class MailingRecipient < ApplicationRecord
  belongs_to :mailing
  belongs_to :organization
  belongs_to :contact, optional: true

  validates :status, inclusion: { in: Catalog::MAILING_RECIPIENT_STATUSES.keys }
  validates :ab_variant, inclusion: { in: Catalog::AB_VARIANTS.keys }, allow_blank: true
  validates :tracking_token, presence: true, uniqueness: true

  before_validation :assign_tracking_token, on: :create

  scope :pending, -> { where(status: "pending") }
  scope :skipped, -> { where(status: "skipped") }
  scope :sent, -> { where(status: "sent") }
  scope :failed, -> { where(status: "failed") }
  scope :queued, -> { where(status: "queued") }
  scope :opened, -> { where.not(opened_at: nil) }
  scope :ordered, -> { joins(:organization).order("organizations.list_position ASC NULLS LAST", "organizations.name ASC") }

  def status_label
    Catalog.label_for(Catalog::MAILING_RECIPIENT_STATUSES, status)
  end

  def pending?
    status == "pending"
  end

  def sent?
    status == "sent"
  end

  def email_ok?
    email.present? && email.match?(URI::MailTo::EMAIL_REGEXP)
  end

  def opened?
    opened_at.present?
  end

  def record_open!(at: Time.current)
    return unless sent?

    first_open = false
    with_lock do
      return unless sent?

      first_open = opened_at.blank?
      attrs = { last_opened_at: at, open_count: open_count + 1 }
      attrs[:opened_at] = at if first_open
      update!(attrs)
    end
    log_open_activity! if first_open
  end

  def merge_context
    opportunity = organization.campaign_opportunity(mailing.project)
    {
      organization: organization,
      contact: contact,
      project: mailing.project,
      opportunity: opportunity,
      ab_variant: ab_variant.presence || opportunity&.ab_variant
    }
  end

  def rendered_html
    MailMerge.render(mailing.body_for(ab_variant), **merge_context)
  end

  def rendered_subject_line
    MailMerge.render(mailing.subject_for(ab_variant), **merge_context)
  end

  def deliver!
    with_lock do
      return if status.in?(%w[sent skipped])
      return abort_delivery!("invio annullato") unless mailing.sending?

      update!(status: "queued")
    end

    return unless mailing.sending?

    html = rendered_html
    subject_line = rendered_subject_line
    CampaignMailer.outreach(self, html: html, subject: subject_line).deliver_now
    record_success!(subject_line)
  rescue StandardError => e
    update!(status: "failed", error_message: e.message.to_s.truncate(500))
  ensure
    mailing.mark_finished_if_done!
  end

  private

  def abort_delivery!(reason)
    update!(status: "skipped", skip_reason: reason)
  end

  def record_success!(subject_line)
    transaction do
      update!(status: "sent", sent_at: Time.current, rendered_subject: subject_line, error_message: nil)
      sync_opportunity!
      log_activity!(subject_line)
    end
  end

  def sync_opportunity!
    opportunity = organization.campaign_opportunity(mailing.project)
    return unless opportunity

    attrs = {}
    attrs[:send_status] = "sent" if opportunity.send_status == "to_send"
    attrs[:sent_on] ||= Date.current if opportunity.sent_on.blank?
    attrs[:pipeline_stage] = "contacted" if opportunity.pipeline_stage == "to_contact"
    attrs[:ab_variant] = ab_variant if mailing.ab_test? && ab_variant.present? && opportunity.ab_variant.blank?
    opportunity.update!(attrs) if attrs.any?
  end

  def assign_tracking_token
    self.tracking_token ||= self.class.generate_tracking_token
  end

  def self.generate_tracking_token
    loop do
      token = SecureRandom.urlsafe_base64(24)
      break token unless exists?(tracking_token: token)
    end
  end

  def log_open_activity!
    organization.activities.create!(
      activity_type: "email_opened",
      subject: rendered_subject.presence || mailing.subject_for(ab_variant),
      description: "Apertura rilevata · campagna #{mailing.name}",
      happened_at: opened_at || Time.current,
      user: mailing.created_by,
      contact: contact,
      opportunity: organization.campaign_opportunity(mailing.project)
    )
  end

  def log_activity!(subject_line)
    variant_note = "variante #{ab_variant}" if mailing.ab_test? && ab_variant.present?
    organization.activities.create!(
      activity_type: "email_sent",
      subject: subject_line.presence || mailing.name,
      description: ["Campagna email: #{mailing.name}", variant_note].compact.join(" · "),
      happened_at: Time.current,
      user: mailing.created_by,
      contact: contact,
      opportunity: organization.campaign_opportunity(mailing.project)
    )
  end
end