# frozen_string_literal: true

module Decidim
  module Meetings
    # This command is executed when the user joins a meeting.
    class JoinMeeting < Rectify::Command
      # Initializes a JoinMeeting Command.
      #
      # meeting - The current instance of the meeting to be joined.
      # user - The user joining the meeting.
      # registration_form - The questionnaire filled by the attendee
      def initialize(meeting, user, registration_form = nil)
        @meeting = meeting
        @user = user
        @registration_form = registration_form
      end

      # Creates a meeting registration if the meeting has registrations enabled
      # and there are available slots.
      #
      # Broadcasts :ok if successful, :invalid otherwise.
      def call
        meeting.with_lock do
          return broadcast(:invalid) unless can_join_meeting?

          if registration_form
            return broadcast(:invalid_form) unless registration_form.valid?
            save_registration_form
          end

          create_registration
          accept_invitation
          send_email_confirmation
          send_notification_confirmation
          notify_admin_over_percentage
          increment_score
        end
        broadcast(:ok)
      end

      private

      attr_reader :meeting, :user, :registration, :registration_form

      def accept_invitation
        meeting.invites.find_by(user: user)&.accept!
      end

      def save_registration_form
        Decidim::Forms::AnswerQuestionnaire.call(registration_form, user, meeting.questionnaire)
      end

      def create_registration
        @registration = Decidim::Meetings::Registration.create!(meeting: meeting, user: user)
      end

      def can_join_meeting?
        meeting.registrations_enabled? && meeting.has_available_slots?
      end

      def send_email_confirmation
        Decidim::Meetings::RegistrationMailer.confirmation(
          @user,
          @meeting,
          @registration
        ).deliver_now
      end

      def send_notification_confirmation
        Decidim::EventsManager.publish(
          event: "decidim.events.meetings.meeting_registration_confirmed",
          event_class: Decidim::Meetings::MeetingRegistrationNotificationEvent,
          resource: @meeting,
          affected_users: [@user],
          extra: {
            registration_code: @registration.code
          }
        )
      end

      def participatory_space_admins
        @meeting.component.participatory_space.admins
      end

      def notify_admin_over_percentage
        return send_notification_over(0.5) if occupied_slots_over?(0.5)
        return send_notification_over(0.8) if occupied_slots_over?(0.8)
        send_notification_over(1.0) if occupied_slots_over?(1.0)
      end

      def send_notification_over(percentage)
        Decidim::EventsManager.publish(
          event: "decidim.events.meetings.meeting_registrations_over_percentage",
          event_class: Decidim::Meetings::MeetingRegistrationsOverPercentageEvent,
          resource: @meeting,
          affected_users: participatory_space_admins,
          extra: {
            percentage: percentage
          }
        )
      end

      def increment_score
        Decidim::Gamification.increment_score(user, :attended_meetings)
      end

      def occupied_slots_over?(percentage)
        @meeting.remaining_slots == (@meeting.available_slots * (1 - percentage)).round
      end
    end
  end
end