feat: Introduce Result type and update UI states

This commit introduces a generic `Result` sealed interface to represent success, error, and loading states for asynchronous operations. It also updates the home screen UI and ViewModel to utilize this `Result` type for displaying different states.

Key changes:
- Added `Result.kt` in `core:util` defining the `Result` sealed interface and an `asResult()` Flow extension.
- Updated `HomeScreenViewModel` to use `asResult()` and map the `ObserveAirportsUseCase` output to `HomeUiState` (Loading, Success, Error).
- Modified `HomeUiState` to be a sealed interface with `Loading`, `Success`, and `Error` subtypes.
- Updated `HomeScreen` to handle different `HomeUiState` values and display appropriate UI (Loading text, Error text, or list of airports).
- Added `core.util` dependency to `ui:home`.
- Updated Moshi and Retrofit Moshi converter dependencies in `model/data/api/build.gradle.kts` and `gradle/libs.versions.toml`.
- Added `moshi` and `moshiKotlinCodegen` versions to `gradle/libs.versions.toml`.
- Removed `converter-moshi` and added `retrofit-converter-moshi` in `gradle/libs.versions.toml`.
- Added `ksp(libs.moshi.kotlin.codegen)` to `model/data/api/build.gradle.kts`.
- Added `INTERNET` permission to `app/src/main/AndroidManifest.xml`.
- Updated `ObserveAirportsUseCaseImpl` to use `cacheKey` when setting airports info and to fetch airports for "pl" (lowercase).
- Added `.editorconfig` file with Kotlin trailing comma settings.

ui/home/build.gradle.kts

@@ -9,6 +9,7 @@ android {
 }
 
 dependencies {
+    implementation(projects.core.util)
     implementation(projects.ui.designsystem)
     implementation(projects.domain.search)
 

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

@@ -8,7 +8,6 @@ import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
-import dev.adriankuta.flights.domain.types.AirportInfo
 import dev.adriankuta.flights.ui.designsystem.theme.FlightsTheme
 import dev.adriankuta.flights.ui.designsystem.theme.PreviewDevices
 
@@ -19,18 +18,24 @@ internal fun HomeScreen(
     val homeUiState by viewModel.uiState.collectAsStateWithLifecycle()
 
     HomeScreen(
-        airports = homeUiState.airports
+        uiState = homeUiState,
     )
 }
 
 @Composable
 private fun HomeScreen(
-    airports: List<AirportInfo>,
+    uiState: HomeUiState,
     modifier: Modifier = Modifier,
 ) {
-    LazyColumn {
-        items(airports) { airport ->
-            Text(airport.name)
+    LazyColumn(
+        modifier = modifier,
+    ) {
+        when (uiState) {
+            is HomeUiState.Error -> item { Text("Error") }
+            HomeUiState.Loading -> item { Text("Loading") }
+            is HomeUiState.Success -> items(uiState.airports) { airport ->
+                Text(airport.name)
+            }
         }
     }
 }
@@ -40,7 +45,7 @@ private fun HomeScreen(
 private fun HomeScreenPreview() {
     FlightsTheme {
         HomeScreen(
-            airports = listOf()
+            uiState = HomeUiState.Loading,
         )
     }
 }

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

@@ -3,17 +3,15 @@ package dev.adriankuta.flights.ui.home
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
+import dev.adriankuta.flights.core.util.Result
+import dev.adriankuta.flights.core.util.asResult
 import dev.adriankuta.flights.domain.search.ObserveAirportsUseCase
 import dev.adriankuta.flights.domain.types.AirportInfo
-import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.SharingStarted
-import kotlinx.coroutines.flow.flatMapLatest
-import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
 import javax.inject.Inject
-import kotlin.time.Duration.Companion.seconds
 
 @HiltViewModel
 class HomeScreenViewModel @Inject constructor(
@@ -26,7 +24,7 @@ class HomeScreenViewModel @Inject constructor(
         .stateIn(
             scope = viewModelScope,
             started = SharingStarted.WhileSubscribed(5_000),
-            initialValue = HomeUiState(),
+            initialValue = HomeUiState.Loading,
         )
 }
 
@@ -34,14 +32,19 @@ private fun homeUiState(
     useCase: ObserveAirportsUseCase
 ): Flow<HomeUiState> {
 
-    return flow {
-        delay(15.seconds)
-        emit("")
-    }.flatMapLatest { useCase() }.map {
-        HomeUiState(it.orEmpty())
-    }
+    return useCase()
+        .asResult()
+        .map { result ->
+            when (result) {
+                is Result.Error -> HomeUiState.Error(result.exception)
+                Result.Loading -> HomeUiState.Loading
+                is Result.Success -> HomeUiState.Success(result.data.orEmpty())
+            }
+        }
 }
 
-internal data class HomeUiState(
-    val airports: List<AirportInfo> = emptyList()
-)
+internal sealed interface HomeUiState {
+    data object Loading : HomeUiState
+    data class Success(val airports: List<AirportInfo>) : HomeUiState
+    data class Error(val exception: Throwable) : HomeUiState
+}