use std::io;
use std::io::BufRead;
use std::collections::HashSet;
use crate::device::*;

#[allow(dead_code)]
fn optimise(mut instrs: Vec<Instr>, ip_reg: usize) -> Vec<Instr> {
    for i in 0..instrs.len() {
        instrs[i].inline_reg(ip_reg, Oper::Num(i));
    }

    instrs
}

#[allow(dead_code)]
fn run_program(instrs: &[Instr], r0: usize, ip_reg: usize) -> usize {
    let mut m = Machine { regs: [r0, 0, 0, 0, 0, 0] };
    m.exec_program(&instrs, ip_reg);
    m.regs[0]
}

pub fn main<T: BufRead>(reader: T) -> io::Result<(String, String)> {
    let (ip_reg, instrs) = parse_program(reader)?;

    let instrs = optimise(instrs, ip_reg);

    // for instr in &instrs { println!("{}", instr); }

    let part1;

    let mut ip = 0;
    let mut m = Machine { regs: [0, 0, 0, 0, 0, 0] };
    loop {
        assert!(ip < instrs.len());
        if ip == 28 {
            part1 = m.regs[4];
            break;
        }
        m.regs[ip_reg] = ip;
        m.exec(&instrs[ip]);
        ip = m.regs[ip_reg] + 1;
    }

    let mut part2 = None;

    let mut seen_machines = HashSet::new();
    let mut seen_values = HashSet::new();

    loop {
        assert!(ip < instrs.len());
        if ip == 28 {
            // println!("{:?}", m);
            if seen_machines.contains(&m) {
                break;
            }
            seen_machines.insert(m.clone());
            if !seen_values.contains(&m.regs[4]) {
                part2 = Some(m.regs[4]);
                seen_values.insert(m.regs[4]);
            }
        }
        m.regs[ip_reg] = ip;
        m.exec(&instrs[ip]);
        ip = m.regs[ip_reg] + 1;
    }

    Ok((part1.to_string(), part2.unwrap().to_string()))
}