use itertools::izip;
use std::collections::{HashMap};
use std::env;
use std::fs::File;
use std::io::{self, BufRead, BufReader};
use std::sync::mpsc::{channel, Receiver, Sender};
use std::time;
use std::thread;

type BusWidth = i128;
type IOType = i128;

fn read_program(filename: &str) -> Vec<BusWidth> {
    let f = File::open(filename).expect(filename);
    let f = BufReader::new(f);

    f.lines()
        .filter(|line| match line {
            Ok(s) => {
                let b = s.as_bytes();
                if b.len() == 0 || b.len() > 0 && b[0] == b'#' { false } else { true }
            },
            _ => true,
        })
        .map(|line| match line {
            Ok(line) => {
                let data:Vec<BusWidth> = line.split(',').map(|e| { e.trim_start().trim_end() })
                .filter(|v| match v.parse::<BusWidth>() { Ok(_) => true, _ => {
                            eprintln!("Could not parse: {:?}", v);
                        false
                    },
                })
                .map(|r| r.parse().unwrap())
                .collect();

                data
            },
            Err(_) => panic!("Could not parse {}.", filename),
        }).flatten().collect()
}

#[derive(Clone, Debug)]
struct Memory {
    mem: Vec<BusWidth>,
}

impl Memory {
    fn new() -> Memory {
        Memory { mem: Vec::new(), }
    }

    fn init(&mut self, mem:Vec<BusWidth>) {
        self.mem = mem;
    }

    fn read(&self, address: usize) -> BusWidth {
        match self.mem.get(address) {
            Some(value) => *value,
            None =>        0,
        }
    }

    fn write(&mut self, address: usize, value: BusWidth) {
        if self.len() < address {
            self.mem.resize(address*2, 0);
        }
        self.mem[address] = value;
    }

    fn len(&self) -> usize {
        self.mem.len()
    }
}

#[derive(Debug)]
struct Registers {
    ip: usize,
    base: usize,
}

#[derive(Debug)]
enum Arithm {
    Add,
    Mul,
    LessThan,
    Equals,
}

#[derive(Debug)]
enum IO {
    In,
    Out,
}

#[derive(Debug)]
enum Jmp {
    JmpTrue,
    JmpFalse,
}

#[derive(Debug)]
enum RegOp {
    BaseMod,
}

#[derive(Debug, PartialEq)]
enum ParameterMode {
    Position,
    Immediate,
    Relative,
}

#[derive(Debug, PartialEq)]
enum DataDirection {
    Read,
    Write,
}

struct Hack {
    out_counter: usize,
    outlog: Vec<IOType>,
    ball: (IOType, IOType),
    paddle: IOType,
}

impl Hack {
    fn new() -> Hack {
        Hack {
            out_counter: 0,
            outlog: vec![],
            ball: (0, 0),
            paddle: 0,
        }
    }
}

struct Intcode {
    r: Registers,
    sender: Sender<IOType>,
    receiver: Receiver<IOType>,
    hack: Hack,
}

struct Game {
    canvas: HashMap<(isize, isize), isize>,
    sender: Sender<IOType>,
    receiver: Receiver<IOType>,
    score: isize,
}

impl Game {
    fn new(sender: Sender<IOType>, receiver: Receiver<IOType>) -> Game {
        Game {
            canvas: HashMap::new(),
            sender,
            receiver,
            score: 0,
        }
    }

    fn run(&mut self) -> isize {
        loop {
            let (x, y, tile_id) = match izip!(self.receiver.iter(), self. receiver.iter(),
                self. receiver.iter()).next()
            {
                Some((x, y, t)) => (x as isize, y as isize, t as isize), _ => break,
            };

            if x ==-1 && y == 0 {
                if tile_id == 0 && self.score != 0 {
                    break;
                }
                self.score = tile_id;
            }
            self.canvas.insert((x, y), tile_id);
            self.draw_tiles();
        }

        self.score
    }


    fn draw_tiles(&mut self) {
        let min_x: isize = match self.canvas.keys().map(|(x, _)| x).min() {
            Some(v) => *v, _ => 0,
        };
        let max_x: isize = match self.canvas.keys().map(|(x, _)| x).max() {
            Some(v) => *v, _ => 0,
        };
        let min_y: isize = match self.canvas.keys().map(|(_, y)| y).min() {
            Some(v) => *v, _ => 0,
        };
        let max_y: isize = match self.canvas.keys().map(|(_, y)| y).max() {
            Some(v) => *v, _ => 0,
        };
        print!("");
        for y in min_y..=max_y {
            for x in min_x..=max_x {
                print!("{}", match self.canvas.get(&(x, y)) {
                    Some(1) => "██",
                    Some(2) => "██",
                    Some(3) => "██",
                    Some(4) => "◖◗",
                    _       => "  ",
                });
            }
            println!("");
        }
        print!("[{};0H", max_y+2);
        println!("Score: {}", self.score);
        println!("");
    }
}

impl Intcode {
    fn new(sender: Sender<IOType>, receiver: Receiver<IOType>) -> Intcode {
        Intcode {
            r: Registers { ip: 0, base: 0, },
            sender,
            receiver,
            hack: Hack::new(),
        }
    }

    fn param_to_argument(&self, mode: &ParameterMode, mem: &Memory, offset: usize,
                         dir: &DataDirection) -> usize
    {
        match mode {
            ParameterMode::Position =>  {
                if mem.read(offset) < 0 {
                    panic!("Attempt to address negative memory at IP: {}");
                }
                mem.read(offset) as usize
            },
            ParameterMode::Immediate => {
                if *dir == DataDirection::Write {
                    panic!("Immediate parameter mode at IP: {}", self.r.ip);
                }
                offset
            },
            ParameterMode::Relative => {
                if (mem.read(offset) + self.r.base as BusWidth) < 0 {
                    panic!("Attempt to address negative memory at IP: {}");
                }
                (mem.read(offset) + self.r.base as BusWidth) as usize
            },
        }
    }

    fn arithm(&self, op: Arithm, modes: Vec<ParameterMode>, memory: &mut Memory) {
        let parameter_directions =
            [DataDirection::Read, DataDirection::Read, DataDirection::Write];
        let params:Vec<usize> = (0..parameter_directions.len())
            .zip(parameter_directions.iter())
            .map(|(p, d)| {
                self.param_to_argument(&modes[p], memory, self.r.ip + 1 + p, d)
            }).collect();
        let left   = params[0];
        let right  = params[1];
        let result = params[2];

        match op {
            Arithm::Add =>      memory.write(result, memory.read(left) + memory.read(right)),
            Arithm::Mul =>      memory.write(result, memory.read(left) * memory.read(right)),
            Arithm::LessThan => memory.write(result, if memory.read(left) <  memory.read(right) {
                1 } else { 0 }),
            Arithm::Equals =>   memory.write(result, if memory.read(left) == memory.read(right) {
                1 } else { 0 }),
        }
    }

    fn jmp(&mut self, op: Jmp, modes: Vec<ParameterMode>, memory: &mut Memory)
    {
        let parameter_directions = [DataDirection::Read, DataDirection::Read];
        let params:Vec<usize> = (0..parameter_directions.len())
            .zip(parameter_directions.iter())
            .map(|(p, d)| {
                self.param_to_argument(&modes[p], memory, self.r.ip + 1 + p, d)
            }).collect();
        let value   = params[0];
        let address = params[1];

        self.r.ip = match op {
            Jmp::JmpTrue =>  (if memory.read(value) != 0 {
                memory.read(address) as usize } else { self.r.ip + 3 }),
            Jmp::JmpFalse => (if memory.read(value) == 0 {
                memory.read(address) as usize } else { self.r.ip + 3 }),
        };

    }

    fn regop(&mut self, op: RegOp, modes: Vec<ParameterMode>, memory: &mut Memory)
    {
        let parameter_directions = [DataDirection::Read];
        let params:Vec<usize> = (0..parameter_directions.len())
            .zip(parameter_directions.iter())
            .map(|(p, d)| {
                self.param_to_argument(&modes[p], memory, self.r.ip + 1 + p, d)
            }).collect();
        let value = memory.read(params[0]);

        match op {
            RegOp::BaseMod => {
                if value < 0 {
                    self.r.base -= (-1 * value) as usize;
                } else {
                    self.r.base += value as usize;
                }
            },
        };
    }

    fn io_in(&mut self, _op: IO, modes: Vec<ParameterMode>, memory:&mut Memory)
    {
        let parameter_directions = [DataDirection::Write];
        let params:Vec<usize> = (0..parameter_directions.len())
            .zip(parameter_directions.iter())
            .map(|(p, d)| {
                self.param_to_argument(&modes[p], memory, self.r.ip + 1 + p, d)
            }).collect();
        let address = params[0];

        let value = self.receiver.recv();
        match value {
            Ok(_) => {
                let v = if self.hack.paddle < self.hack.ball.0 {
                    1
                } else if self.hack.paddle > self.hack.ball.0 {
                    -1
                } else {
                    0
                };
                memory.write(address, v)
            },
            _ => panic!("Could not receive input. Remote disappeared."),
        }
    }

    fn io_out(&mut self, _op: IO, modes: Vec<ParameterMode>, memory:&mut Memory )
    {
        let parameter_directions = [DataDirection::Read];
        let params:Vec<usize> = (0..parameter_directions.len())
            .zip(parameter_directions.iter())
            .map(|(p, d)| {
                self.param_to_argument(&modes[p], memory, self.r.ip + 1 + p, d)
            }).collect();
        let address = params[0];

        let o = memory.read(address);
        self.sender.send(o as IOType).expect("Communication error. Nothing connected to CPU?");
        if (self.hack.out_counter % 3) == 0 {
            self.hack.outlog = Vec::new();
        }
        self.hack.outlog.push(o);
        self.hack.out_counter += 1;
        if (self.hack.out_counter % 3) == 0 {
            match self.hack.outlog[2] {
                3 => self.hack.paddle = self.hack.outlog[0],
                4 => self.hack.ball = ( self.hack.outlog[0], self.hack.outlog[1] ),
                _ => {},
            };
        }
    }

    fn intcode(&mut self, mut memory: Memory)
    {
        while self.r.ip < memory.len() {
            let op = memory.read(self.r.ip) % 100;
            let modes:Vec<ParameterMode> = (2..=4)
                .map(|e| memory.read(self.r.ip) / 10i32.pow(e) as BusWidth % 10)
                .map(|n| match n {
                    0 => ParameterMode::Position,
                    1 => ParameterMode::Immediate,
                    2 => ParameterMode::Relative,
                    p => panic!("Invalid parameter mode {} at IP: {}", p, self.r.ip),
                }).collect();

            match op {
                1 => { self.arithm(Arithm::Add,      modes, &mut memory); self.r.ip += 4 },
                2 => { self.arithm(Arithm::Mul,      modes, &mut memory); self.r.ip += 4 },
                7 => { self.arithm(Arithm::LessThan, modes, &mut memory); self.r.ip += 4 },
                8 => { self.arithm(Arithm::Equals,   modes, &mut memory); self.r.ip += 4 },
                3 => { self.io_in( IO::In,           modes, &mut memory); self.r.ip += 2 },
                4 => { self.io_out(IO::Out,          modes, &mut memory); self.r.ip += 2 },
                5 => { self.jmp(  Jmp::JmpTrue,      modes, &mut memory); },
                6 => { self.jmp(  Jmp::JmpFalse,     modes, &mut memory); },
                9 => { self.regop(RegOp::BaseMod,    modes, &mut memory); self.r.ip += 2},
                99 => break,
                op => panic!("Invalid operation {} at IP: {}", op, self.r.ip),
            }
        }
    }
}

fn play_game(program: &String) -> isize {
    let mut memory = Memory::new();
    memory.init(read_program(&program));
    memory.write(0,2);
    let ( cpu_sender, game_receiver ): (Sender<IOType>, Receiver<IOType>) = channel();
    let ( main_sender, cpu_receiver ): (Sender<IOType>, Receiver<IOType>) = channel();
    let ( game_sender, f ): (Sender<IOType>, Receiver<IOType>) = channel();
    let mut cpu = Intcode::new(cpu_sender, cpu_receiver);
    let mut game = Game::new(game_sender, game_receiver);

    eprintln!("Spawning cpu");
    let cpu_handler = thread::spawn(move || cpu.intcode(memory.clone()));
    eprintln!("Spawning game");
    let game_handler = thread::spawn(move || {
        let n = game.run();
        n
    });

    eprintln!("Starting loop");
    loop {
        let v = 0;
        match main_sender.send(v) {
            Ok(_) => {},
            _ => {break;}
        }
    }

    cpu_handler.join().expect("Problem with cpu thread.");
    match game_handler.join() {
        Ok(v) => v,
        _     => -1,
    }
}

fn main() {
    let args: Vec<String> = env::args().collect();

    let mut opts = getopts::Options::new();
    opts.optflag("e", "use-emergency-panel", "Place white panel at (0,0)");
    opts.reqopt("p", "program", "File to load program from", "FILE");
    let matches = match opts.parse(&args[1..]) {
        Ok(m) => { m }
        Err(f) => { panic!(f.to_string()) }
    };
    let program: String = matches.opt_str("program").unwrap();
    let score = play_game(&program);
    eprintln!("Final score {}", score);
}