require 'multi_json'

module QueueBus
  module Util
    extend self

    class DecodeException < StandardError; end

    # Given a Ruby object, returns a string suitable for storage in a
    # queue.
    def encode(object)
      if MultiJson.respond_to?(:dump) && MultiJson.respond_to?(:load)
        MultiJson.dump object
      else
        MultiJson.encode object
      end
    end

    # Given a string, returns a Ruby object.
    def decode(object)
      return unless object

      begin
        if MultiJson.respond_to?(:dump) && MultiJson.respond_to?(:load)
          MultiJson.load object
        else
          MultiJson.decode object
        end
      rescue ::MultiJson::DecodeError => e
        raise DecodeException, e.message, e.backtrace
      end
    end
    
    def underscore(camel_cased_word)
      word = camel_cased_word.to_s.dup
      word.gsub!('::', '/')
      # word.gsub!(/(?:([A-Za-z\d])|^)(#{inflections.acronym_regex})(?=\b|[^a-z])/) { "#{$1}#{$1 && '_'}#{$2.downcase}" }
      word.gsub!(/([A-Z\d]+)([A-Z][a-z])/,'\1_\2')
      word.gsub!(/([a-z\d])([A-Z])/,'\1_\2')
      word.tr!("-", "_")
      word.downcase!
      word
    end

    def classify(table_name)
      # strip out any leading schema name
      # camelize(singularize(table_name.to_s.sub(/.*\./, '')))
      camelize(table_name.to_s.sub(/.*\./, ''))
    end

    def camelize(term)
      string = term.to_s
      # string = string.sub(/^[a-z\d]*/) { inflections.acronyms[$&] || $&.capitalize }
      string = string.sub(/^[a-z\d]*/) { $&.capitalize }
      # string.gsub!(/(?:_|(\/))([a-z\d]*)/i) { "#{$1}#{inflections.acronyms[$2] || $2.capitalize}" }
      string.gsub!(/(?:_|(\/))([a-z\d]*)/i) { "#{$1}#{$2.capitalize}" }
      string.gsub!(/\//, '::')
      string
    end
    
    def constantize(camel_cased_word)
      names = camel_cased_word.split('::')
      names.shift if names.empty? || names.first.empty?

      names.inject(Object) do |constant, name|
        if constant == Object
          constant.const_get(name)
        else
          candidate = constant.const_get(name)
          next candidate if constant.const_defined?(name, false)
          next candidate unless Object.const_defined?(name)

          # Go down the ancestors to check it it's owned
          # directly before we reach Object or the end of ancestors.
          constant = constant.ancestors.inject do |const, ancestor|
            break const    if ancestor == Object
            break ancestor if ancestor.const_defined?(name, false)
            const
          end

          # owner is in Object, so raise
          constant.const_get(name, false)
        end
      end
    end
  end
end