module Faraday::NestedParamsEncoder

def self.encode(params)
  return nil if params == nil
  if !params.is_a?(Array)
    if !params.respond_to?(:to_hash)
      raise TypeError,
        "Can't convert #{params.class} into Hash."
    end
    params = params.to_hash
    params = params.map do |key, value|
      key = key.to_s if key.kind_of?(Symbol)
      [key, value]
    end
    # Useful default for OAuth and caching.
    # Only to be used for non-Array inputs. Arrays should preserve order.
    params.sort!
  end
  # Helper lambda
  to_query = lambda do |parent, value|
    if value.is_a?(Hash)
      value = value.map do |key, val|
        key = escape(key)
        [key, val]
      end
      value.sort!
      buffer = ""
      value.each do |key, val|
        new_parent = "#{parent}%5B#{key}%5D"
        buffer << "#{to_query.call(new_parent, val)}&"
      end
      return buffer.chop
    elsif value.is_a?(Array)
      buffer = ""
      value.each_with_index do |val, i|
        new_parent = "#{parent}%5B%5D"
        buffer << "#{to_query.call(new_parent, val)}&"
      end
      return buffer.chop
    elsif value.nil?
      return parent
    else
      encoded_value = escape(value)
      return "#{parent}=#{encoded_value}"
    end
  end
  # The params have form [['key1', 'value1'], ['key2', 'value2']].
  buffer = ''
  params.each do |parent, value|
    encoded_parent = escape(parent)
    buffer << "#{to_query.call(encoded_parent, value)}&"
  end
  return buffer.chop
end