class Notifications::Channel < ApplicationRecord
  belongs_to :app
  has_many :templates, class_name: 'Notifications::Template', dependent: :destroy
  has_many :broadcasts, class_name: 'Notifications::Broadcast', dependent: :destroy
  has_many :user_preferences, class_name: 'Notifications::Preference', dependent: :destroy
  has_one :in_app_template, -> { in_app.order(updated_at: :desc) }, class_name: 'Notifications::Template', inverse_of: :channel
  has_one :email_html_template, -> { email.html.order(updated_at: :desc) }, class_name: 'Notifications::Template', inverse_of: :channel
  has_one :email_text_template, -> { email.text.order(updated_at: :desc) }, class_name: 'Notifications::Template', inverse_of: :channel

  validates :name, presence: true, uniqueness: { scope: :app_id, case_sensitive: true }

  scope :internal, -> { where(internal: true) }

  def self.deliver(via:, to:, with:)
    as_notifier(via: via, with: with)
      &.deliver(to)
  end

  def self.deliver_later(via:, to:, with:)
    as_notifier(via: via, with: with)
      &.deliver_later(to)
  end

  def self.as_notifier(via:, with:)
    channel_name = via.to_s.remove('_notifier').remove('Notifier')

    find_by_name(channel_name) # rubocop:disable Rails/DynamicFindBy
      &.as_notifier(with: with)
  end

  def self.find_by_name(channel_name)
    find_by(name: [
              channel_name,
              channel_name.to_s.underscore,
              channel_name.to_s.camelize
            ])
  end

  def deliver(to:, with:)
    as_notifier(with: with)
      .deliver(to)
  end

  def deliver_later(to:, with:)
    as_notifier(with: with)
      .deliver_later(to)
  end

  def as_notifier(with:)
    to_noticed_class
      .with(with)
  end

  private

  def to_noticed_class
    # we need local variables for the `define_method` closures to have access to these data
    in_app_subject_template = in_app_template&.subject
    in_app_body_template = in_app_template&.body
    email_subject_template = (email_html_template || email_text_template)&.subject
    email_html_body_template = email_html_template&.body
    email_text_body_template = email_text_template&.body
    channel_id = id

    klass = Class.new(Noticed::Base) do
      deliver_by :database, if: :in_app_notifications?
      deliver_by :email, mailer: 'NotificationMailer', if: :email_notifications?

      define_method :in_app_notifications? do
        preference = preferences&.in_app?

        return preference unless preference.nil?

        true
      end

      define_method :email_notifications? do
        preference = preferences&.email?

        return preference unless preference.nil?

        true
      end

      define_method :in_app_subject do
        render_template(in_app_subject_template)
      end

      define_method :in_app_body do
        render_template(in_app_body_template).html_safe
      end

      define_method :email_subject do
        render_template(email_subject_template)
      end

      define_method :email_html_body do
        render_template(email_html_body_template)
      end

      define_method :email_text_body do
        render_template(email_text_body_template)
      end

      define_method :preferences do
        recipient.notification_preferences.find_by(channel_id: channel_id)
      end

      define_method :render_template do |template|
        return '' unless template

        template % attributes
      end

      define_method :attributes do
        original = params.symbolize_keys
        Hash.new { |_, k| original[k] || '' }
      end
    end

    # to avoid ever seeing something like #<#<Class:0x00007fd58318d340>:0x00007fd5868c5088> in logs or the console
    Object.const_set "#{app.name.camelize}#{name.camelize}Notifier", klass
  end
end