feat: Implement airport search and selection in StationsScreen

This commit introduces search functionality and airport selection to the StationsScreen. Users can now search for airports and select an origin airport, which will be displayed in a compact view.

Key changes:
- Added a search bar (`OutlinedTextField`) to `StationsScreen` to filter the list of airports.
- Implemented `searchQuery` StateFlow in `StationsScreenViewModel` to hold the current search term.
- Updated `originAirportsUiState` to filter airports based on the `searchQuery`.
- Added `selectedOriginAirport` StateFlow in `StationsScreenViewModel` to manage the selected airport.
- Introduced `AirportInfoCompact` composable to display the selected origin airport.
- Implemented `onAirportSelected` and `clearSelectedAirport` functions in `StationsScreenViewModel` to handle airport selection and clearing.
- Added `BackHandler` to clear the selected airport when the back button is pressed.
- Made `AirportInfoItem` clickable to trigger airport selection.
- Added string resource for "Search airports" placeholder.
- Added Detekt configuration files for `domain/stations` and `ui/stations` modules.
- Added Lint baseline files for `domain/stations` and `ui/stations` modules.
- Used `key` and `animateItem` for better performance and animations in `LazyColumn`.

domain/stations/config/detekt/detekt.yml

@@ -0,0 +1,10 @@
+# Deviations from defaults
+formatting:
+  TrailingCommaOnCallSite:
+    active: true
+    autoCorrect: true
+    useTrailingCommaOnCallSite: true
+  TrailingCommaOnDeclarationSite:
+    active: true
+    autoCorrect: true
+    useTrailingCommaOnDeclarationSite: true

domain/stations/lint-baseline.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<issues format="6" by="lint 8.10.1" type="baseline" client="gradle" dependencies="false" name="AGP (8.10.1)" variant="all" version="8.10.1">
+
+    <issue
+        id="Aligned16KB"
+        message="The native library `arm64-v8a/libmockkjvmtiagent.so` (from `io.mockk:mockk-agent-android:1.14.2`) is not 16 KB aligned">
+        <location
+            file="$GRADLE_USER_HOME/caches/8.11.1/transforms/60089ed8c197d152569cb75de3649edc/transformed/mockk-agent-android-1.14.2/jni/arm64-v8a/libmockkjvmtiagent.so"/>
+    </issue>
+
+</issues>

ui/stations/config/detekt/detekt.yml

@@ -0,0 +1,33 @@
+# Exceptions for compose. See https://detekt.dev/docs/introduction/compose
+naming:
+  FunctionNaming:
+    functionPattern: '[a-zA-Z][a-zA-Z0-9]*'
+
+  TopLevelPropertyNaming:
+    constantPattern: '[A-Z][A-Za-z0-9]*'
+
+complexity:
+  LongParameterList:
+    ignoreAnnotated: ['Composable']
+  TooManyFunctions:
+    ignoreAnnotatedFunctions: ['Preview']
+
+style:
+  MagicNumber:
+    ignorePropertyDeclaration: true
+    ignoreCompanionObjectPropertyDeclaration: true
+    ignoreAnnotated: ['Composable']
+
+  UnusedPrivateMember:
+    ignoreAnnotated: ['Composable']
+
+# Deviations from defaults
+formatting:
+  TrailingCommaOnCallSite:
+    active: true
+    autoCorrect: true
+    useTrailingCommaOnCallSite: true
+  TrailingCommaOnDeclarationSite:
+    active: true
+    autoCorrect: true
+    useTrailingCommaOnDeclarationSite: true

ui/stations/lint-baseline.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<issues format="6" by="lint 8.10.1" type="baseline" client="gradle" dependencies="false" name="AGP (8.10.1)" variant="all" version="8.10.1">
+
+    <issue
+        id="Aligned16KB"
+        message="The native library `arm64-v8a/libmockkjvmtiagent.so` (from `io.mockk:mockk-agent-android:1.14.2`) is not 16 KB aligned">
+        <location
+            file="$GRADLE_USER_HOME/caches/8.11.1/transforms/60089ed8c197d152569cb75de3649edc/transformed/mockk-agent-android-1.14.2/jni/arm64-v8a/libmockkjvmtiagent.so"/>
+    </issue>
+
+    <issue
+        id="Aligned16KB"
+        message="The native library `arm64-v8a/libmockkjvmtiagent.so` (from `io.mockk:mockk-agent-android:1.14.2`) is not 16 KB aligned">
+        <location
+            file="$GRADLE_USER_HOME/caches/8.11.1/transforms/60089ed8c197d152569cb75de3649edc/transformed/mockk-agent-android-1.14.2/jni/arm64-v8a/libmockkjvmtiagent.so"/>
+    </issue>
+
+</issues>

ui/stations/src/main/kotlin/dev/adriankuta/flights/ui/home/StationsScreen.kt

@@ -1,53 +1,125 @@
 package dev.adriankuta.flights.ui.home
 
+import androidx.activity.compose.BackHandler
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.LazyListScope
 import androidx.compose.foundation.lazy.items
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Search
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.key
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import dev.adriankuta.flights.domain.types.AirportInfo
 import dev.adriankuta.flights.domain.types.Country
+import dev.adriankuta.flights.ui.home.components.AirportInfoCompact
 import dev.adriankuta.flights.ui.home.components.AirportInfoItem
 import dev.adriankuta.flights.ui.home.components.CountryItem
+import dev.adriankuta.flights.ui.stations.R
 
 @Composable
 internal fun StationsScreen(
     stationScreenViewModel: StationsScreenViewModel = hiltViewModel(),
 ) {
     val originAirports by stationScreenViewModel.originAirports.collectAsStateWithLifecycle()
+    val searchQuery by stationScreenViewModel.searchQuery.collectAsStateWithLifecycle()
+    val selectedOriginAirport by stationScreenViewModel.selectedOriginAirport.collectAsStateWithLifecycle()
+
+    BackHandler(selectedOriginAirport != null) {
+        stationScreenViewModel.clearSelectedAirport()
+    }
 
     StationsScreen(
         originAirports = originAirports,
+        searchQuery = searchQuery,
+        selectedOriginAirport = selectedOriginAirport,
+        onSearchQueryChang = stationScreenViewModel::onSearchQueryChanged,
+        onAirportSelect = stationScreenViewModel::onAirportSelected,
     )
 }
 
+@OptIn(ExperimentalMaterial3Api::class)
 @Composable
 private fun StationsScreen(
     originAirports: OriginAirportsUiState,
+    searchQuery: String,
+    selectedOriginAirport: AirportInfo?,
+    onSearchQueryChang: (String) -> Unit,
+    onAirportSelect: (AirportInfo) -> Unit,
 ) {
-    LazyColumn(
+    Column(
         modifier = Modifier.fillMaxWidth(),
     ) {
-        when (originAirports) {
+        AnimatedVisibility(selectedOriginAirport != null) {
-            is OriginAirportsUiState.Error -> item { Text("Error") }
+            var airportInfo by remember { mutableStateOf(selectedOriginAirport!!) }
-            is OriginAirportsUiState.Loading -> item { Text("Loading") }
+            LaunchedEffect(selectedOriginAirport) {
-            is OriginAirportsUiState.Success -> groupedAirports(originAirports.groupedAirports)
+                selectedOriginAirport?.let { airportInfo = it }
+            }
+            AirportInfoCompact(
+                data = airportInfo,
+            )
+        }
+
+        OutlinedTextField(
+            value = searchQuery,
+            onValueChange = onSearchQueryChang,
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(16.dp),
+            placeholder = { Text(text = stringResource(R.string.search_airports)) },
+            leadingIcon = { Icon(Icons.Default.Search, contentDescription = null) },
+            singleLine = true,
+        )
+
+        LazyColumn(
+            modifier = Modifier.fillMaxWidth(),
+        ) {
+            when (originAirports) {
+                is OriginAirportsUiState.Error -> item { Text("Error") }
+                is OriginAirportsUiState.Loading -> item { Text("Loading") }
+                is OriginAirportsUiState.Success -> groupedAirports(
+                    data = originAirports.groupedAirports,
+                    onAirportSelected = onAirportSelect,
+                )
+            }
         }
     }
 }
 
 private fun LazyListScope.groupedAirports(
     data: Map<Country, List<AirportInfo>>,
+    onAirportSelected: (AirportInfo) -> Unit,
 ) {
     data.keys.forEach { country ->
-        stickyHeader { CountryItem(country) }
+        stickyHeader {
+            key(country.code) {
+                CountryItem(data = country, modifier = Modifier.animateItem())
+            }
+        }
         items(data[country]!!) { airport ->
-            AirportInfoItem(airport)
+            key(airport.code) {
+                AirportInfoItem(
+                    data = airport,
+                    modifier = Modifier.animateItem(),
+                    onClick = onAirportSelected,
+                )
+            }
         }
     }
 }

ui/stations/src/main/kotlin/dev/adriankuta/flights/ui/home/StationsScreenViewModel.kt

@@ -9,8 +9,10 @@ import dev.adriankuta.flights.domain.stations.ObserveAirportsGroupedByCountry
 import dev.adriankuta.flights.domain.types.AirportInfo
 import dev.adriankuta.flights.domain.types.Country
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
-import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.stateIn
 import javax.inject.Inject
 
@@ -19,8 +21,27 @@ internal class StationsScreenViewModel @Inject constructor(
     observeAirportsGroupedByCountry: ObserveAirportsGroupedByCountry,
 ) : ViewModel() {
 
+    private val _searchQuery = MutableStateFlow("")
+    val searchQuery: StateFlow<String> = _searchQuery
+
+    private val _selectedOriginAirport = MutableStateFlow<AirportInfo?>(null)
+    val selectedOriginAirport: StateFlow<AirportInfo?> = _selectedOriginAirport
+
+    fun onSearchQueryChanged(query: String) {
+        _searchQuery.value = query
+    }
+
+    fun onAirportSelected(airport: AirportInfo) {
+        _selectedOriginAirport.value = airport
+    }
+
+    fun clearSelectedAirport() {
+        _selectedOriginAirport.value = null
+    }
+
     val originAirports = originAirportsUiState(
         useCase = observeAirportsGroupedByCountry,
+        searchQuery = searchQuery,
     ).stateIn(
         scope = viewModelScope,
         started = SharingStarted.WhileSubscribed(5_000),
@@ -30,16 +51,33 @@ internal class StationsScreenViewModel @Inject constructor(
 
 private fun originAirportsUiState(
     useCase: ObserveAirportsGroupedByCountry,
+    searchQuery: StateFlow<String>,
 ): Flow<OriginAirportsUiState> {
-    return useCase()
+    return combine(
-        .asResult()
+        useCase().asResult(),
-        .map { result ->
+        searchQuery,
-            when (result) {
+    ) { result, query ->
-                is Result.Error -> OriginAirportsUiState.Error(result.exception)
+        when (result) {
-                is Result.Loading -> OriginAirportsUiState.Loading
+            is Result.Error -> OriginAirportsUiState.Error(result.exception)
-                is Result.Success -> OriginAirportsUiState.Success(result.data.orEmpty())
+            is Result.Loading -> OriginAirportsUiState.Loading
+            is Result.Success -> {
+                val airports = result.data.orEmpty()
+                if (query.isBlank()) {
+                    OriginAirportsUiState.Success(airports)
+                } else {
+                    val filteredAirports = airports.mapValues { (_, airportList) ->
+                        airportList.filter { airport ->
+                            airport.name.contains(query, ignoreCase = true) ||
+                                airport.code.contains(query, ignoreCase = true) ||
+                                airport.city.name.contains(query, ignoreCase = true) ||
+                                airport.country.name.contains(query, ignoreCase = true)
+                        }
+                    }.filterValues { it.isNotEmpty() }
+                    OriginAirportsUiState.Success(filteredAirports)
+                }
             }
         }
+    }
 }
 
 internal sealed interface OriginAirportsUiState {

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

@@ -0,0 +1,60 @@
+package dev.adriankuta.flights.ui.home.components
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Card
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import dev.adriankuta.flights.domain.types.AirportInfo
+
+@Composable
+internal fun AirportInfoCompact(
+    data: AirportInfo,
+    modifier: Modifier = Modifier,
+) {
+    Card(
+        modifier = modifier
+            .fillMaxWidth()
+            .padding(horizontal = 16.dp, vertical = 8.dp),
+        elevation = CardDefaults.cardElevation(defaultElevation = 2.dp),
+        colors = CardDefaults.cardColors(
+            containerColor = MaterialTheme.colorScheme.primaryContainer,
+        ),
+    ) {
+        Row(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(12.dp),
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            Column(modifier = Modifier.weight(1f)) {
+                Text(
+                    text = data.name,
+                    style = MaterialTheme.typography.titleMedium,
+                    fontWeight = FontWeight.Bold,
+                )
+                Text(
+                    text = "${data.code} • ${data.city.name}",
+                    style = MaterialTheme.typography.bodyMedium,
+                )
+            }
+            if (data.isBase) {
+                Text(
+                    text = "BASE",
+                    style = MaterialTheme.typography.labelMedium,
+                    color = MaterialTheme.colorScheme.primary,
+                    fontWeight = FontWeight.Bold,
+                    modifier = Modifier.padding(start = 8.dp),
+                )
+            }
+        }
+    }
+}

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

@@ -19,12 +19,14 @@ import dev.adriankuta.flights.domain.types.AirportInfo
 internal fun AirportInfoItem(
     data: AirportInfo,
     modifier: Modifier = Modifier,
+    onClick: (AirportInfo) -> Unit = {},
 ) {
     Card(
         modifier = modifier
             .fillMaxWidth()
             .padding(horizontal = 16.dp, vertical = 4.dp),
         elevation = CardDefaults.cardElevation(defaultElevation = 2.dp),
+        onClick = { onClick(data) },
     ) {
         Column(
             modifier = Modifier

ui/stations/src/main/res/values/strings.xml

@@ -1,4 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <string name="stations_screen_title">Stations</string>
+    <string name="search_airports">Search airports</string>
 </resources>