributedText.attributes(at: 1, effectiveRange: nil)[MarkdownAttribute.issue] as! IssueDetailsModel
+        XCTAssertEqual(detailsOne.owner, "owner")
+        XCTAssertEqual(detailsOne.repo, "repo")
+        XCTAssertEqual(detailsOne.number, 123)
+        
+        // Test Cross Repository
+        let testTwo = "https://github.com/differentOwner/differentRepo/issues/321"
+        let resultTwo = CreateCommentModels(markdown: testTwo, width: 300, options: options)
+        let textTwo = resultTwo.first as! NSAttributedStringSizing
+        XCTAssertEqual(textTwo.attributedText.string, "differentOwner/differentRepo#321")
+        XCTAssertNotNil(textTwo.attributedText.attributes(at: 1, effectiveRange: nil)[MarkdownAttribute.issue])
+        
+        let detailsTwo = textTwo.attributedText.attributes(at: 1, effectiveRange: nil)[MarkdownAttribute.issue] as! IssueDetailsModel
+        XCTAssertEqual(detailsTwo.owner, "differentOwner")
+        XCTAssertEqual(detailsTwo.repo, "differentRepo")
+        XCTAssertEqual(detailsTwo.number, 321)
+    }
 
 }