test "Grid usize" {
    var d = try Grid(usize, 100, 100).ParseGridFromCSV("grid-test.txt", ",");

test "Grid usize horizontal-vertical" {
    var d = try Grid(usize, 100, 100, .HV).ParseGridFromCSV("grid-test.txt", ",");
    const ret = try d.dijkstra(std.testing.allocator, .{ 0, 0 }, .{ 99, 99 });
    try std.testing.expectEqual(@as(usize, 366), ret);
}
test "Grid usize move down and right" {
    var d = try Grid(usize, 100, 100, [2][2]isize{ .{ 0, 1 }, .{ 1, 0 } }).ParseGridFromCSV("grid-test.txt", ",");

    var d = try Grid(isize, 100, 100).ParseGridFromCSV("grid-test.txt", ",");

    var d = try Grid(isize, 100, 100, .diagonal).ParseGridFromCSV("grid-test.txt", ",");

    try std.testing.expectEqual(@as(isize, 366), ret);

    try std.testing.expectEqual(@as(isize, 257), ret);

    var d = try Grid(f64, 100, 100).ParseGridFromCSV("grid-test.txt", ",");

    var d = try Grid(f64, 100, 100, .all).ParseGridFromCSV("grid-test.txt", ",");

    try std.testing.expectEqual(@as(f64, 366), ret);

    try std.testing.expectEqual(@as(f64, 181), ret);

pub fn Grid(comptime T: type, comptime GRID_ROWS: usize, comptime GRID_COLS: usize) type {

pub const D2Neighbour = enum {
    horizontal,
    vertical,
    HV,
    diagonal,
    all,
};
const horizontal = [_][2]isize{ .{ 0, -1 }, .{ 0, 1 } };
const vertical = [_][2]isize{ .{ -1, 0 }, .{ 1, 0 } };
const HV = horizontal ++ vertical;
const diagonal = [_][2]isize{ .{ -1, -1 }, .{ -1, 1 }, .{ 1, -1 }, .{ 1, 1 } };
const all = HV ++ diagonal;
pub fn Grid(comptime T: type, comptime GRID_ROWS: usize, comptime GRID_COLS: usize, dir: anytype) type {
    const dir_slice: [][]isize = blk: {
        var dir_array = switch (@typeInfo(@TypeOf(dir))) {
            .EnumLiteral, .Enum => switch (std.enums.nameCast(D2Neighbour, dir)) {
                .horizontal => horizontal,
                .vertical => vertical,
                .HV => HV,
                .diagonal => diagonal,
                .all => all,
            },
            else => dir,
        };
        var ret: [dir_array.len][]isize = undefined;
        for (dir_array) |*sub_array_ptr, idx| ret[idx] = sub_array_ptr;
        break :blk ret[0..];
    };

        directions: [][]isize = dir_slice,

            // XXX: add AutoNeighbours()!
            const directions = [_][2]i2{
                .{ -1, 0 },
                .{ 1, 0 },
                .{ 0, -1 },
                .{ 0, 1 },
            };

                for (directions) |d| {

                for (self.directions) |d| {