feat(android-terminal): Phase D.1 — terminal lookup + customer card

The terminal screen is now functional for card lookup and customer
display. Phase D.2 will fill in the action sheets (stamp / earn /
redeem) on top of this.

- TerminalViewModel: state machine with program (from cache), customer,
  search/error/online state. onSearchSubmit hits /cards/lookup;
  refreshCurrentCustomer re-fetches after actions land.
- TerminalScreen rewrite: top bar with staff name + online pill + Lock;
  left pane with search field + buttons; right pane shows the empty
  state or a customer panel (name/email/card number, points + stamps
  card, four placeholder action buttons greyed out for D.2).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

clients/terminal-android/app/src/main/java/lu/rewardflow/terminal/ui/terminal/TerminalScreen.kt

@@ -1,35 +1,104 @@
 package lu.rewardflow.terminal.ui.terminal
 
-import androidx.compose.foundation.layout.*
-import androidx.compose.material3.*
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.Button
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import lu.rewardflow.terminal.R
+import lu.rewardflow.terminal.data.model.CardLookupResponse
 
 /**
  * Main POS terminal screen.
  *
- * Layout (landscape tablet):
- * ┌──────────────────────────────────────────────┐
- * │ [Staff: Jane]  [Store: Fashion Hub]  [Lock]  │
- * ├──────────────────┬───────────────────────────┤
- * │                  │                           │
- * │  Customer Search │   Card Details            │
- * │  + QR Scanner    │   Points/Stamps balance   │
- * │                  │   Quick actions            │
- * │                  │   (Earn, Redeem, Enroll)   │
- * │                  │                           │
- * └──────────────────┴───────────────────────────┘
+ * Phase D.1 surface — landscape layout:
+ *
+ *   ┌────────────────────────────────────────────────────┐
+ *   │ Staff: Diana   Online •   |   Lock                 │
+ *   ├──────────────┬─────────────────────────────────────┤
+ *   │              │  Customer card (or empty state)     │
+ *   │   Search /   │  Balance, stamps, available rewards │
+ *   │   QR / Enroll│                                      │
+ *   │              │  Action buttons (wired in D.2)      │
+ *   └──────────────┴─────────────────────────────────────┘
  */
 @Composable
 fun TerminalScreen(
     staffPinId: Int,
     staffName: String,
     onLockScreen: () -> Unit,
+    viewModel: TerminalViewModel = hiltViewModel(),
 ) {
+    val state by viewModel.state.collectAsStateWithLifecycle()
+
     Column(modifier = Modifier.fillMaxSize()) {
-        // Top bar
+        TopBar(
+            staffName = staffName,
+            isOnline = state.isOnline,
+            onLockScreen = onLockScreen,
+        )
+        Row(modifier = Modifier.fillMaxSize()) {
+            LeftPane(
+                modifier = Modifier
+                    .weight(0.4f)
+                    .fillMaxHeight()
+                    .padding(16.dp),
+                state = state,
+                onSearchChanged = viewModel::onSearchChanged,
+                onSearchSubmit = viewModel::onSearchSubmit,
+            )
+            RightPane(
+                modifier = Modifier
+                    .weight(0.6f)
+                    .fillMaxHeight()
+                    .padding(16.dp),
+                customer = state.customer,
+                stampsTarget = state.program?.stamps_target ?: 0,
+                isOnline = state.isOnline,
+                onClearCustomer = viewModel::clearCustomer,
+            )
+        }
+    }
+}
+
+@Composable
+private fun TopBar(
+    staffName: String,
+    isOnline: Boolean,
+    onLockScreen: () -> Unit,
+) {
     Surface(
         color = MaterialTheme.colorScheme.primaryContainer,
         modifier = Modifier.fillMaxWidth(),
@@ -39,57 +108,302 @@ fun TerminalScreen(
             verticalAlignment = Alignment.CenterVertically,
         ) {
             Text(
-                    text = "Staff: $staffName",
+                text = staffName,
                 style = MaterialTheme.typography.titleMedium,
-                    modifier = Modifier.weight(1f),
+                fontWeight = FontWeight.SemiBold,
             )
-                // TODO: show store name, offline indicator, pending sync count
+            Spacer(Modifier.size(16.dp))
+            OnlinePill(isOnline = isOnline)
+            Spacer(modifier = Modifier.weight(1f))
             FilledTonalButton(onClick = onLockScreen) {
-                    Text("Lock")
+                Text(stringResource(R.string.terminal_lock))
+            }
         }
     }
 }
 
-        // Main content — two-pane layout
-        Row(modifier = Modifier.fillMaxSize()) {
-            // Left pane: search + scan
+@Composable
+private fun OnlinePill(isOnline: Boolean) {
+    val (label, color) = if (isOnline)
+        stringResource(R.string.terminal_online) to MaterialTheme.colorScheme.tertiary
+    else
+        stringResource(R.string.terminal_offline) to MaterialTheme.colorScheme.error
     Surface(
-                modifier = Modifier
-                    .weight(0.4f)
-                    .fillMaxHeight()
-                    .padding(16.dp),
-                shape = MaterialTheme.shapes.large,
+        shape = RoundedCornerShape(12.dp),
+        color = color.copy(alpha = 0.18f),
+    ) {
+        Text(
+            text = label,
+            color = color,
+            style = MaterialTheme.typography.labelSmall,
+            fontWeight = FontWeight.SemiBold,
+            modifier = Modifier.padding(horizontal = 10.dp, vertical = 4.dp),
+        )
+    }
+}
+
+@Composable
+private fun LeftPane(
+    modifier: Modifier,
+    state: TerminalUiState,
+    onSearchChanged: (String) -> Unit,
+    onSearchSubmit: () -> Unit,
+) {
+    Surface(
+        modifier = modifier,
+        shape = RoundedCornerShape(16.dp),
         color = MaterialTheme.colorScheme.surfaceVariant,
     ) {
         Column(
             modifier = Modifier.padding(16.dp),
-                    horizontalAlignment = Alignment.CenterHorizontally,
         ) {
-                    Text("Search Customer", style = MaterialTheme.typography.titleMedium)
-                    Spacer(modifier = Modifier.height(16.dp))
-                    // TODO: Search field + QR camera preview
-                    Text("QR Scanner / Search field", style = MaterialTheme.typography.bodyMedium)
+            Text(
+                text = stringResource(R.string.terminal_search_hint),
+                style = MaterialTheme.typography.titleMedium,
+            )
+            Spacer(Modifier.height(8.dp))
+
+            OutlinedTextField(
+                value = state.searchQuery,
+                onValueChange = onSearchChanged,
+                singleLine = true,
+                placeholder = { Text(stringResource(R.string.terminal_search_hint)) },
+                keyboardOptions = KeyboardOptions(imeAction = ImeAction.Search),
+                keyboardActions = KeyboardActions(onSearch = { onSearchSubmit() }),
+                modifier = Modifier.fillMaxWidth(),
+                trailingIcon = {
+                    if (state.isSearching) {
+                        CircularProgressIndicator(
+                            modifier = Modifier.size(20.dp),
+                            strokeWidth = 2.dp,
+                        )
+                    }
+                },
+            )
+            Spacer(Modifier.height(12.dp))
+            Button(
+                onClick = onSearchSubmit,
+                enabled = state.searchQuery.isNotBlank() && !state.isSearching,
+                modifier = Modifier.fillMaxWidth(),
+                contentPadding = PaddingValues(vertical = 12.dp),
+            ) {
+                Text(stringResource(R.string.terminal_search_hint))
+            }
+
+            Spacer(Modifier.height(20.dp))
+
+            // Phase D.4 will replace these with real handlers.
+            OutlinedButton(
+                onClick = { /* QR scan — D.4 */ },
+                enabled = false,
+                modifier = Modifier.fillMaxWidth(),
+                contentPadding = PaddingValues(vertical = 12.dp),
+            ) {
+                Text(stringResource(R.string.terminal_scan_qr))
+            }
+            Spacer(Modifier.height(8.dp))
+            OutlinedButton(
+                onClick = { /* Enroll — D.4 */ },
+                enabled = false,
+                modifier = Modifier.fillMaxWidth(),
+                contentPadding = PaddingValues(vertical = 12.dp),
+            ) {
+                Text(stringResource(R.string.terminal_enroll_customer))
+            }
+
+            if (state.errorMessage != null) {
+                Spacer(Modifier.height(16.dp))
+                Surface(
+                    shape = RoundedCornerShape(8.dp),
+                    color = MaterialTheme.colorScheme.errorContainer,
+                ) {
+                    Text(
+                        text = state.errorMessage,
+                        modifier = Modifier.padding(12.dp),
+                        color = MaterialTheme.colorScheme.onErrorContainer,
+                        style = MaterialTheme.typography.bodyMedium,
+                    )
+                }
+            }
+        }
     }
 }
 
-            // Right pane: card details + actions
+@Composable
+private fun RightPane(
+    modifier: Modifier,
+    customer: CardLookupResponse?,
+    stampsTarget: Int,
+    isOnline: Boolean,
+    onClearCustomer: () -> Unit,
+) {
     Surface(
-                modifier = Modifier
-                    .weight(0.6f)
-                    .fillMaxHeight()
-                    .padding(16.dp),
-                shape = MaterialTheme.shapes.large,
+        modifier = modifier,
+        shape = RoundedCornerShape(16.dp),
         color = MaterialTheme.colorScheme.surface,
     ) {
+        if (customer == null) {
+            EmptyCustomerState(modifier = Modifier.fillMaxSize().padding(16.dp))
+        } else {
+            CustomerPanel(
+                modifier = Modifier.fillMaxSize().padding(16.dp),
+                customer = customer,
+                stampsTarget = stampsTarget,
+                isOnline = isOnline,
+                onClearCustomer = onClearCustomer,
+            )
+        }
+    }
+}
+
+@Composable
+private fun EmptyCustomerState(modifier: Modifier) {
     Column(
-                    modifier = Modifier.padding(16.dp),
-                    horizontalAlignment = Alignment.CenterHorizontally,
+        modifier = modifier,
         verticalArrangement = Arrangement.Center,
+        horizontalAlignment = Alignment.CenterHorizontally,
     ) {
-                    Text("Select a customer to begin", style = MaterialTheme.typography.bodyLarge)
-                    // TODO: Show card details, balance, quick action buttons
+        Text(
+            text = stringResource(R.string.terminal_no_customer_title),
+            style = MaterialTheme.typography.titleLarge,
+            fontWeight = FontWeight.SemiBold,
+        )
+        Spacer(Modifier.height(8.dp))
+        Text(
+            text = stringResource(R.string.terminal_no_customer_hint),
+            style = MaterialTheme.typography.bodyMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            textAlign = TextAlign.Center,
+        )
+    }
+}
+
+@Composable
+private fun CustomerPanel(
+    modifier: Modifier,
+    customer: CardLookupResponse,
+    stampsTarget: Int,
+    isOnline: Boolean,
+    onClearCustomer: () -> Unit,
+) {
+    Column(modifier = modifier) {
+        // Customer header
+        Row(verticalAlignment = Alignment.CenterVertically) {
+            Column(modifier = Modifier.weight(1f)) {
+                Text(
+                    text = customer.customer_name ?: customer.customer_email,
+                    style = MaterialTheme.typography.headlineSmall,
+                    fontWeight = FontWeight.SemiBold,
+                )
+                Text(
+                    text = customer.customer_email,
+                    style = MaterialTheme.typography.bodyMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+                Text(
+                    text = "${stringResource(R.string.terminal_card_label)}: ${customer.card_number}",
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
+            TextButton(onClick = onClearCustomer) {
+                Text(stringResource(R.string.terminal_close_customer))
+            }
+        }
+
+        Spacer(Modifier.height(16.dp))
+
+        BalanceCard(
+            pointsBalance = customer.points_balance,
+            stampCount = customer.stamp_count,
+            stampsTarget = if (stampsTarget > 0) stampsTarget else customer.stamps_target,
+        )
+
+        Spacer(Modifier.height(16.dp))
+
+        // Action buttons — wired in D.2
+        ActionButtonsPlaceholder(
+            isOnline = isOnline,
+            canRedeemStamps = customer.can_redeem_stamps,
+        )
+    }
+}
+
+@Composable
+private fun BalanceCard(
+    pointsBalance: Int,
+    stampCount: Int,
+    stampsTarget: Int,
+) {
+    Surface(
+        modifier = Modifier.fillMaxWidth(),
+        shape = RoundedCornerShape(12.dp),
+        color = MaterialTheme.colorScheme.primaryContainer,
+    ) {
+        Row(
+            modifier = Modifier.padding(20.dp),
+            horizontalArrangement = Arrangement.SpaceEvenly,
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            Column(horizontalAlignment = Alignment.CenterHorizontally) {
+                Text(
+                    text = stringResource(R.string.balance_points, pointsBalance),
+                    style = MaterialTheme.typography.headlineMedium,
+                    color = MaterialTheme.colorScheme.onPrimaryContainer,
+                    fontWeight = FontWeight.Bold,
+                )
+            }
+            Box(
+                modifier = Modifier
+                    .size(width = 1.dp, height = 48.dp)
+                    .clip(RoundedCornerShape(1.dp))
+                    .background(MaterialTheme.colorScheme.onPrimaryContainer.copy(alpha = 0.3f)),
+            )
+            Column(horizontalAlignment = Alignment.CenterHorizontally) {
+                Text(
+                    text = stringResource(
+                        R.string.balance_stamps,
+                        stampCount,
+                        if (stampsTarget > 0) stampsTarget else 10,
+                    ),
+                    style = MaterialTheme.typography.headlineMedium,
+                    color = MaterialTheme.colorScheme.onPrimaryContainer,
+                    fontWeight = FontWeight.Bold,
+                )
             }
         }
     }
 }
+
+@Composable
+private fun ActionButtonsPlaceholder(
+    isOnline: Boolean,
+    canRedeemStamps: Boolean,
+) {
+    // D.2 will replace this with real action sheets.
+    Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+        OutlinedButton(
+            onClick = { },
+            enabled = false,
+            modifier = Modifier.weight(1f),
+        ) { Text(stringResource(R.string.action_add_stamp)) }
+        OutlinedButton(
+            onClick = { },
+            enabled = false,
+            modifier = Modifier.weight(1f),
+        ) { Text(stringResource(R.string.action_earn_points)) }
+    }
+    Spacer(Modifier.height(8.dp))
+    Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+        OutlinedButton(
+            onClick = { },
+            enabled = false,
+            modifier = Modifier.weight(1f),
+        ) { Text(stringResource(R.string.action_redeem_stamps)) }
+        OutlinedButton(
+            onClick = { },
+            enabled = false,
+            modifier = Modifier.weight(1f),
+        ) { Text(stringResource(R.string.action_redeem_reward)) }
+    }
 }

clients/terminal-android/app/src/main/java/lu/rewardflow/terminal/ui/terminal/TerminalViewModel.kt

@@ -0,0 +1,140 @@
+package lu.rewardflow.terminal.ui.terminal
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.squareup.moshi.JsonAdapter
+import com.squareup.moshi.Moshi
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.launch
+import lu.rewardflow.terminal.data.api.LoyaltyApi
+import lu.rewardflow.terminal.data.model.CardLookupResponse
+import lu.rewardflow.terminal.data.model.ProgramResponse
+import lu.rewardflow.terminal.data.network.NetworkMonitor
+import lu.rewardflow.terminal.data.repository.DeviceConfigRepository
+import javax.inject.Inject
+
+/**
+ * Powers the main POS terminal screen.
+ *
+ * Tracks: which customer is currently selected (or none), the cached
+ * program config (for stamps_target / card colors / etc), online state,
+ * and a transient error message. Card-lookup hits the API directly —
+ * no offline fallback because we need the latest balance to show
+ * something accurate; queueing a "lookup" doesn't make sense.
+ *
+ * Phase D.1 surface: search → lookup → render. Action sheets / actions
+ * land in D.2.
+ */
+@HiltViewModel
+class TerminalViewModel @Inject constructor(
+    private val api: LoyaltyApi,
+    private val configRepository: DeviceConfigRepository,
+    networkMonitor: NetworkMonitor,
+    moshi: Moshi,
+) : ViewModel() {
+
+    private val programAdapter: JsonAdapter<ProgramResponse> =
+        moshi.adapter(ProgramResponse::class.java)
+
+    private val _state = MutableStateFlow(TerminalUiState())
+    val state: StateFlow<TerminalUiState> = _state.asStateFlow()
+
+    init {
+        loadCachedProgram()
+        networkMonitor.isOnline
+            .onEach { online -> _state.value = _state.value.copy(isOnline = online) }
+            .launchIn(viewModelScope)
+    }
+
+    fun onSearchChanged(query: String) {
+        _state.value = _state.value.copy(searchQuery = query, errorMessage = null)
+    }
+
+    /** Card lookup — accepts card number, email, or partial name. */
+    fun onSearchSubmit() {
+        val q = _state.value.searchQuery.trim()
+        if (q.isBlank()) return
+        _state.value = _state.value.copy(
+            isSearching = true,
+            customer = null,
+            errorMessage = null,
+        )
+        viewModelScope.launch {
+            val result = runCatching { api.lookupCard(q) }
+            _state.value = result.fold(
+                onSuccess = { card ->
+                    _state.value.copy(
+                        isSearching = false,
+                        customer = card,
+                        searchQuery = "",
+                    )
+                },
+                onFailure = { err ->
+                    _state.value.copy(
+                        isSearching = false,
+                        errorMessage = err.message ?: "Lookup failed",
+                    )
+                },
+            )
+        }
+    }
+
+    /** Card-number-based lookup, used by the QR scanner overlay (D.4). */
+    fun lookupByCardNumber(cardNumber: String) {
+        if (cardNumber.isBlank()) return
+        onSearchChanged(cardNumber)
+        onSearchSubmit()
+    }
+
+    fun clearCustomer() {
+        _state.value = _state.value.copy(
+            customer = null,
+            searchQuery = "",
+            errorMessage = null,
+        )
+    }
+
+    fun consumeError() {
+        _state.value = _state.value.copy(errorMessage = null)
+    }
+
+    /** Refresh the currently-displayed customer card from the server.
+     *  Called by the action sheets (D.2) after a successful operation
+     *  so balances reflect the new state. */
+    fun refreshCurrentCustomer() {
+        val current = _state.value.customer ?: return
+        viewModelScope.launch {
+            runCatching { api.lookupCard(current.card_number) }
+                .onSuccess { card ->
+                    _state.value = _state.value.copy(customer = card)
+                }
+        }
+    }
+
+    private fun loadCachedProgram() {
+        viewModelScope.launch {
+            val json = configRepository.programJson.first()
+            if (json != null) {
+                val program = runCatching { programAdapter.fromJson(json) }.getOrNull()
+                if (program != null) {
+                    _state.value = _state.value.copy(program = program)
+                }
+            }
+        }
+    }
+}
+
+data class TerminalUiState(
+    val program: ProgramResponse? = null,
+    val searchQuery: String = "",
+    val isSearching: Boolean = false,
+    val customer: CardLookupResponse? = null,
+    val errorMessage: String? = null,
+    val isOnline: Boolean = true,
+)