# frozen_string_literal: true

# List all Availability's slots for the given resources
class Availabilities::AvailabilitiesService

  def initialize(current_user, level = 'slot')
    @current_user = current_user
    @maximum_visibility = {
      year: Setting.get('visibility_yearly').to_i.months.since,
      other: Setting.get('visibility_others').to_i.months.since
    }
    @service = Availabilities::StatusService.new(current_user&.role)
    @level = level
  end

  # list all slots for the given machine, with visibility relative to the given user
  def machines(machine, user, window)
    availabilities = availabilities(machine.availabilities, 'machines', user, window[:start], window[:end])

    if @level == 'slot'
      availabilities.map(&:slots).flatten.map { |s| @service.slot_reserved_status(s, user, [machine]) }
    else
      availabilities.map { |a| @service.availability_reserved_status(a, user, [machine]) }
    end
  end

  # list all slots for the given space, with visibility relative to the given user
  def spaces(space, user, window)
    availabilities = availabilities(space.availabilities, 'space', user, window[:start], window[:end])

    if @level == 'slot'
      availabilities.map(&:slots).flatten.map { |s| @service.slot_reserved_status(s, user, [space]) }
    else
      availabilities.map { |a| @service.availability_reserved_status(a, user, [space]) }
    end
  end

  # list all slots for the given training(s), with visibility relative to the given user
  def trainings(trainings, user, window)
    tr_availabilities = Availability.includes('trainings_availabilities')
                                    .where('trainings_availabilities.training_id': trainings.map(&:id))
    availabilities = availabilities(tr_availabilities, 'training', user, window[:start], window[:end])

    if @level == 'slot'
      availabilities.map(&:slots).flatten.map { |s| @service.slot_reserved_status(s, user, s.availability.trainings) }
    else
      availabilities.map { |a| @service.availability_reserved_status(a, user, a.trainings) }
    end
  end

  # list all slots for the given event(s), with visibility relative to the given user
  def events(events, user, window)
    ev_availabilities = Availability.includes('event').where('events.id': events.map(&:id))
    availabilities = availabilities(ev_availabilities, 'event', user, window[:start], window[:end])

    if @level == 'slot'
      availabilities.map(&:slots).flatten.map { |s| @service.slot_reserved_status(s, user, [s.availability.event]) }
    else
      availabilities.map { |a| @service.availability_reserved_status(a, user, [a.event]) }
    end
  end

  private

  def subscription_year?(user)
    user&.subscription && user.subscription.plan.interval == 'year' && user.subscription.expired_at >= DateTime.current
  end

  # members must have validated at least 1 training and must have a valid yearly subscription to view
  # the trainings further in the futur. This is used to prevent users with a rolling subscription to take
  # their first training in a very long delay.
  def show_more_trainings?(user)
    user&.trainings&.size&.positive? && subscription_year?(user)
  end

  def availabilities(availabilities, type, user, range_start, range_end)
    # who made the request?
    # 1) an admin (he can see all availabilities from 1 month ago to anytime in the future)
    if @current_user&.admin? || @current_user&.manager?
      window_start = [range_start, 1.month.ago].max
      availabilities.includes(:tags, :plans, :slots)
                    .joins(:slots)
                    .where('availabilities.start_at <= ? AND availabilities.end_at >= ? AND available_type = ?', range_end, window_start, type)
                    .where('slots.start_at > ? AND slots.end_at < ?', window_start, range_end)
                    .where(lock: false)
    # 2) an user (he cannot see past availabilities neither those further than 1 (or 3) months in the future)
    else
      end_at = @maximum_visibility[:other]
      end_at = @maximum_visibility[:year] if subscription_year?(user) && type != 'training'
      end_at = @maximum_visibility[:year] if show_more_trainings?(user) && type == 'training'
      window_end = [end_at, range_end].min
      window_start = [range_start, DateTime.current].max
      availabilities.includes(:tags, :plans, :slots)
                    .joins(:slots)
                    .where('availabilities.start_at <= ? AND availabilities.end_at >= ? AND available_type = ?', window_end, window_start, type)
                    .where('slots.start_at > ? AND slots.end_at < ?', window_start, window_end)
                    .where('availability_tags.tag_id' => user&.tag_ids&.concat([nil]))
                    .where(lock: false)
    end
  end
end