module Teams
  class StaffAssignmentError < StandardError
    attr_reader :message

    def initialize(message)
      @message = message
      super(message)
    end
  end

  class StaffAssignment
    def self.call(team:, user:, staff_kind:, membership: nil)
      new(team: team, user: user, staff_kind: staff_kind, membership: membership).call
    end

    def initialize(team:, user:, staff_kind:, membership: nil)
      @team = team
      @user = user
      @staff_kind = staff_kind.to_s
      @membership = membership
    end

    def call
      unless TeamInvitation::STAFF_KINDS.include?(@staff_kind)
        raise StaffAssignmentError, "Ruolo staff non valido"
      end

      StaffEmailValidator.assert_available!(team: @team, email: @user.email, staff_kind: @staff_kind, except_user: @user)

      ut = @membership || @user.user_teams.find_by!(team: @team)
      return ut if ut.staff_kind == @staff_kind

      ent = Entitlements.new(@team)
      ent.assert_can_invite!(staff_kind: @staff_kind)
      ut.update!(staff_kind: @staff_kind)
      ut
    end

  end

  class StaffEmailValidator
    def self.assert_available!(team:, email:, staff_kind:, except_user: nil)
      new(team: team, email: email, staff_kind: staff_kind, except_user: except_user).assert_available!
    end

    def initialize(team:, email:, staff_kind:, except_user: nil)
      @team = team
      @email = email.to_s.downcase.strip
      @staff_kind = staff_kind.to_s
      @except_user = except_user
    end

    def assert_available!
      if @except_user
        ut = @team.user_teams.find_by(user: @except_user)
        if ut&.staff_kind.present? && ut.staff_kind != @staff_kind
          other_label = ut.staff_kind == "regia" ? "regia" : "trasmissione"
          raise StaffAssignmentError,
                "Questo account è già staff #{other_label}. Trasmissione e regia devono essere email diverse."
        end
      end

      conflict = conflicting_assignment
      return unless conflict

      other_label = conflict[:kind] == "regia" ? "regia" : "trasmissione"
      raise StaffAssignmentError,
            "L'email #{@email} è già assegnata come staff #{other_label}. Trasmissione e regia devono essere persone (email) diverse."
    end

    def conflicting_assignment
      other_kind = @staff_kind == "transmission" ? "regia" : "transmission"

      user_scope = @team.user_teams.joins(:user).where(users: { email: @email }).where(staff_kind: other_kind)
      user_scope = user_scope.where.not(user_id: @except_user.id) if @except_user

      return { kind: other_kind, source: :member } if user_scope.exists?

      inv = @team.team_invitations.pending.where("LOWER(email) = ?", @email).where(staff_kind: other_kind)
      return { kind: other_kind, source: :invitation } if inv.exists?

      nil
    end
  end
end