use std::error::Error;
use std::fs;
use std::str;
use std::i64;
use std::collections::HashMap;

pub fn both(filename: &str) -> Result<(), Box<dyn Error>> {
    let contents = fs::read_to_string(filename)?;

    let mut lowest_sid = 2000;
    let mut highest_sid = 0;
    let mut sids: HashMap<i64, bool> = HashMap::new();

    for line in contents.lines() {
        let mut bstr = line.replace("B", "1");
        bstr = bstr.replace("F", "0");
        bstr = bstr.replace("R", "1");
        bstr = bstr.replace("L", "0");

        let sid = i64::from_str_radix(&bstr, 2).unwrap();
        sids.insert(sid, true);
        if sid > highest_sid {
            highest_sid = sid;
        }
        if sid < lowest_sid {
            lowest_sid = sid;
        }
    }

    let mut my_sid = 0;
    for i in lowest_sid..highest_sid {
        if !sids.contains_key(&i) {
            my_sid = i;
            break
        }
    }

    println!("Highest seat id seen: {}", highest_sid);
    println!("Missing seat id (so mine!): {}", my_sid);

    Ok(())
}