defmodule Chromaprint.MixProject do
  use Mix.Project

  def project do
    [
      app: :chromaprint,
      version: "0.1.0",
      elixir: "~> 1.20-rc",
      start_permanent: Mix.env() == :prod,
      deps: deps(),
      compilers: [:elixir_make] ++ Mix.compilers(),
      make_targets: ["all"],
      make_clean: ["clean"],
      make_env: &make_env/0
    ]
  end

  def application do
    [
      extra_applications: [:logger]
    ]
  end

  defp deps do
    [
      {:elixir_make, "~> 0.9", runtime: false},
    ]
  end

  defp make_env do
    verify_chromaprint_source!()

    %{
      "ERTS_INCLUDE_DIR" => erts_include_dir(),
      "CHROMAPRINT_USE_SYSTEM" =>
        if(System.get_env("CHROMAPRINT_USE_SYSTEM") in ~w(1 true on ON YES yes),
          do: "ON",
          else: "OFF"
        )
    }
  end

  defp erts_include_dir do
    Path.join([
      :code.root_dir() |> to_string(),
      "erts-#{:erlang.system_info(:version)}",
      "include"
    ])
  end

  defp verify_chromaprint_source! do
    use_system = System.get_env("CHROMAPRINT_USE_SYSTEM") in ~w(1 true on ON YES yes)
    submodule_cmake = Path.join([__DIR__, "c_src", "chromaprint", "CMakeLists.txt"])

    if not use_system and not File.exists?(submodule_cmake) do
      Mix.raise("""
      The chromaprint source submodule is missing at c_src/chromaprint/.

      Either initialise it:

          git submodule update --init c_src/chromaprint

      Or, to link against a system-provided libchromaprint (recommended for
      Nix and other sandboxed builds), set CHROMAPRINT_USE_SYSTEM=1 and ensure
      chromaprint.h and libchromaprint can be found via the compiler's default
      paths (or CHROMAPRINT_INCLUDE_DIR / CHROMAPRINT_LIB_DIR if not).
      """)
    end
  end
end