defmodule Mix.Tasks.Attest.Gen.Html do
  require Mix.Phoenix.Schema
  alias Mix.Phoenix.{Context, Schema}
  use Mix.Task
  alias Mix.Tasks.Phx.Gen

  @moduledoc """
  Generates controller, views, and context for an HTML resource.

      mix attest.gen.html UserPage User users

  The first argument is the context module.
  The second argument is the schema module.
  The third argument is the table name of schema.
  """

  @doc false
  def run(args) do
    if Mix.Project.umbrella?() do
      Mix.raise "mix phx.gen.schema can only be run inside an application directory"
    end

    {context, schema} = Gen.Context.build(args)
    binding = [context: context, schema: schema]

    paths = Attest.generator_paths()

    copy_new_files(schema, context, paths, binding)
  end

  defp copy_new_files(schema, context, paths, binding) do
    copy_file_for_schema(schema, paths, binding)
    copy_file_for_migration(schema, paths, binding)
    copy_file_for_html(schema, context, paths, binding)
    schema
  end

  defp copy_file_for_schema(schema, paths, binding) do
    Mix.Phoenix.copy_from paths, "priv/templates/attest.gen.schema", binding, [
      {:eex, "schema.ex", schema.file}
    ]
  end

  defp copy_file_for_migration(%Schema{context_app: ctx_app} = schema, paths, binding) do
    migration_path = Mix.Phoenix.context_app_path(ctx_app, "priv/repo/migrations/#{timestamp()}_create_#{schema.table}.exs")
    Mix.Phoenix.copy_from paths, "priv/templates/attest.gen.schema", binding, [
      {:eex, "migration.exs", migration_path},
    ]
  end

  defp copy_file_for_html(%Schema{context_app: context_app}, %Context{basename: basename}, paths, binding) do
    web_prefix = Mix.Phoenix.web_path(context_app)
    Mix.Phoenix.copy_from paths, "priv/templates/attest.gen.html/registrations", binding, [
      {:eex, "controller.ex", "#{web_prefix}/controllers/#{basename}/registrations_controller.ex"},
      {:eex, "view.ex",       "#{web_prefix}/views/#{basename}/registrations_view.ex"},
      {:eex, "new.html.eex",  "#{web_prefix}/templates/#{basename}/registrations/new.html.eex"},
    ]

    Mix.Phoenix.copy_from paths, "priv/templates/attest.gen.html/sessions", binding, [
      {:eex, "controller.ex", "#{web_prefix}/controllers/#{basename}/sessions_controller.ex"},
      {:eex, "view.ex",       "#{web_prefix}/views/#{basename}/sessions_view.ex"},
      {:eex, "new.html.eex",  "#{web_prefix}/templates/#{basename}/sessions/new.html.eex"},
    ]

  end

  defp timestamp do
    {{y, m, d}, {hh, mm, ss}} = :calendar.universal_time()
    "#{y}#{pad(m)}#{pad(d)}#{pad(hh)}#{pad(mm)}#{pad(ss)}"
  end
  defp pad(i) when i < 10, do: << ?0, ?0 + i >>
  defp pad(i), do: to_string(i)
end