[MBL-2883] RichText parsing and conversion to Swift-friendly normalized types

ServerDrivenUI/Sources/ServerDrivenUI/RichTextElement.swift

@@ -0,0 +1,86 @@
+import Foundation
+
+/// Represents a single block-level element in a RichText list. Used to make implementing
+/// the different views in SwiftUI more easily and with a consistent interface.
+public indirect enum RichTextElement {
+  case text(Text, HeaderLevel?)
+  case listItemOpen
+  case listItemClose
+  case listItem(Text)
+  case audio(Audio)
+  case photo(Photo)
+  case video(Video)
+  case oembed(Oembed)
+  case unknown
+
+  public struct Text {
+    public let text: String
+    public let link: URL?
+    public let styles: [Style]
+    public let children: [RichTextElement]
+
+    public enum Style: String {
+      case strong = "STRONG"
+      case emphasis = "EMPHASIS"
+      case heading1 = "HEADING_1"
+      case heading2 = "HEADING_2"
+      case heading3 = "HEADING_3"
+      case heading4 = "HEADING_4"
+    }
+  }
+
+  public enum HeaderLevel: String {
+    case one = "HEADING_1"
+    case two = "HEADING_2"
+    case three = "HEADING_3"
+    case four = "HEADING_4"
+
+    /// Create a HeaderLevel from an array of style strings from GraphQL, if
+    /// one is present
+    internal init?(styles: [String]?) {
+      for style in styles ?? [] {
+        if let level = HeaderLevel(rawValue: style) {
+          self = level
+          return
+        }
+      }
+      return nil
+    }
+  }
+
+  public struct Audio {
+    public let altText: String?
+    public let assetID: String?
+    public let caption: String?
+    public let url: String?
+  }
+
+  public struct Photo {
+    public let altText: String?
+    public let assetID: String?
+    public let caption: String?
+    public let url: String?
+  }
+
+  public struct Video {
+    public let altText: String?
+    public let assetID: String?
+    public let caption: String?
+    public let url: String?
+  }
+
+  public struct Oembed {
+    public let width: Int
+    public let height: Int
+    public let version: String
+    public let title: String
+    public let type: String
+
+    public let iframeUrl: String?
+    public let originalUrl: String?
+
+    public let thumbnailUrl: String?
+    public let thumbnailWidth: Int?
+    public let thumbnailHeight: Int?
+  }
+}