public class FlatListAdapter extends RecyclerView.Adapter<FlatListAdapter.ViewHolder> {
    private ArrayList<FlatItemModel> flats;
    private Context context;

    private SparseBooleanArray likedItems;

    private int DP_FRIEND_AVATAR_SIZE;
    private int DP_FRIEND_AVATAR_MARGIN;

    public FlatListAdapter(Context context)
    {
        this.flats = new ArrayList<>();
        this.likedItems = new SparseBooleanArray();
        this.context = context;

        DP_FRIEND_AVATAR_SIZE = (int)context.getResources().getDimension(R.dimen.friendsAvatarDiameter);
        DP_FRIEND_AVATAR_MARGIN = (int)context.getResources().getDimension(R.dimen.indicatorMargin);
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.flat, parent, false);
        itemView.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));

        ViewHolder holder = new ViewHolder(itemView);

        return holder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        FlatItemModel flat = flats.get(position);
        if(likedItems.get(position))
        {
            holder.likeButton.setBackground(context.getResources().getDrawable(R.drawable.star_pressed));
        }
        else
        {
            holder.likeButton.setBackground(context.getResources().getDrawable(R.drawable.star_unpressed));
        }
        Glide.with(context).load(flat.getImageUrl()).into(holder.image);
        holder.address.setText(flat.getAddress());
        holder.metres.setText(flat.getMetres() + context.getResources().getString(R.string.m_square));
        holder.stage.setText(flat.getStage());
        holder.rooms.setText(flat.getRooms());
        holder.subwayStation.setText(flat.getSubwayStation());
        holder.timeToSubwayStation.setText(flat.getTimeToSubwayStation());
        holder.price.setText(flat.getPrice());
        holder.friendsAvatarHost.removeAllViewsInLayout();
        if(flat.getFriendPhotoUrls() != null) {
            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams((int)convertDpToPixel(DP_FRIEND_AVATAR_SIZE,
                    context), (int)convertDpToPixel(DP_FRIEND_AVATAR_SIZE, context));
            params.setMarginEnd((int) convertDpToPixel(DP_FRIEND_AVATAR_MARGIN, context));
            if(holder.friendsAvatarHost.getChildAt(0) == null) {
                for (int i = 0; i < 3 & i < flat.getFriendPhotoUrls().size(); i++) {
                    CircleImageView image = new CircleImageView(context);
                    Glide.with(context).load(flat.getFriendPhotoUrls().get(i)).into(image);
                    image.setLayoutParams(params);
                    holder.friendsAvatarHost.addView(image);
                }
                if (flat.getFriendPhotoUrls().size() > 3) {
                    TextView extraFriends = new TextView(context);
                    extraFriends.setLayoutParams(params);
                    extraFriends.setText("+" + (flat.getFriendPhotoUrls().size() - 3));
                    extraFriends.setBackground(context.getResources().getDrawable(R.drawable.round_friends_indicator));
                    extraFriends.setTextColor(holder.address.getTextColors());
                    extraFriends.setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
                    extraFriends.setPadding(0, (int) convertDpToPixel(6, context), 0, 0);
                    holder.friendsAvatarHost.addView(extraFriends);
                }
            }
        }

    }

    @Override
    public long getItemId(int position)
    {
        return flats.get(position).getId();
    }

    public static float convertDpToPixel(float dp, Context context){
        Resources resources = context.getResources();
        DisplayMetrics metrics = resources.getDisplayMetrics();
        float px = dp * ((float)metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT);
        return px;
    }

    @Override
    public int getItemCount() {
        return flats.size();
    }

    public void addItem(FlatItemModel flat)
    {
        this.flats.add(flat);
        Log.d("addItem", "position: " + (getItemCount() - 1));
        likedItems.append(this.getItemCount() - 1, flat.isFavorite());
    }

    class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener
    {
        ImageView image;
        Button likeButton;
        TextView address, metres, stage, rooms, subwayStation, timeToSubwayStation, price;
        LinearLayout friendsAvatarHost;
        public ViewHolder(View itemView) {
            super(itemView);
            image               = (ImageView) itemView.findViewById(R.id.flat_image);

            address             = (TextView) itemView.findViewById(R.id.flat_address);
            metres              = (TextView) itemView.findViewById(R.id.flat_metres);
            stage               = (TextView) itemView.findViewById(R.id.flat_stage);
            rooms               = (TextView) itemView.findViewById(R.id.flat_rooms);
            subwayStation       = (TextView) itemView.findViewById(R.id.flat_subway_station);
            timeToSubwayStation = (TextView) itemView.findViewById(R.id.flat_time_to_subway_station);
            price               = (TextView) itemView.findViewById(R.id.flat_price);

            friendsAvatarHost   = (LinearLayout) itemView.findViewById(R.id.flat_friends_images_host);

            likeButton          = (Button) itemView.findViewById(R.id.flat_like_button);
            likeButton.setOnClickListener(this);
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {
            if(v instanceof Button)
            {
                if(!likedItems.get(getLayoutPosition()))
                {
                    likeButton.setBackground(context.getResources().getDrawable(R.drawable.star_pressed));
                    flats.get(getAdapterPosition()).setIsFavorite(true);
                    likedItems.delete(getLayoutPosition());
                    likedItems.append(getLayoutPosition(), true);
                }
                else
                {
                    likeButton.setBackground(context.getResources().getDrawable(R.drawable.star_unpressed));
                    flats.get(getAdapterPosition()).setIsFavorite(false);
                    likedItems.delete(getLayoutPosition());
                    likedItems.append(getLayoutPosition(), false);
                }
            }
        }
    }
}