# Copyright (c) 2008-16 Peter H. Boling of RailsBling.com
# Released under the MIT license

module SanitizeEmail
  # Tools for overriding addresses
  class OverriddenAddresses

    # Raised when after applying all sanitization rules there are no addresses to send the email to.
    class MissingTo < StandardError; end

    # Raised if there is a recipient type that sanitize_email doesn't recognize.
    # If you get this error please report it.
    # recognized recipient types are: TO, CC, and BCC
    class UnknownOverride < StandardError; end

    REPLACE_AT = [/@/, " at "]
    REPLACE_ALLIGATOR = [/[<>]/, "~"]
    attr_accessor :overridden_to, :overridden_cc, :overridden_bcc,
                  :good_list, # White-listed addresses will not be molested as to, cc, or bcc
                  :bad_list, # Black-listed addresses will be removed from to, cc and bcc when sanitization is engaged
                  :sanitized_to, :sanitized_cc, :sanitized_bcc # Replace non-white-listed addresses with these sanitized addresses.

    def initialize(message, args = {})
      # Not using extract_options! because non-rails compatibility is a goal
      @sanitized_to = args[:sanitized_to] || SanitizeEmail::Config.config[:sanitized_to]
      @sanitized_cc = args[:sanitized_cc] || SanitizeEmail::Config.config[:sanitized_cc]
      @sanitized_bcc = args[:sanitized_bcc] || SanitizeEmail::Config.config[:sanitized_bcc]
      @good_list = args[:good_list] || SanitizeEmail::Config.config[:good_list] || []
      @bad_list = args[:bad_list] || SanitizeEmail::Config.config[:bad_list] || []
      @overridden_to = self.to_override(message.to)
      @overridden_cc = self.cc_override(message.cc)
      @overridden_bcc = self.bcc_override(message.bcc)
    end

    # Allow good listed email addresses, and then remove the bad listed addresses
    def good_listize(real_addresses)
      good_listed = self.clean_addresses(real_addresses, :good_list)
      good_listed = self.clean_addresses(good_listed, :bad_list) unless good_listed.empty?
      good_listed
    end

    def to_override(actual_addresses)
      to = override_email(:to, actual_addresses)
      raise MissingTo, "after overriding :to (#{actual_addresses}) there are no addresses to send in To: header." if to.empty?
      to.join(",")
    end

    def cc_override(actual_addresses)
      override_email(:cc, actual_addresses).join(",")
    end

    def bcc_override(actual_addresses)
      override_email(:bcc, actual_addresses).join(",")
    end

    def override_email(type, actual_addresses)
      # Normalized to an arrays
      #puts "override_email 1: #{type} - #{actual_addresses}"
      real_addresses = Array(actual_addresses)

      #puts "override_email 2: #{type} - #{real_addresses}"
      # If there were no original recipients, then we DO NOT override the nil with the sanitized recipients
      return [] if real_addresses.empty?

      good_listed = good_listize(real_addresses)
      #puts "override_email 3: #{type} - #{good_listed}"
      # If there are good_list addresses to send to then use them as is, no mods needed
      return good_listed unless good_listed.empty?

      # TODO: Allow overriding if an addressed email is on the good list?
      # If there are no sanitized addresses we can't override!
      sanitized_addresses = sanitize_addresses(type)
      #puts "override_email 4: #{type} - #{sanitized_addresses}"
      return [] if sanitized_addresses.empty?

      # At this point it is assured that the address list will need to be sanitized
      # One more check to ensure none of the configured sanitized email addresses are on the bad_list
      sanitized_addresses = self.clean_addresses(sanitized_addresses, :bad_list)
      #puts "override_email 5: #{type} - #{sanitized_addresses}"

      # If we don't want to inject the "email" in the "user name" section of the sanitized recipients,
      # then just return the default sanitized recipients
      return sanitized_addresses unless SanitizeEmail.use_actual_email_as_sanitized_user_name

      with_user_names = self.inject_user_names(real_addresses, sanitized_addresses)
      #puts "real_addresses 2: #{real_addresses}"
      #puts "override_email 6: #{type} - #{with_user_names}"
      # Otherwise inject the email as the "user name"
      return with_user_names
    end

    def address_list_filter(list_type, address)
      # TODO: How does this handle email addresses with user names like "Foo Example <foo@example.org>"
      has_address = self.send(list_type).include?(address)
      case list_type
        when :good_list then
          has_address ? address : nil
        when :bad_list then
          has_address ? nil : address
      end
    end

    def inject_user_names(real_addresses, sanitized_addresses)
      real_addresses.inject([]) do |result, real_recipient|
        if real_recipient.nil?
          new_recipient = sanitized_addresses
        else
          #puts "SANITIZED: #{sanitized_addresses}"
          new_recipient = sanitized_addresses.map { |sanitized| "#{real_recipient.gsub(REPLACE_AT[0], REPLACE_AT[1]).gsub(/[<>]/, '~')} <#{sanitized}>" }
        end
        result << new_recipient
        result
      end.flatten
    end

    def clean_addresses(addresses, list_type)
      # Normalize addresses just in case it isn't an array yet
      addresses.map { |address|
        # If this address is on the good list then let it pass
        self.address_list_filter(list_type, address)
      }.compact.uniq
    end

    def sanitize_addresses(type)
      case type
        when :to then
          Array(self.sanitized_to)
        when :cc then
          Array(self.sanitized_cc)
        when :bcc then
          Array(self.sanitized_bcc)
        else
          raise UnknownOverride, "unknown email override"
      end
    end

  end
end