class OAuth2::Strategy::AuthCode

def assert_valid_params(params)
  raise(ArgumentError, 'client_secret is not allowed in authorize URL query params') if params.key?(:client_secret) || params.key?('client_secret')
end

def authorize_params(params = {})
  params.merge('response_type' => 'code', 'client_id' => @client.id)
end

def authorize_url(params = {})
  assert_valid_params(params)
  @client.authorize_url(authorize_params.merge(params))
end

def get_token(code, params = {}, opts = {})
  params = {'grant_type' => 'authorization_code', 'code' => code}.merge(@client.redirection_params).merge(params)
  params_dup = params.dup
  params.each_key do |key|
    params_dup[key.to_s] = params_dup.delete(key) if key.is_a?(Symbol)
  end
  @client.get_token(params_dup, opts)
end