Blue Archive Gacha Simulator

Here's an implementation of Blue Archive's Gacha System. I believe it to be correct, though I'm always willing to accept corrections if you have any!

Example

Here's what's needed in order to call .roll() and .roll10().

let mut file = File::open("students.json").unwrap();
let mut json = String::new();
file.read_to_string(&mut json).unwrap();

let students: Vec<Student> = serde_json::from_str(&json).unwrap();

This Repo contains students.json (in the examples directory) which is an Array where each object within the array contains a Student's Japanese name, English TL name and rarity.

let banner_students: Vec<Student> = students
    .iter()
    .filter(|student| student.name != "ノゾミ")
    .map(|student| student.clone())
    .collect();

let hoshino = find_student(&students, "ホシノ").unwrap();
let shiroko = find_student(&students, "シロコ").unwrap();
let rate_up_students = vec![shiroko, hoshino];

let gacha = GachaBuilder::new(79.0, 18.5, 2.5)
    .with_pool(banner_students)
    .with_priority(&rate_up_students, 0.7)
    .finish()
    .unwrap();

let pickup_banner = BannerBuilder::new("ピックアップ募集")
    .with_name_translation(Language::English, "Rate-Up Registration")
    .with_sparkable_students(&rate_up_students)
    .with_gacha(&gacha)
    .finish()
    .unwrap();

This example creates the ピックアップ募集 Banner which ran from 2021-02-04 to 2021-02-11. The only student in the game who was not in This banner was ノゾミ, so you can see her being filtered out of the list of all* students to create a list of students in the ピックアップ募集.

After this, we want to determine which units are on rate-up if there are any. In this example, ホシノ and シロコ have increased pull rates.

The Rest of the code consists of instantiating the Gacha and Banner structs using their respective Builders.

After this:

let student: Student = pickup_banner.roll();
// or 
let students: [Student; 10] = pickup_banner.roll10();

can be called (when the Recruitment trait is in scope) to allow for accurate simulation of Blue Archive's Gacha.