1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
// Copyright 2020-2021 Ian Jackson and contributors to Otter
// SPDX-License-Identifier: AGPL-3.0-or-later
// There is NO WARRANTY.

use crate::prelude::*;

use parking_lot::Mutex;

#[derive(Deserialize,Debug,Clone,Default)]
#[serde(transparent)]
pub struct FakeRngSpec(Option<Vec<String>>);

impl FakeRngSpec {
  pub fn make_game_rng(self) -> RngWrap { RngWrap( match self.0 {
    None => None,
    Some(ents) => Some(Arc::new(Mutex::new(FakeRng {
      i: 0,
      ents,
    }))) }
  )}
}

#[derive(Debug,Clone)]
pub struct RngWrap (
  Option<Arc<Mutex<FakeRng>>>
);

#[derive(Debug)]
struct FakeRng {
  i: usize,
  ents: Vec<String>,
}

impl RngWrap {
  pub fn is_fake(&self) -> bool { self.0.is_some() }

  #[throws(MgmtError)]
  pub fn set_fake(&self, v: Vec<String>, _: AuthorisationSuperuser) {
    let mut fake = self.0.as_ref().ok_or(ME::RngIsReal)?.lock();
    fake.i = 0;
    fake.ents = v;
  }

  #[throws(as Option)]
  fn next_fake(&self) -> String {
    let mut fake = self.0.as_ref()?.lock();
    let e = fake.ents.get(fake.i)?.clone();
    fake.i += 1;
    fake.i %= fake.ents.len();
    e
  }

  pub fn shuffle<T:Copy>(&self, slice: &mut [T]) { match self.next_fake() {
    None => {
      let mut rng = thread_rng();
      slice.shuffle(&mut rng);
    },
    Some(s) => {
      let l = slice.len();
      let n: usize = s.parse().unwrap_or(0);
      let front = slice[0..n].to_owned();
      slice.copy_within(n.., 0);
      slice[l-n..].copy_from_slice(&front);
    },
  } }
}