Refactor: Introduce SearchForm and PassengersOptions composables

This commit refactors the HomeScreen by extracting the search form logic into a new `SearchForm` composable and the passenger selection into a `PassengersOptions` composable.

Key changes:
- Created `PassengersOptions.kt` with a composable function to handle adult, teen, and child passenger counts.
- Created `SearchForm.kt` with a composable function that encapsulates airport selection, date picking, passenger options, and the search button.
- Updated `HomeScreen.kt`:
    - Replaced the previous inline form layout with the new `SearchForm` composable.
    - Made the screen content vertically scrollable using `Box` and `verticalScroll`.
    - Passed a new `onSearch` lambda to the `HomeScreenContent`.
- Updated `HomeScreenViewModel.kt`:
    - Modified `updateAdultCount`, `updateTeenCount`, and `updateChildCount` to accept the new count directly instead of a diff.
    - Added a `search()` function (currently logs to Timber).
    - Ensured child count does not exceed adult count when adult count changes.
- Updated `Counter.kt` in `ui/sharedui`:
    - Changed `onCountChange` parameter to `onValueChange` which now receives the new absolute value.
    - Added a `maxVal` parameter to limit the maximum value of the counter.

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

@@ -1,16 +1,10 @@
 package dev.adriankuta.flights.ui.home
 
-import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
-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.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
 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
@@ -25,9 +19,7 @@ import dev.adriankuta.flights.domain.types.MacCity
 import dev.adriankuta.flights.domain.types.Region
 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.SearchForm
-import dev.adriankuta.flights.ui.home.components.DatePicker
-import dev.adriankuta.flights.ui.sharedui.Counter
 import java.time.LocalDate
 
 @Composable
@@ -44,6 +36,7 @@ internal fun HomeScreen(
         onAdultCountChange = viewModel::updateAdultCount,
         onTeenCountChange = viewModel::updateTeenCount,
         onChildCountChange = viewModel::updateChildCount,
+        onSearch = viewModel::search,
     )
 }
 
@@ -56,10 +49,16 @@ private fun HomeScreen(
     onAdultCountChange: (Int) -> Unit,
     onTeenCountChange: (Int) -> Unit,
     onChildCountChange: (Int) -> Unit,
+    onSearch: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
-    Column(
+    val scrollState = rememberScrollState()
-        modifier = modifier.padding(16.dp),
+    Box(
+        modifier = modifier
+            .padding(16.dp)
+            .verticalScroll(
+                state = scrollState,
+            ),
     ) {
         when (uiState) {
             is HomeUiState.Error -> Text("Error")
@@ -72,90 +71,12 @@ private fun HomeScreen(
                 onAdultCountChange = onAdultCountChange,
                 onTeenCountChange = onTeenCountChange,
                 onChildCountChange = onChildCountChange,
+                onSearch = onSearch,
             )
         }
     }
 }
 
-@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,
-        selectedAirport = uiState.selectedOriginAirport,
-        onAirportSelect = onOriginAirportSelect,
-        modifier = Modifier.fillMaxWidth(),
-    )
-
-    Spacer(modifier = Modifier.height(16.dp))
-
-    AirportDropdown(
-        label = "Destination Airport",
-        airports = uiState.destinationAirports,
-        selectedAirport = uiState.selectedDestinationAirport,
-        onAirportSelect = onDestinationAirportSelect,
-        modifier = Modifier.fillMaxWidth(),
-        enabled = uiState.selectedOriginAirport != null,
-    )
-
-    Spacer(modifier = Modifier.height(16.dp))
-
-    DatePicker(
-        label = "Departure Date",
-        selectedDate = uiState.selectedDate,
-        onDateSelect = onDateSelect,
-        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),
-        )
-    }
-}
-
 @PreviewDevices
 @Composable
 private fun HomeScreenLoadingPreview() {
@@ -168,6 +89,7 @@ private fun HomeScreenLoadingPreview() {
             onAdultCountChange = {},
             onTeenCountChange = {},
             onChildCountChange = {},
+            onSearch = {},
         )
     }
 }
@@ -222,6 +144,7 @@ private fun HomeScreenSuccessPreview() {
             onAdultCountChange = {},
             onTeenCountChange = {},
             onChildCountChange = {},
+            onSearch = {},
         )
     }
 }

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

@@ -13,12 +13,13 @@ import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.stateIn
+import timber.log.Timber
 import java.time.LocalDate
 import javax.inject.Inject
 
 @HiltViewModel
 class HomeScreenViewModel @Inject constructor(
-    private val observeAirportsUseCase: ObserveAirportsUseCase,
+    observeAirportsUseCase: ObserveAirportsUseCase,
 ) : ViewModel() {
 
     private val selectedOriginAirport = MutableStateFlow<AirportInfo?>(null)
@@ -71,19 +72,21 @@ class HomeScreenViewModel @Inject constructor(
         selectedDate.value = date
     }
 
-    fun updateAdultCount(diff: Int) {
+    fun updateAdultCount(count: Int) {
-        val newCount = adultCount.value + diff
+        adultCount.value = count
-        adultCount.value = newCount
+        childCount.value = childCount.value.coerceAtMost(count)
     }
 
-    fun updateTeenCount(diff: Int) {
+    fun updateTeenCount(count: Int) {
-        val newCount = teenCount.value + diff
+        teenCount.value = count
-        teenCount.value = newCount
     }
 
-    fun updateChildCount(diff: Int) {
+    fun updateChildCount(count: Int) {
-        val newCount = childCount.value + diff
+        childCount.value = count
-        childCount.value = newCount
+    }
+
+    fun search() {
+        Timber.d("Search clicked")
     }
 }
 

ui/home/src/main/kotlin/dev/adriankuta/flights/ui/home/components/PassengersOptions.kt

@@ -0,0 +1,55 @@
+package dev.adriankuta.flights.ui.home.components
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.IntrinsicSize
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.material3.VerticalDivider
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import dev.adriankuta.flights.ui.home.HomeUiState
+import dev.adriankuta.flights.ui.sharedui.Counter
+
+@Composable
+internal fun PassengersOptions(
+    uiState: HomeUiState.Success,
+    onAdultCountChange: (Int) -> Unit,
+    onTeenCountChange: (Int) -> Unit,
+    onChildCountChange: (Int) -> Unit,
+) {
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .height(intrinsicSize = IntrinsicSize.Min),
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        Counter(
+            value = uiState.passengers.adultCount,
+            onValueChange = onAdultCountChange,
+            label = "Adults",
+            modifier = Modifier.weight(1f),
+            minVal = 1,
+        )
+
+        VerticalDivider()
+
+        Counter(
+            value = uiState.passengers.teenCount,
+            onValueChange = onTeenCountChange,
+            label = "Teens",
+            modifier = Modifier.weight(1f),
+        )
+
+        VerticalDivider()
+
+        Counter(
+            value = uiState.passengers.childCount,
+            onValueChange = onChildCountChange,
+            label = "Children",
+            modifier = Modifier.weight(1f),
+            maxVal = uiState.passengers.adultCount,
+        )
+    }
+}

ui/home/src/main/kotlin/dev/adriankuta/flights/ui/home/components/SearchForm.kt

@@ -0,0 +1,76 @@
+package dev.adriankuta.flights.ui.home.components
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.material3.Button
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import dev.adriankuta.flights.domain.types.AirportInfo
+import dev.adriankuta.flights.ui.home.HomeUiState
+import java.time.LocalDate
+
+@Composable
+internal fun SearchForm(
+    uiState: HomeUiState.Success,
+    onOriginAirportSelect: (AirportInfo) -> Unit,
+    onDestinationAirportSelect: (AirportInfo) -> Unit,
+    onDateSelect: (LocalDate) -> Unit,
+    onAdultCountChange: (Int) -> Unit,
+    onTeenCountChange: (Int) -> Unit,
+    onChildCountChange: (Int) -> Unit,
+    onSearch: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    Column(modifier) {
+        AirportDropdown(
+            label = "Origin Airport",
+            airports = uiState.originAirports,
+            selectedAirport = uiState.selectedOriginAirport,
+            onAirportSelect = onOriginAirportSelect,
+            modifier = Modifier.fillMaxWidth(),
+        )
+
+        Spacer(modifier = Modifier.height(16.dp))
+
+        AirportDropdown(
+            label = "Destination Airport",
+            airports = uiState.destinationAirports,
+            selectedAirport = uiState.selectedDestinationAirport,
+            onAirportSelect = onDestinationAirportSelect,
+            modifier = Modifier.fillMaxWidth(),
+            enabled = uiState.selectedOriginAirport != null,
+        )
+
+        Spacer(modifier = Modifier.height(16.dp))
+
+        DatePicker(
+            label = "Departure Date",
+            selectedDate = uiState.selectedDate,
+            onDateSelect = onDateSelect,
+            modifier = Modifier.fillMaxWidth(),
+            enabled = uiState.selectedDestinationAirport != null,
+        )
+
+        Spacer(modifier = Modifier.height(16.dp))
+
+        Text("Passengers")
+
+        Spacer(modifier = Modifier.height(8.dp))
+
+        PassengersOptions(uiState, onAdultCountChange, onTeenCountChange, onChildCountChange)
+
+        Spacer(modifier = Modifier.height(24.dp))
+
+        Button(
+            onClick = onSearch,
+            modifier = Modifier.fillMaxWidth(),
+            enabled = uiState.selectedOriginAirport != null && uiState.selectedDestinationAirport != null,
+        ) {
+            Text("Search Flights")
+        }
+    }
+}

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

@@ -34,10 +34,11 @@ import dev.adriankuta.flights.ui.designsystem.theme.FlightsTheme
 @Composable
 fun Counter(
     value: Int,
-    onCountChange: (diff: Int) -> Unit,
+    onValueChange: (newValue: Int) -> Unit,
     modifier: Modifier = Modifier,
     label: String? = null,
     minVal: Int = 0,
+    maxVal: Int = Int.MAX_VALUE,
 ) {
     val view = LocalView.current
 
@@ -84,7 +85,7 @@ fun Counter(
                 modifier = Modifier.weight(1f),
                 onClick = {
                     view.performHapticFeedback(HapticFeedbackConstants.KEYBOARD_TAP)
-                    onCountChange(-1)
+                    onValueChange(value - 1)
                 },
                 shape = MaterialTheme.shapes.medium,
                 enabled = value > minVal,
@@ -99,10 +100,10 @@ fun Counter(
                 modifier = Modifier.weight(1f),
                 onClick = {
                     view.performHapticFeedback(HapticFeedbackConstants.KEYBOARD_TAP)
-                    onCountChange(1)
+                    onValueChange(value + 1)
                 },
                 shape = MaterialTheme.shapes.medium,
-                enabled = value < 20,
+                enabled = value < maxVal,
             ) {
                 Text(
                     text = "+",
@@ -124,7 +125,8 @@ private fun CounterPreview() {
         Counter(
             value = tapCounter,
             label = "Taps",
-            onCountChange = { tapCounter += it },
+            onValueChange = { tapCounter += it },
+            maxVal = 20,
         )
     }
 }