Fix currency and added user weighting

app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillActivity.kt

@@ -333,7 +333,7 @@ class EditBillActivity : AppCompatActivity() {
                     viewModel.owersSelection[id] == true && viewModel.parseAmountFromUi(amountStr) > 0
                 }.mapValues {
                     val uiAmount = viewModel.parseAmountFromUi(it.value)
-                    SupportUtil.round2(uiAmount / viewModel.selectedCurrencyRate)
+                    SupportUtil.round2(uiAmount * viewModel.selectedCurrencyRate)
                 }
             } else { // PERCENT
                 val totalAmount = viewModel.amountAsDouble
@@ -342,7 +342,7 @@ class EditBillActivity : AppCompatActivity() {
                 }.mapValues {
                     val percent = viewModel.parseAmountFromUi(it.value)
                     val uiAmount = SupportUtil.round2(totalAmount * percent / 100.0)
-                    SupportUtil.round2(uiAmount / viewModel.selectedCurrencyRate)
+                    SupportUtil.round2(uiAmount * viewModel.selectedCurrencyRate)
                 }
             }
 

app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillScreen.kt

@@ -450,7 +450,10 @@ fun OwerSelectionSection(
                 size = 32.dp
             )
             Spacer(modifier = Modifier.width(8.dp))
-            Text(member.name, modifier = Modifier.weight(1f))
+            val weightSuffix = if (viewModel.hasDifferentWeights && member.weight != 1.0) {
+                " (x${member.weight.toString().removeSuffix(".0")})"
+            } else ""
+            Text("${member.name}$weightSuffix", modifier = Modifier.weight(1f))
 
             if (isSelected || viewModel.splitMode != SplitMode.EVEN) {
                 val focusManager = LocalFocusManager.current
@@ -671,19 +674,115 @@ fun BillAdditionalDetailsSection(
 }
 
 @SuppressLint("ViewModelConstructorInComposable")
-@Preview(showBackground = true)
+@Preview(showBackground = true, name = "Standard Split")
 @Composable
 fun EditBillScreenPreview() {
     MaterialTheme {
         EditBillScreen(
             viewModel = EditBillViewModel().apply {
                 what = "Pizza"
-                amount = "12.50"
+                amount = "12.00"
                 mainCurrencyName = "EUR"
                 members = listOf(
                     DBMember(1, 0, 0, "Alice", true, 1.0, 0, null, null, null, null, null),
                     DBMember(2, 0, 0, "Bob", true, 1.0, 0, null, null, null, null, null)
                 )
+                owersSelection[1] = true
+                owersSelection[2] = true
+                updateSplits()
+            },
+            categories = emptyList(),
+            paymentModes = emptyList(),
+            onSave = {},
+            onBack = {},
+            onDateClick = {},
+            onTimeClick = {},
+            onScan = {}
+        )
+    }
+}
+
+@SuppressLint("ViewModelConstructorInComposable")
+@Preview(showBackground = true, name = "Weighted Split")
+@Composable
+fun EditBillScreenWeightedPreview() {
+    MaterialTheme {
+        EditBillScreen(
+            viewModel = EditBillViewModel().apply {
+                what = "Weighted Pizza"
+                amount = "60.00"
+                mainCurrencyName = "EUR"
+                members = listOf(
+                    DBMember(1, 0, 0, "Alice", true, 2.0, 0, null, null, null, null, null),
+                    DBMember(2, 0, 0, "Bob", true, 1.0, 0, null, null, null, null, null),
+                    DBMember(3, 0, 0, "Charlie", true, 1.0, 0, null, null, null, null, null)
+                )
+                owersSelection[1] = true
+                owersSelection[2] = true
+                owersSelection[3] = true
+                updateSplits()
+            },
+            categories = emptyList(),
+            paymentModes = emptyList(),
+            onSave = {},
+            onBack = {},
+            onDateClick = {},
+            onTimeClick = {},
+            onScan = {}
+        )
+    }
+}
+
+@SuppressLint("ViewModelConstructorInComposable")
+@Preview(showBackground = true, name = "Custom Split (#)")
+@Composable
+fun EditBillScreenCustomPreview() {
+    MaterialTheme {
+        EditBillScreen(
+            viewModel = EditBillViewModel().apply {
+                what = "Custom Split Pizza"
+                amount = "60.00"
+                mainCurrencyName = "EUR"
+                members = listOf(
+                    DBMember(1, 0, 0, "Alice", true, 1.0, 0, null, null, null, null, null),
+                    DBMember(2, 0, 0, "Bob", true, 1.0, 0, null, null, null, null, null)
+                )
+                splitMode = SplitMode.CUSTOM
+                owersSelection[1] = true
+                owersSelection[2] = true
+                owersCustomSplit[1] = "40.00"
+                owersCustomSplit[2] = "20.00"
+            },
+            categories = emptyList(),
+            paymentModes = emptyList(),
+            onSave = {},
+            onBack = {},
+            onDateClick = {},
+            onTimeClick = {},
+            onScan = {}
+        )
+    }
+}
+
+@SuppressLint("ViewModelConstructorInComposable")
+@Preview(showBackground = true, name = "Percent Split (%)")
+@Composable
+fun EditBillScreenPercentPreview() {
+    MaterialTheme {
+        EditBillScreen(
+            viewModel = EditBillViewModel().apply {
+                what = "Percent Split Pizza"
+                amount = "100.00"
+                mainCurrencyName = "EUR"
+                members = listOf(
+                    DBMember(1, 0, 0, "Alice", true, 1.0, 0, null, null, null, null, null),
+                    DBMember(2, 0, 0, "Bob", true, 1.0, 0, null, null, null, null, null)
+                )
+                splitMode = SplitMode.PERCENT
+                owersSelection[1] = true
+                owersSelection[2] = true
+                owersPercentSplit[1] = "70"
+                owersPercentSplit[2] = "30"
             },
             categories = emptyList(),
             paymentModes = emptyList(),

app/src/main/java/net/helcel/cowspent/android/bill_edit/EditBillViewModel.kt

@@ -61,18 +61,18 @@ class EditBillViewModel : ViewModel() {
     val amountAsDouble: Double
         get() = parseAmountFromUi(amount)
 
-    fun getEvenSplit(): Double {
+    val hasDifferentWeights: Boolean
-        val selectedOwersCount = owersSelection.count { it.value }
+        get() = members.isNotEmpty() && members.any { it.weight != members[0].weight }
-        return if (selectedOwersCount > 0) SupportUtil.round2(amountAsDouble / selectedOwersCount) else 0.0
-    }
 
     fun updateSplits() {
         if (splitMode == SplitMode.EVEN) {
-            val even = getEvenSplit()
+            val selectedMembers = members.filter { owersSelection[it.id] == true }
-            val evenStr = if (even == 0.0) "" else SupportUtil.round2(even).toString()
+            val totalWeight = selectedMembers.sumOf { it.weight }
+            val uiAmount = amountAsDouble
             members.forEach { m ->
                 if (owersSelection[m.id] == true) {
-                    owersCustomSplit[m.id] = evenStr
+                    val share = if (totalWeight > 0) (uiAmount * m.weight) / totalWeight else 0.0
+                    owersCustomSplit[m.id] = if (share == 0.0) "" else SupportUtil.round2(share).toString()
                 } else {
                     owersCustomSplit.remove(m.id)
                 }
@@ -180,7 +180,7 @@ class EditBillViewModel : ViewModel() {
     }
 
     fun getFinalAmount(): Double {
-        return SupportUtil.round2(amountAsDouble / selectedCurrencyRate)
+        return SupportUtil.round2(amountAsDouble * selectedCurrencyRate)
     }
 
     fun getFinalComment(): String {
@@ -252,10 +252,9 @@ class EditBillViewModel : ViewModel() {
                 if (selected) {
                     // If we have metadata, the custom splits from DB are also converted. 
                     // We should show them as "Original" if possible? 
-                    // Actually, if we use metadata, we should probably store original splits too, 
+                    // Reverse calculation for display: UI Part = DB Part / Rate
-                    // but for now let's just reverse the rate for display.
                     val dbPart = customSplits[member.id]!!
-                    val uiPart = if (selectedCurrencyRate != 1.0) dbPart * selectedCurrencyRate else dbPart
+                    val uiPart = if (selectedCurrencyRate != 0.0) dbPart / selectedCurrencyRate else dbPart
                     owersCustomSplit[member.id] = SupportUtil.round2(uiPart).toString()
                 }
             }
@@ -263,18 +262,18 @@ class EditBillViewModel : ViewModel() {
             // Even split logic
             splitMode = SplitMode.EVEN
             val billOwerIds = bill.billOwersIds
-            val selectedCount = billOwerIds.size
+            val selectedMembers = members.filter { billOwerIds.contains(it.id) }
+            val totalWeight = selectedMembers.sumOf { it.weight }
             
             // Use UI amount for even split calculation
             val uiAmount = amountAsDouble
-            val evenSplit = if (selectedCount > 0) uiAmount / selectedCount else 0.0
-            val evenSplitStr = if (evenSplit == 0.0) "" else SupportUtil.round2(evenSplit).toString()
 
             for (member in members) {
                 val selected = billOwerIds.contains(member.id)
                 owersSelection[member.id] = selected
                 if (selected) {
-                    owersCustomSplit[member.id] = evenSplitStr
+                    val share = if (totalWeight > 0) (uiAmount * member.weight) / totalWeight else 0.0
+                    owersCustomSplit[member.id] = if (share == 0.0) "" else SupportUtil.round2(share).toString()
                 }
             }
         }

app/src/main/java/net/helcel/cowspent/android/currencies/ManageCurrenciesActivity.kt

@@ -114,7 +114,8 @@ class ManageCurrenciesActivity : AppCompatActivity() {
     }
 
     private fun addOrUpdateCurrency() {
-        val exchangeRate = try { viewModel.newCurrencyRate.toDouble() } catch (_: Exception) { 0.0 }
+        val uiRate = try { viewModel.newCurrencyRate.toDouble() } catch (_: Exception) { 0.0 }
+        val exchangeRate = if (uiRate != 0.0) 1.0 / uiRate else 0.0
         val currencyName = viewModel.newCurrencyName
         val editingId = viewModel.editingCurrencyId
 
@@ -142,7 +143,8 @@ class ManageCurrenciesActivity : AppCompatActivity() {
     private fun startEditing(currency: DBCurrency) {
         viewModel.editingCurrencyId = currency.id
         viewModel.newCurrencyName = currency.name ?: ""
-        viewModel.newCurrencyRate = currency.exchangeRate.toString()
+        val uiRate = if (currency.exchangeRate != 0.0) 1.0 / currency.exchangeRate else 0.0
+        viewModel.newCurrencyRate = uiRate.toString()
     }
 
     private fun cancelEditing() {

app/src/main/java/net/helcel/cowspent/android/currencies/ManageCurrenciesScreen.kt

@@ -304,7 +304,7 @@ fun CurrencyRow(
                     modifier = Modifier.padding(horizontal = 8.dp)
                 )
                 Text(
-                    text = formatAmount(currency.exchangeRate),
+                    text = formatAmount(if (currency.exchangeRate != 0.0) 1.0 / currency.exchangeRate else 0.0),
                     style = MaterialTheme.typography.body1,
                     fontWeight = FontWeight.ExtraBold,
                     color = if (isEditing) MaterialTheme.colors.secondary else MaterialTheme.colors.onSurface