module Stripe

def self.api_error(error, resp, error_obj)
  APIError.new(error[:message], resp.code, resp.body, error_obj, resp.headers)
end

def self.api_url(url='', api_base_url=nil)
  (api_base_url || @api_base) + url
end

def self.authentication_error(error, resp, error_obj)
  AuthenticationError.new(error[:message], resp.code, resp.body, error_obj,
                          resp.headers)
end

def self.ca_bundle_path
  @ca_bundle_path
end

def self.ca_bundle_path=(path)
  @ca_bundle_path = path
  # empty this field so a new store is initialized
  @ca_store = nil
end

def self.ca_store
  @ca_store ||= begin
    store = OpenSSL::X509::Store.new
    store.add_file(ca_bundle_path)
    store
  end
end

def self.card_error(error, resp, error_obj)
  CardError.new(error[:message], error[:param], error[:code],
                resp.code, resp.body, error_obj, resp.headers)
end

def self.execute_request(opts)
  RestClient::Request.execute(opts)
end

def self.execute_request_with_rescues(request_opts, api_base_url, retry_count = 0)
  begin
    response = execute_request(request_opts)
  # We rescue all exceptions from a request so that we have an easy spot to
  # implement our retry logic across the board. We'll re-raise if it's a type
  # of exception that we didn't expect to handle.
  rescue => e
    if should_retry?(e, retry_count)
      retry_count = retry_count + 1
      sleep sleep_time(retry_count)
      retry
    end
    case e
    when SocketError
      response = handle_restclient_error(e, request_opts, retry_count, api_base_url)
    when RestClient::ExceptionWithResponse
      if e.response
        handle_api_error(e.response)
      else
        response = handle_restclient_error(e, request_opts, retry_count, api_base_url)
      end
    when RestClient::Exception, Errno::ECONNREFUSED, OpenSSL::SSL::SSLError
      response = handle_restclient_error(e, request_opts, retry_count, api_base_url)
    # Only handle errors when we know we can do so, and re-raise otherwise.
    # This should be pretty infrequent.
    else
      raise
    end
  end
  response
end

def self.general_api_error(rcode, rbody)
  APIError.new("Invalid response object from API: #{rbody.inspect} " +
               "(HTTP response code was #{rcode})", rcode, rbody)
end

def self.get_uname
  if File.exist?('/proc/version')
    File.read('/proc/version').strip
  else
    case RbConfig::CONFIG['host_os']
    when /linux|darwin|bsd|sunos|solaris|cygwin/i
      get_uname_from_system
    when /mswin|mingw/i
      get_uname_from_system_ver
    else
      "unknown platform"
    end
  end
end

def self.get_uname_from_system
  (`uname -a 2>/dev/null` || '').strip
rescue Errno::ENOENT
  "uname executable not found"
rescue Errno::ENOMEM # couldn't create subprocess
  "uname lookup failed"
end

def self.get_uname_from_system_ver
  (`ver` || '').strip
rescue Errno::ENOENT
  "ver executable not found"
rescue Errno::ENOMEM # couldn't create subprocess
  "uname lookup failed"
end

def self.handle_api_error(resp)
  begin
    error_obj = JSON.parse(resp.body)
    error_obj = Util.symbolize_names(error_obj)
    error = error_obj[:error]
    raise StripeError.new unless error && error.is_a?(Hash)
  rescue JSON::ParserError, StripeError
    raise general_api_error(resp.code, resp.body)
  end
  case resp.code
  when 400, 404
    raise invalid_request_error(error, resp, error_obj)
  when 401
    raise authentication_error(error, resp, error_obj)
  when 402
    raise card_error(error, resp, error_obj)
  when 403
    raise permission_error(error, resp, error_obj)
  when 429
    raise rate_limit_error(error, resp, error_obj)
  else
    raise api_error(error, resp, error_obj)
  end
end

def self.handle_restclient_error(e, request_opts, retry_count, api_base_url=nil)
  api_base_url = @api_base unless api_base_url
  connection_message = "Please check your internet connection and try again. " \
      "If this problem persists, you should check Stripe's service status at " \
      "https://twitter.com/stripestatus, or let us know at support@stripe.com."
  case e
  when RestClient::RequestTimeout
    message = "Could not connect to Stripe (#{api_base_url}). #{connection_message}"
  when RestClient::ServerBrokeConnection
    message = "The connection to the server (#{api_base_url}) broke before the " \
      "request completed. #{connection_message}"
  when OpenSSL::SSL::SSLError
    message = "Could not establish a secure connection to Stripe, you may " \
              "need to upgrade your OpenSSL version. To check, try running " \
              "'openssl s_client -connect api.stripe.com:443' from the " \
              "command line."
  when RestClient::SSLCertificateNotVerified
    message = "Could not verify Stripe's SSL certificate. " \
      "Please make sure that your network is not intercepting certificates. " \
      "(Try going to https://api.stripe.com/v1 in your browser.) " \
      "If this problem persists, let us know at support@stripe.com."
  when SocketError
    message = "Unexpected error communicating when trying to connect to Stripe. " \
      "You may be seeing this message because your DNS is not working. " \
      "To check, try running 'host stripe.com' from the command line."
  else
    message = "Unexpected error communicating with Stripe. " \
      "If this problem persists, let us know at support@stripe.com."
  end
  if retry_count > 0
    message += " Request was retried #{retry_count} times."
  end
  raise APIConnectionError.new(message + "\n\n(Network error: #{e.message})")
end

def self.invalid_request_error(error, resp, error_obj)
  InvalidRequestError.new(error[:message], error[:param], resp.code,
                          resp.body, error_obj, resp.headers)
end

def self.max_network_retries
  @max_network_retries
end

def self.max_network_retries=(val)
  @max_network_retries = val.to_i
end

def self.parse(response)
  begin
    # Would use :symbolize_names => true, but apparently there is
    # some library out there that makes symbolize_names not work.
    response = JSON.parse(response.body)
  rescue JSON::ParserError
    raise general_api_error(response.code, response.body)
  end
  Util.symbolize_names(response)
end

def self.permission_error(error, resp, error_obj)
  PermissionError.new(error[:message], resp.code, resp.body, error_obj, resp.headers)
end

def self.rate_limit_error(error, resp, error_obj)
  RateLimitError.new(error[:message], resp.code, resp.body, error_obj,
                     resp.headers)
end

def self.request(method, url, api_key, params={}, headers={}, api_base_url=nil)
  api_base_url = api_base_url || @api_base
  unless api_key ||= @api_key
    raise AuthenticationError.new('No API key provided. ' \
      'Set your API key using "Stripe.api_key = <API-KEY>". ' \
      'You can generate API keys from the Stripe web interface. ' \
      'See https://stripe.com/api for details, or email support@stripe.com ' \
      'if you have any questions.')
  end
  if api_key =~ /\s/
    raise AuthenticationError.new('Your API key is invalid, as it contains ' \
      'whitespace. (HINT: You can double-check your API key from the ' \
      'Stripe web interface. See https://stripe.com/api for details, or ' \
      'email support@stripe.com if you have any questions.)')
  end
  if verify_ssl_certs
    request_opts = {:verify_ssl => OpenSSL::SSL::VERIFY_PEER,
                    :ssl_cert_store => ca_store}
  else
    request_opts = {:verify_ssl => false}
    unless @verify_ssl_warned
      @verify_ssl_warned = true
      $stderr.puts("WARNING: Running without SSL cert verification. " \
        "You should never do this in production. " \
        "Execute 'Stripe.verify_ssl_certs = true' to enable verification.")
    end
  end
  params = Util.objects_to_ids(params)
  url = api_url(url, api_base_url)
  case method.to_s.downcase.to_sym
  when :get, :head, :delete
    # Make params into GET parameters
    url += "#{URI.parse(url).query ? '&' : '?'}#{Util.encode_parameters(params)}" if params && params.any?
    payload = nil
  else
    if headers[:content_type] && headers[:content_type] == "multipart/form-data"
      payload = params
    else
      payload = Util.encode_parameters(params)
    end
  end
  request_opts.update(:headers => request_headers(api_key, method).update(headers),
                      :method => method, :open_timeout => open_timeout,
                      :payload => payload, :url => url, :timeout => read_timeout)
  response = execute_request_with_rescues(request_opts, api_base_url)
  [parse(response), api_key]
end

def self.request_headers(api_key, method)
  headers = {
    'User-Agent' => "Stripe/v1 RubyBindings/#{Stripe::VERSION}",
    'Authorization' => "Bearer #{api_key}",
    'Content-Type' => 'application/x-www-form-urlencoded'
  }
  # It is only safe to retry network failures on post and delete
  # requests if we add an Idempotency-Key header
  if [:post, :delete].include?(method) && self.max_network_retries > 0
    headers['Idempotency-Key'] ||= SecureRandom.uuid
  end
  headers['Stripe-Version'] = api_version if api_version
  headers['Stripe-Account'] = stripe_account if stripe_account
  begin
    headers.update('X-Stripe-Client-User-Agent' => JSON.generate(user_agent))
  rescue => e
    headers.update('X-Stripe-Client-Raw-User-Agent' => user_agent.inspect,
                   :error => "#{e} (#{e.class})")
  end
end

def self.should_retry?(e, retry_count)
  retry_count < self.max_network_retries &&
    RETRY_EXCEPTIONS.any? { |klass| e.is_a?(klass) }
end

def self.sleep_time(retry_count)
  # Apply exponential backoff with initial_network_retry_delay on the number
  # of attempts so far as inputs. Do not allow the number to exceed
  # max_network_retry_delay.
  sleep_seconds = [initial_network_retry_delay * (2 ** (retry_count - 1)), max_network_retry_delay].min
  # Apply some jitter by randomizing the value in the range of (sleep_seconds
  # / 2) to (sleep_seconds).
  sleep_seconds = sleep_seconds * (0.5 * (1 + rand()))
  # But never sleep less than the base sleep seconds.
  sleep_seconds = [initial_network_retry_delay, sleep_seconds].max
  sleep_seconds
end

def self.uri_encode(params)
  Util.encode_parameters(params)
end

def self.user_agent
  @uname ||= get_uname
  lang_version = "#{RUBY_VERSION} p#{RUBY_PATCHLEVEL} (#{RUBY_RELEASE_DATE})"
  {
    :bindings_version => Stripe::VERSION,
    :lang => 'ruby',
    :lang_version => lang_version,
    :platform => RUBY_PLATFORM,
    :engine => defined?(RUBY_ENGINE) ? RUBY_ENGINE : '',
    :publisher => 'stripe',
    :uname => @uname,
    :hostname => Socket.gethostname,
  }
end