proper handling of currency values

src/main/scala/fahrtenbuch/Database.scala

@@ -19,7 +19,7 @@ import scala.util.Success
 
 object DexieDB {
 
-  private val schemaVersion = 1.1
+  private val schemaVersion = 1.3
 
   private val dexieDB: Dexie = new Dexie.^("fahrtenbuch")
   dexieDB

src/main/scala/fahrtenbuch/components/EntryComponent.scala

@@ -111,13 +111,21 @@ class EntryComponent(
       )
     else
       tr(
-        td(new Date(entry.date.payload).toISOString()),
+        td(new Date(entry.date.payload).toDateString()),
         td(entry.driver.payload),
-        td(entry.startKm.payload),
+        td(
-        td(entry.endKm.payload),
+          entry.startKm.payload
+            .setScale(0, BigDecimal.RoundingMode.HALF_UP)
+            .toString()
+        ),
+        td(
+          entry.endKm.payload
+            .setScale(0, BigDecimal.RoundingMode.HALF_UP)
+            .toString()
+        ),
         td(entry.animal.payload),
-        td(s"${entry.costWear}€"),
+        td(s"${entry.costWear.setScale(2, BigDecimal.RoundingMode.HALF_UP)}€"),
-        td(s"${entry.costTotal}€"),
+        td(s"${entry.costTotal.setScale(2, BigDecimal.RoundingMode.HALF_UP)}€"),
         td(if entry.paid.payload then "Ja" else "Nein"),
         td(
           button(

src/main/scala/fahrtenbuch/components/NewEntryInput.scala

@@ -77,8 +77,9 @@ class NewEntryInput(showNewEntryField: Var[Boolean]):
           onClick --> {
             val id = EntryId.gen()
             val driver = LastWriterWins.now(newEntryDriver.ref.value)
-            val startKm = LastWriterWins.now(newEntryStartKm.ref.value.toDouble)
+            val startKm =
-            val endKm = LastWriterWins.now(newEntryEndKm.ref.value.toDouble)
+              LastWriterWins.now(BigDecimal(newEntryStartKm.ref.value))
+            val endKm = LastWriterWins.now(BigDecimal(newEntryEndKm.ref.value))
             val animal = LastWriterWins.now(newEntryAnimal.ref.value)
             val paid = LastWriterWins.now(newEntryPaid.ref.checked)
             entryEditBus.emit(

src/main/scala/fahrtenbuch/model/Entry.scala

@@ -26,27 +26,37 @@ object EntryId:
 
 case class Entry(
     id: EntryId,
-    startKm: LastWriterWins[Double],
+    startKm: LastWriterWins[BigDecimal],
-    endKm: LastWriterWins[Double],
+    endKm: LastWriterWins[BigDecimal],
     animal: LastWriterWins[String],
     paid: LastWriterWins[Boolean],
     driver: LastWriterWins[String],
-    date: LastWriterWins[Double]
+    date: LastWriterWins[Double],
+    gasPricePerKm: LastWriterWins[BigDecimal] = LastWriterWins.now(0.13),
+    wearPricePerKm: LastWriterWins[BigDecimal] = LastWriterWins.now(0.05)
 ) derives NativeConverter:
   val distance = endKm.payload - startKm.payload
 
-  // 13 cent pro km, 5 cent Abnutzung
+  // initial 13 cent pro km, 5 cent Abnutzung
-  def costGas: Double = distance * 0.13
+  def costGas: BigDecimal = distance * gasPricePerKm.payload
-  def costWear: Double = distance * 0.05
+  def costWear: BigDecimal = distance * wearPricePerKm.payload
-  def costTotal: Double = costGas + costWear
+  def costTotal: BigDecimal = costGas + costWear
 
 object Entry:
   given Lattice[Entry] = Lattice.derived
 
+  given NativeConverter[BigDecimal] with {
+    extension (a: BigDecimal)
+      override def toNative: js.Any =
+        a.toString()
+    override def fromNative(ps: ParseState): BigDecimal =
+      BigDecimal(ps.json.asInstanceOf[String])
+  }
+
   def apply(
       id: EntryId,
-      startKm: LastWriterWins[Double],
+      startKm: LastWriterWins[BigDecimal],
-      endKm: LastWriterWins[Double],
+      endKm: LastWriterWins[BigDecimal],
       animal: LastWriterWins[String],
       paid: LastWriterWins[Boolean],
       driver: LastWriterWins[String]