const Colors = enum {
    white,
    black,
};

    }
    fn setSlice(self: *@This(), squares: []Square) void {
        for (squares) |square| {
            self.set(square);
        }

        std.debug.print("\n", .{});

fn genPawnAttack() [@typeInfo(Colors).Enum.fields.len][@typeInfo(Square).Enum.fields.len]BoardType {
    var ret: [2][64]BoardType = [_][64]BoardType{[_]BoardType{0} ** 64} ** 2;
    const a_file = blk: {
        var bb: BitBoard = .{};
        var a_set = [_]Square{ .a8, .a7, .a6, .a5, .a4, .a3, .a2, .a1 };
        bb.setSlice(&a_set);
        break :blk bb.board;
    };
    const h_file = blk: {
        var bb: BitBoard = .{};
        var h_set = [_]Square{ .h8, .h7, .h6, .h5, .h4, .h3, .h2, .h1 };
        bb.setSlice(&h_set);
        break :blk bb.board;
    };
    var bb: BitBoard = .{};
    for (std.enums.values(Colors)) |color| {
        for (std.enums.values(Square)) |square| {
            bb.board = 0;
            bb.set(square);
            switch (color) {
                .white => {
                    // towards lower file
                    if (bb.board & a_file == 0)
                        ret[@enumToInt(color)][@enumToInt(square)] += bb.board >> 9;
                    // towards higher file
                    if (bb.board & h_file == 0)
                        ret[@enumToInt(color)][@enumToInt(square)] += bb.board >> 7;
                },
                .black => {
                    // towards higher file
                    if (bb.board & h_file == 0)
                        ret[@enumToInt(color)][@enumToInt(square)] += bb.board << 9;
                    // towards lower file
                    if (bb.board & a_file == 0)
                        ret[@enumToInt(color)][@enumToInt(square)] += bb.board << 7;
                },
            }
        }
    }
    return ret;
}
test "PawnAttack" {
    const pa = genPawnAttack();
    { // White
        {
            var bb: BitBoard = .{};
            bb.set(.c5);
            bb.set(.e5);
            try std.testing.expectEqual(
                bb.board,
                pa[@enumToInt(Colors.white)][@enumToInt(Square.d4)],
            );
        }
        {
            // no left attack
            var bb: BitBoard = .{};
            bb.set(.b5);
            try std.testing.expectEqual(
                bb.board,
                pa[@enumToInt(Colors.white)][@enumToInt(Square.a4)],
            );
        }
        {
            // no right attack
            var bb: BitBoard = .{};
            bb.set(.g5);
            try std.testing.expectEqual(
                bb.board,
                pa[@enumToInt(Colors.white)][@enumToInt(Square.h4)],
            );
        }
    }
    { // Black
        {
            var bb: BitBoard = .{};
            bb.set(.c3);
            bb.set(.e3);
            try std.testing.expectEqual(
                bb.board,
                pa[@enumToInt(Colors.black)][@enumToInt(Square.d4)],
            );
        }
        {
            // no left attack
            var bb: BitBoard = .{};
            bb.set(.b3);
            try std.testing.expectEqual(
                bb.board,
                pa[@enumToInt(Colors.black)][@enumToInt(Square.a4)],
            );
        }
        {
            // no right attack
            var bb: BitBoard = .{};
            bb.set(.g3);
            try std.testing.expectEqual(
                bb.board,
                pa[@enumToInt(Colors.black)][@enumToInt(Square.h4)],
            );
        }
    }
}