# frozen_string_literal: true

# EventCreateService class
#
# Used for creating events feed on dashboard after certain user action
#
# Ex.
#   EventCreateService.new.new_issue(issue, current_user)
#
class EventCreateService
  IllegalActionError = Class.new(StandardError)

  def open_issue(issue, current_user)
    create_resource_event(issue, current_user, :opened)

    create_record_event(issue, current_user, Event::CREATED)
  end

  def close_issue(issue, current_user)
    create_resource_event(issue, current_user, :closed)

    create_record_event(issue, current_user, Event::CLOSED)
  end

  def reopen_issue(issue, current_user)
    create_resource_event(issue, current_user, :reopened)

    create_record_event(issue, current_user, Event::REOPENED)
  end

  def open_mr(merge_request, current_user)
    create_resource_event(merge_request, current_user, :opened)

    create_record_event(merge_request, current_user, Event::CREATED)
  end

  def close_mr(merge_request, current_user)
    create_resource_event(merge_request, current_user, :closed)

    create_record_event(merge_request, current_user, Event::CLOSED)
  end

  def reopen_mr(merge_request, current_user)
    create_resource_event(merge_request, current_user, :reopened)

    create_record_event(merge_request, current_user, Event::REOPENED)
  end

  def merge_mr(merge_request, current_user)
    create_resource_event(merge_request, current_user, :merged)

    create_record_event(merge_request, current_user, Event::MERGED)
  end

  def open_milestone(milestone, current_user)
    create_record_event(milestone, current_user, Event::CREATED)
  end

  def close_milestone(milestone, current_user)
    create_record_event(milestone, current_user, Event::CLOSED)
  end

  def reopen_milestone(milestone, current_user)
    create_record_event(milestone, current_user, Event::REOPENED)
  end

  def destroy_milestone(milestone, current_user)
    create_record_event(milestone, current_user, Event::DESTROYED)
  end

  def leave_note(note, current_user)
    create_record_event(note, current_user, Event::COMMENTED)
  end

  def join_project(project, current_user)
    create_event(project, current_user, Event::JOINED)
  end

  def leave_project(project, current_user)
    create_event(project, current_user, Event::LEFT)
  end

  def expired_leave_project(project, current_user)
    create_event(project, current_user, Event::EXPIRED)
  end

  def create_project(project, current_user)
    create_event(project, current_user, Event::CREATED)
  end

  def push(project, current_user, push_data)
    create_push_event(PushEventPayloadService, project, current_user, push_data)
  end

  def bulk_push(project, current_user, push_data)
    create_push_event(BulkPushEventPayloadService, project, current_user, push_data)
  end

  # Create a new wiki page event
  #
  # @param [WikiPage::Meta] wiki_page_meta The event target
  # @param [User] author The event author
  # @param [Integer] action One of the Event::WIKI_ACTIONS
  #
  # @return a tuple of event and either :found or :created
  def wiki_event(wiki_page_meta, author, action)
    return unless Feature.enabled?(:wiki_events)

    raise IllegalActionError, action unless Event::WIKI_ACTIONS.include?(action)

    if duplicate = existing_wiki_event(wiki_page_meta, action)
      return duplicate
    end

    event = create_record_event(wiki_page_meta, author, action)
    # Ensure that the event is linked in time to the metadata, for non-deletes
    unless action == Event::DESTROYED
      time_stamp = wiki_page_meta.updated_at
      event.update_columns(updated_at: time_stamp, created_at: time_stamp)
    end

    event
  end

  private

  def existing_wiki_event(wiki_page_meta, action)
    if action == Event::DESTROYED
      most_recent = Event.for_wiki_meta(wiki_page_meta).recent.first
      return most_recent if most_recent.present? && most_recent.action == action
    else
      Event.for_wiki_meta(wiki_page_meta).created_at(wiki_page_meta.updated_at).first
    end
  end

  def create_record_event(record, current_user, status)
    create_event(record.resource_parent, current_user, status, target_id: record.id, target_type: record.class.name)
  end

  def create_push_event(service_class, project, current_user, push_data)
    # We're using an explicit transaction here so that any errors that may occur
    # when creating push payload data will result in the event creation being
    # rolled back as well.
    event = Event.transaction do
      new_event = create_event(project, current_user, Event::PUSHED)

      service_class.new(new_event, push_data).execute

      new_event
    end

    Users::LastPushEventService.new(current_user)
      .cache_last_push_event(event)

    Users::ActivityService.new(current_user).execute
  end

  def create_event(resource_parent, current_user, status, attributes = {})
    attributes.reverse_merge!(
      action: status,
      author_id: current_user.id
    )

    resource_parent_attr = case resource_parent
                           when Project
                             :project
                           when Group
                             :group
                           end
    attributes[resource_parent_attr] = resource_parent if resource_parent_attr

    Event.create!(attributes)
  end

  def create_resource_event(issuable, current_user, status)
    return unless state_change_tracking_enabled?(issuable)

    ResourceEvents::ChangeStateService.new(resource: issuable, user: current_user)
      .execute(status)
  end

  def state_change_tracking_enabled?(issuable)
    issuable&.respond_to?(:resource_state_events) &&
      ::Feature.enabled?(:track_resource_state_change_events, issuable&.project)
  end
end

EventCreateService.prepend_if_ee('EE::EventCreateService')