Improve parsing of params

lib/find_old_mp3s.ex

@@ -4,42 +4,92 @@ defmodule FindOldMp3s.Application do
   """
 
   def start(_, _) do
-    args = Burrito.Util.Args.get_arguments()
-    |> parse_options
-    |> execute
+    get_options()
+    |> validate_options()
+    |> execute()
+
+    System.halt(0)
   end
 
-  defp parse_options(args) do
-    options = OptionParser.parse(
-      args,
-      switches: [path: :string, type: :string, help: :boolean],
+  defp get_options() do
+    Burrito.Util.Args.get_arguments()
+    |> OptionParser.parse(
+      strict: [path: :string, type: :keep, help: :boolean],
       aliases: [p: :path, t: :type, h: :help]
     )
+  end
 
-    case options do
-      {opts, [], []} ->
-        {:ok, opts}
+  defp validate_options({[], [], []}), do: {:error, :no_parameters}
 
-      {opts, b, c} ->
-        {:error, :parsing_error}
+  defp validate_options({parsed, _argv, _errors}) do
+    cond do
+      Keyword.has_key?(parsed, :help) ->
+        {:error, :show_help}
+
+      Keyword.has_key?(parsed, :path) and Keyword.has_key?(parsed, :type) ->
+        {:ok, parsed}
+
+      true ->
+        {:error, :missing_parameter}
     end
   end
 
-  defp execute({:error, :parsing_error}) do
-    IO.puts """
-    Help command output
+  defp execute({:error, :no_parameters}) do
+    IO.warn("No options given!")
+
+    print_help()
+    System.halt(1)
+  end
+
+  defp execute({:error, :show_help}) do
+    print_help()
+    System.halt(1)
+  end
+
+  defp execute({:error, :missing_parameter}) do
+    IO.warn("Both parameters 'type' and 'path' must be set!")
+
+    print_help()
+    System.halt(1)
+  end
+
+  defp execute({:ok, opts}) do
+    file_types =
+      Keyword.get_values(opts, :type)
+      |> Enum.join(",")
+
+    file_path =
+      Keyword.get(opts, :path)
+      |> Path.expand()
+
+    files = Path.wildcard("#{file_path}/**/*.{#{file_types}}")
+
+    if Enum.empty?(files) do
+      IO.puts("No files found")
+      System.halt(0)
+    end
+
+    Enum.each(files, fn file -> IO.puts(file) end)
+  end
+
+  defp print_help() do
+    IO.puts("""
+    This command will find audio files with low bitrates in a folder folder (recursively) and shows the bitrate and
+    path to those files.
+
+    DESCRIPTION
 
       Possible options:
         Long option    short option    description
         --help         -h              Show this help
-      --type         -t              Give some file audio file type ending like 'ogg' or 'mp3'
+        --type         -t              Give some file audio file type ending like 'ogg' or 'mp3' - can be used multiple
+                                       times
         --path         -p              Root path to search files, search will be recursive
-    """
 
-    System.halt(1)
-  end
+    EXAMPLE
 
-  defp execute() do
-   System.halt(0)
+      find_old_mp3s --path "~" --type "ogg" --type "mp3"
+
+    """)
   end
 end