use rand::distributions::{Alphanumeric, DistString};
use rusty_leveldb::{compressor, CompressorId, Options, DB};

const KEY_LEN: usize = 5;
const VAL_LEN: usize = 8;

fn gen_string(n: usize) -> String {
    Alphanumeric
        .sample_string(&mut rand::thread_rng(), n)
        .to_lowercase()
}

fn write(db: &mut DB, n: usize) {
    time_test::time_test!("write");
    for i in 0..n {
        let (k, v) = (gen_string(KEY_LEN), gen_string(VAL_LEN));

        db.put(k.as_bytes(), v.as_bytes()).unwrap();
        if i % (n / 100) == 0 {
            println!("{}/100 ...", i * 100 / n);
            db.flush().unwrap();
        }
    }

    {
        time_test::time_test!("write-flush");
        db.flush().unwrap();
    }
}

fn read(db: &mut DB, n: usize) -> usize {
    let mut succ = 0;
    time_test::time_test!("read");
    for _ in 0..n {
        let k = gen_string(KEY_LEN);

        if db.get(k.as_bytes()).is_some() {
            succ += 1;
        }
    }
    succ
}

fn main() {
    let n = 1_000_000;
    let m = 10;
    let path = "stresstestdb";
    let mut entries = 0;

    for i in 0..m {
        let opt = Options {
            compressor: compressor::SnappyCompressor::ID,
            ..Default::default()
        };
        let mut db = DB::open(path, opt).unwrap();
        write(&mut db, n);
        entries += n;
        println!("Wrote {} entries ({}/{})", entries, i + 1, m);

        let s = read(&mut db, n);
        println!("Read back {} entries (found {}) ({}/{})", n, s, i + 1, m);
    }
}