// Sample program that inserts and removes key-values like a deque.

use std::time::{Duration, SystemTime};

use clap::{App, Arg};
use rand::{Rng, RngCore, SeedableRng};
use rand_xorshift::XorShiftRng;

fn main() -> Result<(), grebedb::Error> {
    let matches = App::new("GrebeDB insert simulator")
        .arg(
            Arg::with_name("delay")
                .long("delay")
                .takes_value(true)
                .default_value("0.5")
                .help("Delay between insert/remove batches in seconds."),
        )
        .get_matches();

    let delay = matches.value_of("delay").unwrap();
    let delay = delay.parse::<f32>().unwrap();

    let path = std::path::PathBuf::from("grebedb_example_data/queue_simulator/");

    std::fs::create_dir_all(&path)?;

    let options = grebedb::Options::default();
    let mut db = grebedb::Database::open_path(path, options)?;

    let mut counter = 0u64;

    loop {
        let mut rng = XorShiftRng::seed_from_u64(counter);

        for _ in 0..rng.gen_range(50..150) {
            let duration = SystemTime::now()
                .duration_since(SystemTime::UNIX_EPOCH)
                .unwrap();
            let ms = duration.as_micros() as u64;
            let key = format!("{:016x}{:016x}", ms, counter);

            let mut rng = XorShiftRng::seed_from_u64(counter);
            let mut buffer = vec![0u8; 1024];
            rng.fill_bytes(&mut buffer);

            db.put(key, buffer)?;

            counter += 1;
        }

        let mut keys_to_remove = Vec::new();
        let mut cursor = db.cursor()?;

        for _ in 0..100 {
            if let Some((key, _value)) = cursor.next() {
                keys_to_remove.push(key);
            } else {
                break;
            }
        }

        for key in keys_to_remove {
            db.remove(key)?;
        }

        if delay > 0.0 {
            std::thread::sleep(Duration::from_secs_f32(delay))
        }
    }
}