defmodule Mix.Tasks.Compile.Comeonin do
  @shortdoc "Compiles Comeonin"

  def run(_) do
    File.rm_rf!("priv")
    File.mkdir("priv")
    {exec, args} = case :os.type do
      {:win32, _} ->
        {"nmake", ["/F", "Makefile.win", "priv\\bcrypt_nif.dll"]}
      {:unix, os} when os in [:freebsd, :openbsd] ->
        {"gmake", ["priv/bcrypt_nif.so"]}
      _ ->
        {"make", ["priv/bcrypt_nif.so"]}
    end

    if System.find_executable(exec) do
      build(exec, args)
      Mix.Project.build_structure
      :ok
    else
      nocompiler_error(exec)
    end
  end

  def build(exec, args) do
    {result, error_code} = System.cmd(exec, args, stderr_to_stdout: true)
    IO.binwrite result
    if error_code != 0, do: build_error(exec)
  end

  defp nocompiler_error("nmake") do
    raise Mix.Error, message: nocompiler_message("nmake") <> windows_message()
  end
  defp nocompiler_error(exec) do
    raise Mix.Error, message: nocompiler_message(exec) <> nix_message()
  end

  defp build_error("nmake") do
    raise Mix.Error, message: build_message() <> windows_message()
  end
  defp build_error(_) do
    raise Mix.Error, message: build_message() <> nix_message()
  end

  defp nocompiler_message(exec) do
    """
    Could not find the program `#{exec}`.

    You will need to install the C compiler `#{exec}` to be able to build
    Comeonin.

    """
  end

  defp build_message do
    """
    Could not compile Comeonin.

    Please make sure that you are using Erlang / OTP version 18.0 or later
    and that you have a C compiler installed.

    """
  end

  defp windows_message do
    """
    One option is to install a recent version of
    [Visual C++ Build Tools](http://landinghub.visualstudio.com/visual-cpp-build-tools)
    either manually or using [Chocolatey](https://chocolatey.org/) -
    `choco install VisualCppBuildTools`.

    After installing Visual C++ Build Tools, look in the `Program Files (x86)`
    folder and search for `Microsoft Visual Studio`. Note down the full path
    of the folder with the highest version number.

    Open the `run` command and type in the following command (make sure that
    the path and version number are correct):

    `cmd /K "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" amd64`

    This should open up a command prompt with the necessary environment variables set,
    and from which you will be able to run the commands `mix compile`, `mix deps.compile`
    and `mix test`.

    See https://github.com/riverrun/comeonin/wiki/Requirements for more
    information.
    """
  end

  defp nix_message do
    """
    Please follow the directions below for the operating system you are
    using:

    Mac OS X: You need to have gcc and make installed. Try running the
    commands `gcc --version` and / or `make --version`. If these programs
    are not installed, you will be prompted to install them.

    Linux: You need to have gcc and make installed. If you are using
    Ubuntu or any other Debian-based system, install the packages
    `build-essential`. Also install `erlang-dev` package if not
    included in your Erlang/OTP version.

    See https://github.com/riverrun/comeonin/wiki/Requirements for more
    information.
    """
  end
end

defmodule Comeonin.Mixfile do
  use Mix.Project

  @version "2.5.2"

  @description """
  Password hashing (bcrypt, pbkdf2_sha512) library for Elixir.
  """

  def project do
    [app: :comeonin,
     version: @version,
     elixir: "~> 1.2",
     name: "Comeonin",
     description: @description,
     package: package(),
     source_url: "https://github.com/riverrun/comeonin",
     compilers: [:comeonin] ++ Mix.compilers,
     deps: deps()]
  end

  def application do
    [applications: [:crypto, :logger]]
  end

  defp deps do
    [{:earmark, "~> 0.2", only: :dev},
     {:ex_doc,  "~> 0.12", only: :dev}]
  end

  defp package do
    [files: ["lib", "c_src", "mix.exs", "Makefile*", "README.md", "LICENSE"],
     maintainers: ["David Whitlock"],
     licenses: ["BSD"],
     links: %{"GitHub" => "https://github.com/riverrun/comeonin",
      "Docs" => "http://hexdocs.pm/comeonin"}]
  end
end