From 8a76966062fcd60265acbe0e3fca46535980dc85 Mon Sep 17 00:00:00 2001
From: Nathan Mattes <hallo@bullenscheisse.de>
Date: Wed, 16 Feb 2022 18:13:29 +0100
Subject: [PATCH] Add more steps from the book but with additoinal tests

---
 issues/lib/issues/cli.ex | 13 +++++++++++++
 issues/test/cli_test.exs | 25 ++++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/issues/lib/issues/cli.ex b/issues/lib/issues/cli.ex
index d6d88d3..52c9c67 100644
--- a/issues/lib/issues/cli.ex
+++ b/issues/lib/issues/cli.ex
@@ -51,6 +51,8 @@ defmodule Issues.CLI do
   def process({user, project, count}) do
     Issues.GithubIssues.fetch(user, project)
     |> decode_response()
+    |> sort_into_descending_order
+    |> last(count)
   end
 
   def decode_response({:ok, body}), do: body
@@ -58,4 +60,15 @@ defmodule Issues.CLI do
     IO.puts "Error fetching from Github: #{error["message"]}"
     System.halt(2)
   end
+
+  def sort_into_descending_order(list_of_issues) do
+    list_of_issues
+    |> Enum.sort(fn lhs, rhs -> Map.get(lhs, "created_at") >= Map.get(rhs, "created_at") end) 
+  end
+
+  def last(list, count) do
+    list
+    |> Enum.take(count)
+    |> Enum.reverse
+  end
 end
diff --git a/issues/test/cli_test.exs b/issues/test/cli_test.exs
index 5d4652c..952aa2a 100644
--- a/issues/test/cli_test.exs
+++ b/issues/test/cli_test.exs
@@ -2,7 +2,12 @@ defmodule CliTest do
   use ExUnit.Case
   doctest Issues
 
-  import Issues.CLI, only: [parse_args: 1]
+  import Issues.CLI,
+    only: [
+      parse_args: 1,
+      sort_into_descending_order: 1,
+      last: 2
+    ]
 
   test ":help returned by option parsing the -h and --help options" do
     assert parse_args(["-h", "anything"]) == :help
@@ -16,4 +21,22 @@ defmodule CliTest do
   test "two values and default count returned if two values given" do
     assert parse_args(["user", "project"]) == {"user", "project", 4}
   end
+
+  test "sort descending orders the correct way" do
+    result = sort_into_descending_order(fake_created_at_list(["c", "a", "b"]))
+    issues = for issue <- result, do: Map.get(issue, "created_at")
+    assert issues == ~w{ c b a }
+  end
+
+  defp fake_created_at_list(values) do
+    for value <- values, do: %{"created_at" => value, "other_data" => "xxx"}
+  end
+
+  test "fetch the last two elements of a list" do
+    list = [1,2,3,4,5]
+    count = 2
+    expected = [2, 1]
+    result = last(list, count)
+    assert expected == result
+  end
 end