[wallet] DD51: initial rendering based on currency spec

bug 0008329

(cherry picked from commit 4789103406f44ba797c7bfee3112cc6aaa228683)

2 files changed, 80 insertions, 2 deletions

diff --git a/taler-kotlin-android/src/main/java/net/taler/common/Amount.kt b/taler-kotlin-android/src/main/java/net/taler/common/Amount.kt
index 5fb36fa..d6188cf 100644
--- a/taler-kotlin-android/src/main/java/net/taler/common/Amount.kt
+++ b/taler-kotlin-android/src/main/java/net/taler/common/Amount.kt
@@ -16,11 +16,14 @@
 
 package net.taler.common
 
+import android.os.Build
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.Serializer
 import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
+import java.text.DecimalFormat
+import java.text.NumberFormat
 import kotlin.math.floor
 import kotlin.math.pow
 import kotlin.math.roundToInt
@@ -54,6 +57,11 @@ public data class Amount(
      * of 50_000_000 would correspond to 50 cents.
      */
     val fraction: Int,
+
+    /**
+     * Currency specification for amount
+     */
+    val spec: CurrencySpecification? = null,
 ) : Comparable<Amount> {
 
     public companion object {
@@ -170,6 +178,8 @@ public data class Amount(
         return Amount(checkCurrency(currency), this.value, this.fraction)
     }
 
+    fun withSpec(spec: CurrencySpecification?) = copy(spec = spec)
+
     public operator fun minus(other: Amount): Amount {
         check(currency == other.currency) { "Can only subtract from same currency" }
         var resultValue = value
@@ -196,8 +206,40 @@ public data class Amount(
         return "$currency:$amountStr"
     }
 
-    override fun toString(): String {
-        return "$amountStr $currency"
+    override fun toString() = toString(
+        showSymbol = true,
+        negative = false,
+    )
+
+    fun toString(
+        showSymbol: Boolean = true,
+        negative: Boolean = false,
+    ): String {
+        val symbols = DecimalFormat().decimalFormatSymbols
+
+        val format = if (showSymbol) {
+            NumberFormat.getCurrencyInstance()
+        } else {
+            // Make sure monetary separators are the ones used!
+            symbols.decimalSeparator = symbols.monetaryDecimalSeparator
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
+                symbols.groupingSeparator = symbols.monetaryGroupingSeparator
+            }
+
+            NumberFormat.getInstance()
+        }
+
+        if (spec != null) {
+            symbols.currencySymbol = spec.symbol(this)
+            format.maximumFractionDigits = spec.numFractionalNormalDigits
+            format.minimumFractionDigits = spec.numFractionalTrailingZeroDigits
+        } else {
+            symbols.currencySymbol = currency
+        }
+
+        (format as DecimalFormat).decimalFormatSymbols = symbols
+
+        return format.format((if (negative) "-$amountStr" else amountStr).toBigDecimal())
     }
 
     override fun compareTo(other: Amount): Int {
diff --git a/taler-kotlin-android/src/main/java/net/taler/common/CurrencySpecification.kt b/taler-kotlin-android/src/main/java/net/taler/common/CurrencySpecification.kt
new file mode 100644
index 0000000..4aa8968
--- /dev/null
+++ b/taler-kotlin-android/src/main/java/net/taler/common/CurrencySpecification.kt
@@ -0,0 +1,36 @@
+/*
+ * This file is part of GNU Taler
+ * (C) 2024 Taler Systems S.A.
+ *
+ * GNU Taler 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, or (at your option) any later version.
+ *
+ * GNU Taler 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
+ * GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+package net.taler.common
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class CurrencySpecification(
+    val name: String,
+    @SerialName("num_fractional_input_digits")
+    val numFractionalInputDigits: Int,
+    @SerialName("num_fractional_normal_digits")
+    val numFractionalNormalDigits: Int,
+    @SerialName("num_fractional_trailing_zero_digits")
+    val numFractionalTrailingZeroDigits: Int,
+    @SerialName("alt_unit_names")
+    val altUnitNames: Map<Int, String>,
+) {
+    // TODO: add support for alt units
+    fun symbol(amount: Amount): String = altUnitNames[0] ?: amount.currency
+}
\ No newline at end of file