adding impression pixels for duckplayer in landscape mode (#3493)

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Task/Issue URL:
https://app.asana.com/0/1201141132935289/1208637202774549/f
Tech Design URL:
CC:

**Description**:

the DuckPlayer frontend will start sending a generic 'telemetry' events
soon - this PR adds support for the first one, but in a format that can
be expanded later without needing new handlers.

Core/PixelEvent.swift

@@ -793,6 +793,7 @@ extension Pixel {
         case duckPlayerViewFromSERP
         case duckPlayerViewFromOther
         case duckPlayerOverlayYoutubeImpressions
+        case duckPlayerLandscapeLayoutImpressions
         case duckPlayerOverlayYoutubeWatchHere
         case duckPlayerSettingAlwaysDuckPlayer
         case duckPlayerSettingAlwaysSettings
@@ -1664,6 +1665,9 @@ extension Pixel.Event {
 
         // MARK: - WebView Error Page shown
         case .webViewErrorPageShown: return "m_errorpageshown"
+
+        // MARK: - DuckPlayer FE Application Telemetry
+        case .duckPlayerLandscapeLayoutImpressions: return "duckplayer_landscape_layout_impressions"
         }
     }
 }

DuckDuckGo/DuckPlayer/DuckPlayer.swift

@@ -92,6 +92,50 @@ public enum DuckPlayerReferrer {
         }
 }
 
+// Wrapper to allow sibling properties on each event in the future.
+struct TelemetryEvent: Decodable {
+    let attributes: Attributes
+}
+
+// This is the first example of a new telemetry event
+struct ImpressionAttributes: Decodable {
+    enum Layout: String, Decodable {
+        case landscape = "landscape-layout"
+    }
+
+    let name: String
+    let value: Layout
+}
+
+// Designed to represent the discriminated union used by the FE (where all events are schema-driven)
+enum Attributes: Decodable {
+
+    // more events can be added here later, without needing a new handler
+    case impression(ImpressionAttributes)
+
+    private enum CodingKeys: String, CodingKey {
+        case name
+    }
+
+    init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+        let name = try container.decode(String.self, forKey: .name)
+
+        switch name {
+        case "impression":
+            let attributes = try ImpressionAttributes(from: decoder)
+            self = .impression(attributes)
+
+        default:
+            throw DecodingError.dataCorruptedError(
+                forKey: .name,
+                in: container,
+                debugDescription: "Unknown name value: \(name)"
+            )
+        }
+    }
+}
+
 protocol DuckPlayerProtocol: AnyObject {
 
     var settings: DuckPlayerSettings { get }
@@ -104,7 +148,8 @@ protocol DuckPlayerProtocol: AnyObject {
     func openVideoInDuckPlayer(url: URL, webView: WKWebView)
     func openDuckPlayerSettings(params: Any, message: WKScriptMessage) async -> Encodable?
     func openDuckPlayerInfo(params: Any, message: WKScriptMessage) async -> Encodable?
-
+    func telemetryEvent(params: Any, message: WKScriptMessage) async -> Encodable?
+
     func initialSetupPlayer(params: Any, message: WKScriptMessage) async -> Encodable?
     func initialSetupOverlay(params: Any, message: WKScriptMessage) async -> Encodable?
 
@@ -239,6 +284,23 @@ final class DuckPlayer: DuckPlayerProtocol {
         return nil
     }
 
+    @MainActor
+    public func telemetryEvent(params: Any, message: WKScriptMessage) async -> Encodable? {
+        guard let event: TelemetryEvent = DecodableHelper.decode(from: params) else {
+            return nil
+        }
+
+        switch event.attributes {
+        case .impression(let attrs):
+            switch attrs.value {
+            case .landscape:
+                Pixel.fire(pixel: .duckPlayerLandscapeLayoutImpressions)
+            }
+        }
+
+        return nil
+    }
+
     private func encodeUserValues() -> UserValues {
         return UserValues(
             duckPlayerMode: featureFlagger.isFeatureOn(.duckPlayer) ? settings.mode : .disabled,

DuckDuckGo/DuckPlayer/YoutubePlayerUserScript.swift

@@ -37,6 +37,7 @@ final class YoutubePlayerUserScript: NSObject, Subfeature {
         static let initialSetup = "initialSetup"
         static let openSettings = "openSettings"
         static let openInfo = "openInfo"
+        static let telemetryEvent = "telemetryEvent"
     }
 
     init(duckPlayer: DuckPlayerProtocol) {
@@ -79,6 +80,8 @@ final class YoutubePlayerUserScript: NSObject, Subfeature {
             return duckPlayer.openDuckPlayerSettings
         case Handlers.openInfo:
             return duckPlayer.openDuckPlayerInfo
+        case Handlers.telemetryEvent:
+            return duckPlayer.telemetryEvent
         default:
             assertionFailure("YoutubePlayerUserScript: Failed to parse User Script message: \(methodName)")
             return nil

DuckDuckGoTests/DuckPlayerMocks.swift

@@ -118,6 +118,11 @@ final class MockDuckPlayerSettings: DuckPlayerSettings {
 
 final class MockDuckPlayer: DuckPlayerProtocol {
 
+    func telemetryEvent(params: Any, message: WKScriptMessage) async -> (any Encodable)? {
+        nil
+    }
+
+
     var hostView: UIViewController?
 
     func openDuckPlayerSettings(params: Any, message: WKScriptMessage) async -> (any Encodable)? {