defmodule Mix.Tasks.Ecto.Gen.Migration.Arango do
  use Mix.Task

  import Mix.Ecto
  import Mix.ArangoXEcto
  import Mix.Generator
  import Macro, only: [camelize: 1, underscore: 1]

  @shortdoc "Generates a new migration for a collection"

  @moduledoc """
  Generates a migration.

  The repository must be set under `:ecto_repos` in the current app
  configuration or given via the `-r` option.

  ## Examples

      mix ecto.gen.migration create_users
      mix ecto.gen.migration create_users -r Custom.Repo

  The generated migration filename will be prefixed with the current timestamp
  in UTC which is used for versioning and ordering.

  By default, the migration will be generated to the
  `priv/YOUR_REPO/migrations` directory of the current application but it can
  be configured to be any subdirectory of `priv` by specifying the `:priv` key
  under the repository configuration.

  This generator will automatically open the generated file if you have
  `ECTO_EDITOR` set in your environment variable.

  ## Command line options

    * `-r`, `--repo` - the repo to generate migration for

  """

  @aliases [
    r: :repo
  ]

  @switches [
    repo: [:string, :keep]
  ]

  @impl true
  def run(args) do
    Mix.Task.run("app.start")
    repos = parse_repo(args)

    for repo <- repos do
      case OptionParser.parse!(args, strict: @switches, aliases: @aliases) do
        {_, [name]} ->
          path = Path.join(path_to_priv_repo(repo), "migrations")
          base_name = "#{underscore(name)}.exs"
          file = Path.join(path, "#{timestamp()}_#{base_name}")

          unless File.dir?(path), do: create_directory(path)

          fuzzy_path = Path.join(path, "*_#{base_name}")

          if Path.wildcard(fuzzy_path) != [] do
            Mix.raise(
              "Migration can't be created since there is already a migration file with the name #{
                name
              }"
            )
          end

          assigns = [
            repo: repo,
            mod: Module.concat([repo, Migrations, camelize(name)])
          ]

          create_file(file, migration_template(assigns))

        {_, _} ->
          Mix.raise(
            "expected ecto.gen.migration to receive the migration file name, " <>
              "got: #{inspect(Enum.join(args, " "))}"
          )
      end
    end
  end

  embed_template(:migration, """
  defmodule <%= inspect @mod %> do
    alias <%= @repo %>

    def up do
      :ok
    end

    def down do
      :ok
    end
  end
  """)
end