Getkura/ann_wrapper

##################################################
# ANN_Wrapper
##################################################

require "net/http"
require "nokogiri"
require 'ann_wrapper/ann_anime'
require 'ann_wrapper/ann_manga'
require 'ann_wrapper/ann_report'

# wrapper class for ANN API
module ANN_Wrapper
extend ANN_Wrapper

    @@type = "anime"

    # ANN API anime url
    ANN_URL         = "http://cdn.animenewsnetwork.com/encyclopedia"
    ANN_API_URL     = "#{ANN_URL}/api.xml"
    ANN_REPORTS_URL = "#{ANN_URL}/reports.xml"

    # fetch up to 50 items(Animes or Mangas) in one request
    def batch_items(ids, api_url=ANN_API_URL)
        # append id to API url and send request
        url = "#{api_url}?title=#{ids.first.to_s}"
        ids[1..-1].each do |id|
            url << "/#{id.to_s}"
        end

        ann = fetch(url)

        return [ann] if ann.is_a?(ANN_Error)

        all_items = ann.xpath("//ann/#{@@type}")
        warnings = ann.xpath('//ann/warning')

        return [ANN_Error.new(get_xml_error(ann))] if all_items.empty? and warnings.empty?

        all_items = all_items.map { |item| Object.const_get("ANN_#{@@type.capitalize}").new(item) }
        warnings = warnings.map { |warning| ANN_Error.new(get_xml_error(warning)) }

        all_items.push(*warnings)
    end

    # fetch anime and convert to ANN_Anime
    def fetch_item(id, api_url=ANN_API_URL)
        batch_items([id], api_url).first
    end

    # fetch list of titles via reports
    def fetch_titles(options = {})
        options[:type]    ||= "anime"
        options[:nskip]   ||= 0
        options[:nlist]   ||= 50
        options[:name]    ||= ""
        options[:api_url] ||= ANN_REPORTS_URL

        url = "#{options[:api_url]}?id=155&type=#{options[:type]}&name=#{options[:name]}&nskip=#{options[:nskip]}&nlist=#{options[:nlist]}"

        report = fetch(url)

        return report if report.is_a?(ANN_Error)

        reports = report.xpath('//report/item')

        return ANN_Error.new(get_xml_error(report)) if reports.nil?

        reports.map { |item| ANN_Report.new(item) }
    end

  def method_missing(meth, *args, &block)
    if meth.to_s =~ /^(fetch|batch)_(anime|manga)$/
      @@type = $2
      $1 == 'fetch' ? fetch_item(*args) : batch_items(*args)
    else
      super
    end
  end

    private
        # fetch data from ANN API via http GET request
        # returns Nokogiri or ANN_Error
        def fetch(url)
            begin
                # send http GET request with uri parsed from url
                resp = Net::HTTP.get_response(URI.parse(url))

                # get the response body and try converting to Nokogiri object
                Nokogiri.XML(resp.body)
            rescue
                ANN_Error.new("Could not reach valid URL")
            end
        end

        # attempt to grab error message from XMLObject
        def get_xml_error(xobj)
            begin
                xobj.at_xpath('//ann/warning').content
            rescue NoMethodError
                "unrecognized response body"
            end
        end
    end