const std = @import("std");

pub fn Node(T: type) type {
	return struct {
		const Self = @This();

		parent: ?*Self = null,
		state: T,

		pub fn init(state: T) Self {
			return Self { .state = state };
		}

		pub fn push(self: *Self, state: T, allocator: std.mem.Allocator) !*Self {
			const node = try allocator.create(Self);
			node.parent = self;
			node.state = state;
			return node;
		}

		pub fn clone(self: *Self, state: T, allocator: std.mem.Allocator) !*Self {
			const node = try allocator.create(Self);
			node.parent = self.parent;
			node.state = state;
			return node;
		}

		pub fn pop(self: *Self, allocator: std.mem.Allocator) struct { T, ?*Self } {
			const parent = self.parent;
			const state = self.state;

			allocator.destroy(self);

			return .{ state, parent };
		}

		pub fn format(
			self: *const Self,
			comptime fmt: []const u8,
			options: std.fmt.FormatOptions,
			writer: anytype,
		) !void {
			_ = fmt;
			_ = options;

			try writer.print("Node {{ {} }}", .{ self.state });
		}
	};
}