feat: Add passenger counter to home screen

This commit introduces a passenger counter component to the home screen, allowing users to specify the number of adults, teens, and children for their flight search.

Key changes:
- Added `ui:sharedui` module dependency to `ui:home`.
- Updated `PreviewDevices` annotation to include `showBackground = true`.
- Modified `HomeScreen`:
    - Added parameters to `HomeContent` and `SearchForm` for passenger count change callbacks.
    - Integrated the `Counter` composable from `ui:sharedui` for adults, teens, and children.
    - Added `VerticalDivider` between counters.
    - Updated previews to reflect passenger counter integration.
- Updated `HomeScreenViewModel`:
    - Introduced `MutableStateFlow` for `adultCount`, `teenCount`, and `childCount`.
    - Created `passengersState` flow by combining individual passenger count flows.
    - Updated `homeUiState` to include `passengersState`.
    - Added public functions `updateAdultCount`, `updateTeenCount`, and `updateChildCount` to modify passenger counts with validation.
    - Added `PassengersState` data class to hold passenger counts.
- Updated `Counter` composable in `ui:sharedui`:
    - Added an optional `minVal` parameter (defaulting to 0) to define the minimum allowed value for the counter.
    - Ensured the decrement button is disabled when the counter value reaches `minVal`.
    - Centered text in increment and decrement buttons.

ui/designsystem/src/main/kotlin/dev/adriankuta/flights/ui/designsystem/theme/PreviewDevices.kt

@@ -2,8 +2,8 @@ package dev.adriankuta.flights.ui.designsystem.theme
 
 import androidx.compose.ui.tooling.preview.Preview
 
-@Preview(name = "phone", device = "spec:shape=Normal,width=360,height=640,unit=dp,dpi=480")
+@Preview(name = "phone", device = "spec:shape=Normal,width=360,height=640,unit=dp,dpi=480", showBackground = true)
-@Preview(name = "landscape", device = "spec:shape=Normal,width=640,height=360,unit=dp,dpi=480")
+@Preview(name = "landscape", device = "spec:shape=Normal,width=640,height=360,unit=dp,dpi=480", showBackground = true)
-@Preview(name = "foldable", device = "spec:shape=Normal,width=673,height=841,unit=dp,dpi=480")
+@Preview(name = "foldable", device = "spec:shape=Normal,width=673,height=841,unit=dp,dpi=480", showBackground = true)
-@Preview(name = "tablet", device = "spec:shape=Normal,width=1280,height=800,unit=dp,dpi=480")
+@Preview(name = "tablet", device = "spec:shape=Normal,width=1280,height=800,unit=dp,dpi=480", showBackground = true)
 annotation class PreviewDevices

ui/home/build.gradle.kts

@@ -11,6 +11,7 @@ android {
 dependencies {
     implementation(projects.core.util)
     implementation(projects.ui.designsystem)
+    implementation(projects.ui.sharedui)
     implementation(projects.domain.search)
 
     implementation(libs.androidx.hilt.navigation.compose)

ui/home/src/main/kotlin/dev/adriankuta/flights/ui/home/HomeScreen.kt

@@ -1,11 +1,16 @@
 package dev.adriankuta.flights.ui.home
 
+import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.IntrinsicSize
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.material3.Text
+import androidx.compose.material3.VerticalDivider
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
@@ -22,6 +27,7 @@ import dev.adriankuta.flights.ui.designsystem.theme.FlightsTheme
 import dev.adriankuta.flights.ui.designsystem.theme.PreviewDevices
 import dev.adriankuta.flights.ui.home.components.AirportDropdown
 import dev.adriankuta.flights.ui.home.components.DatePicker
+import dev.adriankuta.flights.ui.sharedui.Counter
 import java.time.LocalDate
 
 @Composable
@@ -35,6 +41,9 @@ internal fun HomeScreen(
         onOriginAirportSelect = viewModel::selectOriginAirport,
         onDestinationAirportSelect = viewModel::selectDestinationAirport,
         onDateSelect = viewModel::selectDate,
+        onAdultCountChange = viewModel::updateAdultCount,
+        onTeenCountChange = viewModel::updateTeenCount,
+        onChildCountChange = viewModel::updateChildCount,
     )
 }
 
@@ -44,6 +53,9 @@ private fun HomeScreen(
     onOriginAirportSelect: (AirportInfo) -> Unit,
     onDestinationAirportSelect: (AirportInfo) -> Unit,
     onDateSelect: (LocalDate) -> Unit,
+    onAdultCountChange: (Int) -> Unit,
+    onTeenCountChange: (Int) -> Unit,
+    onChildCountChange: (Int) -> Unit,
     modifier: Modifier = Modifier,
 ) {
     Column(
@@ -52,7 +64,29 @@ private fun HomeScreen(
         when (uiState) {
             is HomeUiState.Error -> Text("Error")
             HomeUiState.Loading -> Text("Loading")
-            is HomeUiState.Success -> {
+            is HomeUiState.Success -> SearchForm(
+                uiState = uiState,
+                onOriginAirportSelect = onOriginAirportSelect,
+                onDestinationAirportSelect = onDestinationAirportSelect,
+                onDateSelect = onDateSelect,
+                onAdultCountChange = onAdultCountChange,
+                onTeenCountChange = onTeenCountChange,
+                onChildCountChange = onChildCountChange,
+            )
+        }
+    }
+}
+
+@Composable
+private fun ColumnScope.SearchForm(
+    uiState: HomeUiState.Success,
+    onOriginAirportSelect: (AirportInfo) -> Unit,
+    onDestinationAirportSelect: (AirportInfo) -> Unit,
+    onDateSelect: (LocalDate) -> Unit,
+    onAdultCountChange: (Int) -> Unit,
+    onTeenCountChange: (Int) -> Unit,
+    onChildCountChange: (Int) -> Unit,
+) {
     AirportDropdown(
         label = "Origin Airport",
         airports = uiState.originAirports,
@@ -81,8 +115,44 @@ private fun HomeScreen(
         modifier = Modifier.fillMaxWidth(),
         enabled = uiState.selectedDestinationAirport != null,
     )
-            }
+
-        }
+    Spacer(modifier = Modifier.height(16.dp))
+
+    Text("Passengers")
+
+    Spacer(modifier = Modifier.height(8.dp))
+
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .height(intrinsicSize = IntrinsicSize.Min),
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        Counter(
+            value = uiState.passengers.adultCount,
+            onCountChange = onAdultCountChange,
+            label = "Adults",
+            modifier = Modifier.weight(1f),
+            minVal = 1,
+        )
+
+        VerticalDivider()
+
+        Counter(
+            value = uiState.passengers.teenCount,
+            onCountChange = onTeenCountChange,
+            label = "Teens",
+            modifier = Modifier.weight(1f),
+        )
+
+        VerticalDivider()
+
+        Counter(
+            value = uiState.passengers.childCount,
+            onCountChange = onChildCountChange,
+            label = "Children",
+            modifier = Modifier.weight(1f),
+        )
     }
 }
 
@@ -95,6 +165,9 @@ private fun HomeScreenLoadingPreview() {
             onOriginAirportSelect = {},
             onDestinationAirportSelect = {},
             onDateSelect = {},
+            onAdultCountChange = {},
+            onTeenCountChange = {},
+            onChildCountChange = {},
         )
     }
 }
@@ -137,10 +210,18 @@ private fun HomeScreenSuccessPreview() {
                 selectedOriginAirport = mockAirports.first(),
                 selectedDestinationAirport = mockAirports.last(),
                 selectedDate = LocalDate.now(),
+                passengers = PassengersState(
+                    adultCount = 2,
+                    teenCount = 1,
+                    childCount = 1,
+                ),
             ),
             onOriginAirportSelect = {},
             onDestinationAirportSelect = {},
             onDateSelect = {},
+            onAdultCountChange = {},
+            onTeenCountChange = {},
+            onChildCountChange = {},
         )
     }
 }

ui/home/src/main/kotlin/dev/adriankuta/flights/ui/home/HomeScreenViewModel.kt

@@ -10,6 +10,7 @@ import dev.adriankuta.flights.domain.types.AirportInfo
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.stateIn
 import java.time.LocalDate
@@ -23,12 +24,20 @@ class HomeScreenViewModel @Inject constructor(
     private val selectedOriginAirport = MutableStateFlow<AirportInfo?>(null)
     private val selectedDestinationAirport = MutableStateFlow<AirportInfo?>(null)
     private val selectedDate = MutableStateFlow(LocalDate.now())
+    private val adultCount = MutableStateFlow(1)
+    private val teenCount = MutableStateFlow(0)
+    private val childCount = MutableStateFlow(0)
 
     internal val uiState = homeUiState(
         useCase = observeAirportsUseCase,
         selectedOriginAirport = selectedOriginAirport,
         selectedDestinationAirport = selectedDestinationAirport,
         selectedDate = selectedDate,
+        passengersState = passengersState(
+            adultCount = adultCount,
+            teenCount = teenCount,
+            childCount = childCount,
+        ),
     )
         .stateIn(
             scope = viewModelScope,
@@ -61,20 +70,37 @@ class HomeScreenViewModel @Inject constructor(
     fun selectDate(date: LocalDate) {
         selectedDate.value = date
     }
+
+    fun updateAdultCount(diff: Int) {
+        val newCount = adultCount.value + diff
+        adultCount.value = newCount
+    }
+
+    fun updateTeenCount(diff: Int) {
+        val newCount = teenCount.value + diff
+        teenCount.value = newCount
+    }
+
+    fun updateChildCount(diff: Int) {
+        val newCount = childCount.value + diff
+        childCount.value = newCount
+    }
 }
 
 private fun homeUiState(
     useCase: ObserveAirportsUseCase,
-    selectedOriginAirport: MutableStateFlow<AirportInfo?>,
+    selectedOriginAirport: StateFlow<AirportInfo?>,
-    selectedDestinationAirport: MutableStateFlow<AirportInfo?>,
+    selectedDestinationAirport: StateFlow<AirportInfo?>,
-    selectedDate: MutableStateFlow<LocalDate>,
+    selectedDate: StateFlow<LocalDate>,
+    passengersState: Flow<PassengersState>,
 ): Flow<HomeUiState> {
     return combine(
         useCase().asResult(),
         selectedOriginAirport,
         selectedDestinationAirport,
         selectedDate,
-    ) { result, origin, destination, date ->
+        passengersState,
+    ) { result, origin, destination, date, passengers ->
         when (result) {
             is Result.Error -> HomeUiState.Error(result.exception)
             is Result.Loading -> HomeUiState.Loading
@@ -86,12 +112,31 @@ private fun homeUiState(
                     selectedOriginAirport = origin,
                     selectedDestinationAirport = destination,
                     selectedDate = date,
+                    passengers = passengers,
                 )
             }
         }
     }
 }
 
+private fun passengersState(
+    adultCount: StateFlow<Int>,
+    teenCount: StateFlow<Int>,
+    childCount: StateFlow<Int>,
+): Flow<PassengersState> {
+    return combine(
+        adultCount,
+        teenCount,
+        childCount,
+    ) { adults, teens, children ->
+        PassengersState(
+            adultCount = adults,
+            teenCount = teens,
+            childCount = children,
+        )
+    }
+}
+
 internal sealed interface HomeUiState {
     data object Loading : HomeUiState
     data class Success(
@@ -100,7 +145,14 @@ internal sealed interface HomeUiState {
         val selectedOriginAirport: AirportInfo? = null,
         val selectedDestinationAirport: AirportInfo? = null,
         val selectedDate: LocalDate = LocalDate.now(),
+        val passengers: PassengersState,
     ) : HomeUiState
 
     data class Error(val exception: Throwable) : HomeUiState
 }
+
+internal data class PassengersState(
+    val adultCount: Int,
+    val teenCount: Int,
+    val childCount: Int,
+)

ui/sharedui/src/main/kotlin/dev/adriankuta/flights/ui/sharedui/Counter.kt

@@ -37,6 +37,7 @@ fun Counter(
     onCountChange: (diff: Int) -> Unit,
     modifier: Modifier = Modifier,
     label: String? = null,
+    minVal: Int = 0,
 ) {
     val view = LocalView.current
 
@@ -86,11 +87,12 @@ fun Counter(
                     onCountChange(-1)
                 },
                 shape = MaterialTheme.shapes.medium,
-                enabled = value > 0,
+                enabled = value > minVal,
             ) {
                 Text(
                     text = "-",
                     style = MaterialTheme.typography.labelLarge,
+                    textAlign = TextAlign.Center,
                 )
             }
             Button(
@@ -105,6 +107,7 @@ fun Counter(
                 Text(
                     text = "+",
                     style = MaterialTheme.typography.labelLarge,
+                    textAlign = TextAlign.Center,
                 )
             }
         }