defmodule HexagonTpu.MixProject do
  use Mix.Project

  @version "0.1.2"
  @github_url "https://github.com/monoflow-ayvu/hexagon-tpu"
  # cc_precompiler assembles arch-vendor-os-abi, so abi is just "gnu".
  @mix_target_triplets %{
    "dragon_q6a" => {"aarch64", "nerves", "gnu"}
  }

  def project do
    maybe_set_target_triplet_from_mix_target()

    [
      app: :hexagon_tpu,
      version: @version,
      elixir: "~> 1.17",
      start_permanent: Mix.env() == :prod,
      deps: deps(),
      package: package(),
      description:
        "QNN (Qualcomm AI Engine Direct) NIF bindings for the Hexagon NPU (QCS6490/HTP)",
      compilers: [:elixir_make] ++ Mix.compilers(),
      # Precompiled artifacts serve Hex consumers; anyone hacking on this
      # repo (dev/test) or setting HEXAGON_TPU_BUILD=1 builds from source.
      make_force_build:
        Mix.env() in [:dev, :test] or System.get_env("HEXAGON_TPU_BUILD") in ["1", "true"],
      make_precompiler: {:nif, CCPrecompiler},
      make_precompiler_url: "#{@github_url}/releases/download/v#{@version}/@{artefact_filename}",
      make_precompiler_filename: "hexagon_tpu_nif",
      make_precompiler_priv_paths: ["hexagon_tpu_nif.so"],
      cc_precompiler: [
        compilers: %{
          {:unix, :linux} => %{
            # current_target_from_env() drops the vendor, so dragon_q6a builds
            # resolve to plain aarch64-linux-gnu. Prefer the Nerves toolchain
            # when it's on PATH, fall back to the distro cross gcc.
            "aarch64-linux-gnu" => {aarch64_cc("gcc"), aarch64_cc("g++")},
            "aarch64-nerves-linux-gnu" => {
              "aarch64-nerves-linux-gnu-gcc",
              "aarch64-nerves-linux-gnu-g++"
            },
            # Host build: only useful with the QNN CPU backend / HTP simulator.
            "x86_64-linux-gnu" => {"gcc", "g++"}
          }
        }
      ]
    ]
  end

  defp aarch64_cc(tool) do
    nerves = "aarch64-nerves-linux-gnu-#{tool}"
    if System.find_executable(nerves), do: nerves, else: "aarch64-linux-gnu-#{tool}"
  end

  defp maybe_set_target_triplet_from_mix_target do
    case Map.get(@mix_target_triplets, System.get_env("MIX_TARGET")) do
      nil ->
        :ok

      {arch, vendor, abi} ->
        unless keep_external_target_triplet?() do
          System.put_env("TARGET_ARCH", arch)
          System.put_env("TARGET_VENDOR", vendor)
          System.put_env("TARGET_OS", "linux")
          System.put_env("TARGET_ABI", abi)
        end
    end
  end

  defp keep_external_target_triplet? do
    case System.get_env("HEXAGON_TPU_KEEP_TARGET_TRIPLET") do
      nil -> false
      value -> String.downcase(value) in ["1", "true", "yes"]
    end
  end

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

  defp deps do
    [
      {:nx, "~> 0.9"},
      {:telemetry, "~> 1.0"},
      {:elixir_make, "~> 0.8", runtime: false},
      {:cc_precompiler, "~> 0.1", runtime: false},
      {:ex_doc, ">= 0.0.0", only: :dev, runtime: false}
    ]
  end

  defp package do
    files =
      ~w(
        c_src
        cmake
        lib
        CMakeLists.txt
        Makefile
        README.md
        mix.exs
      )
      |> maybe_add_checksum()

    [
      name: "hexagon_tpu",
      licenses: ["Apache-2.0"],
      links: %{"GitHub" => @github_url},
      files: files
    ]
  end

  defp maybe_add_checksum(files) do
    if File.exists?("checksum.exs"), do: ["checksum.exs" | files], else: files
  end
end