#include "interference.h"

// Convert a two-dimensional coordinate into a one-dimensional cell index.
#define PACK(x, y) ((y * SZ) + x)

interference_t interference;

void interference_init() {
    for (uint8_t y = 0; y < SZ; y++) {
        for (uint8_t x = 0; x < SZ; x++) {
            uint8_t cell = PACK(x, y);
            cellset_t *row = &interference.rows[cell];
            cellset_init(row);

            // rows
            for (uint8_t ox = 0; ox < SZ; ox++) {
                cellset_add_exclude(row, cell, PACK(ox, y));
            }

            // columns
            for (uint8_t oy = 0; oy < SZ; oy++) {
                cellset_add_exclude(row, cell, PACK(x, oy));
            }

            // boxes
            uint8_t box_x = (x / 3) * 3;
            uint8_t box_y = (y / 3) * 3;

            for (uint8_t oy = box_y; oy < box_y + 3; oy++) {
                for (uint8_t ox = box_x; ox < box_x + 3; ox++) {
                    cellset_add_exclude(row, cell, PACK(ox, oy));
                }
            }
        }
    }
}