Argumentation can serve as an effective computational tool and as a useful abstraction for various agent activities and in particular for agent reasoning. In this paper we further support this claim by mapping a form of normative BDI agents onto assumption-based argumentation. By way of this mapping we equip our agents with the capability of resolving conflicts amongst norms, beliefs, desires and intentions. This conflict resolution is achieved by using a variety of agents' preferences, ranging from total to partial orderings over norms, beliefs, desires and intentions, to entirely dynamic preferences defined in terms of rules. We define one mapping for each preference representation. We illustrate the mappings with examples and use an existing computational tool for assumption-based argumentation, the CaSAPI system, to animate conflict resolution within our agents. Finally, we study how the different mappings relate to one another.