More robust "=" logic

core/ui/src/main/java/com/sadellie/unitto/core/ui/common/textfield/TextFieldValueExtensions.kt

@@ -20,6 +20,7 @@ package com.sadellie.unitto.core.ui.common.textfield
 
 import androidx.compose.ui.text.TextRange
 import androidx.compose.ui.text.input.TextFieldValue
+import androidx.lifecycle.SavedStateHandle
 import com.sadellie.unitto.core.base.Token
 
 fun TextFieldValue.addTokens(tokens: String): TextFieldValue {
@@ -131,6 +132,18 @@ fun TextFieldValue.deleteTokens(): TextFieldValue {
     )
 }
 
+/**
+ * Tries to get a [TextFieldValue]. Places cursor at the end.
+ *
+ * @receiver [SavedStateHandle] Where to look for.
+ * @param key Key to find
+ * @return [TextFieldValue] with cursor at the end.
+ */
+fun SavedStateHandle.getTextField(key: String): TextFieldValue =
+    with(get(key) ?: "") {
+        TextFieldValue(this, TextRange(this.length))
+    }
+
 /**
  * <b>!!! Recursive !!!</b> (one wrong step and you are dead 💀)
  */

feature/calculator/src/androidTest/java/com/sadellie/unitto/feature/calculator/CalculatorScreenTest.kt

@@ -63,7 +63,7 @@ class CalculatorScreenTest {
             CalculatorScreen(
                 uiState = CalculatorUIState.Ready(
                     input = TextFieldValue(),
-                    output = CalculationResult.Default(),
+                    output = CalculationResult.Empty,
                     radianMode = false,
                     precision = 3,
                     outputFormat = OutputFormat.PLAIN,
@@ -97,7 +97,7 @@ class CalculatorScreenTest {
             CalculatorScreen(
                 uiState = CalculatorUIState.Ready(
                     input = TextFieldValue(),
-                    output = CalculationResult.Default(),
+                    output = CalculationResult.Empty,
                     radianMode = false,
                     precision = 3,
                     outputFormat = OutputFormat.PLAIN,

feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorUIState.kt

@@ -45,6 +45,8 @@ internal sealed class CalculatorUIState {
 sealed class CalculationResult {
     data class Default(val text: String = "") : CalculationResult()
 
+    data object Empty: CalculationResult()
+
     data object DivideByZeroError : CalculationResult() {
         @StringRes
         val label: Int = R.string.calculator_divide_by_zero_error

feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/CalculatorViewModel.kt

@@ -28,6 +28,7 @@ import com.sadellie.unitto.core.ui.common.textfield.AllFormatterSymbols
 import com.sadellie.unitto.core.ui.common.textfield.addBracket
 import com.sadellie.unitto.core.ui.common.textfield.addTokens
 import com.sadellie.unitto.core.ui.common.textfield.deleteTokens
+import com.sadellie.unitto.core.ui.common.textfield.getTextField
 import com.sadellie.unitto.data.common.isExpression
 import com.sadellie.unitto.data.common.setMinimumRequiredScale
 import com.sadellie.unitto.data.common.stateIn
@@ -45,6 +46,7 @@ import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.mapLatest
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
 import java.math.BigDecimal
 import javax.inject.Inject
 
@@ -55,24 +57,23 @@ internal class CalculatorViewModel @Inject constructor(
     private val savedStateHandle: SavedStateHandle,
 ) : ViewModel() {
     private val _inputKey = "CALCULATOR_INPUT"
-    private val _input = MutableStateFlow(
+    private val _input = MutableStateFlow(savedStateHandle.getTextField(_inputKey))
-        with(savedStateHandle[_inputKey] ?: "") {
+    private val _result = MutableStateFlow<CalculationResult>(CalculationResult.Empty)
-            TextFieldValue(this, TextRange(this.length))
-        }
-    )
-    private val _result = MutableStateFlow<CalculationResult>(CalculationResult.Default())
     private val _equalClicked = MutableStateFlow(false)
+    private val _prefs = userPrefsRepository.calculatorPrefs
+        .stateIn(viewModelScope, null)
 
     val uiState: StateFlow<CalculatorUIState> = combine(
         _input,
         _result,
-        userPrefsRepository.calculatorPrefs,
+        _prefs,
         calculatorHistoryRepository.historyFlow,
-        _equalClicked,
+    ) { input, result, prefs, history ->
-    ) { input, result, prefs, history, showError ->
+        prefs ?: return@combine CalculatorUIState.Loading
+
         return@combine CalculatorUIState.Ready(
             input = input,
-            output = if (!showError and (result !is CalculationResult.Default)) CalculationResult.Default() else result,
+            output = result,
             radianMode = prefs.radianMode,
             precision = prefs.precision,
             outputFormat = prefs.outputFormat,
@@ -85,12 +86,31 @@ internal class CalculatorViewModel @Inject constructor(
         )
     }
         .mapLatest { ui ->
+            if (ui !is CalculatorUIState.Ready) return@mapLatest ui
+            if (_equalClicked.value) return@mapLatest ui
+
+            if (!ui.input.text.isExpression()) {
+                _result.update { CalculationResult.Empty }
+                return@mapLatest ui
+            }
+
+            _result.update {
+                try {
+                    CalculationResult.Default(
                         calculate(
                             input = ui.input.text,
                             radianMode = ui.radianMode,
-                outputFormat = ui.outputFormat,
-                precision = ui.precision
                         )
+                            .setMinimumRequiredScale(ui.precision)
+                            .trimZeros()
+                            .toStringWith(ui.outputFormat)
+                    )
+                } catch (e: ExpressionException.DivideByZero) {
+                    CalculationResult.Empty
+                } catch (e: Exception) {
+                    CalculationResult.Empty
+                }
+            }
 
             ui
         }
@@ -130,9 +150,11 @@ internal class CalculatorViewModel @Inject constructor(
     }
 
     fun clearInput() = _input.update {
+        _equalClicked.update { false }
         savedStateHandle[_inputKey] = ""
         TextFieldValue()
     }
+
     fun onCursorChange(selection: TextRange) = _input.update { it.copy(selection = selection) }
 
     fun updateRadianMode(newValue: Boolean) = viewModelScope.launch {
@@ -143,56 +165,47 @@ internal class CalculatorViewModel @Inject constructor(
         calculatorHistoryRepository.clear()
     }
 
-    fun evaluate() = viewModelScope.launch(Dispatchers.IO) {
+    fun evaluate() = viewModelScope.launch {
-        when (val result = _result.value) {
+        val prefs = _prefs.value ?: return@launch
-            is CalculationResult.Default -> {
+        if (_equalClicked.value) return@launch
-                calculatorHistoryRepository.add(
+        if (!_input.value.text.isExpression()) return@launch
-                    expression = _input.value.text.replace("-", Token.Operator.minus),
+
-                    result = result.text
+        val result = try {
-                )
+            calculate(_input.value.text, prefs.radianMode)
-                _input.update { TextFieldValue(result.text, TextRange(result.text.length)) }
+        } catch (e: ExpressionException.DivideByZero) {
-                _result.update { CalculationResult.Default() }
             _equalClicked.update { true }
-            }
+            _result.update { CalculationResult.DivideByZeroError }
-
+            return@launch
-            is CalculationResult.DivideByZeroError -> {
+        } catch (e: ExpressionException.FactorialCalculation) {
             _equalClicked.update { true }
-            }
+            _result.update { CalculationResult.Error }
-
+            return@launch
-            is CalculationResult.Error -> {
+        } catch (e: Exception) {
-                // skip for generic error (bad expression and stuff
+            _equalClicked.update { true }
-            }
+            _result.update { CalculationResult.Error }
-        }
-    }
-
-    private fun calculate(
-        input: String,
-        radianMode: Boolean,
-        outputFormat: Int,
-        precision: Int,
-    ) = viewModelScope.launch(Dispatchers.Default) {
-        if (!input.isExpression()) {
-            _result.update { CalculationResult.Default() }
             return@launch
         }
+            .setMinimumRequiredScale(prefs.precision)
+            .trimZeros()
+            .toStringWith(prefs.outputFormat)
 
-        _result.update {
+        calculatorHistoryRepository.add(
-            try {
+            expression = _input.value.text.replace("-", Token.Operator.minus),
-                CalculationResult.Default(
+            result = result
-                    Expression(input, radianMode = radianMode)
+        )
+
+        _input.update { TextFieldValue(result, TextRange(result.length)) }
+        _result.update { CalculationResult.Empty }
+    }
+
+    private suspend fun calculate(
+        input: String,
+        radianMode: Boolean,
+    ): BigDecimal = withContext(Dispatchers.Default) {
+        Expression(input, radianMode)
             .calculate()
             .also {
                 if (it > BigDecimal.valueOf(Double.MAX_VALUE)) throw ExpressionException.TooBig()
             }
-                        .setMinimumRequiredScale(precision)
-                        .trimZeros()
-                        .toStringWith(outputFormat)
-                )
-            } catch (e: ExpressionException.DivideByZero) {
-                CalculationResult.DivideByZeroError
-            } catch (e: Exception) {
-                CalculationResult.Error
-            }
-        }
     }
 }

feature/calculator/src/main/java/com/sadellie/unitto/feature/calculator/components/TextBox.kt

@@ -22,6 +22,7 @@ import android.content.res.Configuration
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.sizeIn
@@ -83,6 +84,15 @@ fun TextBox(
         )
         if (LocalConfiguration.current.orientation == Configuration.ORIENTATION_PORTRAIT) {
             when (output) {
+                is CalculationResult.Empty -> {
+                    Spacer(
+                        modifier = Modifier
+                            .weight(2f)
+                            .fillMaxWidth()
+                            .padding(horizontal = 8.dp)
+                    )
+                }
+
                 is CalculationResult.Default -> {
                     var outputTF by remember(output) {
                         mutableStateOf(TextFieldValue(output.text))

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

@@ -28,6 +28,7 @@ import com.sadellie.unitto.core.ui.common.textfield.AllFormatterSymbols
 import com.sadellie.unitto.core.ui.common.textfield.addBracket
 import com.sadellie.unitto.core.ui.common.textfield.addTokens
 import com.sadellie.unitto.core.ui.common.textfield.deleteTokens
+import com.sadellie.unitto.core.ui.common.textfield.getTextField
 import com.sadellie.unitto.data.common.combine
 import com.sadellie.unitto.data.common.isExpression
 import com.sadellie.unitto.data.common.stateIn
@@ -64,11 +65,7 @@ internal class ConverterViewModel @Inject constructor(
 ) : ViewModel() {
 
     private val converterInputKey = "CONVERTER_INPUT"
-    private val _input = MutableStateFlow(
+    private val _input = MutableStateFlow(savedStateHandle.getTextField(converterInputKey))
-        with(savedStateHandle[converterInputKey] ?: "") {
-            TextFieldValue(this, TextRange(this.length))
-        }
-    )
     private val _calculation = MutableStateFlow<BigDecimal?>(null)
     private val _result = MutableStateFlow<ConverterResult>(ConverterResult.Loading)
     private val _unitFrom = MutableStateFlow<AbstractUnit?>(null)