const std = @import("std");

const mem = std.mem;
const Allocator = mem.Allocator;

const Group = @This();

gid: u32,
name: [:0]const u8,
//
members: [:null]const ?[:0]const u8,

pub fn clone(self: *const Group, allocator: Allocator) Allocator.Error!Group {
    var members = try allocator.allocSentinel(?[:0]const u8, self.members.len, null);
    errdefer allocator.free(members);
    members.len = self.members.len;

    for (self.members) |member, i| {
        const member_name = member.?;
        members[i] = try allocator.dupeZ(u8, member_name);
    }

    return Group{
        .gid = self.gid,
        .name = try allocator.dupeZ(u8, self.name),
        .members = members,
    };
}

pub fn deinit(self: *Group, allocator: Allocator) void {
    allocator.free(self.name);
    for (self.members) |member| {
        allocator.free(member.?);
    }
    allocator.free(self.members);
    self.* = undefined;
}

const testing = std.testing;

test "Group.clone" {
    // TODO: how to do this on stack?
    var member1 = try testing.allocator.dupeZ(u8, "member1");
    defer testing.allocator.free(member1);

    var group = Group{
        .gid = 1,
        .name = "foo",
        .members = &[_:null]?[:0]const u8{ member1, "member2", null },
    };

    var cloned = try group.clone(testing.allocator);
    defer cloned.deinit(testing.allocator);

    group.gid = 2;
    group.name = "bar";
    member1[0] = 'x';
    try testing.expectEqual(cloned.gid, 1);
    try testing.expectEqualSlices(u8, cloned.name, "foo");
    try testing.expectEqualSlices(u8, cloned.members[0].?, "member1");
}