class MailIdentity < ApplicationRecord
  include Auditable

  encrypts :smtp_password

  require "openssl"

  has_many :mailings, dependent: :restrict_with_exception

  ENCRYPTIONS = Catalog::MAIL_ENCRYPTIONS.keys.freeze

  # Mapping host SMTP → IMAP tipici dei provider usati in produzione.
  IMAP_HOST_HINTS = {
    "aruba.it" => "imaps.aruba.it",
    "smtps.aruba.it" => "imaps.aruba.it",
    "smtp.aruba.it" => "imaps.aruba.it",
    "gmail.com" => "imap.gmail.com",
    "smtp.gmail.com" => "imap.gmail.com",
    "outlook.com" => "outlook.office365.com",
    "smtp.office365.com" => "outlook.office365.com"
  }.freeze

  validates :name, :from_name, :from_email, :smtp_host, :smtp_port, presence: true
  validates :from_email, format: { with: URI::MailTo::EMAIL_REGEXP }
  validates :reply_to, format: { with: URI::MailTo::EMAIL_REGEXP }, allow_blank: true
  validates :smtp_port, numericality: { in: 1..65535 }
  validates :imap_port, numericality: { in: 1..65535 }, allow_nil: true
  validates :encryption, inclusion: { in: ENCRYPTIONS }
  validates :smtp_authentication, inclusion: { in: Catalog::MAIL_AUTH_METHODS.keys }
  validate :encryption_matches_port

  before_validation :apply_imap_defaults

  scope :active, -> { where(active: true) }
  scope :imap_enabled, -> { where(imap_enabled: true) }
  scope :ordered, -> { order(:name) }

  def from_header
    %(#{from_name} <#{from_email}>)
  end

  def smtp_settings
    settings = {
      address: smtp_host,
      port: smtp_port,
      enable_starttls_auto: encryption == "starttls",
      ssl: encryption == "tls",
      openssl_verify_mode: verify_ssl? ? OpenSSL::SSL::VERIFY_PEER : OpenSSL::SSL::VERIFY_NONE,
      open_timeout: 15,
      read_timeout: 60
    }
    if smtp_username.present?
      settings[:user_name] = smtp_username
      settings[:password] = smtp_password
      settings[:authentication] = smtp_authentication.to_sym
    end
    settings
  end

  def imap_username
    smtp_username.presence || from_email
  end

  def effective_imap_host
    imap_host.presence || inferred_imap_host
  end

  def effective_imap_port
    (imap_port.presence || 993).to_i
  end

  def imap_ready?
    imap_enabled? && effective_imap_host.present? && effective_imap_port.positive?
  end

  def imap_settings
    {
      address: effective_imap_host,
      port: effective_imap_port,
      ssl: true,
      user_name: imap_username,
      password: smtp_password
    }
  end

  def inferred_imap_host
    host = smtp_host.to_s.downcase.strip
    return if host.blank?

    IMAP_HOST_HINTS.each do |needle, imap|
      return imap if host == needle || host.end_with?(".#{needle}") || host.include?(needle)
    end

    # Fallback generico: smtp.X → imap.X, smtps.X → imaps.X
    if host.start_with?("smtps.")
      host.sub(/\Asmtps\./, "imaps.")
    elsif host.start_with?("smtp.")
      host.sub(/\Asmtp\./, "imap.")
    end
  end

  private

  def apply_imap_defaults
    self.imap_port = 993 if imap_port.blank?
    self.imap_enabled = true if imap_enabled.nil?
    self.imap_host = inferred_imap_host if imap_host.blank? && inferred_imap_host.present?
  end

  def encryption_matches_port
    return if smtp_port.blank? || encryption.blank?

    if encryption == "tls" && smtp_port == 587
      errors.add(:smtp_port, "con SSL/TLS va usata la porta 465 (es. smtps.aruba.it)")
    elsif encryption == "starttls" && smtp_port == 465
      errors.add(:smtp_port, "con STARTTLS va usata la porta 587 (es. smtp.aruba.it)")
    end
  end
end