feat(receive): add adaptive receive flow and document opening

shared/src/iosMain/kotlin/com/vnidrop/app/MainViewController.kt

@@ -1,5 +1,7 @@
 package com.vnidrop.app
 
 import androidx.compose.ui.window.ComposeUIViewController
+import com.vnidrop.app.feature.receive.ExternalInvitationController
 
-fun MainViewController() = ComposeUIViewController { App(rememberIosAppDependencies()) }
+fun MainViewController(externalInvitations: ExternalInvitationController) =
+	ComposeUIViewController { App(rememberIosAppDependencies(externalInvitations)) }

shared/src/iosMain/kotlin/com/vnidrop/app/Platform.ios.kt

@@ -4,6 +4,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.remember
 import com.vnidrop.app.core.rememberFileSystemService
 import com.vnidrop.app.notifications.IosLocalNotificationService
+import com.vnidrop.app.feature.receive.ExternalInvitationController
 import platform.Foundation.NSBundle
 import platform.Foundation.NSApplicationSupportDirectory
 import platform.Foundation.NSSearchPathForDirectoriesInDomains
@@ -11,7 +12,7 @@ import platform.Foundation.NSUserDomainMask
 import platform.UIKit.UIDevice
 
 @Composable
-fun rememberIosAppDependencies(): AppDependencies {
+fun rememberIosAppDependencies(externalInvitations: ExternalInvitationController): AppDependencies {
 	val fileSystemService = rememberFileSystemService()
 	return remember(fileSystemService) {
 		val device = UIDevice.currentDevice
@@ -25,6 +26,7 @@ fun rememberIosAppDependencies(): AppDependencies {
 			deviceInfoProvider = IosDeviceInfoProvider(device),
 			fileSystemService = fileSystemService,
 			localNotificationService = IosLocalNotificationService(),
+			externalInvitations = externalInvitations,
 		)
 	}
 }

shared/src/iosMain/kotlin/com/vnidrop/app/feature/receive/ReceiveInvitationActions.ios.kt

@@ -0,0 +1,66 @@
+package com.vnidrop.app.feature.receive
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import kotlinx.cinterop.ExperimentalForeignApi
+import kotlinx.cinterop.readBytes
+import platform.Foundation.NSFileManager
+import platform.Foundation.NSURL
+import platform.UIKit.UIApplication
+import platform.UIKit.UIDocumentPickerDelegateProtocol
+import platform.UIKit.UIDocumentPickerViewController
+import platform.UIKit.UIModalPresentationFormSheet
+import platform.UniformTypeIdentifiers.UTTypeData
+import platform.darwin.NSObject
+
+private var retainedInvitationDelegate: InvitationDocumentDelegate? = null
+
+@Composable
+actual fun rememberReceiveInvitationActions(): ReceiveInvitationActions = remember {
+	object : ReceiveInvitationActions {
+		override val fileAvailability = ReceiveMethodAvailability.Available
+		override val qrAvailability = ReceiveMethodAvailability.Unavailable
+		override val nfcAvailability = ReceiveMethodAvailability.Unavailable
+
+		@OptIn(ExperimentalForeignApi::class)
+		override fun pickInvitation(onResult: (Result<String>) -> Unit) {
+			val presenter = UIApplication.sharedApplication.keyWindow?.rootViewController
+				?: return onResult(Result.failure(IllegalStateException("Could not find an iOS view controller")))
+			val picker = UIDocumentPickerViewController(forOpeningContentTypes = listOf(UTTypeData), asCopy = true)
+			val delegate = InvitationDocumentDelegate(onResult)
+			retainedInvitationDelegate = delegate
+			picker.delegate = delegate
+			picker.modalPresentationStyle = UIModalPresentationFormSheet
+			presenter.presentViewController(picker, animated = true, completion = null)
+		}
+
+		override fun scanQrCode(onResult: (Result<String>) -> Unit) =
+			onResult(Result.failure(UnsupportedOperationException("QR scanning is not enabled for this iOS build")))
+
+		override fun readNfcInvitation(onResult: (Result<String>) -> Unit) =
+			onResult(Result.failure(UnsupportedOperationException("NFC reading is not enabled for this iOS build")))
+
+		override fun cancel() = Unit
+	}
+}
+
+private class InvitationDocumentDelegate(
+	private val onResult: (Result<String>) -> Unit,
+) : NSObject(), UIDocumentPickerDelegateProtocol {
+	@OptIn(ExperimentalForeignApi::class)
+	override fun documentPicker(controller: UIDocumentPickerViewController, didPickDocumentsAtURLs: List<*>) {
+		val url = didPickDocumentsAtURLs.firstOrNull() as? NSURL
+		onResult(runCatching {
+			requireNotNull(url) { "The selected invitation URL was invalid" }
+			val path = url.path ?: error("The invitation path was invalid")
+			val data = NSFileManager.defaultManager.contentsAtPath(path) ?: error("The invitation could not be opened")
+			require(data.length.toLong() <= MaxInvitationBytes) { "The invitation is too large" }
+			data.bytes?.readBytes(data.length.toInt())?.decodeToString() ?: error("The invitation is empty")
+		})
+		retainedInvitationDelegate = null
+	}
+
+	override fun documentPickerWasCancelled(controller: UIDocumentPickerViewController) {
+		retainedInvitationDelegate = null
+	}
+}