book_genre_automation.rb

class Book::GenreAutomation
  attr_accessor :book

  def initialize(book_id)
    self.book = Book.find(book_id)
  end

  def run
    genres_array = fetch_genres_from_openai

    return if genres_array.blank?

    book.genres.clear

    genres_array.each do |genre_name|
      genre = Genre.find_by(name: genre_name)

      puts "adding genre #{genre_name} to document profile #{book.id}"
      book.genres << genre if genre.present?
    end
  end

  def fetch_genres_from_openai
    client = OpenAI::Client.new

    # rubocop:todo Layout/LineLength
    prompt = 'You are going to be given a book title, description, and author and a list of genres. Given that context, return a JSON array of genres that best fit the book. If you are unsure, you can leave the array empty.'
    # rubocop:enable Layout/LineLength

    genres = Genre.all.map(&:name).join(', ')

    content = <<-CONTENT
      #{prompt}

      Book Title:
      #{book.title}

      Book Author(s):
      #{book.authors.join(', ')}

      Book Description:
      #{book.description}

      Genres: """
      #{genres}
      """

      Return in this format:
      { genres: [] }
    CONTENT

    response = client.chat(
      parameters: {
        model: 'gpt-4o', # Required.
        response_format: { type: 'json_object' },
        messages: [{ role: 'user', content: content }], # Required.
        temperature: 0.7
      }
    )

    genres_json = response.dig('choices', 0, 'message', 'content')
    JSON.parse(genres_json)['genres']
  rescue StandardError
    puts "Error in DocumentProfile::GenreAutomation for #{documentProfile.id}"
    []
  end
end