discourse-rewind/app/services/discourse_rewind/rewind/action/reading_time.rb

# frozen_string_literal: true

# For showcasing the reading time of a user
# Should we show book covers or just the names?
module DiscourseRewind
  class Rewind::Action::ReadingTime < Rewind::Action::BaseReport
    FakeData = {
      data: {
        reading_time: 2_880_000,
        book: "The Combined Cosmere works + Wheel of Time",
        isbn: "978-0812511819",
        series: true,
      },
      identifier: "reading-time",
    }

    def call
      return FakeData if Rails.env.development?

      reading_time = UserVisit.where(user_id: user.id).where(visited_at: date).sum(:time_read)
      book = best_book_fit(reading_time)

      return if book.nil?

      {
        data: {
          reading_time: reading_time,
          book: book[:title],
          isbn: book[:isbn],
          series: book[:series],
        },
        identifier: "reading-time",
      }
    end

    def popular_books
      {
        "The Hunger Games" => {
          reading_time: 19_740,
          isbn: "978-0439023481",
        },
        "The Metamorphosis" => {
          reading_time: 3120,
          isbn: "978-0553213690",
        },
        "To Kill a Mockingbird" => {
          reading_time: 22_800,
          isbn: "978-0061120084",
        },
        "Pride and Prejudice" => {
          reading_time: 25_200,
          isbn: "978-1503290563",
        },
        "1984" => {
          reading_time: 16_800,
          isbn: "978-0451524935",
        },
        "The Lord of the Rings" => {
          reading_time: 108_000,
          isbn: "978-0544003415",
        },
        "Harry Potter and the Sorcerer's Stone" => {
          reading_time: 24_600,
          isbn: "978-0590353427",
        },
        "The Great Gatsby" => {
          reading_time: 12_600,
          isbn: "978-0743273565",
        },
        "The Little Prince" => {
          reading_time: 5400,
          isbn: "978-0156012195",
        },
        "Animal Farm" => {
          reading_time: 7200,
          isbn: "978-0451526342",
        },
        "The Catcher in the Rye" => {
          reading_time: 18_000,
          isbn: "978-0316769488",
        },
        "Jane Eyre" => {
          reading_time: 34_200,
          isbn: "978-0141441146",
        },
        "Fahrenheit 451" => {
          reading_time: 15_000,
          isbn: "978-1451673319",
        },
        "The Hobbit" => {
          reading_time: 27_000,
          isbn: "978-0547928227",
        },
        "The Da Vinci Code" => {
          reading_time: 37_800,
          isbn: "978-0307474278",
        },
        "Little Women" => {
          reading_time: 30_000,
          isbn: "978-0147514011",
        },
        "One Hundred Years of Solitude" => {
          reading_time: 46_800,
          isbn: "978-0060883287",
        },
        "And Then There Were None" => {
          reading_time: 16_200,
          isbn: "978-0062073488",
        },
        "The Alchemist" => {
          reading_time: 10_800,
          isbn: "978-0061122415",
        },
        "The Hitchhiker's Guide to the Galaxy" => {
          reading_time: 12_600,
          isbn: "978-0345391803",
        },
        "The Complete works of Shakespeare" => {
          reading_time: 180_000,
          isbn: "978-1853268953",
          series: true,
        },
        "The Game of Thrones Series" => {
          reading_time: 360_000,
          isbn: "978-0007477159",
          series: true,
        },
        "Malazan Book of the Fallen" => {
          reading_time: 720_000,
          isbn: "978-0765348821",
          series: true,
        },
        "Terry Pratchett’s Discworld series" => {
          reading_time: 1_440_000,
          isbn: "978-9123684458",
          series: true,
        },
        "The Wandering Inn web series" => {
          reading_time: 2_160_000,
          isbn: "the-wandering-inn",
          series: true,
        },
        "The Combined Cosmere works + Wheel of Time" => {
          reading_time: 2_880_000,
          isbn: "978-0812511819",
          series: true,
        },
        "The Star Trek novels" => {
          reading_time: 3_600_000,
          isbn: "978-1852860691",
          series: true,
        },
      }.symbolize_keys
    end

    def best_book_fit(reading_time)
      reading_time_rest = reading_time
      books = []

      while reading_time_rest > 0
        best_fit = popular_books.min_by { |_, v| (v[:reading_time] - reading_time_rest).abs }
        break if best_fit.nil?

        books << best_fit.first
        reading_time_rest -= best_fit.last[:reading_time]
      end

      return if books.empty?

      book_title =
        books.group_by { |book| book }.transform_values(&:count).max_by { |_, count| count }.first

      { title: book_title, isbn: popular_books[book_title][:isbn] }
    end
  end
end