Share extension (#3506)

* Setup simple share extension

* Switch the app url scheme to be the full bundle identifier

* Setup a share extension that show a SwiftUI view, uses rust tracing and redirects to the hosting aplication

* Move media as json through the custom scheme into the main app and deep link into the media upload preview screen

* Fix message forwarding and global search screen room summary provider filtering.

* Tweak the message forwarding and global search screen designs.

* Add a room selection screen to use after receiving a share request from the share extension

* Fix share extension entitlements

* Share the temporary directory between the main app and the extensions; rename the caches one.

* Remove the no longer needed notification avatar flipping fix.

* Extract the placeholder avatar image generator from the NSE

* Nest `AvatarSize` within the new `Avatars` enum

* Donate an `INSendMessageIntent` to the system every time we send a message so they appear as share suggestions

* Support suggestions in the share extension itself

* Improve sharing animations and fix presentation when room already on the stack

* Clear all routes when sharing without a preselected room.

* Fix broken unit tests

* Various initial tweaks following code review.

* Correctly clean up and dismiss the share extension for all paths.

* Move the share extension path to a constants enum

* Rename UserSessionFlowCoordinator specific share extension states and events

* Add UserSession and Room flow coordinator share route tests

* Tweak the share extension logic.

ElementX/Sources/Application/AppCoordinator.swift

@@ -235,6 +235,12 @@ class AppCoordinator: AppCoordinatorProtocol, AuthenticationFlowCoordinatorDeleg
                 } else {
                     handleAppRoute(.childEventOnRoomAlias(eventID: eventID, alias: alias))
                 }
+            case .share:
+                guard isExternalURL else {
+                    MXLog.error("Received unexpected internal share route")
+                    break
+                }
+                handleAppRoute(route)
             default:
                 break
             }

ElementX/Sources/Application/Navigation/AppRoutes.swift

@@ -8,7 +8,7 @@
 import Foundation
 import MatrixRustSDK
 
-enum AppRoute: Equatable {
+enum AppRoute: Equatable, Hashable {
     /// The app's home screen.
     case roomList
     /// A room, shown as the root of the stack (popping any child rooms).
@@ -41,6 +41,8 @@ enum AppRoute: Equatable {
     case settings
     /// The setting screen for key backup.
     case chatBackupSettings
+    /// An external share request e.g. from the ShareExtension
+    case share(ShareExtensionPayload)
 }
 
 struct AppRouteURLParser {
@@ -48,6 +50,7 @@ struct AppRouteURLParser {
     
     init(appSettings: AppSettings) {
         urlParsers = [
+            AppGroupURLParser(),
             MatrixPermalinkParser(),
             ElementWebURLParser(domains: appSettings.elementWebHosts),
             ElementCallURLParser()
@@ -73,6 +76,30 @@ protocol URLParser {
     func route(from url: URL) -> AppRoute?
 }
 
+struct AppGroupURLParser: URLParser {
+    func route(from url: URL) -> AppRoute? {
+        guard let scheme = url.scheme,
+              scheme == InfoPlistReader.app.appScheme,
+              url.pathComponents.last == ShareExtensionConstants.urlPath else {
+            return nil
+        }
+        
+        guard let query = url.query(percentEncoded: false),
+              let queryData = query.data(using: .utf8) else {
+            MXLog.error("Failed processing share parameters")
+            return nil
+        }
+        
+        do {
+            let payload = try JSONDecoder().decode(ShareExtensionPayload.self, from: queryData)
+            return .share(payload)
+        } catch {
+            MXLog.error("Failed decoding share payload with error: \(error)")
+            return nil
+        }
+    }
+}
+
 /// The parser for Element Call links. This always returns a `.genericCallLink`.
 struct ElementCallURLParser: URLParser {
     private let knownHosts = ["call.element.io"]