# frozen_string_literal:true

require "valid_email2"
require "resolv"
require "mail"
require "valid_email2/dns_records_cache"

module ValidEmail2
  class Address
    attr_accessor :address

    PROHIBITED_DOMAIN_CHARACTERS_REGEX = /[+!_\/\s'#`]/
    DEFAULT_RECIPIENT_DELIMITER = '+'
    DOT_DELIMITER = '.'

    def self.prohibited_domain_characters_regex
      @prohibited_domain_characters_regex ||= PROHIBITED_DOMAIN_CHARACTERS_REGEX
    end

    def self.prohibited_domain_characters_regex=(val)
      @prohibited_domain_characters_regex = val
    end

    def self.permitted_multibyte_characters_regex
      @permitted_multibyte_characters_regex
    end

    def self.permitted_multibyte_characters_regex=(val)
      @permitted_multibyte_characters_regex = val
    end

    def initialize(address, dns_timeout = 5, dns_nameserver = nil)
      @parse_error = false
      @raw_address = address
      @dns_timeout = dns_timeout
      @dns_nameserver = dns_nameserver

      begin
        @address = Mail::Address.new(address)
      rescue Mail::Field::ParseError
        @parse_error = true
      end

      @parse_error ||= address_contain_multibyte_characters?
    end

    def valid?
      return @valid unless @valid.nil?
      return false  if @parse_error

      @valid = valid_domain? && valid_address?
    end

    def valid_domain?
      domain = address.domain
      return false if domain.nil?

      domain !~ self.class.prohibited_domain_characters_regex &&
        domain.include?('.') &&
        !domain.include?('..') &&
        !domain.start_with?('.') &&
        !domain.start_with?('-') &&
        !domain.include?('-.')
    end

    def valid_address?
      return false if address.address != @raw_address

      !address.local.include?('..') &&
        !address.local.end_with?('.') &&
        !address.local.start_with?('.')
    end

    def dotted?
      valid? && address.local.include?(DOT_DELIMITER)
    end

    def subaddressed?
      valid? && address.local.include?(DEFAULT_RECIPIENT_DELIMITER)
    end

    def disposable?
      disposable_domain? || disposable_mx_server?
    end

    def disposable_domain?
      domain_is_in?(ValidEmail2.disposable_emails)
    end

    def disposable_mx_server?
      valid? && mx_server_is_in?(ValidEmail2.disposable_emails)
    end

    def allow_listed?
      domain_is_in?(ValidEmail2.allow_list)
    end

    def deny_listed?
      valid? && domain_is_in?(ValidEmail2.deny_list)
    end

    def valid_mx?
      return false unless valid?
      return false if null_mx?

      mx_or_a_servers.any?
    end

    def valid_strict_mx?
      return false unless valid?
      return false if null_mx?

      mx_servers.any?
    end

    private

    def domain_is_in?(domain_list)
      address_domain = address.domain.downcase
      return true if domain_list.include?(address_domain)

      i = address_domain.index('.')
      return false unless i

      domain_list.include?(address_domain[(i + 1)..-1])
    end

    def mx_server_is_in?(domain_list)
      mx_servers.any? { |mx_server|
        return false unless mx_server.respond_to?(:exchange)

        mx_server = mx_server.exchange.to_s

        domain_list.any? { |domain|
          mx_server.end_with?(domain) && mx_server =~ /\A(?:.+\.)*?#{domain}\z/
        }
      }
    end

    def address_contain_multibyte_characters?
      return false if @raw_address.nil?

      return false if @raw_address.ascii_only?

      @raw_address.each_char.any? { |char| char.bytesize > 1 && char !~ self.class.permitted_multibyte_characters_regex }
    end

    def resolv_config
      @resolv_config ||= begin
        config = Resolv::DNS::Config.default_config_hash
        config[:nameserver] = @dns_nameserver if @dns_nameserver
        config
      end

      @resolv_config
    end

    def mx_servers
      @mx_servers_cache ||= ValidEmail2::DnsRecordsCache.new

      @mx_servers_cache.fetch(address.domain.downcase) do
        Resolv::DNS.open(resolv_config) do |dns|
          dns.timeouts = @dns_timeout
          dns.getresources(address.domain, Resolv::DNS::Resource::IN::MX)
        end
      end
    end

    def null_mx?
      mx_servers.length == 1 && mx_servers.first.preference == 0 && mx_servers.first.exchange.length == 0
    end

    def mx_or_a_servers
      @mx_or_a_servers_cache ||= ValidEmail2::DnsRecordsCache.new

      @mx_or_a_servers_cache.fetch(address.domain.downcase) do
        Resolv::DNS.open(resolv_config) do |dns|
          dns.timeouts = @dns_timeout
          (mx_servers.any? && mx_servers) ||
            dns.getresources(address.domain, Resolv::DNS::Resource::IN::A)
        end
      end
    end
  end
end