From 2590fe67b87b0d86fe0def504cf34689520ab820 Mon Sep 17 00:00:00 2001
From: "Erik C. Thauvin" <erik@thauvin.net>
Date: Tue, 25 May 2021 17:57:46 -0700
Subject: [PATCH] Added toCurrency

---
 README.md                                           |  6 ++++++
 examples/build.gradle.kts                           |  2 +-
 .../kotlin/net/thauvin/erik/crypto/CryptoPrice.kt   | 13 +++++++++++++
 .../net/thauvin/erik/crypto/CryptoPriceTest.kt      | 13 +++++++++++++
 4 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 20ccb22..de1767e 100644
--- a/README.md
+++ b/README.md
@@ -47,6 +47,12 @@ CryptoPrice(val base: String, val currency: String, val amount: Double)
 ```
 The parameter names match the [Coinbase API](https://developers.coinbase.com/api/v2#get-spot-price).
 
+To display the amount as a fomatted currency use the `toCurrency` function:
+
+```kotlin
+val price = CryptoPrice("BTC", "EUR", 12345.67)
+println(price.toCurrency()) // will print €12,345.67
+```
 ### Extending
 
 A generic `apiCall()` function is available to access other [API data endpoints](https://developers.coinbase.com/api/v2#data-endpoints). For example to retried the current [buy price](https://developers.coinbase.com/api/v2#get-buy-price) of a cryptocurrency:
diff --git a/examples/build.gradle.kts b/examples/build.gradle.kts
index 1b19674..36e7564 100644
--- a/examples/build.gradle.kts
+++ b/examples/build.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-    id("org.jetbrains.kotlin.jvm") version "1.5.0"
+    id("org.jetbrains.kotlin.jvm") version "1.5.10"
     id("com.github.ben-manes.versions") version "0.38.0"
     application
 }
diff --git a/src/main/kotlin/net/thauvin/erik/crypto/CryptoPrice.kt b/src/main/kotlin/net/thauvin/erik/crypto/CryptoPrice.kt
index 884196b..defaed1 100644
--- a/src/main/kotlin/net/thauvin/erik/crypto/CryptoPrice.kt
+++ b/src/main/kotlin/net/thauvin/erik/crypto/CryptoPrice.kt
@@ -38,7 +38,9 @@ import okhttp3.Request
 import org.json.JSONException
 import org.json.JSONObject
 import java.io.IOException
+import java.text.NumberFormat
 import java.time.LocalDate
+import java.util.Currency
 
 /**
  * A small Kotlin/Java library for retrieving cryptocurrencies current market prices.
@@ -134,4 +136,15 @@ open class CryptoPrice(val base: String, val currency: String, val amount: Doubl
             return body.toPrice()
         }
     }
+
+    /**
+     * Return the [amount] as a currency formatted string. (eg: $1,203.33)
+     */
+    @Throws(IllegalArgumentException::class)
+    fun toCurrency(): String {
+        return NumberFormat.getCurrencyInstance().let {
+            it.setCurrency(Currency.getInstance(currency))
+            it.format(amount)
+        }
+    }    
 }
diff --git a/src/test/kotlin/net/thauvin/erik/crypto/CryptoPriceTest.kt b/src/test/kotlin/net/thauvin/erik/crypto/CryptoPriceTest.kt
index cd5d7f7..e4608de 100644
--- a/src/test/kotlin/net/thauvin/erik/crypto/CryptoPriceTest.kt
+++ b/src/test/kotlin/net/thauvin/erik/crypto/CryptoPriceTest.kt
@@ -80,6 +80,19 @@ class CryptoPriceTest {
         }
     }
 
+    @Test
+    @Throws(IllegalArgumentException::class)
+    fun testToCurrency() {
+        val eur = CryptoPrice("BTC", "EUR", 12345.67)
+        assertEquals(eur.toCurrency(), "€12,345.67", "EUR format")
+        
+        val gbp = CryptoPrice("ETH", "GBP", 12345.67)
+        assertEquals(gbp.toCurrency(), "£12,345.67", "GBP format")
+        
+        val aud = CryptoPrice("BTC", "AUD", 12345.67)
+        assertEquals(aud.toCurrency(), "A$12,345.67", "AUD format")
+    }
+
     @Test
     @Throws(CryptoException::class)
     fun testToPrice() {