Fix markdown-formatter customization accessibility

CHANGELOG.md

@@ -18,6 +18,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### ✅ Added
 - Validates file size limit per attachment type defined in Stream's Dashboard [#3105](https://github.com/GetStream/stream-chat-swift/pull/3105)
 - Make it easier to customize `ComposerVC.updateContent()` [#3112](https://github.com/GetStream/stream-chat-swift/pull/3112)
+- Add support markdown font styling customization [#3101](https://github.com/GetStream/stream-chat-swift/pull/3101)
+
 ### 🐞 Fixed
 - Fix support for markdown ordered list with all numbers [#3090](https://github.com/GetStream/stream-chat-swift/pull/3090)
 - Fix support for markdown italic and bold styles inside snake-styled text [#3094](https://github.com/GetStream/stream-chat-swift/pull/3094)

DemoApp/StreamChat/StreamChatWrapper+DemoApp.swift

@@ -60,5 +60,17 @@ extension StreamChatWrapper {
         Components.default.messageActionsVC = DemoChatMessageActionsVC.self
         Components.default.reactionsSorting = { $0.type.position < $1.type.position }
         Components.default.messageLayoutOptionsResolver = DemoChatMessageLayoutOptionsResolver()
+
+        // Customize MarkdownFormatter
+        let defaultFormatter = DefaultMarkdownFormatter()
+        defaultFormatter.styles.bodyFont.color = .systemOrange
+        defaultFormatter.styles.codeFont.color = .systemPurple
+        defaultFormatter.styles.h1Font.color = .systemBlue
+        defaultFormatter.styles.h2Font.color = .systemRed
+        defaultFormatter.styles.h3Font.color = .systemYellow
+        defaultFormatter.styles.h4Font.color = .systemGreen
+        defaultFormatter.styles.h5Font.color = .systemBrown
+        defaultFormatter.styles.h6Font.color = .systemPink
+        Appearance.default.formatters.markdownFormatter = defaultFormatter
     }
 }

Scripts/updateDependency.sh

@@ -74,7 +74,7 @@ if [[ $dependency_directory == *"DifferenceKit"* ]]; then
 fi
 
 if [[ $dependency_directory == *"SwiftyMarkdown"* ]]; then
-    # We currently use customized version of SwiftyLineProcessor.swift
+    # We currently use customized version of SwiftyMarkdown
     git restore $output_directory/SwiftyMarkdown/SwiftyLineProcessor.swift || true
     git restore $output_directory/SwiftyMarkdown/SwiftyTokeniser.swift || true
 fi

Sources/StreamChatUI/Appearance+Formatters/MarkdownFormatter.swift

@@ -19,14 +19,15 @@ public protocol MarkdownFormatter {
 
 /// Default implementation for the Markdown formatter
 open class DefaultMarkdownFormatter: MarkdownFormatter {
-    enum Attributes {
-        enum Code {
-            static let fontName: String = "CourierNewPSMT"
-        }
-    }
+    public var styles: MarkdownStyles
+    public var markdownRegexPattern: String
 
-    private let markdownRegexPattern: String =
-        "((?:\\`(.*?)\\`)|(?:\\*{1,2}(.*?)\\*{1,2})|(?:\\~{2}(.*?)\\~{2})|(?:\\_{1,2}(.*?)\\_{1,2})|^(>){1}|(#){1,6}|(=){3,10}|(-){1,3}|(\\d{1,3}\\.)|(?:\\[(.*?)\\])(?:\\((.*?)\\))|(?:\\[(.*?)\\])(?:\\[(.*?)\\])|(\\]\\:))+"
+    private let defaultMarkdownRegex = "((?:\\`(.*?)\\`)|(?:\\*{1,2}(.*?)\\*{1,2})|(?:\\~{2}(.*?)\\~{2})|(?:\\_{1,2}(.*?)\\_{1,2})|^(>){1}|(#){1,6}|(=){3,10}|(-){1,3}|(\\d{1,3}\\.)|(?:\\[(.*?)\\])(?:\\((.*?)\\))|(?:\\[(.*?)\\])(?:\\[(.*?)\\])|(\\]\\:))+"
+
+    public init() {
+        styles = MarkdownStyles()
+        markdownRegexPattern = defaultMarkdownRegex
+    }
 
     private lazy var regex: NSRegularExpression? = {
         guard let regex = try? NSRegularExpression(pattern: markdownRegexPattern, options: .anchorsMatchLines) else {
@@ -43,7 +44,99 @@ open class DefaultMarkdownFormatter: MarkdownFormatter {
 
     open func format(_ string: String) -> NSAttributedString {
         let markdownFormatter = SwiftyMarkdown(string: string)
-        markdownFormatter.code.fontName = Attributes.Code.fontName
+        modify(swiftyMarkdownFont: markdownFormatter.code, with: styles.codeFont)
+        modify(swiftyMarkdownFont: markdownFormatter.body, with: styles.bodyFont)
+        modify(swiftyMarkdownFont: markdownFormatter.link, with: styles.linkFont)
+        modify(swiftyMarkdownFont: markdownFormatter.h1, with: styles.h1Font)
+        modify(swiftyMarkdownFont: markdownFormatter.h2, with: styles.h2Font)
+        modify(swiftyMarkdownFont: markdownFormatter.h3, with: styles.h3Font)
+        modify(swiftyMarkdownFont: markdownFormatter.h4, with: styles.h4Font)
+        modify(swiftyMarkdownFont: markdownFormatter.h5, with: styles.h5Font)
+        modify(swiftyMarkdownFont: markdownFormatter.h6, with: styles.h6Font)
         return markdownFormatter.attributedString()
     }
+
+    private func modify(swiftyMarkdownFont: FontProperties, with font: MarkdownFont) {
+        if let fontName = font.name {
+            swiftyMarkdownFont.fontName = fontName
+        }
+        if let fontSize = font.size {
+            swiftyMarkdownFont.fontSize = fontSize
+        }
+        if let fontColor = font.color {
+            swiftyMarkdownFont.color = fontColor
+        }
+        if let fontStyle = font.styling?.asSwiftyMarkdownFontStyle() {
+            swiftyMarkdownFont.fontStyle = fontStyle
+        }
+    }
+}
+
+/// Configures the font style properties for base Markdown elements
+public struct MarkdownStyles {
+
+    /// The regular paragraph font.
+    public var bodyFont: MarkdownFont = .init()
+
+    /// The font used for coding blocks in markdown text.
+    public var codeFont: MarkdownFont = .init()
+
+    /// The font used for links found in markdown text.
+    public var linkFont: MarkdownFont = .init()
+
+    /// The font used for H1 headers in markdown text.
+    public var h1Font: MarkdownFont = .init()
+
+    /// The font used for H2 headers in markdown text.
+    public var h2Font: MarkdownFont = .init()
+
+    /// The font used for H3 headers in markdown text.
+    public var h3Font: MarkdownFont = .init()
+
+    /// The font used for H4 headers in markdown text.
+    public var h4Font: MarkdownFont = .init()
+
+    /// The font used for H5 headers in markdown text.
+    public var h5Font: MarkdownFont = .init()
+
+    /// The font used for H6 headers in markdown text.
+    public var h6Font: MarkdownFont = .init()
+
+    public init() {
+        codeFont.name = "CourierNewPSMT"
+    }
+}
+
+public struct MarkdownFont {
+    public var name: String?
+    public var size: Double?
+    public var color: UIColor?
+    public var styling: MarkdownFontStyle?
+
+    public init() {
+        name = nil
+        size = nil
+        color = nil
+        styling = nil
+    }
+}
+
+public enum MarkdownFontStyle: Int {
+    case normal
+    case bold
+    case italic
+    case boldItalic
+
+    func asSwiftyMarkdownFontStyle() -> FontStyle {
+        switch self {
+        case .normal:
+            return .normal
+        case .bold:
+            return .bold
+        case .italic:
+            return .italic
+        case .boldItalic:
+            return .boldItalic
+        }
+    }
 }

Tests/StreamChatUITests/Utils/DefaultMarkdownFormatter_Tests.swift

@@ -234,7 +234,7 @@ final class DefaultMarkdownFormatter_Tests: XCTestCase {
                 XCTAssertEqual(expectedBoldAttributedSubstring, attributedString.attributedSubstring(from: range).string)
             } else if let fontAttribute = fontAttribute,
                       let fontNameAttribute = fontAttribute.fontDescriptor.fontAttributes[.name] as? String,
-                      fontNameAttribute == DefaultMarkdownFormatter.Attributes.Code.fontName {
+                      fontNameAttribute == DefaultMarkdownFormatter().styles.codeFont.name {
                 XCTAssertEqual(expectedCodeAttributedSubstring, attributedString.attributedSubstring(from: range).string)
             } else if let linkAttribute = attributes[.link] as? NSURL,
                       let url = linkAttribute.absoluteString {