# Copyright (C) 2012-2021 Zammad Foundation, http://zammad-foundation.org/

class OnlineNotification < ApplicationModel
  include OnlineNotification::Assets

  belongs_to :user, optional: true
  # rubocop:disable Rails/InverseOf
  belongs_to :object, class_name: 'ObjectLookup', foreign_key: 'object_lookup_id', optional: true
  belongs_to :type,   class_name: 'TypeLookup',   foreign_key: 'type_lookup_id', optional: true
  # rubocop:enable Rails/InverseOf

  after_create    :notify_clients_after_change
  after_update    :notify_clients_after_change
  after_destroy   :notify_clients_after_change

=begin

add a new online notification for this user

  OnlineNotification.add(
    type:          'Assigned to you',
    object:        'Ticket',
    o_id:          ticket.id,
    seen:          false,
    user_id:       2,
    created_by_id: 1,
    updated_by_id: 1,
    created_at:    Time.zone.now,
    updated_at:    Time.zone.now,
  )

=end

  def self.add(data)

    # lookups
    if data[:type]
      type_id = TypeLookup.by_name(data[:type])
    end
    if data[:object]
      object_id = ObjectLookup.by_name(data[:object])
    end

    # check if object for online notification exists
    exists_by_object_and_id?(data[:object], data[:o_id])

    record = {
      o_id:             data[:o_id],
      object_lookup_id: object_id,
      type_lookup_id:   type_id,
      seen:             data[:seen],
      user_id:          data[:user_id],
      created_by_id:    data[:created_by_id],
      updated_by_id:    data[:updated_by_id] || data[:created_by_id],
      created_at:       data[:created_at] || Time.zone.now,
      updated_at:       data[:updated_at] || Time.zone.now,
    }

    OnlineNotification.create!(record)
  end

=begin

remove whole online notifications of an object

  OnlineNotification.remove('Ticket', 123)

=end

  def self.remove(object_name, o_id)
    object_id = ObjectLookup.by_name(object_name)
    OnlineNotification.where(
      object_lookup_id: object_id,
      o_id:             o_id,
    ).destroy_all
  end

=begin

remove whole online notifications of an object by type

  OnlineNotification.remove_by_type('Ticket', 123, type, user)

=end

  def self.remove_by_type(object_name, o_id, type_name, user)
    object_id = ObjectLookup.by_name(object_name)
    type_id = TypeLookup.by_name(type_name)
    OnlineNotification.where(
      object_lookup_id: object_id,
      type_lookup_id:   type_id,
      o_id:             o_id,
      user_id:          user.id,
    ).destroy_all
  end

=begin

return all online notifications of an user

  notifications = OnlineNotification.list(user, limit)

=end

  def self.list(user, limit)
    OnlineNotification.where(user_id: user.id)
                      .order(created_at: :desc)
                      .limit(limit)
  end

=begin

return all online notifications of an object

  notifications = OnlineNotification.list_by_object('Ticket', 123)

=end

  def self.list_by_object(object_name, o_id)
    object_id = ObjectLookup.by_name(object_name)
    OnlineNotification.where(
      object_lookup_id: object_id,
      o_id:             o_id,
    )
                                      .order(created_at: :desc)
                                      .limit(10_000)

  end

=begin

mark online notification as seen by object

  OnlineNotification.seen_by_object('Ticket', 123, user_id)

=end

  def self.seen_by_object(object_name, o_id)
    object_id     = ObjectLookup.by_name(object_name)
    notifications = OnlineNotification.where(
      object_lookup_id: object_id,
      o_id:             o_id,
      seen:             false,
    )
    notifications.each do |notification|
      notification.seen = true
      notification.save
    end
    true
  end

  def notify_clients_after_change
    Sessions.send_to(
      user_id,
      {
        event: 'OnlineNotification::changed',
        data:  {}
      }
    )
  end

=begin

check if all notifications are seen for dedicated object

  OnlineNotification.all_seen?('Ticket', 123)

returns:

  true # false

=end

  def self.all_seen?(object_name, o_id)
    notifications = OnlineNotification.list_by_object(object_name, o_id)
    notifications.each do |onine_notification|
      return false if !onine_notification['seen']
    end
    true
  end

=begin

check if notification was created for certain user

  OnlineNotification.exists?(for_user, object, o_id, type, created_by_user, seen)

returns:

  true # false

=end

  # rubocop:disable Metrics/ParameterLists
  def self.exists?(user, object_name, o_id, type_name, created_by_user, seen)
    # rubocop:enable Metrics/ParameterLists
    object_id     = ObjectLookup.by_name(object_name)
    type_id       = TypeLookup.by_name(type_name)
    notifications = OnlineNotification.list(user, 10)
    notifications.each do |notification|
      next if notification.o_id != o_id
      next if notification.object_lookup_id != object_id
      next if notification.type_lookup_id != type_id
      next if notification.created_by_id != created_by_user.id
      next if notification.seen != seen

      return true
    end
    false
  end

=begin

cleanup old online notifications

  OnlineNotification.cleanup

with dedicated times

  max_age = Time.zone.now - 9.months
  max_own_seen = Time.zone.now - 10.minutes
  max_auto_seen = Time.zone.now - 8.hours

  OnlineNotification.cleanup(max_age, max_own_seen, max_auto_seen)

=end

  def self.cleanup(max_age = Time.zone.now - 9.months, max_own_seen = Time.zone.now - 10.minutes, max_auto_seen = Time.zone.now - 8.hours)
    OnlineNotification.where('created_at < ?', max_age).delete_all
    OnlineNotification.where('seen = ? AND updated_at < ?', true, max_own_seen).each do |notification|

      # delete own "seen" notifications after 1 hour
      next if notification.user_id == notification.updated_by_id && notification.updated_at > max_own_seen

      # delete notifications which are set to "seen" by somebody else after 8 hours
      next if notification.user_id != notification.updated_by_id && notification.updated_at > max_auto_seen

      notification.delete
    end

    # notify all agents
    User.with_permissions('ticket.agent').each do |user|
      Sessions.send_to(
        user.id,
        {
          event: 'OnlineNotification::changed',
          data:  {}
        }
      )
      sleep 2 # slow down client requests
    end

    true
  end

end