case Code.ensure_loaded(Igniter.Mix.Task) do
  {:module, Igniter.Mix.Task} ->
    defmodule Mix.Tasks.Oidcc.Gen.ProviderConfigurationWorker do
      @example """
      mix oidcc.gen.provider_configuration_worker \\
        --name MyApp.OpenIDProvider \\
        --issuer https://accounts.google.com \
      """

      @shortdoc "Generate an OpenID Connect provider configuration worker"

      @moduledoc """
      #{@shortdoc}

      Adds an `Oidcc.ProviderConfiguration.Worker` to your application and
      configures it via the `runtime.exs` configuration file.

      ## Example

      ```bash
      #{@example}
      ```

      ## Options

      * `--name` or `-n` - The name of the provider configuration worker
      * `--issuer` or `-i` - The issuer of the provider
      """

      use Igniter.Mix.Task

      alias Igniter.Project.Application
      alias Igniter.Project.Config
      alias Igniter.Project.Module

      @impl Igniter.Mix.Task
      def info(_argv, _composing_task) do
        %Igniter.Mix.Task.Info{
          # dependencies to add
          adds_deps: [],
          # dependencies to add and call their associated installers, if they exist
          installs: [],
          # An example invocation
          example: @example,
          # Accept additional arguments that are not in your schema
          # Does not guarantee that, when composed, the only options you get are the ones you define
          extra_args?: false,
          # A list of environments that this should be installed in, only relevant if this is an installer.
          only: nil,
          # a list of positional arguments, i.e `[:file]`
          positional: [],
          # Other tasks your task composes using `Igniter.compose_task`, passing in the CLI argv
          # This ensures your option schema includes options from nested tasks
          composes: [],
          # `OptionParser` schema
          schema: [name: :string, issuer: :string],
          # CLI aliases
          aliases: [n: :name, i: :issuer]
        }
      end

      @impl Igniter.Mix.Task
      def igniter(igniter) do
        options = setup_options(igniter)

        igniter
        |> configure_issuer(options)
        |> add_application_worker(options)
      end

      defp setup_options(igniter) do
        igniter.args.options
        |> Keyword.update(
          :name,
          Module.module_name(igniter, "OpenIDProvider"),
          &Module.parse/1
        )
        |> Keyword.put(:app_name, Igniter.Project.Application.app_name(igniter))
      end

      defp configure_issuer(igniter, options) do
        env_prefix =
          options[:name] |> Macro.underscore() |> String.upcase() |> String.replace("/", "_")

        config =
          case Keyword.fetch(options, :issuer) do
            {:ok, issuer} ->
              quote do
                [issuer: System.get_env(unquote("#{env_prefix}_ISSUER"), unquote(issuer))]
              end

            :error ->
              quote do
                [issuer: System.fetch_env!(unquote("#{env_prefix}_ISSUER"))]
              end
          end

        Config.configure_new(
          igniter,
          "runtime.exs",
          options[:app_name],
          [options[:name]],
          {:code, config}
        )
      end

      defp add_application_worker(igniter, options) do
        Application.add_new_child(
          igniter,
          {Oidcc.ProviderConfiguration.Worker,
           {:code,
            quote do
              %{
                name: unquote(options[:name]),
                issuer:
                  Application.fetch_env!(unquote(options[:app_name]), unquote(options[:name]))[
                    :issuer
                  ]
              }
            end}}
        )
      end
    end

  _ ->
    defmodule Mix.Tasks.Oidcc.Gen.ProviderConfigurationWorker do
      @shortdoc "Generate an OpenID Connect provider configuration worker | Install `igniter` to use"
      @moduledoc @shortdoc

      use Mix.Task

      @impl Mix.Task
      def run(_argv) do
        Mix.shell().error("""
        The task 'oidcc.gen.provider_configuration_worker' requires igniter to be run.

        Please install igniter and try again.

        For more information, see: https://hexdocs.pm/igniter
        """)

        exit({:shutdown, 1})
      end
    end
end
