require "addressable/uri"
require "retryable"
require_relative "../exception.rb"

module Auth0
  module Mixins
    # here's the proxy for Rest calls based on rest-client, we're building all request on that gem
    # for now, if you want to feel free to use your own http client
    module HTTPProxy
      attr_accessor :headers, :base_uri, :timeout, :retry_count
      DEAFULT_RETRIES = 3
      MAX_ALLOWED_RETRIES = 10
      MAX_REQUEST_RETRY_JITTER = 250
      MAX_REQUEST_RETRY_DELAY = 1000
      MIN_REQUEST_RETRY_DELAY = 100

      # proxying requests from instance methods to HTTP class methods
      %i(get post post_file put patch delete delete_with_body).each do |method|
        define_method(method) do |uri, body = {}, extra_headers = {}|
          body = body.delete_if { |_, v| v.nil? }

          Retryable.retryable(retry_options) do
            request(method, uri, body, extra_headers)
          end
        end
      end

      def retry_options
        sleep_timer = lambda do |attempt|
          wait = 1000 * 2**attempt # Exponential delay with each subsequent request attempt.
          wait += rand(wait..wait+MAX_REQUEST_RETRY_JITTER) # Add jitter to the delay window.
          wait = [MAX_REQUEST_RETRY_DELAY, wait].min # Cap delay at MAX_REQUEST_RETRY_DELAY.
          wait = [MIN_REQUEST_RETRY_DELAY, wait].max # Ensure delay is no less than MIN_REQUEST_RETRY_DELAY.
          wait / 1000.to_f.round(2) # convert ms to seconds
        end

        tries = 1 + [Integer(retry_count || DEAFULT_RETRIES), MAX_ALLOWED_RETRIES].min # Cap retries at MAX_ALLOWED_RETRIES

        {
          tries: tries,
          sleep: sleep_timer,
          on: Auth0::RateLimitEncountered
        }
      end

      def encode_uri(uri)
        # if a base_uri is set then the uri can be encoded as a path
        path = base_uri ? Addressable::URI.new(path: uri).normalized_path : Addressable::URI.escape(uri)
        url(path)
      end

      def url(path)
        "#{base_uri}#{path}"
      end

      def add_headers(h = {})
        raise ArgumentError, 'Headers must be an object which responds to #to_hash' unless h.respond_to?(:to_hash)
        @headers ||= {}
        @headers.merge!(h.to_hash)
      end

      def safe_parse_json(body)
        JSON.parse(body.to_s)
      rescue JSON::ParserError
        body
      end

      def request(method, uri, body, extra_headers)
        result = if method == :get
          # Mutate the headers property to add parameters.
          add_headers({params: body})
          # Merge custom headers into existing ones for this req.
          # This prevents future calls from using them.
          get_headers = headers.merge extra_headers
          # Make the call with extra_headers, if provided.
          call(:get, encode_uri(uri), timeout, get_headers)
        elsif method == :delete
          call(:delete, encode_uri(uri), timeout, add_headers({params: body}))
        elsif method == :delete_with_body
          call(:delete, encode_uri(uri), timeout, headers, body.to_json)
        elsif method == :post_file
          body.merge!(multipart: true)
          # Ignore the default Content-Type headers and let the HTTP client define them
          post_file_headers = headers.slice(*headers.keys - ['Content-Type'])
          # Actual call with the altered headers
          call(:post, encode_uri(uri), timeout, post_file_headers, body)
        else
          call(method, encode_uri(uri), timeout, headers, body.to_json)
        end

        case result.code
        when 200...226 then safe_parse_json(result.body)
        when 400       then raise Auth0::BadRequest.new(result.body, code: result.code, headers: result.headers)
        when 401       then raise Auth0::Unauthorized.new(result.body, code: result.code, headers: result.headers)
        when 403       then raise Auth0::AccessDenied.new(result.body, code: result.code, headers: result.headers)
        when 404       then raise Auth0::NotFound.new(result.body, code: result.code, headers: result.headers)
        when 429       then raise Auth0::RateLimitEncountered.new(result.body, code: result.code, headers: result.headers)
        when 500       then raise Auth0::ServerError.new(result.body, code: result.code, headers: result.headers)
        else           raise Auth0::Unsupported.new(result.body, code: result.code, headers: result.headers)
        end
      end

      def call(method, url, timeout, headers, body = nil)
        RestClient::Request.execute(
          method: method,
          url: url,
          timeout: timeout,
          headers: headers,
          payload: body
        )
      rescue RestClient::Exception => e
        case e
        when RestClient::RequestTimeout
          raise Auth0::RequestTimeout.new(e.message)
        else
          return e.response
        end
      end
    end
  end
end