Refactor app state handling

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

@@ -3,19 +3,14 @@ package com.vnidrop.app
 import androidx.compose.foundation.layout.BoxWithConstraints
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
-import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
-import androidx.compose.runtime.rememberCoroutineScope
-import androidx.compose.runtime.setValue
 import androidx.compose.ui.platform.LocalClipboardManager
 import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.tooling.preview.Preview
-import com.vnidrop.app.core.CoreRepository
-import com.vnidrop.app.core.PickedShareFile
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import androidx.lifecycle.viewmodel.compose.viewModel
 import com.vnidrop.app.core.rememberShareFilePicker
-import com.vnidrop.app.core.sharePickedFile
 import com.vnidrop.app.logging.AppLogger
 import com.vnidrop.app.platform.PlatformSystemAppearance
 import com.vnidrop.app.ui.navigation.AppDestination
@@ -23,51 +18,49 @@ import com.vnidrop.app.ui.screens.ReceiveScreen
 import com.vnidrop.app.ui.screens.SendScreen
 import com.vnidrop.app.ui.screens.SettingsScreen
 import com.vnidrop.app.ui.shell.AppShell
-import com.vnidrop.app.ui.state.AppUiState
-import com.vnidrop.app.ui.state.ReceiveUiState
-import com.vnidrop.app.ui.state.SendUiState
 import com.vnidrop.app.ui.state.windowClassFor
 import com.vnidrop.app.ui.theme.VniDropTheme
 import com.vnidrop.app.ui.theme.rememberResolvedDarkTheme
-import kotlinx.coroutines.launch
 
 @Composable
 @Preview
 fun App() {
 	val platform = remember { getPlatform() }
-	val repository = remember { CoreRepository() }
-	val coreState by repository.state.collectAsState()
-	var appState by remember { mutableStateOf(AppUiState()) }
-	val appDataDir = platform.defaultCoreDataDir
-	var sendState by remember { mutableStateOf(SendUiState()) }
-	var receiveState by remember { mutableStateOf(ReceiveUiState(outputDirectory = platform.defaultReceiveDir)) }
-	var selectedFile by remember { mutableStateOf<PickedShareFile?>(null) }
-	val scope = rememberCoroutineScope()
+	val viewModel = viewModel {
+		VniDropAppViewModel(
+			appDataDir = platform.defaultCoreDataDir,
+			defaultReceiveDir = platform.defaultReceiveDir,
+			platformName = platform.name,
+		)
+	}
+	val state by viewModel.state.collectAsStateWithLifecycle()
+	val coreState by viewModel.coreState.collectAsStateWithLifecycle()
 	val clipboard = LocalClipboardManager.current
 	val picker = rememberShareFilePicker(
 		onFilePicked = { file ->
-			AppLogger.info("file-picker", "file selected", mapOf("name" to file.displayName))
-			selectedFile = file
-			sendState = sendState.withSelectedFile(file)
+			viewModel.onEvent(VniDropAppEvent.ShareFilePicked(file))
 		},
 		onError = { error ->
-			AppLogger.warn("file-picker", "file picker error", mapOf("reason" to error))
-			scope.launch { repository.setError(error) }
+			viewModel.onEvent(VniDropAppEvent.ShareFilePickFailed(error))
 		},
 	)
 
-	LaunchedEffect(Unit) {
-		AppLogger.initialize(appDataDir)
-		AppLogger.info("lifecycle", "app started", mapOf("platform" to platform.name))
-		AppLogger.info("core", "automatic initialize requested", mapOf("appDataDir" to appDataDir))
-		repository.initialize(appDataDir)
+	LaunchedEffect(viewModel) {
+		viewModel.effectFlow.collect { effect ->
+			when (effect) {
+				VniDropAppEffect.OpenShareFilePicker -> {
+					AppLogger.info("file-picker", "open share file picker")
+					picker.pickFile()
+				}
+				is VniDropAppEffect.CopyTicket -> {
+					AppLogger.info("send", "ticket copied")
+					clipboard.setText(AnnotatedString(effect.ticket))
+				}
+			}
+		}
 	}
 
-	LaunchedEffect(coreState.lastShare?.transferId) {
-		coreState.lastShare?.let { share -> repository.refreshReceiverRequests(share.transferId) }
-	}
-
-	val isDarkTheme = rememberResolvedDarkTheme(appState.themeMode)
+	val isDarkTheme = rememberResolvedDarkTheme(state.app.themeMode)
 	PlatformSystemAppearance(isDarkTheme)
 	LaunchedEffect(isDarkTheme) {
 		AppLogger.info("appearance", "system appearance synchronized", mapOf("dark" to isDarkTheme.toString()))
@@ -77,84 +70,30 @@ fun App() {
 		BoxWithConstraints {
 			val windowClass = windowClassFor(maxWidth.value)
 			AppShell(
-				selectedDestination = appState.destination,
+				selectedDestination = state.app.destination,
 				windowClass = windowClass,
-				onDestinationSelected = { appState = appState.copy(destination = it) },
+				onDestinationSelected = { viewModel.onEvent(VniDropAppEvent.DestinationSelected(it)) },
 			) {
-				when (appState.destination) {
+				when (state.app.destination) {
 					AppDestination.Send -> SendScreen(
 						coreState = coreState,
-						sendState = sendState,
-						onSendStateChange = { sendState = it },
-						onSelectFile = {
-							AppLogger.info("file-picker", "open share file picker")
-							picker.pickFile()
-						},
-						onCreateShare = {
-							scope.launch {
-								AppLogger.info("send", "create share requested", mapOf("source" to sendState.selectedSource))
-								sendState = sendState.copy(isSharing = true)
-								val file = selectedFile
-								if (file == null) {
-									repository.sharePath(sendState.selectedSource, sendState.transferName, sendState.senderName)
-								} else {
-									sharePickedFile(repository, file, sendState.transferName, sendState.senderName)
-								}
-								sendState = sendState.copy(isSharing = false)
-							}
-						},
-						onCopyTicket = { ticket ->
-							AppLogger.info("send", "ticket copied")
-							clipboard.setText(AnnotatedString(ticket))
-						},
-						onUseLocally = { ticket ->
-							receiveState = receiveState.copy(ticket = ticket)
-							appState = appState.copy(destination = AppDestination.Receive)
-						},
-						onRefreshRequests = { transferId -> scope.launch { repository.refreshReceiverRequests(transferId) } },
-						onRespondRequest = { requestId, accepted ->
-							scope.launch {
-								repository.respondReceiverRequest(
-									requestId = requestId,
-									accepted = accepted,
-									reason = if (accepted) null else "sender-refused",
-								)
-							}
-						},
+						sendState = state.send,
+						onEvent = viewModel::onEvent,
 					)
 					AppDestination.Receive -> ReceiveScreen(
 						coreState = coreState,
-						receiveState = receiveState,
-						onReceiveStateChange = { receiveState = it },
-						onInspect = { scope.launch { repository.inspectTicket(receiveState.ticket) } },
-						onReceive = {
-							scope.launch {
-								AppLogger.info("receive", "receive requested")
-								receiveState = receiveState.copy(isReceiving = true)
-								repository.receive(receiveState.ticket, receiveState.outputDirectory, receiveState.receiverName)
-								receiveState = receiveState.copy(isReceiving = false)
-							}
-						},
+						receiveState = state.receive,
+						onEvent = viewModel::onEvent,
 					)
 					AppDestination.Settings -> SettingsScreen(
 						deviceInfo = platform.deviceInfo,
 						coreState = coreState,
-						themeMode = appState.themeMode,
+						themeMode = state.app.themeMode,
 						windowClass = windowClass,
-						onThemeModeChange = {
-							AppLogger.info("appearance", "theme mode changed", mapOf("mode" to it.name))
-							appState = appState.copy(themeMode = it)
-						},
+						onThemeModeChange = { viewModel.onEvent(VniDropAppEvent.ThemeModeChanged(it)) },
 					)
 				}
 			}
 		}
 	}
 }
-
-private fun SendUiState.withSelectedFile(file: PickedShareFile): SendUiState =
-	copy(
-		selectedSource = file.value,
-		selectedDisplayName = file.displayName,
-		transferName = if (transferName == "VniDrop transfer" || transferName.isBlank()) file.displayName else transferName,
-	)

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

@@ -0,0 +1,230 @@
+package com.vnidrop.app
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.vnidrop.app.core.CoreRepository
+import com.vnidrop.app.core.CoreUiState
+import com.vnidrop.app.core.PickedShareFile
+import com.vnidrop.app.core.sharePickedFile
+import com.vnidrop.app.logging.AppLogger
+import com.vnidrop.app.ui.navigation.AppDestination
+import com.vnidrop.app.ui.state.AppUiState
+import com.vnidrop.app.ui.state.ReceiveUiState
+import com.vnidrop.app.ui.state.SendUiState
+import com.vnidrop.app.ui.theme.ThemeMode
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.receiveAsFlow
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.launch
+
+data class VniDropAppState(
+	val app: AppUiState = AppUiState(),
+	val send: SendUiState = SendUiState(),
+	val receive: ReceiveUiState = ReceiveUiState(),
+)
+
+sealed interface VniDropAppEvent {
+	data class DestinationSelected(val destination: AppDestination) : VniDropAppEvent
+	data class ThemeModeChanged(val mode: ThemeMode) : VniDropAppEvent
+	data object SelectFileClicked : VniDropAppEvent
+	data class ShareFilePicked(val file: PickedShareFile) : VniDropAppEvent
+	data class ShareFilePickFailed(val reason: String) : VniDropAppEvent
+	data object ClearSelectedSourceClicked : VniDropAppEvent
+	data class TransferNameChanged(val value: String) : VniDropAppEvent
+	data class SenderNameChanged(val value: String) : VniDropAppEvent
+	data object CreateShareClicked : VniDropAppEvent
+	data class CopyTicketClicked(val ticket: String) : VniDropAppEvent
+	data class UseTicketLocallyClicked(val ticket: String) : VniDropAppEvent
+	data class RefreshReceiverRequestsClicked(val transferId: ULong) : VniDropAppEvent
+	data class RespondReceiverRequestClicked(val requestId: String, val accepted: Boolean) : VniDropAppEvent
+	data class ReceiveTicketChanged(val value: String) : VniDropAppEvent
+	data class OutputDirectoryChanged(val value: String) : VniDropAppEvent
+	data class ReceiverNameChanged(val value: String) : VniDropAppEvent
+	data object InspectTicketClicked : VniDropAppEvent
+	data object ReceiveClicked : VniDropAppEvent
+}
+
+sealed interface VniDropAppEffect {
+	data object OpenShareFilePicker : VniDropAppEffect
+	data class CopyTicket(val ticket: String) : VniDropAppEffect
+}
+
+class VniDropAppViewModel(
+	appDataDir: String,
+	defaultReceiveDir: String,
+	platformName: String,
+	private val repository: CoreRepository = CoreRepository(),
+) : ViewModel() {
+	private val _state = MutableStateFlow(VniDropAppState(receive = ReceiveUiState(outputDirectory = defaultReceiveDir)))
+	val state: StateFlow<VniDropAppState> = _state
+	val coreState: StateFlow<CoreUiState> = repository.state
+
+	private val effects = Channel<VniDropAppEffect>(Channel.BUFFERED)
+	val effectFlow = effects.receiveAsFlow()
+
+	private var selectedFile: PickedShareFile? = null
+
+	init {
+		AppLogger.initialize(appDataDir)
+		AppLogger.info("lifecycle", "app started", mapOf("platform" to platformName))
+		AppLogger.info("core", "automatic initialize requested", mapOf("appDataDir" to appDataDir))
+		viewModelScope.launch {
+			repository.initialize(appDataDir)
+		}
+	}
+
+	fun onEvent(event: VniDropAppEvent) {
+		when (event) {
+			is VniDropAppEvent.DestinationSelected -> updateAppState { copy(destination = event.destination) }
+			is VniDropAppEvent.ThemeModeChanged -> setThemeMode(event.mode)
+			VniDropAppEvent.SelectFileClicked -> sendEffect(VniDropAppEffect.OpenShareFilePicker)
+			is VniDropAppEvent.ShareFilePicked -> setSelectedFile(event.file)
+			is VniDropAppEvent.ShareFilePickFailed -> setFilePickerError(event.reason)
+			VniDropAppEvent.ClearSelectedSourceClicked -> clearSelectedSource()
+			is VniDropAppEvent.TransferNameChanged -> updateSendState { copy(transferName = event.value) }
+			is VniDropAppEvent.SenderNameChanged -> updateSendState { copy(senderName = event.value) }
+			VniDropAppEvent.CreateShareClicked -> createShare()
+			is VniDropAppEvent.CopyTicketClicked -> sendEffect(VniDropAppEffect.CopyTicket(event.ticket))
+			is VniDropAppEvent.UseTicketLocallyClicked -> useTicketLocally(event.ticket)
+			is VniDropAppEvent.RefreshReceiverRequestsClicked -> refreshReceiverRequests(event.transferId)
+			is VniDropAppEvent.RespondReceiverRequestClicked -> respondReceiverRequest(event.requestId, event.accepted)
+			is VniDropAppEvent.ReceiveTicketChanged -> updateReceiveState { copy(ticket = event.value) }
+			is VniDropAppEvent.OutputDirectoryChanged -> updateReceiveState { copy(outputDirectory = event.value) }
+			is VniDropAppEvent.ReceiverNameChanged -> updateReceiveState { copy(receiverName = event.value) }
+			VniDropAppEvent.InspectTicketClicked -> inspectTicket()
+			VniDropAppEvent.ReceiveClicked -> receive()
+		}
+	}
+
+	private fun setThemeMode(mode: ThemeMode) {
+		AppLogger.info("appearance", "theme mode changed", mapOf("mode" to mode.name))
+		updateAppState { copy(themeMode = mode) }
+	}
+
+	private fun setSelectedFile(file: PickedShareFile) {
+		AppLogger.info("file-picker", "file selected", mapOf("name" to file.displayName))
+		selectedFile = file
+		updateSendState { withSelectedFile(file) }
+	}
+
+	private fun setFilePickerError(reason: String) {
+		AppLogger.warn("file-picker", "file picker error", mapOf("reason" to reason))
+		viewModelScope.launch { repository.setError(reason) }
+	}
+
+	private fun clearSelectedSource() {
+		selectedFile = null
+		updateSendState {
+			copy(
+				selectedSource = "",
+				selectedDisplayName = "",
+			)
+		}
+	}
+
+	private fun createShare() {
+		val sendState = state.value.send
+		if (!sendState.canCreateShare(coreState.value.isInitialized)) return
+
+		viewModelScope.launch {
+			AppLogger.info("send", "create share requested", mapOf("source" to sendState.selectedSource))
+			updateSendState { copy(isSharing = true) }
+			try {
+				val file = selectedFile
+				if (file == null) {
+					repository.sharePath(sendState.selectedSource, sendState.transferName, sendState.senderName)
+				} else {
+					sharePickedFile(repository, file, sendState.transferName, sendState.senderName)
+				}
+				repository.state.value.lastShare?.let { share ->
+					repository.refreshReceiverRequests(share.transferId)
+				}
+			} finally {
+				updateSendState { copy(isSharing = false) }
+			}
+		}
+	}
+
+	private fun useTicketLocally(ticket: String) {
+		updateReceiveState { copy(ticket = ticket) }
+		updateAppState { copy(destination = AppDestination.Receive) }
+	}
+
+	private fun refreshReceiverRequests(transferId: ULong) {
+		viewModelScope.launch {
+			repository.refreshReceiverRequests(transferId)
+		}
+	}
+
+	private fun respondReceiverRequest(requestId: String, accepted: Boolean) {
+		viewModelScope.launch {
+			repository.respondReceiverRequest(
+				requestId = requestId,
+				accepted = accepted,
+				reason = if (accepted) null else "sender-refused",
+			)
+		}
+	}
+
+	private fun inspectTicket() {
+		val receiveState = state.value.receive
+		if (!receiveState.canInspect(coreState.value.isInitialized)) return
+
+		viewModelScope.launch {
+			repository.inspectTicket(receiveState.ticket)
+		}
+	}
+
+	private fun receive() {
+		val receiveState = state.value.receive
+		if (!receiveState.canReceive(coreState.value.isInitialized)) return
+
+		viewModelScope.launch {
+			AppLogger.info("receive", "receive requested")
+			updateReceiveState { copy(isReceiving = true) }
+			try {
+				repository.receive(receiveState.ticket, receiveState.outputDirectory, receiveState.receiverName)
+			} finally {
+				updateReceiveState { copy(isReceiving = false) }
+			}
+		}
+	}
+
+	private fun sendEffect(effect: VniDropAppEffect) {
+		viewModelScope.launch {
+			effects.send(effect)
+		}
+	}
+
+	private fun updateAppState(reducer: AppUiState.() -> AppUiState) {
+		_state.update { current ->
+			val next = current.app.reducer()
+			if (next == current.app) current else current.copy(app = next)
+		}
+	}
+
+	private fun updateSendState(reducer: SendUiState.() -> SendUiState) {
+		_state.update { current ->
+			val next = current.send.reducer()
+			if (next == current.send) current else current.copy(send = next)
+		}
+	}
+
+	private fun updateReceiveState(reducer: ReceiveUiState.() -> ReceiveUiState) {
+		_state.update { current ->
+			val next = current.receive.reducer()
+			if (next == current.receive) current else current.copy(receive = next)
+		}
+	}
+}
+
+private fun SendUiState.withSelectedFile(file: PickedShareFile): SendUiState =
+	copy(
+		selectedSource = file.value,
+		selectedDisplayName = file.displayName,
+		transferName = if (transferName == DefaultTransferName || transferName.isBlank()) file.displayName else transferName,
+	)
+
+private const val DefaultTransferName = "VniDrop transfer"

shared/src/commonMain/kotlin/com/vnidrop/app/ui/screens/ReceiveScreen.kt

@@ -5,6 +5,7 @@ import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.unit.dp
+import com.vnidrop.app.VniDropAppEvent
 import com.vnidrop.app.core.CoreUiState
 import com.vnidrop.app.ui.components.AppCard
 import com.vnidrop.app.ui.components.Field
@@ -27,9 +28,7 @@ import vnidrop.shared.generated.resources.ticket_card_title
 fun ReceiveScreen(
 	coreState: CoreUiState,
 	receiveState: ReceiveUiState,
-	onReceiveStateChange: (ReceiveUiState) -> Unit,
-	onInspect: () -> Unit,
-	onReceive: () -> Unit,
+	onEvent: (VniDropAppEvent) -> Unit,
 ) {
 	Column(verticalArrangement = Arrangement.spacedBy(14.dp)) {
 		ScreenHeader(stringResource(Res.string.receive_title), stringResource(Res.string.receive_subtitle))
@@ -37,33 +36,30 @@ fun ReceiveScreen(
 		AppCard(title = stringResource(Res.string.ticket_card_title)) {
 			Field(
 				value = receiveState.ticket,
-				onValueChange = { onReceiveStateChange(receiveState.copy(ticket = it)) },
+				onValueChange = { onEvent(VniDropAppEvent.ReceiveTicketChanged(it)) },
 				label = stringResource(Res.string.field_ticket),
 				minLines = 4,
 			)
 			Field(
 				value = receiveState.outputDirectory,
-				onValueChange = { onReceiveStateChange(receiveState.copy(outputDirectory = it)) },
+				onValueChange = { onEvent(VniDropAppEvent.OutputDirectoryChanged(it)) },
 				label = stringResource(Res.string.field_output_directory),
 			)
 			Field(
 				value = receiveState.receiverName,
-				onValueChange = { onReceiveStateChange(receiveState.copy(receiverName = it)) },
+				onValueChange = { onEvent(VniDropAppEvent.ReceiverNameChanged(it)) },
 				label = stringResource(Res.string.field_receiver_name),
 			)
 			Row(horizontalArrangement = Arrangement.spacedBy(10.dp)) {
 				SecondaryButton(
 					text = stringResource(Res.string.button_inspect_ticket),
-					onClick = onInspect,
-					enabled = coreState.isInitialized && receiveState.ticket.isNotBlank(),
+					onClick = { onEvent(VniDropAppEvent.InspectTicketClicked) },
+					enabled = receiveState.canInspect(coreState.isInitialized),
 				)
 				PrimaryButton(
 					text = if (receiveState.isReceiving) stringResource(Res.string.button_receiving) else stringResource(Res.string.button_receive),
-					onClick = onReceive,
-					enabled = coreState.isInitialized &&
-						receiveState.ticket.isNotBlank() &&
-						receiveState.outputDirectory.isNotBlank() &&
-						!receiveState.isReceiving,
+					onClick = { onEvent(VniDropAppEvent.ReceiveClicked) },
+					enabled = receiveState.canReceive(coreState.isInitialized),
 				)
 			}
 		}

shared/src/commonMain/kotlin/com/vnidrop/app/ui/screens/SendScreen.kt

@@ -7,6 +7,7 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
+import com.vnidrop.app.VniDropAppEvent
 import com.vnidrop.app.core.CoreUiState
 import com.vnidrop.app.ui.components.AppCard
 import com.vnidrop.app.ui.components.Field
@@ -48,36 +49,25 @@ import vnidrop.shared.generated.resources.transfer_details_title
 fun SendScreen(
 	coreState: CoreUiState,
 	sendState: SendUiState,
-	onSendStateChange: (SendUiState) -> Unit,
-	onSelectFile: () -> Unit,
-	onCreateShare: () -> Unit,
-	onCopyTicket: (String) -> Unit,
-	onUseLocally: (String) -> Unit,
-	onRefreshRequests: (ULong) -> Unit,
-	onRespondRequest: (String, Boolean) -> Unit,
+	onEvent: (VniDropAppEvent) -> Unit,
 ) {
 	Column(verticalArrangement = Arrangement.spacedBy(14.dp)) {
 		ScreenHeader(stringResource(Res.string.send_title), stringResource(Res.string.send_subtitle))
 		ErrorSection(coreState)
 		SendSourceCard(
 			sendState = sendState,
-			onSendStateChange = onSendStateChange,
-			onSelectFile = onSelectFile,
+			onEvent = onEvent,
 		)
 		SendDetailsCard(
 			coreState = coreState,
 			sendState = sendState,
-			onSendStateChange = onSendStateChange,
-			onCreateShare = onCreateShare,
+			onEvent = onEvent,
 		)
 		coreState.lastShare?.let { share ->
 			ShareResultCard(
 				share = share,
 				requests = coreState.receiverRequests,
-				onCopyTicket = onCopyTicket,
-				onUseLocally = onUseLocally,
-				onRefreshRequests = onRefreshRequests,
-				onRespondRequest = onRespondRequest,
+				onEvent = onEvent,
 			)
 		}
 		ProgressSection(coreState)
@@ -87,10 +77,9 @@ fun SendScreen(
 @Composable
 private fun SendSourceCard(
 	sendState: SendUiState,
-	onSendStateChange: (SendUiState) -> Unit,
-	onSelectFile: () -> Unit,
+	onEvent: (VniDropAppEvent) -> Unit,
 ) {
-		AppCard(title = stringResource(Res.string.source_title)) {
+	AppCard(title = stringResource(Res.string.source_title)) {
 		if (sendState.selectedSource.isBlank()) {
 			EmptyText(stringResource(Res.string.send_source_empty))
 		} else {
@@ -98,11 +87,14 @@ private fun SendSourceCard(
 			MetadataRow(stringResource(Res.string.metadata_source), sendState.selectedSource)
 		}
 		Row(horizontalArrangement = Arrangement.spacedBy(10.dp)) {
-			PrimaryButton(stringResource(Res.string.button_select_file), onClick = onSelectFile)
+			PrimaryButton(
+				text = stringResource(Res.string.button_select_file),
+				onClick = { onEvent(VniDropAppEvent.SelectFileClicked) },
+			)
 			SecondaryButton(
 				text = stringResource(Res.string.button_clear),
-				onClick = { onSendStateChange(sendState.copy(selectedSource = "", selectedDisplayName = "")) },
-				enabled = sendState.selectedSource.isNotBlank(),
+				onClick = { onEvent(VniDropAppEvent.ClearSelectedSourceClicked) },
+				enabled = sendState.hasSelectedSource,
 			)
 		}
 	}
@@ -112,24 +104,23 @@ private fun SendSourceCard(
 private fun SendDetailsCard(
 	coreState: CoreUiState,
 	sendState: SendUiState,
-	onSendStateChange: (SendUiState) -> Unit,
-	onCreateShare: () -> Unit,
+	onEvent: (VniDropAppEvent) -> Unit,
 ) {
 	AppCard(title = stringResource(Res.string.transfer_details_title)) {
 		Field(
 			value = sendState.transferName,
-			onValueChange = { onSendStateChange(sendState.copy(transferName = it)) },
+			onValueChange = { onEvent(VniDropAppEvent.TransferNameChanged(it)) },
 			label = stringResource(Res.string.field_transfer_name),
 		)
 		Field(
 			value = sendState.senderName,
-			onValueChange = { onSendStateChange(sendState.copy(senderName = it)) },
+			onValueChange = { onEvent(VniDropAppEvent.SenderNameChanged(it)) },
 			label = stringResource(Res.string.field_sender_name),
 		)
 		PrimaryButton(
 			text = if (sendState.isSharing) stringResource(Res.string.button_creating_ticket) else stringResource(Res.string.button_create_share_ticket),
-			onClick = onCreateShare,
-			enabled = coreState.isInitialized && sendState.selectedSource.isNotBlank() && !sendState.isSharing,
+			onClick = { onEvent(VniDropAppEvent.CreateShareClicked) },
+			enabled = sendState.canCreateShare(coreState.isInitialized),
 		)
 	}
 }
@@ -138,10 +129,7 @@ private fun SendDetailsCard(
 private fun ShareResultCard(
 	share: ShareResult,
 	requests: List<ReceiverRequest>,
-	onCopyTicket: (String) -> Unit,
-	onUseLocally: (String) -> Unit,
-	onRefreshRequests: (ULong) -> Unit,
-	onRespondRequest: (String, Boolean) -> Unit,
+	onEvent: (VniDropAppEvent) -> Unit,
 ) {
 	AppCard(title = stringResource(Res.string.share_ticket_title), trailing = {
 		StatusPill("${share.fileCount} file${if (share.fileCount == 1UL) "" else "s"}", tone = PillTone.Brand)
@@ -150,14 +138,28 @@ private fun ShareResultCard(
 		MetadataRow(stringResource(Res.string.metadata_size), formatBytes(share.totalSize))
 		TicketText(share.ticket)
 		Row(horizontalArrangement = Arrangement.spacedBy(10.dp)) {
-			PrimaryButton(stringResource(Res.string.button_copy), onClick = { onCopyTicket(share.ticket) })
-			SecondaryButton(stringResource(Res.string.button_use_locally), onClick = { onUseLocally(share.ticket) })
-			SecondaryButton(stringResource(Res.string.button_refresh), onClick = { onRefreshRequests(share.transferId) })
+			PrimaryButton(
+				text = stringResource(Res.string.button_copy),
+				onClick = { onEvent(VniDropAppEvent.CopyTicketClicked(share.ticket)) },
+			)
+			SecondaryButton(
+				text = stringResource(Res.string.button_use_locally),
+				onClick = { onEvent(VniDropAppEvent.UseTicketLocallyClicked(share.ticket)) },
+			)
+			SecondaryButton(
+				text = stringResource(Res.string.button_refresh),
+				onClick = { onEvent(VniDropAppEvent.RefreshReceiverRequestsClicked(share.transferId)) },
+			)
 		}
 		if (requests.isNotEmpty()) {
 			SectionDivider()
 			Text(stringResource(Res.string.receiver_requests_title), fontWeight = FontWeight.SemiBold)
-			ReceiverRequestList(requests = requests, onRespondRequest = onRespondRequest)
+			ReceiverRequestList(
+				requests = requests,
+				onRespondRequest = { requestId, accepted ->
+					onEvent(VniDropAppEvent.RespondReceiverRequestClicked(requestId, accepted))
+				},
+			)
 		}
 	}
 }

shared/src/commonMain/kotlin/com/vnidrop/app/ui/state/AppUiModels.kt

@@ -33,14 +33,26 @@ data class SendUiState(
 	val transferName: String = "VniDrop transfer",
 	val senderName: String = "",
 	val isSharing: Boolean = false,
-)
+) {
+	val hasSelectedSource: Boolean
+		get() = selectedSource.isNotBlank()
+
+	fun canCreateShare(isCoreInitialized: Boolean): Boolean =
+		isCoreInitialized && hasSelectedSource && !isSharing
+}
 
 data class ReceiveUiState(
 	val ticket: String = "",
 	val outputDirectory: String = "",
 	val receiverName: String = "",
 	val isReceiving: Boolean = false,
-)
+) {
+	fun canInspect(isCoreInitialized: Boolean): Boolean =
+		isCoreInitialized && ticket.isNotBlank()
+
+	fun canReceive(isCoreInitialized: Boolean): Boolean =
+		isCoreInitialized && ticket.isNotBlank() && outputDirectory.isNotBlank() && !isReceiving
+}
 
 data class TransferProgress(
 	val transferId: ULong?,