require "html_terminator/version"
require 'sanitize'

module HtmlTerminator
  SANITIZE_OPTIONS = {
    :elements => ["b", "em", "i", "strong", "u", "br"]
  }

  def self.sanitize(val)
    if val.is_a?(String) && !skip_sanitize?(val)
      Sanitize.fragment(val, SANITIZE_OPTIONS).strip.gsub(/&/, "&")
    else
      val
    end
  end

  # Don't sanitize if only one bracket is present.
  # Without this, "1 < 2" gets incorrectly sanitized as "1".
  def self.skip_sanitize?(val)
    val.count("<") + val.count(">") == 1
  end

  module ClassMethods
    def terminate_html(*args)
      class_attribute :html_terminator_fields

      # Table may not exist yet when schema is initially getting loaded
      if self.table_exists?
        # By default all fields are to be seen by the terminator
        self.html_terminator_fields = self.columns.inject([]) do |list, col|
          if col.type == :string or col.type == :text
            list << col.name.to_sym
          end

          list
        end

        if args.length == 1
          if args[0].is_a?(Symbol)
            self.html_terminator_fields = args
          elsif args[0].is_a?(Object)
            self.html_terminator_fields -= (args[0][:except] || [])
          end
        elsif args.length > 1
          self.html_terminator_fields = args
        end

        unless self.html_terminator_fields.empty?
          # sanitize writes
          before_validation :terminate_html

          # sanitize reads
          self.html_terminator_fields.each do |attr|
            define_method(attr) do |*rargs|
              # sanitize it
              HtmlTerminator.sanitize super(*rargs)
            end
          end
        end
      end
    end
  end

  module InstanceMethods
    def terminate_html
      self.html_terminator_fields.each do |field|
        value = self[field]

        unless value.nil?
          self[field] = HtmlTerminator.sanitize(value)
        end
      end
    end
  end

  def self.included(base)
    base.send :extend, ClassMethods
    base.send :include, InstanceMethods
  end
end

ActiveRecord::Base.send :include, HtmlTerminator