# frozen_string_literal: true

module BellyWash
  class Nocturnal
    DAYS_INTO_WEEK = {
      sunday: 0, monday: 1, tuesday: 2, wednesday: 3,
      thursday: 4, friday: 5, saturday: 6
    }.freeze

    def self.timeline(from:, to:, range:)
      list = []
      item = new(from).send("beginning_of_#{range}")
      while item < to
        list << item
        item = BellyWash::Nocturnal.new(list.last).send("next_#{range}")
      end
      list
    end

    def initialize(at)
      @at = at
      @tz = BellyWash.config.tz
    end

    def change(**fractions)
      Time.new(
        fractions.fetch(:year, @at.year),
        fractions.fetch(:month, @at.month),
        fractions.fetch(:day, @at.day),
        fractions.fetch(:hour, @at.hour),
        fractions.fetch(:minute, @at.min),
        0, # second
        @tz.utc_offset
      )
    end

    def beginning_of_minute
      change
    end

    def next_minute
      Nocturnal.new(
        beginning_of_minute + 60
      ).beginning_of_minute
    end

    def beginning_of_hour
      change(minute: 0)
    end

    def next_hour
      Nocturnal.new(
        beginning_of_hour + 60 * 60
      ).beginning_of_hour
    end

    def beginning_of_day
      change(hour: 0, minute: 0)
    end

    def next_day
      Nocturnal.new(
        beginning_of_day + 60 * 60 * 24
      ).beginning_of_day
    end

    def beginning_of_week
      today = beginning_of_day

      (today.to_date - days_to_week_start).to_time
    end

    def next_week
      Nocturnal.new(
        beginning_of_week + 60 * 60 * 24 * 7
      ).beginning_of_week
    end

    def days_to_week_start
      start_day_number = DAYS_INTO_WEEK.fetch(
        BellyWash.config.beginning_of_week
      )

      (@at.wday - start_day_number) % 7
    end

    def beginning_of_month
      change(day: 1, hour: 0, minute: 0)
    end

    def next_month
      Nocturnal.new(
        beginning_of_month + 60 * 60 * 24 * 31
      ).beginning_of_month
    end

    def beginning_of_quarter
      first_quarter_month = @at.month - (2 + @at.month) % 3

      change(
        month: first_quarter_month,
        day: 1,
        hour: 0,
        minute: 0
      )
    end

    def next_quarter
      Nocturnal.new(
        beginning_of_quarter + 60 * 60 * 24 * 31 * 3
      ).beginning_of_quarter
    end

    def beginning_of_year
      change(month: 1, day: 1, hour: 0, minute: 0)
    end

    def next_year
      Nocturnal.new(
        beginning_of_year + 60 * 60 * 24 * 31 * 12
      ).beginning_of_year
    end
  end
end