module BenchHelper
  module_function

  def clear_data
    Comment.delete_all
    Post.delete_all
    User.delete_all
  end

  def seed_data
    data_config = {
      comments_per_post: 2,
      posts: 20
    }

    anchor_time = Time.new(2017,7,1).utc
    id = 1
    user = User.create!(id: id, first_name: 'Diana', last_name: 'Prince', birthday: anchor_time, created_at: anchor_time, updated_at: anchor_time)
    id += 1

    data_config[:posts].times do
      post = Post.create!(id: id, user_id: user.id, title: 'Some Post', body: 'awesome content', created_at: anchor_time, updated_at: anchor_time)
      id += 1
      data_config[:comments_per_post].times do
        Comment.create!(id: id, author: 'me', comment: 'nice blog', post_id: post.id, created_at: anchor_time, updated_at: anchor_time)
        id += 1
      end
    end
  end

  def validate_render(render_gem)
    expected_json_file = File.join("support", "json_document-#{render_gem}.json")
    json_document = test_render(render_gem)
    assert_equal_json("[#{render_gem}] :test_render", expected_json_file, json_document)
    json_document = test_manual_eagerload(render_gem)
    assert_equal_json("[#{render_gem}] :test_manual_eagerload", expected_json_file, json_document)
  end

  require "fileutils"
  def assert_equal_json(description, expected_json_file, actual_json_document)
    # 1. in tmp/
    temp_dir = "tmp"
    FileUtils.mkdir_p(temp_dir)
    # 2. write pretty actual json doc
    actual_json_file = File.join(temp_dir, "actual--#{File.basename(expected_json_file)}")
    actual_json_document = JSON.pretty_generate(actual_json_document)
    File.write(actual_json_file, actual_json_document)
    # 3. if expected json doc missing, copy actual to expected
    unless File.exist?(expected_json_file)
      FileUtils.cp(actual_json_file, expected_json_file)
    end
    # 4. Check for differences
    cmd = "diff --suppress-common-lines --side-by-side #{expected_json_file} #{actual_json_file}"
    diff = `#{cmd}`.chomp
    # 5. If none, 'true', they are equal
    #    else make a full diff for later review
    return true if diff.empty?
    cmd = "diff --side-by-side #{expected_json_file} #{actual_json_file} > #{File.join(temp_dir, "actual--#{File.basename(expected_json_file)}")}.diff"
    system(cmd)
    # 6. abort run, print brief diff
    abort "#{description}. Invalid JSON document.\nDiff:\n#{diff}}"
  end

  def test_render(render_gem)
    render_data(
      User.first,
      render_gem
    )
  end

  def test_manual_eagerload(render_gem)
    render_data(
      User.includes(posts: [:comments]).first,
      render_gem
    )
  end

  # protected

  def render_data(data, render_gem)
    case render_gem
    when :ams then render_with_ams(data)
    when :jsonapi_rb then render_with_jsonapi_rb(data)
    else fail ArgumentError, "Cannot render unknown gem '#{render_gem.inspect}'"
    end
  end

  def render_with_ams(data)
    ActiveModelSerializers::SerializableResource.new(
      data,
      include: 'posts.comments',
      adapter: :json_api
    ).as_json
  end

  def render_with_jsonapi_rb(data)
    JSONAPI::Serializable::Renderer.new.render(
      data,
      include: 'posts.comments',
      class: { User: SerializableUser, Post: SerializablePost, Comment: SerializableComment }
    )
  end
end