#include "puzzle_options.h"

// this macro just does the validation that is always the same
#define TILE_TO_IX(bail) \
    if (tile.value < '1' || tile.value > '9') { bail; } \
    uint8_t ix = tile.value - '1'

// all of these are set operations for a bitfield with 9 bits!
// (done in the most obvious way possible)

void puzzle_options_init(puzzle_options_t* puzzle_options) {
    puzzle_options->bitfield = 0x1FF;  // 9 set bits
}

void puzzle_options_add(puzzle_options_t* puzzle_options, tile_t tile) {
    TILE_TO_IX(return);
    puzzle_options->bitfield |= 1 << ix;
}

bool puzzle_options_remove(puzzle_options_t* puzzle_options, tile_t tile) {
    TILE_TO_IX(return false);

    uint16_t old = puzzle_options->bitfield;
    puzzle_options->bitfield &= ~(1 << ix);
    uint16_t new = puzzle_options->bitfield;

    return old != new;
}

bool puzzle_options_contains(puzzle_options_t* puzzle_options, tile_t tile) {
    TILE_TO_IX(return false);
    return (puzzle_options->bitfield & (1 << ix)) != 0;
}

uint8_t puzzle_options_count(puzzle_options_t* puzzle_options) {
    uint8_t count = 0;
    for (uint8_t ix = 0; ix < 9; ix++) {
        if ((puzzle_options->bitfield & (1 << ix)) != 0) {
            count++;
        }
    }
    return count;
}

bool puzzle_options_is_empty(puzzle_options_t* puzzle_options) {
    return puzzle_options->bitfield == 0;
}