feat(send): multi-file shares and receivers polish

Allow selecting multiple files on Android, desktop, and iOS and share them
as one transfer through the core multi-source path. Update the composer UI
for multi-file review, hide unfinished iOS receive methods, and surface
refusal reasons on the receivers list.

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

@@ -142,6 +142,13 @@ interface CoreGateway {
 		senderName: String,
 		accessPolicy: ShareAccessPolicy,
 	): Result<Share>
+	/** Multi-source share used by multi-file pickers. */
+	suspend fun shareSources(
+		sources: List<uniffi.vnidrop.ShareSource>,
+		transferName: String,
+		senderName: String,
+		accessPolicy: ShareAccessPolicy,
+	): Result<Share>
 	suspend fun inspectTicket(ticket: String): Result<TicketInspectionModel>
 	suspend fun receive(ticket: String, outputDir: String, receiverName: String): Result<Unit>
 	suspend fun receiveWithOutputSink(ticket: String, outputSink: ReceiveOutputSink, receiverName: String): Result<Unit>

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

@@ -197,12 +197,13 @@ class CoreRepository(
 
 	override suspend fun refresh(): Result<Unit> = runCore { refreshSnapshot() }
 
-	private suspend fun shareSources(
+	override suspend fun shareSources(
 		sources: List<ShareSource>,
 		transferName: String,
 		senderName: String,
 		accessPolicy: ShareAccessPolicy,
 	): Result<Share> = runCore {
+		require(sources.isNotEmpty()) { "Select at least one file to share" }
 		withPlatformPathAccess(sources) {
 			requireCore().shareFiles(
 				sources = sources,

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

@@ -10,7 +10,8 @@ data class PickedShareFile(
 )
 
 interface ShareFilePicker {
-	fun pickFile()
+	/** Opens a platform picker that may return one or more files. */
+	fun pickFiles()
 }
 
 interface ReceiveFolderPicker {
@@ -19,7 +20,7 @@ interface ReceiveFolderPicker {
 
 @Composable
 expect fun rememberShareFilePicker(
-	onFilePicked: (PickedShareFile) -> Unit,
+	onFilesPicked: (List<PickedShareFile>) -> Unit,
 	onError: (String) -> Unit,
 ): ShareFilePicker
 

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

@@ -36,6 +36,14 @@ interface FileSystemService {
 		transferName: String,
 		senderName: String,
 		accessPolicy: ShareAccessPolicy,
+	): Result<Share> = sharePickedFiles(repository, listOf(file), transferName, senderName, accessPolicy)
+
+	suspend fun sharePickedFiles(
+		repository: CoreGateway,
+		files: List<PickedShareFile>,
+		transferName: String,
+		senderName: String,
+		accessPolicy: ShareAccessPolicy,
 	): Result<Share>
 }
 

shared/src/commonMain/kotlin/com/vnidrop/app/feature/send/SendRoute.kt

@@ -17,13 +17,13 @@ fun SendRoute(
 	val state by viewModel.state.collectAsStateWithLifecycle()
 	val coreState by viewModel.coreState.collectAsStateWithLifecycle()
 	val clipboard = LocalClipboardManager.current
-	val picker = rememberShareFilePicker(viewModel::onFilePicked, viewModel::onFilePickFailed)
+	val picker = rememberShareFilePicker(viewModel::onFilesPicked, viewModel::onFilePickFailed)
 	val shareActions = rememberTransferShareActions()
 
 	LaunchedEffect(viewModel) {
 		viewModel.effectFlow.collect { effect ->
 			when (effect) {
-				SendEffect.OpenFilePicker -> picker.pickFile()
+				SendEffect.OpenFilePicker -> picker.pickFiles()
 				is SendEffect.CopyTicket -> clipboard.setText(AnnotatedString(effect.ticket))
 			}
 		}
@@ -38,6 +38,7 @@ fun SendRoute(
 		onDismissComposer = viewModel::dismissComposer,
 		onSelectFile = viewModel::selectFile,
 		onClearFile = viewModel::clearSelectedSource,
+		onRemoveFile = viewModel::removeSelectedFile,
 		onTransferNameChanged = viewModel::setTransferName,
 		onSenderNameChanged = viewModel::setSenderName,
 		onAccessPolicyChanged = viewModel::setAccessPolicy,

shared/src/commonMain/kotlin/com/vnidrop/app/feature/send/SendScreen.kt

@@ -25,6 +25,7 @@ fun SendScreen(
 	onDismissComposer: () -> Unit,
 	onSelectFile: () -> Unit,
 	onClearFile: () -> Unit,
+	onRemoveFile: (String) -> Unit = {},
 	onTransferNameChanged: (String) -> Unit,
 	onSenderNameChanged: (String) -> Unit,
 	onAccessPolicyChanged: (ShareAccessPolicy) -> Unit,
@@ -83,6 +84,7 @@ fun SendScreen(
 				windowClass = windowClass,
 				onSelectFile = onSelectFile,
 				onClearFile = onClearFile,
+				onRemoveFile = onRemoveFile,
 				onTransferNameChanged = onTransferNameChanged,
 				onSenderNameChanged = onSenderNameChanged,
 				onAccessPolicyChanged = onAccessPolicyChanged,

shared/src/commonMain/kotlin/com/vnidrop/app/feature/send/SendViewModel.kt

@@ -29,7 +29,7 @@ import vnidrop.shared.generated.resources.transfer_nfc_written
 
 data class SendState(
 	val isComposerOpen: Boolean = false,
-	val selectedFile: PickedShareFile? = null,
+	val selectedFiles: List<PickedShareFile> = emptyList(),
 	val transferName: String = "",
 	val senderName: String = "",
 	val accessPolicy: ShareAccessPolicy = ShareAccessPolicy.RequireApproval,
@@ -42,8 +42,12 @@ data class SendState(
 	val isDeleteConfirmationOpen: Boolean = false,
 	val isDeleting: Boolean = false,
 ) {
+	val selectedFile: PickedShareFile? get() = selectedFiles.singleOrNull()
+	val totalSelectedBytes: ULong
+		get() = selectedFiles.fold(0UL) { acc, file -> acc + (file.sizeBytes ?: 0UL) }
+
 	fun canCreateShare(coreInitialized: Boolean): Boolean =
-		coreInitialized && selectedFile != null && transferName.isNotBlank() && !isSharing
+		coreInitialized && selectedFiles.isNotEmpty() && transferName.isNotBlank() && !isSharing
 }
 
 enum class TransferDetailPanel { Activity, Receivers, Share }
@@ -111,7 +115,7 @@ class SendViewModel(
 		_state.update {
 			it.copy(
 				isComposerOpen = true,
-				selectedFile = null,
+				selectedFiles = emptyList(),
 				transferName = "",
 				accessPolicy = ShareAccessPolicy.RequireApproval,
 			)
@@ -123,7 +127,7 @@ class SendViewModel(
 		_state.update {
 			it.copy(
 				isComposerOpen = false,
-				selectedFile = null,
+				selectedFiles = emptyList(),
 				transferName = "",
 				accessPolicy = ShareAccessPolicy.RequireApproval,
 			)
@@ -132,12 +136,13 @@ class SendViewModel(
 
 	fun selectFile() = sendEffect(SendEffect.OpenFilePicker)
 
-	fun onFilePicked(file: PickedShareFile) {
+	fun onFilesPicked(files: List<PickedShareFile>) {
+		if (files.isEmpty()) return
 		_state.update {
 			it.copy(
 				isComposerOpen = true,
-				selectedFile = file,
-				transferName = file.displayName,
+				selectedFiles = files,
+				transferName = defaultTransferName(files),
 			)
 		}
 	}
@@ -145,7 +150,21 @@ class SendViewModel(
 	fun onFilePickFailed(reason: String) = messages.error(IllegalStateException(reason))
 
 	fun clearSelectedSource() {
-		_state.update { it.copy(selectedFile = null, transferName = "") }
+		_state.update { it.copy(selectedFiles = emptyList(), transferName = "") }
+	}
+
+	fun removeSelectedFile(value: String) {
+		_state.update { current ->
+			val remaining = current.selectedFiles.filterNot { it.value == value }
+			current.copy(
+				selectedFiles = remaining,
+				transferName = when {
+					remaining.isEmpty() -> ""
+					current.transferName == defaultTransferName(current.selectedFiles) -> defaultTransferName(remaining)
+					else -> current.transferName
+				},
+			)
+		}
 	}
 
 	fun setTransferName(value: String) = _state.update { it.copy(transferName = value) }
@@ -218,24 +237,25 @@ class SendViewModel(
 
 	fun createShare() {
 		val current = state.value
-		val file = current.selectedFile ?: return
+		if (current.selectedFiles.isEmpty()) return
 		if (!current.canCreateShare(coreState.value.isInitialized)) return
 		viewModelScope.launch {
 			_state.update { it.copy(isSharing = true) }
-			val result = fileSystemService.sharePickedFile(
+			val result = fileSystemService.sharePickedFiles(
 				repository = repository,
-				file = file,
+				files = current.selectedFiles,
 				transferName = current.transferName.trim(),
 				senderName = current.senderName.trim(),
 				accessPolicy = current.accessPolicy,
 			)
 			result.fold(
 				onSuccess = { share ->
-					file.thumbnailBytes?.let { filePreviewRepository.save(share.transferId, it) }
+					current.selectedFiles.firstNotNullOfOrNull { it.thumbnailBytes }
+						?.let { filePreviewRepository.save(share.transferId, it) }
 					_state.update {
 						it.copy(
 							isComposerOpen = false,
-							selectedFile = null,
+							selectedFiles = emptyList(),
 							transferName = "",
 							accessPolicy = ShareAccessPolicy.RequireApproval,
 							isSharing = false,
@@ -251,6 +271,12 @@ class SendViewModel(
 		}
 	}
 
+	private fun defaultTransferName(files: List<PickedShareFile>): String = when (files.size) {
+		0 -> ""
+		1 -> files.first().displayName
+		else -> "${files.size} files"
+	}
+
 	private fun sendEffect(effect: SendEffect) {
 		viewModelScope.launch { effects.send(effect) }
 	}

shared/src/commonMain/kotlin/com/vnidrop/app/feature/send/TransferComposer.kt

@@ -16,6 +16,7 @@ import androidx.compose.foundation.selection.selectable
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.RadioButton
 import androidx.compose.material3.Surface
@@ -39,9 +40,10 @@ import com.vnidrop.app.ui.state.formatBytes
 import com.vnidrop.app.ui.theme.LocalVniDropColors
 import org.jetbrains.compose.resources.stringResource
 import vnidrop.shared.generated.resources.Res
-import vnidrop.shared.generated.resources.button_change_file
-import vnidrop.shared.generated.resources.button_choose_file
+import vnidrop.shared.generated.resources.button_change_files
+import vnidrop.shared.generated.resources.button_choose_files
 import vnidrop.shared.generated.resources.button_clear
+import vnidrop.shared.generated.resources.button_remove_file
 import vnidrop.shared.generated.resources.button_share_file
 import vnidrop.shared.generated.resources.button_sharing_file
 import vnidrop.shared.generated.resources.field_sender_name
@@ -55,6 +57,7 @@ import vnidrop.shared.generated.resources.send_choose_file_body
 import vnidrop.shared.generated.resources.send_choose_file_title
 import vnidrop.shared.generated.resources.send_file_size_unknown
 import vnidrop.shared.generated.resources.send_review_title
+import vnidrop.shared.generated.resources.send_selected_files_count
 
 @Composable
 internal fun TransferComposer(
@@ -63,6 +66,7 @@ internal fun TransferComposer(
 	windowClass: WindowClass,
 	onSelectFile: () -> Unit,
 	onClearFile: () -> Unit,
+	onRemoveFile: (String) -> Unit,
 	onTransferNameChanged: (String) -> Unit,
 	onSenderNameChanged: (String) -> Unit,
 	onAccessPolicyChanged: (ShareAccessPolicy) -> Unit,
@@ -72,16 +76,15 @@ internal fun TransferComposer(
 		modifier = Modifier.fillMaxWidth().verticalScroll(rememberScrollState()).padding(horizontal = 20.dp, vertical = 12.dp),
 		verticalArrangement = Arrangement.spacedBy(16.dp),
 	) {
-		val file = state.selectedFile
-		if (file == null) {
+		if (state.selectedFiles.isEmpty()) {
 			ChooseFileStep(onSelectFile)
 		} else {
 			ReviewFileStep(
-				file = file,
 				state = state,
 				windowClass = windowClass,
 				onSelectFile = onSelectFile,
 				onClearFile = onClearFile,
+				onRemoveFile = onRemoveFile,
 				onTransferNameChanged = onTransferNameChanged,
 				onSenderNameChanged = onSenderNameChanged,
 				onAccessPolicyChanged = onAccessPolicyChanged,
@@ -107,18 +110,18 @@ private fun ChooseFileStep(onSelectFile: () -> Unit) {
 			verticalArrangement = Arrangement.spacedBy(14.dp),
 		) {
 			Icon(SendIcons.File, contentDescription = null, tint = LocalVniDropColors.current.brandLink, modifier = Modifier.size(32.dp))
-			PrimaryButton(stringResource(Res.string.button_choose_file), onClick = onSelectFile)
+			PrimaryButton(stringResource(Res.string.button_choose_files), onClick = onSelectFile)
 		}
 	}
 }
 
 @Composable
 private fun ReviewFileStep(
-	file: PickedShareFile,
 	state: SendState,
 	windowClass: WindowClass,
 	onSelectFile: () -> Unit,
 	onClearFile: () -> Unit,
+	onRemoveFile: (String) -> Unit,
 	onTransferNameChanged: (String) -> Unit,
 	onSenderNameChanged: (String) -> Unit,
 	onAccessPolicyChanged: (ShareAccessPolicy) -> Unit,
@@ -126,7 +129,20 @@ private fun ReviewFileStep(
 	coreInitialized: Boolean,
 ) {
 	Text(stringResource(Res.string.send_review_title), style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.SemiBold)
-	SelectedFileCard(file)
+	if (state.selectedFiles.size > 1) {
+		Text(
+			stringResource(Res.string.send_selected_files_count, state.selectedFiles.size),
+			color = LocalVniDropColors.current.foregroundLighter,
+			style = MaterialTheme.typography.bodyMedium,
+		)
+	}
+	state.selectedFiles.forEach { file ->
+		SelectedFileCard(
+			file = file,
+			canRemove = state.selectedFiles.size > 1 && !state.isSharing,
+			onRemove = { onRemoveFile(file.value) },
+		)
+	}
 	Field(state.transferName, onTransferNameChanged, stringResource(Res.string.field_transfer_name))
 	Field(state.senderName, onSenderNameChanged, stringResource(Res.string.field_sender_name))
 	Text(stringResource(Res.string.send_access_title), style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold)
@@ -147,12 +163,12 @@ private fun ReviewFileStep(
 	if (windowClass == WindowClass.Phone) {
 		Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
 			ShareButton(state, coreInitialized, onCreateShare, Modifier.fillMaxWidth())
-			QuietButton(stringResource(Res.string.button_change_file), onClick = onSelectFile, modifier = Modifier.fillMaxWidth(), enabled = !state.isSharing)
+			QuietButton(stringResource(Res.string.button_change_files), onClick = onSelectFile, modifier = Modifier.fillMaxWidth(), enabled = !state.isSharing)
 		}
 	} else {
 		Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
 			ShareButton(state, coreInitialized, onCreateShare)
-			QuietButton(stringResource(Res.string.button_change_file), onClick = onSelectFile, enabled = !state.isSharing)
+			QuietButton(stringResource(Res.string.button_change_files), onClick = onSelectFile, enabled = !state.isSharing)
 			QuietButton(stringResource(Res.string.button_clear), onClick = onClearFile, enabled = !state.isSharing)
 		}
 	}
@@ -169,7 +185,11 @@ private fun ShareButton(state: SendState, coreInitialized: Boolean, onCreateShar
 }
 
 @Composable
-private fun SelectedFileCard(file: PickedShareFile) {
+private fun SelectedFileCard(
+	file: PickedShareFile,
+	canRemove: Boolean,
+	onRemove: () -> Unit,
+) {
 	Surface(shape = RoundedCornerShape(14.dp), color = LocalVniDropColors.current.backgroundSurface200) {
 		Row(modifier = Modifier.fillMaxWidth().padding(14.dp), verticalAlignment = Alignment.CenterVertically) {
 			Box(Modifier.size(44.dp).background(LocalVniDropColors.current.backgroundSurface300, RoundedCornerShape(11.dp))) {
@@ -184,6 +204,11 @@ private fun SelectedFileCard(file: PickedShareFile) {
 					style = MaterialTheme.typography.bodySmall,
 				)
 			}
+			if (canRemove) {
+				IconButton(onClick = onRemove) {
+					Icon(SendIcons.Delete, stringResource(Res.string.button_remove_file), tint = LocalVniDropColors.current.destructiveDefault)
+				}
+			}
 		}
 	}
 }

shared/src/commonMain/kotlin/com/vnidrop/app/feature/send/TransferDetails.kt

@@ -181,6 +181,9 @@ private fun ReceiverRow(receiver: ReceiverRequestModel) {
 			Text(it, color = LocalVniDropColors.current.foregroundLighter, style = MaterialTheme.typography.bodySmall)
 		}
 		Text(receiverStatusText(receiver.status), color = receiverStatusColor(receiver.status), style = MaterialTheme.typography.bodySmall, fontWeight = FontWeight.Medium)
+		receiver.reason?.takeIf { it.isNotBlank() }?.let { reason ->
+			Text(reason, color = LocalVniDropColors.current.foregroundLighter, style = MaterialTheme.typography.bodySmall)
+		}
 	}
 }