use serde::{Deserialize, Serialize};
use serde_json::{Value, value::RawValue};
use std::hint::black_box;
use std::time::Instant;

#[derive(Deserialize)]
struct Input {
    source: Box<RawValue>,
    update: bool,
    ticks: String,
}

#[derive(Serialize)]
struct Sample {
    elapsed_ns: u128,
    checksum: usize,
    output: String,
}

fn transform(source: &str, update: bool) -> String {
    let mut value: Value = serde_json::from_str(source).expect("valid JSON input");
    let object = value.as_object_mut().expect("object input");
    if update {
        object.insert("active".into(), Value::Bool(true));
        serde_json::to_string(&value).expect("serializable object")
    } else {
        serde_json::to_string(object.get("data").expect("data field")).expect("serializable value")
    }
}

fn main() {
    let argument = std::env::args().nth(1).expect("one JSON argument");
    let input: Input = serde_json::from_str(&argument).expect("valid input fields");
    let output = transform(input.source.get(), input.update);
    let mut checksum = 0;
    let started = Instant::now();
    for _ in input.ticks.bytes() {
        checksum += transform(black_box(input.source.get()), input.update).len();
    }
    let sample = Sample {
        elapsed_ns: started.elapsed().as_nanos(),
        checksum,
        output,
    };
    println!("{}", serde_json::to_string(&sample).unwrap());
}