module Geokit
  module Geocoders
    # Yahoo geocoder implementation.  Requires the Geokit::Geocoders::YAHOO variable to
    # contain a Yahoo API key.  Conforms to the interface set by the Geocoder class.
    class YahooGeocoder < Geocoder
      config :key, :secret

      private
      def self.submit_url(address)
        address_str = address.is_a?(GeoLoc) ? address.to_geocodeable_s : address
        query_string = "?q=#{Geokit::Inflector::url_escape(address_str)}&flags=J"

        o = OauthUtil.new
        o.consumer_key = key
        o.consumer_secret = secret
        base = "http://yboss.yahooapis.com/geo/placefinder"
        parsed_url = URI.parse("#{base}#{query_string}")
        "#{base}?#{o.sign(parsed_url).query_string}"
      end

      # Template method which does the geocode lookup.
      def self.do_geocode(address)
        url = submit_url(address)
        res = call_geocoder_service(url)
        return GeoLoc.new if !res.is_a?(Net::HTTPSuccess)
        json = res.body
        logger.debug "Yahoo geocoding. Address: #{address}. Result: #{json}"
        parse :json, json
      end

      def self.parse_json(results)
        boss_results = results && results['bossresponse'] && results['bossresponse']['placefinder'] && results['bossresponse']['placefinder']['results']
        return GeoLoc.new unless boss_results && boss_results.first
        loc = nil
        boss_results.each do |result|
          extracted_geoloc = extract_geoloc(result)
          if loc.nil?
            loc = extracted_geoloc
          else
            loc.all.push(extracted_geoloc)
          end
        end
        loc
      end

      def self.extract_geoloc(result_json)
        loc = GeoLoc.new
        loc.lat      = result_json['latitude']
        loc.lng      = result_json['longitude']
        loc.provider = 'yahoo'
        set_address_components(result_json, loc)
        set_precision(result_json, loc)
        loc.success  = true
        loc
      end

      def self.set_address_components(result_json, loc)
        loc.country_code   = result_json['countrycode']
        loc.street_address = result_json['line1'].to_s.empty? ? nil : result_json['line1']
        loc.city           = result_json['city']
        loc.state          = loc.is_us? ? result_json['statecode'] : result_json['state']
        loc.zip            = result_json['postal']
      end

      def self.set_precision(result_json, loc)
        loc.precision = case result_json['quality'].to_i
                        when 9,10         then 'country'
                        when 19..30       then 'state'
                        when 39,40        then 'city'
                        when 49,50        then 'neighborhood'
                        when 59,60,64     then 'zip'
                        when 74,75        then 'zip+4'
                        when 70..72       then 'street'
                        when 80..87       then 'address'
                        when 62,63,90,99  then 'building'
                        else 'unknown'
                        end

        loc.accuracy = %w{unknown country state state city zip zip+4 street address building}.index(loc.precision)
      end
    end
  end
end

# Oauth Util
# from gist: https://gist.github.com/erikeldridge/383159
# A utility for signing an url using OAuth in a way that's convenient for debugging
# Note: the standard Ruby OAuth lib is here http://github.com/mojodna/oauth
# License: http://gist.github.com/375593
# Usage: see example.rb below
 
require 'uri'
require 'cgi'
require 'openssl'
require 'base64'
 
class OauthUtil
  
  attr_accessor :consumer_key, :consumer_secret, :token, :token_secret, :req_method, 
                :sig_method, :oauth_version, :callback_url, :params, :req_url, :base_str
  
  def initialize
    @consumer_key = ''
    @consumer_secret = ''
    @token = ''
    @token_secret = ''
    @req_method = 'GET'
    @sig_method = 'HMAC-SHA1'
    @oauth_version = '1.0'
    @callback_url = ''
  end
  
  # openssl::random_bytes returns non-word chars, which need to be removed. using alt method to get length
  # ref http://snippets.dzone.com/posts/show/491
  def nonce
    Array.new( 5 ) { rand(256) }.pack('C*').unpack('H*').first
  end
  
  def percent_encode( string )
    # ref http://snippets.dzone.com/posts/show/1260
    URI.escape( string, Regexp.new("[^#{URI::PATTERN::UNRESERVED}]") ).gsub('*', '%2A')
  end
  
  # @ref http://oauth.net/core/1.0/#rfc.section.9.2
  def signature
    key = percent_encode( @consumer_secret ) + '&' + percent_encode( @token_secret )
    
    # ref: http://blog.nathanielbibler.com/post/63031273/openssl-hmac-vs-ruby-hmac-benchmarks
    digest = OpenSSL::Digest::Digest.new( 'sha1' )
    hmac = OpenSSL::HMAC.digest( digest, key, @base_str )
    
    # ref http://groups.google.com/group/oauth-ruby/browse_thread/thread/9110ed8c8f3cae81
    Base64.encode64( hmac ).chomp.gsub( /\n/, '' )
  end
  
  # sort (very important as it affects the signature), concat, and percent encode
  # @ref http://oauth.net/core/1.0/#rfc.section.9.1.1
  # @ref http://oauth.net/core/1.0/#9.2.1
  # @ref http://oauth.net/core/1.0/#rfc.section.A.5.1
  def query_string
    pairs = []
    @params.sort.each { | key, val | 
      pairs.push( "#{ percent_encode( key ) }=#{ percent_encode( val.to_s ) }" )
    }
    pairs.join '&'
  end

  def timestamp
    Time.now.to_i.to_s
  end
  
  # organize params & create signature
  def sign( parsed_url )
    
    @params = {
      'oauth_consumer_key' => @consumer_key,
      'oauth_nonce' => nonce,
      'oauth_signature_method' => @sig_method,
      'oauth_timestamp' => timestamp,
      'oauth_version' => @oauth_version
    }
 
    # if url has query, merge key/values into params obj overwriting defaults
    if parsed_url.query
      CGI.parse( parsed_url.query ).each do |k,v|
        if v.is_a?(Array) && v.count == 1
          @params[k] = v.first
        else
          @params[k] = v
        end
      end
    end
    
    # @ref http://oauth.net/core/1.0/#rfc.section.9.1.2
    @req_url = parsed_url.scheme + '://' + parsed_url.host + parsed_url.path
    
    # create base str. make it an object attr for ez debugging
    # ref http://oauth.net/core/1.0/#anchor14
    @base_str = [ 
      @req_method, 
      percent_encode( req_url ), 
      
      # normalization is just x-www-form-urlencoded
      percent_encode( query_string ) 
      
    ].join( '&' )
 
    # add signature
    @params[ 'oauth_signature' ] = signature
    
    self
  end
end