class AccessKey < ApplicationRecord
  DEFAULT_ROTATION_FREQUENCY_DAYS = 30
  KEY_LENGTH = 32

  validates :raw_key, presence: true
  validates :generated_at, presence: true
  validates :auto_rotation_frequency_days,
            numericality: { only_integer: true, greater_than: 0 }

  def self.current
    order(generated_at: :desc, id: :desc).first || create_current!
  end

  def self.create_current!
    create!(
      raw_key: generate_raw_key,
      generated_at: Time.current,
      auto_rotate: true,
      auto_rotation_frequency_days: DEFAULT_ROTATION_FREQUENCY_DAYS
    )
  end

  def self.rotate!
    previous_key = current

    transaction do
      UserSession.delete_all
      create!(
        raw_key: generate_raw_key,
        generated_at: Time.current,
        auto_rotate: previous_key.auto_rotate,
        auto_rotation_frequency_days: previous_key.auto_rotation_frequency_days
      )
    end
  end

  def self.rotate_if_needed!
    key = current
    return key unless key.auto_rotate? && key.expired?

    rotate!
  end

  def self.generate_raw_key
    SecureRandom.urlsafe_base64(KEY_LENGTH)
  end

  def matches?(submitted_key)
    ActiveSupport::SecurityUtils.secure_compare(raw_key, submitted_key.to_s)
  rescue ArgumentError
    false
  end

  def expired?
    generated_at <= auto_rotation_frequency_days.days.ago
  end

  def disable_auto_rotation!
    update!(auto_rotate: false)
  end

  def enable_auto_rotation!
    update!(auto_rotate: true)
  end
end