pikesley/ultron

module Ultron
  class Entities
    include Enumerable

    def self.method_missing method_name, *args
      mname = method_name.to_s
      query = nil
      path  = self.name_for_path

      mname.split(/_and_/).each do |part|
        case part
          when 'get'
            true # just so this method actually exists

          when 'sample'
            true

          when 'find'
            path = '%s/%s' % [path, args.shift]

          when /by_(.*)/
            path = self.send(:by_something, $1, args.shift)

          when 'with', 'where'
            query = self.send(:by_params, args.shift)

          when 'vanilla_comics'
            query = self.send(:by_params, format: 'comic', formatType: 'comic', noVariants: true)

          else
            raise NoMethodError

        end
      end

      url      = get_url path, query
      response = self.response url

      set = self.new response['data'], url

      return set.sample if mname == 'sample'
      mname == 'find' ? set.first : set
    end

    def self.response url
      response = Ultron::Connection.perform url
      case response['code'].to_s
        when /^4/, /^5/
          raise MarvelException.new response
        when 'ResourceNotFound'
          raise UltronException.new 'Resource does not exist. Check %s' % Config.instance.config.api_docs
        when 'RequestThrottled'
          raise UltronException.new 'You have exceeded your rate limit. Please try again later'
      end

      raise UltronException.new 'The search returned no results' unless response['data']['results'].any?

      response
    end

    def self.by_something something, id
      [something.pluralize, id, self.name_for_path].join '/'
    end

    def self.by_params params
      params.map { |k, v| '%s=%s&' % [k, v] }.join
    end

    def self.get_url path, query = nil
      Ultron::URL.new path, query
    end

    def self.name_for_path
      self.name.split('::')[-1].downcase
    end

    # instance methods

    attr_reader :metadata, :url

    def initialize data, url
      @results_set = data['results']
      @metadata    = OpenStruct.new data
      @url         = url
    end

    def [] key
      OpenStruct.new @results_set[key]
    end

    def each
      @results_set.each do |item|
        yield OpenStruct.new item
      end
    end

    def random_offset
      Random.rand @metadata.total
    end

    def sample
      sample_params = 'offset=%d&limit=1&' % random_offset
      full_url = self.class.get_url @url.path, '%s%s' % [@url.query, sample_params]
      response = Ultron::Connection.perform full_url
      self.class.new(response['data'], full_url).first
    end

    def == other
      other.url == @url
    end
  end
end