use aoc2019::*;
use rpds::vector::Vector;
use rpds::RedBlackTreeMap;
use std::io;
use std::io::prelude::*;
use std::process;
use structopt::StructOpt;

#[derive(Debug, StructOpt)]
#[structopt(name = "Day 13: Care Package")]
/// Executes an Intcode game
///
/// The program is read from stdin as a series of comma-separated
/// values. Newlines are ignored.
///
/// See https://adventofcode.com/2019/day/13 for details.
struct Opt {
    #[structopt(short = "i", long = "input")]
    input: Vec<Intcode>,
}

fn main() {
    let stdin = io::stdin();
    let opt = Opt::from_args();

    let program: IntcodeProgram = stdin
        .lock()
        .split(b',')
        .map(|x| exit_on_failed_assertion(x, "Error reading input"))
        .map(|x| exit_on_failed_assertion(String::from_utf8(x), "Input was not valid UTF-8"))
        .map(|x| exit_on_failed_assertion(x.trim().parse::<Intcode>(), "Invalid number"))
        .collect::<IntcodeProgram>()
        .with_input(opt.input.into_iter().collect());

    let result = exit_on_failed_assertion(program.execute(), "Program errored");

    println!("{}", count_blocks(result));
}

fn exit_on_failed_assertion<A, E: std::error::Error>(data: Result<A, E>, message: &str) -> A {
    match data {
        Ok(data) => data,
        Err(e) => {
            eprintln!("{}: {}", message, e);
            process::exit(1);
        }
    }
}

fn render_screen(output: Vector<Intcode>) -> RedBlackTreeMap<(Intcode, Intcode), Intcode> {
    (0..output.len() / 3)
        .map(|i| i * 3)
        .map(|i| {
            (
                output[i].clone(),
                output[i + 1].clone(),
                output[i + 2].clone(),
            )
        })
        .fold(RedBlackTreeMap::new(), |acc, (x, y, tile)| {
            acc.insert((x, y), tile)
        })
}

fn count_blocks(output: Vector<Intcode>) -> usize {
    render_screen(output)
        .values()
        .filter(|val| **val == Intcode::from(2))
        .count()
}