#pragma once

namespace roro {

// Selection and scrolling for a grid of `cols` columns showing `visibleRows` rows at a time, filled
// row by row. Left and Right go through every item and wrap around; Up and Down stay in the
// column and wrap around, landing on the last item where the last row has no such column.
class GridModel {
   public:
    GridModel(int cols, int visibleRows) : cols_(cols), rows_(visibleRows) {}

    void setCount(int count);
    int count() const { return count_; }
    int selected() const { return selected_; }  // -1 when empty
    int cols() const { return cols_; }
    int rows() const { return count_ ? (count_ - 1) / cols_ + 1 : 0; }
    int firstVisibleRow() const { return first_; }
    int visibleRows() const { return rows_; }

    void select(int index);
    void left();
    void right();
    void up();
    void down();

   private:
    int cols_, rows_;
    int count_ = 0;
    int selected_ = -1;
    int first_ = 0;
};

}  // namespace roro