Move cursor logic to EpochViewModel.kt

feature/epoch/src/main/java/com/sadellie/unitto/feature/epoch/EpochScreen.kt

@@ -20,18 +20,14 @@ package com.sadellie.unitto.feature.epoch
 
 import androidx.compose.foundation.layout.padding
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.getValue
-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.text.TextRange
 import androidx.compose.ui.unit.dp
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
-import com.sadellie.unitto.core.ui.common.UnittoTopAppBar
 import com.sadellie.unitto.core.ui.common.PortraitLandscape
+import com.sadellie.unitto.core.ui.common.UnittoTopAppBar
 import com.sadellie.unitto.feature.epoch.component.EpochKeyboard
 import com.sadellie.unitto.feature.epoch.component.TopPart
 
@@ -47,7 +43,8 @@ internal fun EpochRoute(
         addSymbol = viewModel::addSymbol,
         deleteSymbol = viewModel::deleteSymbol,
         swap = viewModel::swap,
-        clearSymbols = viewModel::clearSymbols
+        clearSymbols = viewModel::clearSymbols,
+        onCursorChange = viewModel::onCursorChange
     )
 }
 
@@ -55,17 +52,16 @@ internal fun EpochRoute(
 private fun EpochScreen(
     navigateUpAction: () -> Unit,
     uiState: EpochUIState,
-    addSymbol: (String, Int) -> Unit,
-    deleteSymbol: (Int) -> Unit,
+    addSymbol: (String) -> Unit,
+    deleteSymbol: () -> Unit,
     clearSymbols: () -> Unit,
-    swap: () -> Unit
+    swap: () -> Unit,
+    onCursorChange: (IntRange) -> Unit
 ) {
     UnittoTopAppBar(
         title = stringResource(R.string.epoch_converter),
         navigateUpAction = navigateUpAction
     ) { padding ->
-        var selection: TextRange by remember { mutableStateOf(TextRange.Zero) }
-
         PortraitLandscape(
             modifier = Modifier.padding(padding),
             content1 = { topContentModifier ->
@@ -74,31 +70,17 @@ private fun EpochScreen(
                     dateToUnix = uiState.dateToUnix,
                     dateValue = uiState.dateField,
                     unixValue = uiState.unixField,
-                    swap = {
-                        swap()
-                        selection = TextRange.Zero
-                    },
-                    selection = selection,
-                    onCursorChange = { selection = it.selection }
+                    swap = swap,
+                    selection = TextRange(uiState.selection.first, uiState.selection.last),
+                    onCursorChange = onCursorChange
                 )
             },
             content2 = { bottomModifier ->
                 EpochKeyboard(
                     modifier = bottomModifier,
-                    addSymbol = {
-                        addSymbol(it, selection.start)
-                        selection = TextRange(selection.start + 1)
-                    },
-                    clearSymbols = {
-                        clearSymbols()
-                        selection = TextRange.Zero
-                    },
-                    deleteSymbol = {
-                        if (selection.start != 0) {
-                            deleteSymbol(selection.start - 1)
-                            selection = TextRange(selection.start - 1)
-                        }
-                    }
+                    addSymbol = addSymbol,
+                    clearSymbols = clearSymbols,
+                    deleteSymbol = deleteSymbol
                 )
             }
         )

feature/epoch/src/main/java/com/sadellie/unitto/feature/epoch/EpochViewModel.kt

@@ -28,13 +28,13 @@ import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.flow.update
-import java.lang.Integer.min
 import javax.inject.Inject
 
 data class EpochUIState(
     val dateField: String = "",
     val unixField: String = "",
-    val dateToUnix: Boolean = true
+    val dateToUnix: Boolean = true,
+    val selection: IntRange = 0..0
 )
 
 @HiltViewModel
@@ -42,15 +42,17 @@ class EpochViewModel @Inject constructor() : ViewModel() {
 
     private val _input: MutableStateFlow<String> = MutableStateFlow("")
     private val _fromDateToUnix: MutableStateFlow<Boolean> = MutableStateFlow(true)
+    private val _selection: MutableStateFlow<IntRange> = MutableStateFlow(IntRange(0, 0))
 
     val uiState: StateFlow<EpochUIState> = combine(
-        _input, _fromDateToUnix
-    ) { input, fromDateToUnix ->
+        _input, _fromDateToUnix, _selection
+    ) { input, fromDateToUnix, selection ->
         if (fromDateToUnix) {
             EpochUIState(
                 dateField = input,
                 unixField = EpochDateConverter.convertDateToUnix(input),
-                dateToUnix = fromDateToUnix
+                dateToUnix = fromDateToUnix,
+                selection = selection
             )
         } else {
             val date = try {
@@ -62,29 +64,48 @@ class EpochViewModel @Inject constructor() : ViewModel() {
             EpochUIState(
                 unixField = input,
                 dateField = date,
-                dateToUnix = fromDateToUnix
+                dateToUnix = fromDateToUnix,
+                selection = selection
             )
         }
     }.stateIn(
         viewModelScope, SharingStarted.WhileSubscribed(5000L), EpochUIState()
     )
 
-    fun addSymbol(symbol: String, position: Int) {
+    fun addSymbol(symbol: String) {
+        val selection = _selection.value
         val maxSymbols = if (_fromDateToUnix.value) 14 else 10
         if (_input.value.length >= maxSymbols) return
-        _input.update { it.replaceRange(position, position, symbol) }
-    }
 
-    fun deleteSymbol(position: Int) {
-        _input.update {
-            it.removeRange(position, min(position + 1, _input.value.length))
+        _input.update { 
+            if (it.isEmpty()) symbol else it.replaceRange(selection.first, selection.last, symbol)
         }
+        _selection.update { it.first + 1..it.first + 1 }
     }
 
-    fun clearSymbols() = _input.update { "" }
+    fun deleteSymbol() {
+        val selection = _selection.value
+        val newSelectionStart = when (selection.last) {
+            0 -> return
+            selection.first -> _selection.value.first - 1
+            else -> _selection.value.first
+        }
 
-    fun swap() = _fromDateToUnix.update {
+        _selection.update { newSelectionStart..newSelectionStart }
+        _input.update { it.removeRange(newSelectionStart, selection.last) }
+    }
+
+    fun clearSymbols() {
+        _selection.update { 0..0 }
+        _input.update { "" }
+    }
+
+    fun swap() {
         clearSymbols()
-        !it
+        _fromDateToUnix.update { !it }
+    }
+
+    fun onCursorChange(selectionRange: IntRange) {
+        _selection.update { selectionRange }
     }
 }

feature/epoch/src/main/java/com/sadellie/unitto/feature/epoch/component/DateUnixTextFields.kt

@@ -33,7 +33,7 @@ import com.sadellie.unitto.core.ui.theme.NumbersTextStyleDisplayMedium
 @Composable
 internal fun DateUnixTextFields(
     fromTextFieldValue: TextFieldValue,
-    onCursorChange: (TextFieldValue) -> Unit,
+    onCursorChange: (IntRange) -> Unit,
     fromSupportText: String,
     toTextValue: String,
     toSupportText: String,
@@ -47,7 +47,7 @@ internal fun DateUnixTextFields(
         ) {
             BasicTextField(
                 value = fromTextFieldValue,
-                onValueChange = onCursorChange,
+                onValueChange = { onCursorChange(it.selection.start..it.selection.end) },
                 textStyle = NumbersTextStyleDisplayMedium.copy(
                     textAlign = TextAlign.Start,
                     color = MaterialTheme.colorScheme.onBackground

feature/epoch/src/main/java/com/sadellie/unitto/feature/epoch/component/TopPart.kt

@@ -37,7 +37,7 @@ fun TopPart(
     dateValue: String,
     unixValue: String,
     selection: TextRange,
-    onCursorChange: (TextFieldValue) -> Unit
+    onCursorChange: (IntRange) -> Unit
 ) {
     Column(
         modifier = modifier,