defmodule Mix.Tasks.AppGen.Context do
  @shortdoc "Creates a ecto context with functions from EctoShorts as well as tests"
  @moduledoc """
  You can use this to create ecto schema contexts and related tests

  ***Note: You must have [`ecto`](https://github.com/mikaak/ecto) installed to use this***

  #### Example
  `--repo` is a required flag for the ecto repo

  ```bash
  > mix app_gen.context --repo MyApp.Repo MyContext.MySchema
  ```
  """

  use Mix.Task

  alias Mix.AppGenHelpers
  alias AppGen.{EctoContextGenerator, EctoContextTestGenerator}

  def run(args) do
    AppGenHelpers.ensure_not_in_umbrella!("app_gen.gen.context")

    {opts, extra_args, _} = OptionParser.parse(args,
      switches: [
        no_tests: :boolean,
        no_contexts: :boolean,
        force: :boolean,
        quiet: :boolean,
        repo: :string
      ]
    )

    ecto_schemas = Enum.map(extra_args, &AppGenHelpers.string_to_module/1)

    if Enum.empty?(ecto_schemas) do
      raise to_string(IO.ANSI.format([
        :red, "No schemas provided to ", :bright, "app_gen.context", :reset,
        :red, ", you must provide at least one", :reset
      ]))
    end

    repo_str = if opts[:repo] do
      opts[:repo] |> AppGenHelpers.string_to_module |> inspect
    else
      "the default repo"
    end

    Mix.shell().info(IO.ANSI.format([
      :green, "Creating Ecto contexts in ", :bright, repo_str, :reset,
      :green, " for schemas ", :bright, "#{ecto_schemas |> Enum.map(&inspect/1) |> Enum.join(", ")}"
    ], true))

    generate_files_from_schemas(ecto_schemas, opts)
  end

  def generate_files_from_schemas(ecto_schemas, opts) do
    ecto_schemas
      |> Enum.group_by(&EctoContextGenerator.context_module/1)
      |> Enum.each(fn {context, schemas} ->
        unless opts[:no_contexts] do
          generate_context_file(context, schemas, opts)
        end

        unless opts[:no_tests] do
          generate_test_file(context, schemas, opts)
        end
      end)
  end

  defp generate_context_file(context, schemas, opts) do
    context_contents = EctoContextGenerator.create_context_module_for_schemas(
      opts[:repo],
      context,
      schemas
    )

    context_path = EctoContextGenerator.context_path(context)

    AppGenHelpers.write_app_gen_file(
      Path.dirname(context_path),
      Path.basename(context_path),
      context_contents,
      opts
    )
  end

  defp generate_test_file(context, schemas, opts) do
    test_contents = EctoContextTestGenerator.create_test_module_for_schemas(
      context,
      schemas
    )

    test_path = EctoContextTestGenerator.test_path(context)

    AppGenHelpers.write_app_gen_file(
      Path.dirname(test_path),
      Path.basename(test_path),
      test_contents,
      opts
    )
  end
end