public class ChatRecyclerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    private static final int VIEW_TYPE_SYSTEM = 0;
    private static final int VIEW_TYPE_OUTGOING = 1;
    private static final int VIEW_TYPE_INBOX = 2;

    private List<ChatMessageModel> mMessages;
    public ChatRecyclerAdapter(List<ChatMessageModel> messages) {
        mMessages = messages;
    }

    public void add(ChatMessageModel chatMessage) {
        mMessages.add(chatMessage);
        notifyItemInserted(mMessages.size() - 1);
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
        RecyclerView.ViewHolder viewHolder = null;

        switch (viewType) {
            case VIEW_TYPE_OUTGOING:
                View viewMessageOutgoing = layoutInflater.inflate(R.layout.item_chat_outgoing, parent, false);
                viewHolder = new OutgoingMessageViewHolder(viewMessageOutgoing);
                break;
            case VIEW_TYPE_INBOX:
                View viewMessageInbox = layoutInflater.inflate(R.layout.item_chat_inbox, parent, false);
                viewHolder = new InboxMessageViewHolder(viewMessageInbox);
                break;
        }
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        if (mMessages.get(position).getSenderId().equals(UserSession.getInstance().getCurrentUid())) {
            configureOutgoingMessageViewHolder((OutgoingMessageViewHolder) holder, position);
        } else {
            configureInboxMessageViewHolder((InboxMessageViewHolder) holder, position);
        }
    }

    private void configureOutgoingMessageViewHolder(OutgoingMessageViewHolder outgoingMessageViewHolder, int position) {
        ChatMessageModel chatMessage = mMessages.get(position);
        Log.i("TEST", chatMessage.getMessage());

        outgoingMessageViewHolder.txtMessageText.setText(chatMessage.getMessage());
    }

    private void configureInboxMessageViewHolder(InboxMessageViewHolder inboxMessageViewHolder, int position) {
        ChatMessageModel chatMessage = mMessages.get(position);

        Log.i("TEST", chatMessage.getMessage());

        inboxMessageViewHolder.txtMessageText.setText(chatMessage.getMessage());
    }

    @Override
    public int getItemCount() {
        if (mMessages != null) {
            return mMessages.size();
        }
        return 0;
    }

    @Override
    public int getItemViewType(int position) {
        if (mMessages.get(position).getSenderId().equals(UserSession.getInstance().getCurrentUid())) {
            return VIEW_TYPE_OUTGOING;
        } else {
            return VIEW_TYPE_INBOX;
        }
    }

    private static class OutgoingMessageViewHolder extends RecyclerView.ViewHolder {
        private TextView txtMessageText;
        public OutgoingMessageViewHolder(View itemView) {
            super(itemView);
            txtMessageText = (TextView) itemView.findViewById(R.id.text_view_message_text);
        }
    }

    private static class InboxMessageViewHolder extends RecyclerView.ViewHolder {
        private TextView txtMessageText;

        public InboxMessageViewHolder(View itemView) {
            super(itemView);
            txtMessageText = (TextView) itemView.findViewById(R.id.text_view_message_text);
        }
    }
}