class Geocoder::Lookup::GooglePremier

def cache_key(query)
  "#{protocol}://maps.googleapis.com/maps/api/geocode/json?" + hash_to_query(cache_key_params(query))
end

def cache_key_params(query)
  query_url_google_params(query).merge(super).reject do |k,v|
    [:key, :client, :channel].include?(k)
  end
end

def name
  "Google Premier"
end

def query_url(query)
  path = "/maps/api/geocode/json?" + url_query_string(query)
  "#{protocol}://maps.googleapis.com#{path}&signature=#{sign(path)}"
end

def query_url_params(query)
  query_url_google_params(query).merge(super).merge(
    :key => nil, # don't use param inherited from Google lookup
    :client => configuration.api_key[1],
    :channel => configuration.api_key[2]
  )
end

def required_api_key_parts
  ["private key"]
end

def result_root_attr
  'results'
end

def sign(string)
  raw_private_key = url_safe_base64_decode(configuration.api_key[0])
  digest = OpenSSL::Digest.new('sha1')
  raw_signature = OpenSSL::HMAC.digest(digest, raw_private_key, string)
  url_safe_base64_encode(raw_signature)
end

def url_safe_base64_decode(base64_string)
  Base64.decode64(base64_string.tr('-_', '+/'))
end

def url_safe_base64_encode(raw)
  Base64.encode64(raw).tr('+/', '-_').strip
end