require 'pathname'

require 'killbill/http_servlet'
require 'killbill/creator'

module Killbill
  # There are various types of plugins one can write for Killbill:
  #
  #   1)  notifications plugins, which listen to external bus events and can react to it
  #   2)  payment plugins, which are used to issue payments against a payment gateway
  module Plugin
    class JPlugin

      attr_reader :delegate_plugin

      # Called by the Killbill lifecycle when initializing the plugin
      def start_plugin
        @delegate_plugin.start_plugin
      end

      # Called by the Killbill lifecycle when stopping the plugin
      def stop_plugin
        @delegate_plugin.stop_plugin
      end

      def is_active
        @delegate_plugin.active
      end

      # Called by the Killbill lifecycle when instantiating the plugin
      def initialize(plugin_class_name, services = {})
        @delegate_plugin = Creator.new(plugin_class_name).create(services)
      end

      # Called by the Killbill lifecycle to register the servlet
      def rack_handler
        config_ru = Pathname.new("#{@delegate_plugin.root}/config.ru").expand_path
        if config_ru.file?
          logger.info "Found Rack configuration file at #{config_ru.to_s}"
          instance = Killbill::Plugin::RackHandler.instance
          instance.configure(logger, config_ru.to_s) unless instance.configured?
          instance
        else
          logger.info "No Rack configuration file found at #{config_ru.to_s}"
          nil
        end
      end

      def logger
        require 'logger'
        @delegate_plugin.nil? ? ::Logger.new(STDOUT) : @delegate_plugin.logger
      end

      protected

      def do_call_handle_exception(method_name, *args)
         begin
           rargs = convert_args(method_name, args)
           res = @delegate_plugin.send(method_name.to_s.snake_case.to_sym, *rargs)
           yield(res)
         rescue Exception => e
           wrap_and_throw_exception(method_name, e)
         ensure
           @delegate_plugin.after_request
         end
       end

       def wrap_and_throw_exception(api, e)
         message = "#{api} failure: #{e}"
         unless e.backtrace.nil?
           message = "#{message}\n#{e.backtrace.join("\n")}"
         end
         logger.warn message
         raise Java::com.ning.billing.payment.plugin.api.PaymentPluginApiException.new("#{api} failure", e.message)
       end

       def convert_args(api, args)
          args.collect! do |a|
           if a.nil?
             nil
           elsif a.java_kind_of? java.util.UUID
             JConverter.from_uuid(a)
           elsif a.java_kind_of? java.math.BigDecimal
             JConverter.from_big_decimal(a)
           elsif a.java_kind_of? Java::com.ning.billing.catalog.api.Currency
             a.to_string
           elsif a.java_kind_of? Java::com.ning.billing.payment.api.PaymentMethodPlugin
             JConverter.from_payment_method_plugin(a)
           elsif a.java_kind_of? Java::com.ning.billing.beatrix.bus.api.ExtBusEvent
             JConverter.from_ext_bus_event(a)
           elsif ((a.java_kind_of? Java::boolean) || (a.java_kind_of? java.lang.Boolean))
             JConverter.from_boolean(a)
           # Require because it looks like if non boxed value are passed they already arrive as Ruby type
           elsif ((a.java_kind_of? TrueClass) || (a.java_kind_of? FalseClass))
             a
           elsif a.java_kind_of? java.util.List
             result = Array.new
             if a.size > 0
               first_element = a.get(0)
               if first_element.java_kind_of? Java::com.ning.billing.payment.plugin.api.PaymentMethodInfoPlugin
                 a.each do |el|
                   result << JConverter.from_payment_method_info_plugin(el)
                 end
               else
                 raise Java::com.ning.billing.payment.plugin.api.PaymentPluginApiException.new("#{api} failure", "Unexpected parameter type #{first_element.class} for list")
               end
             end
             result
           else
             # Since we don't pass the Context at this point, we can't raise any exceptions for unexpected types.
             #raise Java::com.ning.billing.payment.plugin.api.PaymentPluginApiException.new("#{api} failure", "Unexpected parameter type #{a.class}")
             nil
           end
          end
          # Remove last argument if this is null (it means we passed a context)
          args.delete_at(-1) if args[-1].nil?
          args
        end

    end
  end
end