# frozen_string_literal: true

module Members
  # This class serves as more of an app-wide way we add/create members
  # All roads to add members should take this path.
  class CreatorService
    class << self
      def parsed_access_level(access_level)
        access_levels.fetch(access_level) { access_level.to_i }
      end

      def access_levels
        Gitlab::Access.sym_options_with_owner
      end

      def add_users( # rubocop:disable Metrics/ParameterLists
        source,
        users,
        access_level,
        current_user: nil,
        expires_at: nil,
        tasks_to_be_done: [],
        tasks_project_id: nil,
        ldap: nil,
        blocking_refresh: nil
      )
        return [] unless users.present?

        # If this user is attempting to manage Owner members and doesn't have permission, do not allow
        return [] if managing_owners?(current_user, access_level) && cannot_manage_owners?(source, current_user)

        emails, users, existing_members = parse_users_list(source, users)

        Member.transaction do
          (emails + users).map! do |user|
            new(source,
                user,
                access_level,
                existing_members: existing_members,
                current_user: current_user,
                expires_at: expires_at,
                tasks_to_be_done: tasks_to_be_done,
                tasks_project_id: tasks_project_id,
                ldap: ldap,
                blocking_refresh: blocking_refresh)
              .execute
          end
        end
      end

      def add_user( # rubocop:disable Metrics/ParameterLists
        source,
        user,
        access_level,
        current_user: nil,
        expires_at: nil,
        ldap: nil,
        blocking_refresh: nil
      )
        add_users(source,
                  [user],
                  access_level,
                  current_user: current_user,
                  expires_at: expires_at,
                  ldap: ldap,
                  blocking_refresh: blocking_refresh).first
      end

      private

      def managing_owners?(current_user, access_level)
        current_user && Gitlab::Access.sym_options_with_owner[access_level] == Gitlab::Access::OWNER
      end

      def parse_users_list(source, list)
        emails = []
        user_ids = []
        users = []
        existing_members = {}

        list.each do |item|
          case item
          when User
            users << item
          when Integer
            user_ids << item
          when /\A\d+\Z/
            user_ids << item.to_i
          when Devise.email_regexp
            emails << item
          end
        end

        # the below will automatically discard invalid user_ids
        users.concat(User.id_in(user_ids)) if user_ids.present?
        # de-duplicate just in case as there is no controlling if user records and ids are sent multiple times
        users.uniq!

        users_by_emails = source.users_by_emails(emails) # preloads our request store for all emails
        # in case emails belong to a user that is being invited by user or user_id, remove them from
        # emails and let users/user_ids handle it.
        parsed_emails = emails.select do |email|
          user = users_by_emails[email]
          !user || (users.exclude?(user) && user_ids.exclude?(user.id))
        end

        if users.present? || users_by_emails.present?
          # helps not have to perform another query per user id to see if the member exists later on when fetching
          existing_members = source.members_and_requesters.with_user(users + users_by_emails.values).index_by(&:user_id)
        end

        [parsed_emails, users, existing_members]
      end
    end

    def initialize(source, user, access_level, **args)
      @source = source
      @user = user
      @access_level = self.class.parsed_access_level(access_level)
      @args = args
    end

    private_class_method :new

    def execute
      find_or_build_member
      commit_member
      after_commit_tasks

      member
    end

    private

    delegate :new_record?, to: :member
    attr_reader :source, :user, :access_level, :member, :args

    def assign_member_attributes
      member.attributes = member_attributes
    end

    def commit_member
      if can_commit_member?
        assign_member_attributes
        commit_changes
      else
        add_commit_error
      end
    end

    def can_commit_member?
      # There is no current user for bulk actions, in which case anything is allowed
      return true if skip_authorization?

      if new_record?
        can_create_new_member?
      else
        can_update_existing_member?
      end
    end

    def can_create_new_member?
      raise NotImplementedError
    end

    def can_update_existing_member?
      raise NotImplementedError
    end

    # Populates the attributes of a member.
    #
    # This logic resides in a separate method so that EE can extend this logic,
    # without having to patch the `add_user` method directly.
    def member_attributes
      {
        created_by: member.created_by || current_user,
        access_level: access_level,
        expires_at: args[:expires_at]
      }
    end

    def commit_changes
      if member.request?
        approve_request
      else
        # Calling #save triggers callbacks even if there is no change on object.
        # This previously caused an incident due to the hard to predict
        # behaviour caused by the large number of callbacks.
        # See https://gitlab.com/gitlab-com/gl-infra/production/-/issues/6351
        # and https://gitlab.com/gitlab-org/gitlab/-/merge_requests/80920#note_911569038
        # for details.
        member.save if member.changed?
      end
    end

    def after_commit_tasks
      create_member_task
    end

    def create_member_task
      return unless member.persisted?
      return if member_task_attributes.value?(nil)
      return if member.member_task.present?

      member.create_member_task(member_task_attributes)
    end

    def member_task_attributes
      {
        tasks_to_be_done: args[:tasks_to_be_done],
        project_id: args[:tasks_project_id]
      }
    end

    def approve_request
      ::Members::ApproveAccessRequestService.new(current_user,
                                                 access_level: access_level)
                                            .execute(
                                              member,
                                              skip_authorization: ldap,
                                              skip_log_audit_event: ldap
                                            )
    end

    def current_user
      args[:current_user]
    end

    def skip_authorization?
      !current_user
    end

    def add_commit_error
      msg = if new_record?
              _('not authorized to create member')
            else
              _('not authorized to update member')
            end

      member.errors.add(:base, msg)
    end

    def find_or_build_member
      @user = parse_user_param

      @member = if user.is_a?(User)
                  find_or_initialize_member_by_user
                else
                  source.members.build(invite_email: user)
                end

      @member.blocking_refresh = args[:blocking_refresh]
    end

    # This method is used to find users that have been entered into the "Add members" field.
    # These can be the User objects directly, their IDs, their emails, or new emails to be invited.
    def parse_user_param
      case user
      when User
        user
      when Integer
        # might not return anything - this needs enhancement
        User.find_by(id: user) # rubocop:todo CodeReuse/ActiveRecord
      else
        # must be an email or at least we'll consider it one
        source.users_by_emails([user])[user] || user
      end
    end

    def find_or_initialize_member_by_user
      # We have to use `members_and_requesters` here since the given `members` is modified in the models
      # to act more like a scope(removing the requested_at members) and therefore ActiveRecord has issues with that
      # on build and refreshing that relation.
      existing_members[user.id] || source.members_and_requesters.build(user_id: user.id) # rubocop:disable CodeReuse/ActiveRecord
    end

    def ldap
      args[:ldap] || false
    end

    def existing_members
      args[:existing_members] || {}
    end
  end
end

Members::CreatorService.prepend_mod_with('Members::CreatorService')