Refactor unit selector screens

decrease duplicate logic in ConverterViewModel

data/common/src/main/java/com/sadellie/unitto/data/common/FlowUtils.kt

@@ -154,5 +154,45 @@ fun <T1, T2, T3, T4, T5, T6, T7, T8, T9, R> combine(
         )
     }
 
+@Suppress("UNCHECKED_CAST", "UNUSED")
+fun <T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, R> combine(
+    flow: Flow<T1>,
+    flow2: Flow<T2>,
+    flow3: Flow<T3>,
+    flow4: Flow<T4>,
+    flow5: Flow<T5>,
+    flow6: Flow<T6>,
+    flow7: Flow<T7>,
+    flow8: Flow<T8>,
+    flow9: Flow<T9>,
+    flow10: Flow<T10>,
+    transform: suspend (T1, T2, T3, T4, T5, T6, T7, T8, T9, T10) -> R,
+): Flow<R> =
+    kotlinx.coroutines.flow.combine(
+        flow,
+        flow2,
+        flow3,
+        flow4,
+        flow5,
+        flow6,
+        flow7,
+        flow8,
+        flow9,
+        flow10
+    ) { args: Array<*> ->
+        transform(
+            args[0] as T1,
+            args[1] as T2,
+            args[2] as T3,
+            args[3] as T4,
+            args[4] as T5,
+            args[5] as T6,
+            args[6] as T7,
+            args[7] as T8,
+            args[8] as T9,
+            args[9] as T10,
+        )
+    }
+
 fun <T> Flow<T>.stateIn(scope: CoroutineScope, initialValue: T): StateFlow<T> =
     stateIn(scope, SharingStarted.WhileSubscribed(5000L), initialValue)

feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterScreen.kt

@@ -97,8 +97,8 @@ import java.util.Locale
 @Composable
 internal fun ConverterRoute(
     viewModel: ConverterViewModel = hiltViewModel(),
-    navigateToLeftScreen: () -> Unit,
+    navigateToLeftScreen: (uiState: UnitConverterUIState) -> Unit,
-    navigateToRightScreen: () -> Unit,
+    navigateToRightScreen: (uiState: UnitConverterUIState) -> Unit,
     navigateToMenu: () -> Unit,
     navigateToSettings: () -> Unit,
 ) {
@@ -124,8 +124,8 @@ internal fun ConverterRoute(
 @Composable
 private fun ConverterScreen(
     uiState: UnitConverterUIState,
-    navigateToLeftScreen: () -> Unit,
+    navigateToLeftScreen: (uiState: UnitConverterUIState) -> Unit,
-    navigateToRightScreen: () -> Unit,
+    navigateToRightScreen: (uiState: UnitConverterUIState) -> Unit,
     navigateToSettings: () -> Unit,
     navigateToMenu: () -> Unit,
     swapUnits: () -> Unit,
@@ -207,9 +207,9 @@ private fun NumberBase(
     onValueChange: (TextFieldValue) -> Unit,
     processInput: (String) -> Unit,
     deleteDigit: () -> Unit,
-    navigateToLeftScreen: () -> Unit,
+    navigateToLeftScreen: (uiState: UnitConverterUIState) -> Unit,
     swapUnits: () -> Unit,
-    navigateToRightScreen: () -> Unit,
+    navigateToRightScreen: (uiState: UnitConverterUIState) -> Unit,
     clearInput: () -> Unit,
 ) {
     PortraitLandscape(
@@ -239,8 +239,8 @@ private fun NumberBase(
                     unitFromLabel = stringResource(uiState.unitFrom.displayName),
                     unitToLabel = stringResource(uiState.unitTo.displayName),
                     swapUnits = swapUnits,
-                    navigateToLeftScreen = navigateToLeftScreen,
+                    navigateToLeftScreen = { navigateToLeftScreen(uiState) },
-                    navigateToRightScreen = navigateToRightScreen
+                    navigateToRightScreen = { navigateToRightScreen(uiState) }
                 )
             }
         },
@@ -263,9 +263,9 @@ private fun Default(
     onFocusOnInput2: (Boolean) -> Unit,
     processInput: (String) -> Unit,
     deleteDigit: () -> Unit,
-    navigateToLeftScreen: () -> Unit,
+    navigateToLeftScreen: (uiState: UnitConverterUIState) -> Unit,
     swapUnits: () -> Unit,
-    navigateToRightScreen: () -> Unit,
+    navigateToRightScreen: (uiState: UnitConverterUIState) -> Unit,
     clearInput: () -> Unit,
     refreshCurrencyRates: (AbstractUnit) -> Unit,
     addBracket: () -> Unit,
@@ -327,7 +327,9 @@ private fun Default(
                                 .weight(1f)
                         ) {
                             ExpressionTextField(
-                                modifier = Modifier.fillMaxWidth().weight(1f),
+                                modifier = Modifier
+                                    .fillMaxWidth()
+                                    .weight(1f),
                                 value = uiState.input1,
                                 minRatio = 0.7f,
                                 onValueChange = onValueChange,
@@ -345,7 +347,9 @@ private fun Default(
                                 .weight(1f)
                         ) {
                             ExpressionTextField(
-                                modifier = Modifier.fillMaxWidth().weight(1f)
+                                modifier = Modifier
+                                    .fillMaxWidth()
+                                    .weight(1f)
                                     .onFocusEvent { state -> onFocusOnInput2(state.hasFocus) },
                                 value = uiState.input2,
                                 minRatio = 0.7f,
@@ -405,8 +409,8 @@ private fun Default(
                     unitFromLabel = stringResource(uiState.unitFrom.displayName),
                     unitToLabel = stringResource(uiState.unitTo.displayName),
                     swapUnits = swapUnits,
-                    navigateToLeftScreen = navigateToLeftScreen,
+                    navigateToLeftScreen = { navigateToLeftScreen(uiState) },
-                    navigateToRightScreen = navigateToRightScreen
+                    navigateToRightScreen = { navigateToRightScreen(uiState) }
                 )
             }
         },

feature/converter/src/main/java/com/sadellie/unitto/feature/converter/ConverterViewModel.kt

@@ -33,7 +33,6 @@ import com.sadellie.unitto.data.common.isExpression
 import com.sadellie.unitto.data.common.stateIn
 import com.sadellie.unitto.data.converter.UnitID
 import com.sadellie.unitto.data.model.UnitGroup
-import com.sadellie.unitto.data.model.UnitsListSorting
 import com.sadellie.unitto.data.model.repository.UnitsRepository
 import com.sadellie.unitto.data.model.repository.UserPreferencesRepository
 import com.sadellie.unitto.data.model.unit.AbstractUnit
@@ -45,12 +44,10 @@ import io.github.sadellie.evaluatto.ExpressionException
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.getAndUpdate
 import kotlinx.coroutines.flow.mapLatest
-import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -74,13 +71,6 @@ internal class ConverterViewModel @Inject constructor(
     private val _unitFrom = MutableStateFlow<AbstractUnit?>(null)
     private val _unitTo = MutableStateFlow<AbstractUnit?>(null)
 
-    private val _leftQuery = MutableStateFlow(TextFieldValue())
-    private val _leftUnits = MutableStateFlow<Map<UnitGroup, List<AbstractUnit>>>(emptyMap())
-    private val _leftUnitGroup = MutableStateFlow<UnitGroup?>(null)
-
-    private val _rightQuery = MutableStateFlow(TextFieldValue())
-    private val _rightUnits = MutableStateFlow<Map<UnitGroup, List<AbstractUnit>>>(emptyMap())
-
     private val _currenciesState = MutableStateFlow<CurrencyRateUpdateState>(CurrencyRateUpdateState.Nothing)
     private var _loadCurrenciesJob: Job? = null
 
@@ -160,81 +150,6 @@ internal class ConverterViewModel @Inject constructor(
         }
         .stateIn(viewModelScope, UnitConverterUIState.Loading)
 
-    val leftSideUIState = combine(
-        _unitFrom,
-        _leftQuery,
-        _leftUnits,
-        _leftUnitGroup,
-        userPrefsRepository.converterPrefs,
-        unitsRepo.units
-    ) { unitFrom, query, units, unitGroup, prefs, _ ->
-        unitFrom ?: return@combine LeftSideUIState.Loading
-
-        return@combine LeftSideUIState.Ready(
-            unitFrom = unitFrom,
-            sorting = prefs.unitConverterSorting,
-            shownUnitGroups = prefs.shownUnitGroups,
-            favorites = prefs.unitConverterFavoritesOnly,
-            query = query,
-            units = units,
-            unitGroup = unitGroup
-        )
-    }
-        .mapLatest {
-            if (it !is LeftSideUIState.Ready) return@mapLatest it
-
-            filterUnitsLeft(
-                query = it.query,
-                unitGroup = it.unitGroup,
-                favoritesOnly = it.favorites,
-                sorting = it.sorting,
-                shownUnitGroups = it.shownUnitGroups,
-            )
-            it
-        }
-        .stateIn(viewModelScope, SharingStarted.Lazily, LeftSideUIState.Loading)
-
-    val rightSideUIState = combine(
-        _unitFrom,
-        _unitTo,
-        _input1,
-        _calculation,
-        _rightQuery,
-        _rightUnits,
-        userPrefsRepository.converterPrefs,
-        _currenciesState,
-        unitsRepo.units,
-    ) { unitFrom, unitTo, input, calculation, query, units, prefs, currenciesState, _ ->
-        unitFrom ?: return@combine RightSideUIState.Loading
-        unitTo ?: return@combine RightSideUIState.Loading
-
-        return@combine RightSideUIState.Ready(
-            unitFrom = unitFrom,
-            unitTo = unitTo,
-            sorting = prefs.unitConverterSorting,
-            favorites = prefs.unitConverterFavoritesOnly,
-            input = (calculation?.toPlainString() ?: input.text).replace(Token.Operator.minus, "-"),
-            scale = prefs.precision,
-            outputFormat = prefs.outputFormat,
-            formatterSymbols = AllFormatterSymbols.getById(prefs.separator),
-            currencyRateUpdateState = currenciesState,
-            query = query,
-            units = units,
-        )
-    }
-        .mapLatest {
-            if (it !is RightSideUIState.Ready) return@mapLatest it
-
-            filterUnitsRight(
-                query = it.query,
-                unitGroup = it.unitFrom.group,
-                favoritesOnly = it.favorites,
-                sorting = it.sorting,
-            )
-            it
-        }
-        .stateIn(viewModelScope, SharingStarted.Lazily, RightSideUIState.Loading)
-
     fun swapUnits() {
         _unitFrom
             .getAndUpdate { _unitTo.value }
@@ -380,56 +295,6 @@ internal class ConverterViewModel @Inject constructor(
         }
     }
 
-    fun queryChangeLeft(query: TextFieldValue) = _leftQuery.update { query }
-
-    fun queryChangeRight(query: TextFieldValue) = _rightQuery.update { query }
-
-    fun favoritesOnlyChange(enabled: Boolean) = viewModelScope.launch {
-        userPrefsRepository.updateUnitConverterFavoritesOnly(enabled)
-    }
-
-    fun updateUnitGroupLeft(unitGroup: UnitGroup?) = _leftUnitGroup.update { unitGroup }
-
-    fun favoriteUnit(unit: AbstractUnit) = viewModelScope.launch {
-        unitsRepo.favorite(unit)
-    }
-
-    private fun filterUnitsLeft(
-        query: TextFieldValue,
-        unitGroup: UnitGroup?,
-        favoritesOnly: Boolean,
-        sorting: UnitsListSorting,
-        shownUnitGroups: List<UnitGroup>,
-    ) = viewModelScope.launch(Dispatchers.Default) {
-        _leftUnits.update {
-            unitsRepo.filterUnits(
-                query = query.text,
-                unitGroup = unitGroup,
-                favoritesOnly = favoritesOnly,
-                hideBrokenUnits = false,
-                sorting = sorting,
-                shownUnitGroups = shownUnitGroups
-            )
-        }
-    }
-
-    private fun filterUnitsRight(
-        query: TextFieldValue,
-        unitGroup: UnitGroup?,
-        favoritesOnly: Boolean,
-        sorting: UnitsListSorting,
-    ) = viewModelScope.launch(Dispatchers.Default) {
-        _rightUnits.update {
-            unitsRepo.filterUnits(
-                query = query.text,
-                unitGroup = unitGroup,
-                favoritesOnly = favoritesOnly,
-                hideBrokenUnits = true,
-                sorting = sorting,
-            )
-        }
-    }
-
     private fun convertDefault(
         unitFrom: DefaultUnit,
         unitTo: DefaultUnit,

feature/converter/src/main/java/com/sadellie/unitto/feature/converter/LeftSideUIState.kt

@@ -1,38 +0,0 @@
-/*
- * Unitto is a calculator for Android
- * Copyright (c) 2023-2024 Elshan Agaev
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-package com.sadellie.unitto.feature.converter
-
-import androidx.compose.ui.text.input.TextFieldValue
-import com.sadellie.unitto.data.model.UnitGroup
-import com.sadellie.unitto.data.model.UnitsListSorting
-import com.sadellie.unitto.data.model.unit.AbstractUnit
-
-internal sealed class LeftSideUIState {
-    data object Loading : LeftSideUIState()
-
-    data class Ready(
-        val unitFrom: AbstractUnit,
-        val query: TextFieldValue,
-        val units: Map<UnitGroup, List<AbstractUnit>> = emptyMap(),
-        val favorites: Boolean,
-        val shownUnitGroups: List<UnitGroup>,
-        val unitGroup: UnitGroup?,
-        val sorting: UnitsListSorting,
-    ) : LeftSideUIState()
-}

feature/converter/src/main/java/com/sadellie/unitto/feature/converter/UnitFromSelectorScreen.kt

@@ -49,31 +49,32 @@ import com.sadellie.unitto.feature.converter.components.UnitsList
 import java.math.BigDecimal
 
 @Composable
-internal fun LeftSideRoute(
+internal fun UnitFromSelectorRoute(
-    viewModel: ConverterViewModel,
+    unitSelectorViewModel: UnitSelectorViewModel,
+    converterViewModel: ConverterViewModel,
     navigateUp: () -> Unit,
     navigateToUnitGroups: () -> Unit,
 ) {
     when (
-        val uiState = viewModel.leftSideUIState.collectAsStateWithLifecycle().value
+        val uiState = unitSelectorViewModel.unitFromUIState.collectAsStateWithLifecycle().value
     ) {
-        is LeftSideUIState.Loading -> EmptyScreen()
+        is UnitSelectorUIState.UnitFrom -> UnitFromSelectorScreen(
-        is LeftSideUIState.Ready -> LeftSideScreen(
             uiState = uiState,
-            onQueryChange = viewModel::queryChangeLeft,
+            onQueryChange = unitSelectorViewModel::updateSelectorQuery,
-            toggleFavoritesOnly = viewModel::favoritesOnlyChange,
+            toggleFavoritesOnly = unitSelectorViewModel::updateShowFavoritesOnly,
-            updateUnitFrom = viewModel::updateUnitFrom,
+            updateUnitFrom = converterViewModel::updateUnitFrom,
-            updateUnitGroup = viewModel::updateUnitGroupLeft,
+            updateUnitGroup = unitSelectorViewModel::updateSelectedUnitGroup,
-            favoriteUnit = viewModel::favoriteUnit,
+            favoriteUnit = unitSelectorViewModel::favoriteUnit,
             navigateUp = navigateUp,
             navigateToUnitGroups = navigateToUnitGroups,
         )
+        else -> EmptyScreen()
     }
 }
 
 @Composable
-private fun LeftSideScreen(
+private fun UnitFromSelectorScreen(
-    uiState: LeftSideUIState.Ready,
+    uiState: UnitSelectorUIState.UnitFrom,
     onQueryChange: (TextFieldValue) -> Unit,
     toggleFavoritesOnly: (Boolean) -> Unit,
     updateUnitFrom: (AbstractUnit) -> Unit,
@@ -87,8 +88,6 @@ private fun LeftSideScreen(
     val chipsRowLazyListState = rememberLazyListState()
 
     LaunchedEffect(uiState.unitFrom, uiState.shownUnitGroups) {
-        updateUnitGroup(uiState.unitFrom.group)
-
         kotlin.runCatching {
             val groupToSelect = uiState.shownUnitGroups.indexOf(uiState.unitFrom.group)
             if (groupToSelect > -1) {
@@ -108,8 +107,8 @@ private fun LeftSideScreen(
                     onQueryChange = onQueryChange,
                     navigateUp = navigateUp,
                     trailingIcon = {
-                        FavoritesButton(uiState.favorites) {
+                        FavoritesButton(uiState.showFavoritesOnly) {
-                            toggleFavoritesOnly(!uiState.favorites)
+                            toggleFavoritesOnly(!uiState.showFavoritesOnly)
                         }
                     },
                     scrollBehavior = scrollBehavior
@@ -119,7 +118,7 @@ private fun LeftSideScreen(
                     modifier = Modifier
                         .padding(start = 8.dp, end = 8.dp, bottom = 4.dp)
                         .fillMaxWidth(),
-                    chosenUnitGroup = uiState.unitGroup,
+                    chosenUnitGroup = uiState.selectedUnitGroup,
                     items = uiState.shownUnitGroups,
                     selectAction = updateUnitGroup,
                     navigateToSettingsAction = navigateToUnitGroups
@@ -130,7 +129,7 @@ private fun LeftSideScreen(
         val resources = LocalContext.current.resources
         UnitsList(
             modifier = Modifier.padding(paddingValues),
-            groupedUnits = uiState.units,
+            searchResult = uiState.units,
             navigateToUnitGroups = navigateToUnitGroups,
             currentUnitId = uiState.unitFrom.id,
             supportLabel = { resources.getString(it.shortName) },
@@ -146,7 +145,7 @@ private fun LeftSideScreen(
 
 @Preview
 @Composable
-private fun LeftSideScreenPreview() {
+private fun UnitFromSelectorScreenPreview() {
     val units: Map<UnitGroup, List<AbstractUnit>> = mapOf(
         UnitGroup.LENGTH to listOf(
             NormalUnit(UnitID.meter, BigDecimal.valueOf(1.0E+18), UnitGroup.LENGTH, R.string.unit_meter, R.string.unit_meter_short),
@@ -159,14 +158,14 @@ private fun LeftSideScreenPreview() {
         )
     )
 
-    LeftSideScreen(
+    UnitFromSelectorScreen(
-        uiState = LeftSideUIState.Ready(
+        uiState = UnitSelectorUIState.UnitFrom(
             unitFrom = units.values.first().first(),
-            units = units,
             query = TextFieldValue("test"),
-            favorites = false,
+            units = UnitSearchResult.Success(units),
+            selectedUnitGroup = UnitGroup.SPEED,
             shownUnitGroups = UnitGroup.entries,
-            unitGroup = units.keys.toList().first(),
+            showFavoritesOnly = false,
             sorting = UnitsListSorting.USAGE,
         ),
         onQueryChange = {},

feature/converter/src/main/java/com/sadellie/unitto/feature/converter/UnitSelectorUIState.kt

@@ -1,6 +1,6 @@
 /*
  * Unitto is a calculator for Android
- * Copyright (c) 2023-2024 Elshan Agaev
+ * Copyright (c) 2024 Elshan Agaev
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -24,20 +24,39 @@ import com.sadellie.unitto.data.model.UnitGroup
 import com.sadellie.unitto.data.model.UnitsListSorting
 import com.sadellie.unitto.data.model.unit.AbstractUnit
 
-internal sealed class RightSideUIState {
+internal sealed class UnitSelectorUIState {
-    data object Loading : RightSideUIState()
+    data object Loading : UnitSelectorUIState()
 
-    data class Ready(
+    data class UnitFrom(
+        val query: TextFieldValue,
+        val unitFrom: AbstractUnit,
+        val shownUnitGroups: List<UnitGroup>,
+        val showFavoritesOnly: Boolean,
+        val units: UnitSearchResult,
+        val selectedUnitGroup: UnitGroup?,
+        val sorting: UnitsListSorting,
+    ) : UnitSelectorUIState()
+
+    data class UnitTo(
+        val query: TextFieldValue,
         val unitFrom: AbstractUnit,
         val unitTo: AbstractUnit,
-        val query: TextFieldValue,
+        val showFavoritesOnly: Boolean,
-        val units: Map<UnitGroup, List<AbstractUnit>>,
+        val units: UnitSearchResult,
-        val favorites: Boolean,
+        val input: String?,
         val sorting: UnitsListSorting,
-        val input: String,
         val scale: Int,
         val outputFormat: Int,
         val formatterSymbols: FormatterSymbols,
-        val currencyRateUpdateState: CurrencyRateUpdateState,
+    ) : UnitSelectorUIState()
-    ) : RightSideUIState()
+}
+
+internal sealed class UnitSearchResult {
+    data object Empty : UnitSearchResult()
+
+    data object Loading : UnitSearchResult()
+
+    data class Success(
+        val units: Map<UnitGroup, List<AbstractUnit>>
+    ) : UnitSearchResult()
 }

feature/converter/src/main/java/com/sadellie/unitto/feature/converter/UnitSelectorViewModel.kt

@@ -0,0 +1,149 @@
+/*
+ * Unitto is a calculator for Android
+ * Copyright (c) 2024 Elshan Agaev
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.sadellie.unitto.feature.converter
+
+import androidx.compose.ui.text.input.TextFieldValue
+import androidx.lifecycle.SavedStateHandle
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.sadellie.unitto.core.ui.common.textfield.AllFormatterSymbols
+import com.sadellie.unitto.data.common.stateIn
+import com.sadellie.unitto.data.model.UnitGroup
+import com.sadellie.unitto.data.model.repository.UnitsRepository
+import com.sadellie.unitto.data.model.repository.UserPreferencesRepository
+import com.sadellie.unitto.data.model.unit.AbstractUnit
+import com.sadellie.unitto.feature.converter.navigation.inputArg
+import com.sadellie.unitto.feature.converter.navigation.unitFromIdArg
+import com.sadellie.unitto.feature.converter.navigation.unitGroupArg
+import com.sadellie.unitto.feature.converter.navigation.unitToIdArg
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.mapLatest
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+@HiltViewModel
+internal class UnitSelectorViewModel @Inject constructor(
+    private val userPrefsRepository: UserPreferencesRepository,
+    private val unitsRepo: UnitsRepository,
+    savedStateHandle: SavedStateHandle
+) : ViewModel() {
+    private val _query = MutableStateFlow(TextFieldValue())
+    private val _searchResults = MutableStateFlow<UnitSearchResult>(UnitSearchResult.Loading)
+    private val _selectedUnitGroup = MutableStateFlow(savedStateHandle.get<UnitGroup>(unitGroupArg))
+    private val _unitFromId = savedStateHandle.get<String>(unitFromIdArg)
+    private val _unitToId = savedStateHandle.get<String>(unitToIdArg)
+    private val _input = savedStateHandle.get<String>(inputArg)
+
+    val unitFromUIState: StateFlow<UnitSelectorUIState> = combine(
+        _query,
+        _searchResults,
+        _selectedUnitGroup,
+        userPrefsRepository.converterPrefs,
+    ) { query, searchResults, selectedUnitGroup, prefs ->
+        if (_unitFromId.isNullOrEmpty()) return@combine UnitSelectorUIState.Loading
+
+        return@combine UnitSelectorUIState.UnitFrom(
+            query = query,
+            unitFrom = unitsRepo.getById(_unitFromId),
+            shownUnitGroups = prefs.shownUnitGroups,
+            showFavoritesOnly = prefs.unitConverterFavoritesOnly,
+            units = searchResults,
+            selectedUnitGroup = selectedUnitGroup,
+            sorting = prefs.unitConverterSorting,
+        )
+    }
+        .mapLatest { ui ->
+            if (ui is UnitSelectorUIState.UnitFrom) {
+                _searchResults.update {
+                    val result = unitsRepo.filterUnits(
+                        query = ui.query.text,
+                        unitGroup = ui.selectedUnitGroup,
+                        favoritesOnly = ui.showFavoritesOnly,
+                        hideBrokenUnits = false,
+                        sorting = ui.sorting,
+                        shownUnitGroups = ui.shownUnitGroups
+                    )
+
+                    if (result.isEmpty()) UnitSearchResult.Empty else UnitSearchResult.Success(result)
+                }
+            }
+
+            ui
+        }
+        .stateIn(viewModelScope, UnitSelectorUIState.Loading)
+
+    val unitToUIState: StateFlow<UnitSelectorUIState> = combine(
+        _query,
+        _searchResults,
+        userPrefsRepository.converterPrefs,
+        unitsRepo.units,
+    ) { query, searchResults, prefs, _ ->
+        if (_unitFromId.isNullOrEmpty()) return@combine UnitSelectorUIState.Loading
+        if (_unitToId.isNullOrEmpty()) return@combine UnitSelectorUIState.Loading
+
+        UnitSelectorUIState.UnitTo(
+            query = query,
+            unitFrom = unitsRepo.getById(_unitFromId),
+            unitTo = unitsRepo.getById(_unitToId),
+            showFavoritesOnly = prefs.unitConverterFavoritesOnly,
+            units = searchResults,
+            input = _input,
+            sorting = prefs.unitConverterSorting,
+            scale = prefs.precision,
+            outputFormat = prefs.outputFormat,
+            formatterSymbols = AllFormatterSymbols.getById(prefs.separator),
+        )
+    }
+        .mapLatest { ui ->
+            if (ui is UnitSelectorUIState.UnitTo) {
+                _searchResults.update {
+                    if (ui.unitFrom.group == UnitGroup.CURRENCY) unitsRepo.updateRates(ui.unitFrom)
+
+                    val result = unitsRepo.filterUnits(
+                        query = ui.query.text,
+                        unitGroup = ui.unitFrom.group,
+                        favoritesOnly = ui.showFavoritesOnly,
+                        hideBrokenUnits = true,
+                        sorting = ui.sorting,
+                    )
+
+                    if (result.isEmpty()) UnitSearchResult.Empty else UnitSearchResult.Success(result)
+                }
+            }
+            ui
+        }
+        .stateIn(viewModelScope, UnitSelectorUIState.Loading)
+
+    fun updateSelectorQuery(value: TextFieldValue) = _query.update { value }
+
+    fun updateShowFavoritesOnly(value: Boolean) = viewModelScope.launch {
+        userPrefsRepository.updateUnitConverterFavoritesOnly(value)
+    }
+
+    fun updateSelectedUnitGroup(value: UnitGroup?) = _selectedUnitGroup.update { value }
+
+    fun favoriteUnit(unit: AbstractUnit) = viewModelScope.launch(Dispatchers.IO) {
+        unitsRepo.favorite(unit)
+    }
+}

feature/converter/src/main/java/com/sadellie/unitto/feature/converter/UnitToSelectorScreen.kt

@@ -47,31 +47,31 @@ import com.sadellie.unitto.feature.converter.components.UnitsList
 import java.math.BigDecimal
 
 @Composable
-internal fun RightSideRoute(
+internal fun UnitToSelectorRoute(
-    viewModel: ConverterViewModel,
+    unitSelectorViewModel: UnitSelectorViewModel,
+    converterViewModel: ConverterViewModel,
     navigateUp: () -> Unit,
     navigateToUnitGroups: () -> Unit,
 ) {
     when (
-        val uiState = viewModel.rightSideUIState.collectAsStateWithLifecycle().value
+        val uiState = unitSelectorViewModel.unitToUIState.collectAsStateWithLifecycle().value
     ) {
-        is RightSideUIState.Loading -> EmptyScreen()
+        is UnitSelectorUIState.UnitTo -> UnitToSelectorScreen(
-        is RightSideUIState.Ready ->
+            uiState = uiState,
-            RightSideScreen(
+            onQueryChange = unitSelectorViewModel::updateSelectorQuery,
-                uiState = uiState,
+            toggleFavoritesOnly = unitSelectorViewModel::updateShowFavoritesOnly,
-                onQueryChange = viewModel::queryChangeRight,
+            updateUnitTo = converterViewModel::updateUnitTo,
-                toggleFavoritesOnly = viewModel::favoritesOnlyChange,
+            favoriteUnit = unitSelectorViewModel::favoriteUnit,
-                updateUnitTo = viewModel::updateUnitTo,
+            navigateUp = navigateUp,
-                favoriteUnit = viewModel::favoriteUnit,
+            navigateToUnitGroups = navigateToUnitGroups,
-                navigateUp = navigateUp,
+        )
-                navigateToUnitGroups = navigateToUnitGroups,
+        else -> EmptyScreen()
-            )
     }
 }
 
 @Composable
-private fun RightSideScreen(
+private fun UnitToSelectorScreen(
-    uiState: RightSideUIState.Ready,
+    uiState: UnitSelectorUIState.UnitTo,
     onQueryChange: (TextFieldValue) -> Unit,
     toggleFavoritesOnly: (Boolean) -> Unit,
     updateUnitTo: (AbstractUnit) -> Unit,
@@ -89,8 +89,8 @@ private fun RightSideScreen(
                 onQueryChange = onQueryChange,
                 navigateUp = navigateUp,
                 trailingIcon = {
-                    FavoritesButton(uiState.favorites) {
+                    FavoritesButton(uiState.showFavoritesOnly) {
-                        toggleFavoritesOnly(!uiState.favorites)
+                        toggleFavoritesOnly(!uiState.showFavoritesOnly)
                     }
                 },
                 scrollBehavior = scrollBehavior
@@ -100,7 +100,7 @@ private fun RightSideScreen(
         val resources = LocalContext.current.resources
         UnitsList(
             modifier = Modifier.padding(paddingValues),
-            groupedUnits = uiState.units,
+            searchResult = uiState.units,
             navigateToUnitGroups = navigateToUnitGroups,
             currentUnitId = uiState.unitTo.id,
             supportLabel = {
@@ -112,7 +112,6 @@ private fun RightSideScreen(
                     scale = uiState.scale,
                     outputFormat = uiState.outputFormat,
                     formatterSymbols = uiState.formatterSymbols,
-                    readyCurrencies = uiState.currencyRateUpdateState is CurrencyRateUpdateState.Ready,
                 )
             },
             onClick = {
@@ -128,15 +127,13 @@ private fun RightSideScreen(
 private fun formatUnitToSupportLabel(
     unitFrom: AbstractUnit?,
     unitTo: AbstractUnit?,
-    input: String,
+    input: String?,
     shortName: String,
     scale: Int,
     outputFormat: Int,
     formatterSymbols: FormatterSymbols,
-    readyCurrencies: Boolean,
 ): String {
-    if ((unitFrom?.group == UnitGroup.CURRENCY) and !readyCurrencies) return shortName
+    if (input.isNullOrEmpty()) return shortName
-    if (input.isEmpty()) return shortName
 
     try {
         if ((unitFrom is DefaultUnit) and (unitTo is DefaultUnit)) {
@@ -168,7 +165,7 @@ private fun formatUnitToSupportLabel(
 
 @Preview
 @Composable
-private fun RightSideScreenPreview() {
+private fun UnitToSelectorPreview() {
     val units: Map<UnitGroup, List<AbstractUnit>> = mapOf(
         UnitGroup.LENGTH to listOf(
             NormalUnit(UnitID.meter, BigDecimal.valueOf(1.0E+18), UnitGroup.LENGTH, R.string.unit_meter, R.string.unit_meter_short),
@@ -181,19 +178,18 @@ private fun RightSideScreenPreview() {
         )
     )
 
-    RightSideScreen(
+    UnitToSelectorScreen(
-        uiState = RightSideUIState.Ready(
+        uiState = UnitSelectorUIState.UnitTo(
             unitFrom = units.values.first().first(),
-            units = units,
+            unitTo = units.values.first().first(),
-            query = TextFieldValue(),
+            query = TextFieldValue("test"),
-            favorites = false,
+            units = UnitSearchResult.Success(units),
+            showFavoritesOnly = false,
             sorting = UnitsListSorting.USAGE,
-            unitTo = units.values.first()[1],
             input = "100",
             scale = 3,
             outputFormat = OutputFormat.PLAIN,
             formatterSymbols = FormatterSymbols.Spaces,
-            currencyRateUpdateState = CurrencyRateUpdateState.Nothing
         ),
         onQueryChange = {},
         toggleFavoritesOnly = {},

feature/converter/src/main/java/com/sadellie/unitto/feature/converter/components/UnitsList.kt

@@ -33,12 +33,13 @@ import com.sadellie.unitto.data.converter.UnitID
 import com.sadellie.unitto.data.model.UnitGroup
 import com.sadellie.unitto.data.model.unit.AbstractUnit
 import com.sadellie.unitto.data.model.unit.NormalUnit
+import com.sadellie.unitto.feature.converter.UnitSearchResult
 import java.math.BigDecimal
 
 @Composable
 internal fun UnitsList(
     modifier: Modifier,
-    groupedUnits: Map<UnitGroup, List<AbstractUnit>>,
+    searchResult: UnitSearchResult,
     navigateToUnitGroups: () -> Unit,
     currentUnitId: String,
     supportLabel: (AbstractUnit) -> String,
@@ -47,14 +48,14 @@ internal fun UnitsList(
 ) {
     Crossfade(
         modifier = modifier,
-        targetState = groupedUnits.isNotEmpty(),
+        targetState = searchResult,
         label = "Units list"
-    ) { hasUnits ->
+    ) { result ->
-        when (hasUnits) {
+        when (result) {
-            true -> LazyColumn(
+            is UnitSearchResult.Success -> LazyColumn(
                 modifier = Modifier.fillMaxSize()
             ) {
-                groupedUnits.forEach { (group, units) ->
+                result.units.forEach { (group, units) ->
                     item(group.name) {
                         UnitGroupHeader(Modifier.animateItemPlacement(), group)
                     }
@@ -73,11 +74,13 @@ internal fun UnitsList(
                 }
             }
 
-            false -> SearchPlaceholder(
+            UnitSearchResult.Empty -> SearchPlaceholder(
                 onButtonClick = navigateToUnitGroups,
                 supportText = stringResource(R.string.converter_no_results_support),
                 buttonLabel = stringResource(R.string.open_settings_label)
             )
+
+            UnitSearchResult.Loading -> Unit
         }
     }
 }
@@ -100,7 +103,7 @@ private fun PreviewUnitsList() {
 
     UnitsList(
         modifier = Modifier.fillMaxSize(),
-        groupedUnits = groupedUnits,
+        searchResult = UnitSearchResult.Success(units = groupedUnits),
         navigateToUnitGroups = {},
         currentUnitId = UnitID.mile,
         supportLabel = { resources.getString(it.shortName) },

feature/converter/src/main/java/com/sadellie/unitto/feature/converter/navigation/ConverterNavigation.kt

@@ -22,19 +22,42 @@ import androidx.compose.runtime.remember
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.navigation.NavGraphBuilder
 import androidx.navigation.NavHostController
+import androidx.navigation.NavType
+import androidx.navigation.navArgument
 import androidx.navigation.navDeepLink
 import com.sadellie.unitto.core.ui.model.DrawerItem
 import com.sadellie.unitto.core.ui.unittoComposable
 import com.sadellie.unitto.core.ui.unittoNavigation
+import com.sadellie.unitto.data.model.UnitGroup
 import com.sadellie.unitto.feature.converter.ConverterRoute
 import com.sadellie.unitto.feature.converter.ConverterViewModel
-import com.sadellie.unitto.feature.converter.LeftSideRoute
+import com.sadellie.unitto.feature.converter.CurrencyRateUpdateState
-import com.sadellie.unitto.feature.converter.RightSideRoute
+import com.sadellie.unitto.feature.converter.UnitConverterUIState
+import com.sadellie.unitto.feature.converter.UnitFromSelectorRoute
+import com.sadellie.unitto.feature.converter.UnitToSelectorRoute
 
 private val graph = DrawerItem.Converter.graph
 private val start = DrawerItem.Converter.start
-private const val LEFT = "left"
+
-private const val RIGHT = "right"
+private const val UNIT_FROM = "unitFromSelector"
+private const val UNIT_TO = "unitToSelector"
+internal const val unitGroupArg = "unitGroupArg"
+internal const val unitFromIdArg = "unitFromId"
+internal const val unitToIdArg = "unitToIdArg"
+internal const val inputArg = "inputArg"
+
+private const val UNIT_FROM_ROUTE = "$UNIT_FROM/{$unitFromIdArg}/{$unitGroupArg}"
+private const val UNIT_TO_ROUTE = "$UNIT_TO/{$unitFromIdArg}/{$unitToIdArg}/{$inputArg}"
+private fun NavHostController.navigateLeft(
+    unitFromId: String,
+    unitGroup: UnitGroup,
+) = navigate("$UNIT_FROM/$unitFromId/$unitGroup")
+
+private fun NavHostController.navigateRight(
+    unitFromId: String,
+    unitToId: String,
+    input: String?,
+) = navigate("$UNIT_TO/$unitFromId/$unitToId/$input")
 
 fun NavGraphBuilder.converterGraph(
     openDrawer: () -> Unit,
@@ -58,36 +81,107 @@ fun NavGraphBuilder.converterGraph(
 
             ConverterRoute(
                 viewModel = parentViewModel,
-                navigateToLeftScreen = { navController.navigate(LEFT) },
+                // Navigation logic is here, but should actually be in ConverterScreen
-                navigateToRightScreen = { navController.navigate(RIGHT) },
+                navigateToLeftScreen = { uiState: UnitConverterUIState ->
+                    when (uiState) {
+                        is UnitConverterUIState.Default -> navController
+                            .navigateLeft(uiState.unitFrom.id, uiState.unitFrom.group)
+
+                        is UnitConverterUIState.NumberBase -> navController
+                            .navigateLeft(uiState.unitFrom.id, uiState.unitFrom.group)
+
+                        else -> Unit
+                    }
+                },
+                navigateToRightScreen = { uiState: UnitConverterUIState ->
+                    when (uiState) {
+                        is UnitConverterUIState.Default -> {
+                            // Don't allow converting if still loading currencies
+                            val convertingCurrencies = uiState.unitFrom.group == UnitGroup.CURRENCY
+                            val currenciesReady =
+                                uiState.currencyRateUpdateState is CurrencyRateUpdateState.Ready
+
+                            val input: String? = if (convertingCurrencies and !currenciesReady) {
+                                null
+                            } else {
+                                (uiState.calculation?.toPlainString() ?: uiState.input1.text)
+                                    .ifEmpty { null }
+                            }
+
+                            navController.navigateRight(
+                                uiState.unitFrom.id,
+                                uiState.unitTo.id,
+                                input
+                            )
+                        }
+
+                        is UnitConverterUIState.NumberBase -> {
+                            val input = uiState.input.text.ifEmpty { null }
+                            navController.navigateRight(
+                                uiState.unitFrom.id,
+                                uiState.unitTo.id,
+                                input
+                            )
+                        }
+
+                        UnitConverterUIState.Loading -> Unit
+                    }
+                },
                 navigateToSettings = navigateToSettings,
                 navigateToMenu = openDrawer
             )
         }
 
-        unittoComposable(LEFT) { backStackEntry ->
+        unittoComposable(
+            route = UNIT_FROM_ROUTE,
+            arguments = listOf(
+                navArgument(unitFromIdArg) {
+                    type = NavType.StringType
+                },
+                navArgument(unitGroupArg) {
+                    type = NavType.EnumType(UnitGroup::class.java)
+                },
+            )
+        ) { backStackEntry ->
             val parentEntry = remember(backStackEntry) {
                 navController.getBackStackEntry(graph)
             }
 
             val parentViewModel = hiltViewModel<ConverterViewModel>(parentEntry)
 
-            LeftSideRoute(
+            UnitFromSelectorRoute(
-                viewModel = parentViewModel,
+                unitSelectorViewModel = hiltViewModel(),
+                converterViewModel = parentViewModel,
                 navigateUp = navController::navigateUp,
                 navigateToUnitGroups = navigateToUnitGroups
             )
         }
 
-        unittoComposable(RIGHT) { backStackEntry ->
+        unittoComposable(
+            route = UNIT_TO_ROUTE,
+            arguments = listOf(
+                navArgument(unitFromIdArg) {
+                    type = NavType.StringType
+                },
+                navArgument(unitToIdArg) {
+                    type = NavType.StringType
+                },
+                navArgument(inputArg) {
+                    type = NavType.StringType
+                    nullable = true
+                    defaultValue = null
+                },
+            )
+        ) { backStackEntry ->
             val parentEntry = remember(backStackEntry) {
                 navController.getBackStackEntry(graph)
             }
 
             val parentViewModel = hiltViewModel<ConverterViewModel>(parentEntry)
 
-            RightSideRoute(
+            UnitToSelectorRoute(
-                viewModel = parentViewModel,
+                unitSelectorViewModel = hiltViewModel(),
+                converterViewModel = parentViewModel,
                 navigateUp = navController::navigateUp,
                 navigateToUnitGroups = navigateToUnitGroups
             )