From c184aea7877e4904c4f86d345556602ee7e2941d Mon Sep 17 00:00:00 2001
From: nelsonic <nelson+github@dwyl.io>
Date: Sun, 26 Apr 2020 11:40:34 +0100
Subject: [PATCH] create decode_to_int/1 to decode integer values #14

---
 lib/base58.ex        | 31 ++++++++++++++++++++++++++++---
 test/base58_test.exs | 28 ++++++++++++++++++++++++----
 2 files changed, 52 insertions(+), 7 deletions(-)

diff --git a/lib/base58.ex b/lib/base58.ex
index 966a361..d5b5514 100644
--- a/lib/base58.ex
+++ b/lib/base58.ex
@@ -13,7 +13,7 @@ defmodule Base58 do
     "Cn8eVZg"
 
     iex> Base58.encode(42)
-    "m8Uq"
+    "4yP"
   """
   def encode(""), do: ""
   def encode(binary) when is_binary(binary) do
@@ -30,8 +30,21 @@ defmodule Base58 do
   end
 
   # If the parameter is not a binary convert it to binary before encode.
-  def encode(anything) do
-    :erlang.term_to_binary(anything)
+  def encode(int) when is_integer(int) do
+    int
+    |> Integer.to_string()
+    |> encode()
+  end
+
+  def encode(val) when is_float(val) do
+    val
+    |> Float.to_string()
+    |> encode()
+  end
+
+  def encode(atom) when is_atom(atom) do
+    atom
+    |> Atom.to_string()
     |> encode()
   end
 
@@ -86,4 +99,16 @@ defmodule Base58 do
   defp recurse([head | tail], acc) do
     recurse(tail, (acc * 58) + Enum.find_index(@alnum, &(&1 == head)))
   end
+
+  @doc """
+  `decode_to_int/1` decodes the given Base58 string back to an Integer.
+  ## Examples
+
+    iex> Base58.encode(42) |> Base58.decode_to_int()
+    42
+  """
+  def decode_to_int(encoded) do
+    decode(encoded)
+    |> String.to_integer()
+  end
 end
diff --git a/test/base58_test.exs b/test/base58_test.exs
index 9ed4cbe..01db845 100644
--- a/test/base58_test.exs
+++ b/test/base58_test.exs
@@ -16,10 +16,14 @@ defmodule Base58Test do
 
     test "converts any value to binary and then Base58 encodes it" do
       # Integer
-      assert "m8UW" == encode(23)
-      assert "8NmHr9odQSJL4n" == encode(3.14)
+      assert "4pa" == encode(23)
+      assert "4pa" == encode("23")
+      # Float
+      assert "2JstGb" == encode(3.14)
+      assert "2JstGb" == encode("3.14")
       # Atom
-      assert "2g14LRptojh8i" == encode(:hello)
+      assert "Cn8eVZg" == encode(:hello)
+      assert "Cn8eVZg" == encode("hello")
     end
 
     test "returns z when binary is represented by 57" do
@@ -34,7 +38,7 @@ defmodule Base58Test do
       assert "Z" == encode(" ")
     end
 
-    test "encode <<0>> retuens 1" do
+    test "encode <<0>> returns 1" do
       assert "1" == encode(<<0>>)
     end
 
@@ -47,6 +51,22 @@ defmodule Base58Test do
       assert decode(encode("123")) == "123"
     end
 
+    test "decode :atom" do
+      assert encode(:hello) |> decode() == "hello"
+    end
+
+    test "decode_to_int(encode(int) == int)" do
+      int = 42
+      decoded = Base58.encode(int) |> Base58.decode_to_int()
+      assert decoded == int
+    end
+
+    property "Check a batch of int values can be decoded" do
+      check all(int <- integer()) do
+        assert decode_to_int(encode(int)) == int
+      end
+    end
+
     property "Compare result with Base58 package" do
       check all(bin <- binary()) do
         case bin == "" do