defmodule Mix.Tasks.Release do
  @moduledoc false
  use Mix.Task
  alias Mix.Project

  def run([level]) do
    case level do
      "patch" ->
        IO.puts next_patch_level_version()
      "minor" ->
        IO.puts "Please implement me!"
      "major" ->
        IO.puts "Please implement me!"
       _ ->
         IO.puts "Sorry friend... The only sub commands I know are: patch, minor, and major"
    end
  end

  def current_version do
    Project.config[:version]
  end

  def version_bits(ver) do
    ver |> String.split(".")
  end

  def current_version_bits do
    current_version() |> version_bits()
  end

  def current_patch_level(ver_bits) do
     ver_bits |> List.last |> String.to_integer
  end

  def next_patch_level(level) do
    level + 1
  end

  def next_version(ver_bits, level) do
    ver_bits |>  List.replace_at(-1, "#{level}") |> Enum.join(".")
  end

  def next_patch_level_version do
      bits = current_version_bits()
      next = (bits |> current_patch_level()) + 1
      next_version(bits, next)
  end
end