defmodule Mix.Tasks.Sbom.Cyclonedx do
  @shortdoc "Generates CycloneDX SBoM"

  use Mix.Task
  import Mix.Generator

  @default_path "bom.xml"

  @moduledoc """
  Generates a Software Bill-of-Materials (SBoM) in CycloneDX format.

  ## Options

    * `--output` (`-o`): the full path to the SBoM output file (default:
      #{@default_path})
    * `--force` (`-f`): overwite existing files without prompting for
      confirmation
    * `--dev` (`-d`): include dependencies for non-production environments
      (including `dev`, `test` or `docs`); by default only dependencies for
      MIX_ENV=prod are returned
    * `--recurse` (`-r`): in an umbrella project, generate individual output
      files for each application, rather than a single file for the entire
      project

  """

  @doc false
  def run(all_args) do
    {opts, _args} =
      OptionParser.parse!(
        all_args,
        aliases: [o: :output, f: :force, d: :dev, r: :recurse],
        strict: [output: :string, force: :boolean, dev: :boolean, recurse: :boolean]
      )

    output_path = opts[:output] || @default_path
    environment = (!opts[:dev] && :prod) || nil

    # Mix.Task.run("deps.loadpaths", ["--no-compile", "--no-load-deps"])

    apps = Mix.Project.apps_paths()

    if opts[:recurse] && apps do
      Enum.each(apps, &generate_bom(&1, output_path, environment, opts[:force]))
    else
      generate_bom(output_path, environment, opts[:force])
    end
  end

  defp generate_bom(output_path, environment, force) do
    case SBoM.components_for_project(environment) do
      {:ok, components} ->
        xml = SBoM.CycloneDX.bom(components)
        create_file(output_path, xml, force: force)

      {:error, :unresolved_dependency} ->
        dependency_error()
    end
  end

  defp generate_bom({app, path}, output_path, environment, force) do
    Mix.Project.in_project(app, path, fn _module ->
      generate_bom(output_path, environment, force)
    end)
  end

  defp dependency_error do
    shell = Mix.shell()
    shell.error("Unchecked dependencies; please run `mix deps.get`")
    Mix.raise("Can't continue due to errors on dependencies")
  end
end