Add native file picker to core test UI

shared/src/androidMain/kotlin/com/vnidrop/app/core/FilePicker.android.kt

@@ -0,0 +1,72 @@
+package com.vnidrop.app.core
+
+import android.content.Context
+import android.net.Uri
+import android.provider.OpenableColumns
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.platform.LocalContext
+
+@Composable
+actual fun rememberShareFilePicker(
+	onFilePicked: (PickedShareFile) -> Unit,
+	onError: (String) -> Unit,
+): ShareFilePicker {
+	val context = LocalContext.current
+	val launcher = rememberLauncherForActivityResult(ActivityResultContracts.OpenDocument()) { uri ->
+		if (uri != null) {
+			onFilePicked(PickedShareFile(uri.toString(), context.displayName(uri)))
+		}
+	}
+	return remember(launcher) {
+		object : ShareFilePicker {
+			override fun pickFile() {
+				launcher.launch(arrayOf("*/*"))
+			}
+		}
+	}
+}
+
+actual suspend fun sharePickedFile(
+	repository: CoreRepository,
+	file: PickedShareFile,
+	transferName: String,
+	senderName: String,
+) {
+	val context = AndroidContextHolder.context
+		errorIfNull(context, "Android context has not been attached")
+		.contentResolver
+		.openFileDescriptor(Uri.parse(file.value), "r")
+		.use { descriptor ->
+			checkNotNull(descriptor) { "Could not open selected file descriptor" }
+			repository.shareFileDescriptor(
+				fd = descriptor.fd,
+				displayName = file.displayName,
+				transferName = transferName,
+				senderName = senderName,
+			)
+		}
+}
+
+private object AndroidContextHolder {
+	var context: Context? = null
+}
+
+fun attachAndroidFilePickerContext(context: Context) {
+	AndroidContextHolder.context = context.applicationContext
+}
+
+private fun Context.displayName(uri: Uri): String {
+	contentResolver.query(uri, null, null, null, null)?.use { cursor ->
+		val nameIndex = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
+		if (nameIndex >= 0 && cursor.moveToFirst()) {
+			return cursor.getString(nameIndex)
+		}
+	}
+	return uri.lastPathSegment ?: "transfer"
+}
+
+private fun <T : Any> errorIfNull(value: T?, message: String): T =
+	value ?: error(message)

shared/src/commonMain/kotlin/com/vnidrop/app/App.kt

@@ -21,6 +21,9 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import com.vnidrop.app.core.CoreRepository
+import com.vnidrop.app.core.PickedShareFile
+import com.vnidrop.app.core.rememberShareFilePicker
+import com.vnidrop.app.core.sharePickedFile
 import kotlinx.coroutines.launch
 
 @Composable
@@ -32,11 +35,22 @@ fun App() {
 	val scope = rememberCoroutineScope()
 	var appDataDir by remember { mutableStateOf(platform.defaultCoreDataDir) }
 	var sourcePath by remember { mutableStateOf("") }
+	var selectedFile by remember { mutableStateOf<PickedShareFile?>(null) }
 	var transferName by remember { mutableStateOf("VniDrop transfer") }
 	var senderName by remember { mutableStateOf("") }
 	var ticket by remember { mutableStateOf("") }
 	var receiveDir by remember { mutableStateOf(platform.defaultReceiveDir) }
 	var receiverName by remember { mutableStateOf("") }
+	val shareFilePicker = rememberShareFilePicker(
+		onFilePicked = { file ->
+			selectedFile = file
+			sourcePath = file.value
+			if (transferName.isBlank() || transferName == "VniDrop transfer") {
+				transferName = file.displayName
+			}
+		},
+		onError = { error -> scope.launch { repository.setError(error) } },
+	)
 
 	MaterialTheme {
 		Surface(
@@ -73,13 +87,19 @@ fun App() {
 				}
 
 				item {
-					CoreCard(title = "Share path") {
+					CoreCard(title = "Share file") {
 						OutlinedTextField(
 							value = sourcePath,
-							onValueChange = { sourcePath = it },
-							label = { Text("Source file path") },
+							onValueChange = {
+								sourcePath = it
+								selectedFile = null
+							},
+							label = { Text("Selected file") },
 							modifier = Modifier.fillMaxWidth(),
 						)
+						Button(onClick = { shareFilePicker.pickFile() }) {
+							Text("Select file")
+						}
 						OutlinedTextField(
 							value = transferName,
 							onValueChange = { transferName = it },
@@ -93,10 +113,15 @@ fun App() {
 							modifier = Modifier.fillMaxWidth(),
 						)
 						Button(
-							enabled = state.isInitialized && sourcePath.isNotBlank(),
+							enabled = state.isInitialized && (selectedFile != null || sourcePath.isNotBlank()),
 							onClick = {
 								scope.launch {
-									repository.sharePath(sourcePath, transferName, senderName)
+									val picked = selectedFile
+									if (picked != null) {
+										sharePickedFile(repository, picked, transferName, senderName)
+									} else {
+										repository.sharePath(sourcePath, transferName, senderName)
+									}
 								}
 							},
 						) {

shared/src/commonMain/kotlin/com/vnidrop/app/core/CoreRepository.kt

@@ -135,6 +135,10 @@ class CoreRepository(
 		refreshStatus()
 	}
 
+	suspend fun setError(message: String) {
+		_state.update { it.copy(error = message) }
+	}
+
 	private suspend fun runCore(block: suspend () -> Unit) {
 		withContext(dispatcher) {
 			try {

shared/src/commonMain/kotlin/com/vnidrop/app/core/FilePicker.kt

@@ -0,0 +1,25 @@
+package com.vnidrop.app.core
+
+import androidx.compose.runtime.Composable
+
+data class PickedShareFile(
+	val value: String,
+	val displayName: String,
+)
+
+interface ShareFilePicker {
+	fun pickFile()
+}
+
+@Composable
+expect fun rememberShareFilePicker(
+	onFilePicked: (PickedShareFile) -> Unit,
+	onError: (String) -> Unit,
+): ShareFilePicker
+
+expect suspend fun sharePickedFile(
+	repository: CoreRepository,
+	file: PickedShareFile,
+	transferName: String,
+	senderName: String,
+)

shared/src/iosMain/kotlin/com/vnidrop/app/core/FilePicker.ios.kt

@@ -0,0 +1,67 @@
+package com.vnidrop.app.core
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import kotlinx.cinterop.ExperimentalForeignApi
+import platform.Foundation.NSURL
+import platform.UIKit.UIApplication
+import platform.UIKit.UIDocumentPickerDelegateProtocol
+import platform.UIKit.UIDocumentPickerViewController
+import platform.UIKit.UIModalPresentationFormSheet
+import platform.UniformTypeIdentifiers.UTTypeItem
+import platform.darwin.NSObject
+
+private var retainedPickerDelegate: DocumentPickerDelegate? = null
+
+@Composable
+actual fun rememberShareFilePicker(
+	onFilePicked: (PickedShareFile) -> Unit,
+	onError: (String) -> Unit,
+): ShareFilePicker = remember(onFilePicked, onError) {
+	object : ShareFilePicker {
+		@OptIn(ExperimentalForeignApi::class)
+		override fun pickFile() {
+			val presenter = UIApplication.sharedApplication.keyWindow?.rootViewController
+			if (presenter == null) {
+				onError("Could not find an iOS view controller for the document picker")
+				return
+			}
+
+			val picker = UIDocumentPickerViewController(forOpeningContentTypes = listOf(UTTypeItem), asCopy = false)
+			val delegate = DocumentPickerDelegate(onFilePicked, onError)
+			retainedPickerDelegate = delegate
+			picker.delegate = delegate
+			picker.modalPresentationStyle = UIModalPresentationFormSheet
+			presenter.presentViewController(picker, animated = true, completion = null)
+		}
+	}
+}
+
+actual suspend fun sharePickedFile(
+	repository: CoreRepository,
+	file: PickedShareFile,
+	transferName: String,
+	senderName: String,
+) {
+	repository.shareSecurityScopedFileUrl(file.value, file.displayName, transferName, senderName)
+}
+
+private class DocumentPickerDelegate(
+	private val onFilePicked: (PickedShareFile) -> Unit,
+	private val onError: (String) -> Unit,
+) : NSObject(), UIDocumentPickerDelegateProtocol {
+	override fun documentPicker(controller: UIDocumentPickerViewController, didPickDocumentsAtURLs: List<*>) {
+		val url = didPickDocumentsAtURLs.firstOrNull() as? NSURL
+		if (url == null) {
+			onError("The selected iOS document URL was invalid")
+		} else {
+			val displayName = url.lastPathComponent ?: "transfer"
+			onFilePicked(PickedShareFile(url.absoluteString ?: url.path.orEmpty(), displayName))
+		}
+		retainedPickerDelegate = null
+	}
+
+	override fun documentPickerWasCancelled(controller: UIDocumentPickerViewController) {
+		retainedPickerDelegate = null
+	}
+}

shared/src/jvmMain/kotlin/com/vnidrop/app/core/FilePicker.jvm.kt

@@ -0,0 +1,39 @@
+package com.vnidrop.app.core
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import java.awt.FileDialog
+import java.awt.Frame
+import java.io.File
+
+@Composable
+actual fun rememberShareFilePicker(
+	onFilePicked: (PickedShareFile) -> Unit,
+	onError: (String) -> Unit,
+): ShareFilePicker = remember(onFilePicked, onError) {
+	object : ShareFilePicker {
+		override fun pickFile() {
+			try {
+				val dialog = FileDialog(null as Frame?, "Select file to share", FileDialog.LOAD)
+				dialog.isVisible = true
+				val directory = dialog.directory
+				val file = dialog.file
+				if (directory != null && file != null) {
+					val selected = File(directory, file)
+					onFilePicked(PickedShareFile(selected.absolutePath, selected.name))
+				}
+			} catch (error: Throwable) {
+				onError(error.message ?: error.toString())
+			}
+		}
+	}
+}
+
+actual suspend fun sharePickedFile(
+	repository: CoreRepository,
+	file: PickedShareFile,
+	transferName: String,
+	senderName: String,
+) {
+	repository.sharePath(file.value, transferName, senderName)
+}