day11.rs

use std::io::{BufReader, BufRead};
use std::fs::File;
use std::collections::HashMap;


struct Machine {
    prog_ptr: i64,
    relative_base: i64,
    program: Vec<i64>,
    input: Vec<i64>,
    output: Vec<i64>,
    state: MachineState
}

#[derive(PartialEq)]
enum MachineState {
    ReadyToRun,
    WaitingForInput,
    OutputAvailable,
    Terminated
}

enum InstructionResult {
    Continue,
    WaitForInput,
    OutputDelivered,
    Invalid,
    Exit
}

enum ParameterMode {
    Position = 0,
    Direct = 1,
    Relative= 2
}

impl Machine {
    fn resume(&mut self) {
        loop {
            let a = self.run_one_instruction();
            match a {
                InstructionResult::Continue => { self.state = MachineState::ReadyToRun },
                InstructionResult::WaitForInput => { self.state = MachineState::WaitingForInput; break; },
                InstructionResult::OutputDelivered => { self.state = MachineState::OutputAvailable; break; },
                InstructionResult::Exit => { self.state = MachineState::Terminated; break; },
                _ => panic!("Unexpected action."),
            }
        }    
    }

    fn grow_storage_if_required(&mut self, location: i64) {
        if location >= self.program.len() as i64 {
            self.program.resize((location + 1) as usize, 0)
        }
    }

    fn get(&mut self, location: i64) -> i64 {
        self.grow_storage_if_required(location);
        self.program[location as usize]
    }

    fn put(&mut self, location: i64, value: i64) {
        self.grow_storage_if_required(location);
        self.program[location as usize] = value;
    }

    fn next_cell(&mut self) -> i64 {
        let ind = self.prog_ptr;
        self.prog_ptr += 1;
        self.get(ind)
    }

    fn get_parameter_value(&mut self, mode: i64) -> i64 {
        let value = self.next_cell();
        if mode == ParameterMode::Position as i64 {
            return self.get(value)
        } else if mode == ParameterMode::Direct as i64 {
            return value
        } else if mode == ParameterMode::Relative as i64 {
            return self.get(value + self.relative_base)
        } else {
            panic!("Unknown parameter mode: {}", mode)
        }
    }

    fn get_storage_location(&mut self, mode: i64) -> i64 {
        if mode == ParameterMode::Relative as i64 {
            self.next_cell() + self.relative_base
        } else {
            self.next_cell()
        }
    }

    const ADD: i64 =  1;
    const MULT: i64 =  2;
    const INPUT: i64 = 3;
    const OUTPUT: i64 = 4;
    const JUMP_TRUE: i64 = 5;
    const JUMP_FALSE: i64 = 6;
    const LESS_THAN: i64 = 7;
    const EQUALS: i64 = 8;
    const RELATIVE_BASE_OFFSET: i64 = 9;
    const EXIT: i64 =  99;

    fn run_one_instruction(&mut self) -> InstructionResult {
        let saved_prog_ptr = self.prog_ptr;
        let next_instruction_code = self.next_cell();
        let next_op_code = next_instruction_code % 100;
        let mode_par_1 =  (next_instruction_code / 100) % 10;
        let mode_par_2 = (next_instruction_code / 1000) % 10;
        let mode_par_3 = (next_instruction_code / 10000) % 10;
        match next_op_code {
            Machine::ADD => {
                let t1 = self.get_parameter_value(mode_par_1);
                let t2 = self.get_parameter_value(mode_par_2);
                let store_at = self.get_storage_location(mode_par_3);
                self.put(store_at, t1 + t2);
                InstructionResult::Continue
            },
            Machine::MULT => {
                let f1 = self.get_parameter_value(mode_par_1);
                let f2 = self.get_parameter_value(mode_par_2);
                let store_at = self.get_storage_location(mode_par_3);
                self.put(store_at, f1 * f2);
                InstructionResult::Continue
            },
            Machine::INPUT => {
                if !self.input.is_empty() {
                    let store_at = self.get_storage_location(mode_par_1);
                    let c = self.input.remove(0);
                    self.put(store_at, c);
                    InstructionResult::Continue
                } else {
                    self.prog_ptr = saved_prog_ptr;
                    InstructionResult::WaitForInput
                }
            },
            Machine::JUMP_TRUE => {
                let value = self.get_parameter_value(mode_par_1);
                let jump_target = self.get_parameter_value(mode_par_2);
                if value != 0 {
                    self.prog_ptr = jump_target
                }
                InstructionResult::Continue
            },
            Machine::JUMP_FALSE => {
                let value = self.get_parameter_value(mode_par_1);
                let jump_target = self.get_parameter_value(mode_par_2);
                if value == 0 {
                    self.prog_ptr = jump_target
                }
                InstructionResult::Continue
            },
            Machine::LESS_THAN => {
                let p1 = self.get_parameter_value(mode_par_1);
                let p2 = self.get_parameter_value(mode_par_2);
                let store_at = self.get_storage_location(mode_par_3);
                let result = if p1 < p2 { 1 } else { 0 };
                self.put(store_at, result);
                InstructionResult::Continue
            },
            Machine::EQUALS => {
                let p1 = self.get_parameter_value(mode_par_1);
                let p2 = self.get_parameter_value(mode_par_2);
                let store_at = self.get_storage_location(mode_par_3);
                let result = if p1 == p2 { 1 } else { 0 };
                self.put(store_at, result);
                InstructionResult::Continue
            },
            Machine::OUTPUT => {
                let v = self.get_parameter_value(mode_par_1);
                self.output.push(v);
                InstructionResult::OutputDelivered
            },
            Machine::RELATIVE_BASE_OFFSET => {
                let v = self.get_parameter_value(mode_par_1);
                self.relative_base += v;
                InstructionResult::Continue
            },
            Machine::EXIT => InstructionResult::Exit,
            _ => InstructionResult::Invalid
        }
    }    
}

fn load_program(program_file: &String) -> Vec<i64> {
    let mut prog: Vec<i64> = vec![];
    let file = File::open(program_file).expect("Could not open program file!");
    let reader = BufReader::new(file);

    let line = reader.lines().next().expect("Could not read from file");
    let line = line.expect("No string there.");
    for s in line.split(",") {
        let c = i64::from_str_radix(&s, 10).expect("Could not parse int");
        prog.push(c);
    }
    prog
}

fn main() {
    let program_file = "prog".to_string();
    let program: Vec<i64> = load_program(&program_file);
    let mut machine = Machine {
        prog_ptr: 0,
        relative_base: 0,
        program: program.clone(),
        input: vec!(),
        output: vec!(),
        state: MachineState::ReadyToRun
    };

    let mut robot = PaintingRobot {
        position: (0,0),
        state: RobotState::ReadyToPaint,
        painted_boards: HashMap::new(),
        direction: Direction::Up,
    };

   robot.paint_at_current_position(Color::White);

    loop {
        match machine.state {
            MachineState::Terminated => break,
            MachineState::OutputAvailable => {
                match robot.state {
                    RobotState::ReadyToPaint => {
                        let color_value = machine.output.remove(0);
                        let color = match color_value {
                            0 => Color::Black,
                            1 => Color::White,
                            _ => panic!("Unexpected color code {}", color_value)
                        };
                        robot.paint_at_current_position(color as Color);
                        robot.state = RobotState::ReadyToTurn;
                    },
                    RobotState::ReadyToTurn => {
                        let turn_value = machine.output.remove(0);
                        let turn = match turn_value {
                            0 => TurnDirection::Left,
                            1 => TurnDirection::Right,
                            _ => panic!("Unexcpected turn code {}", turn_value)
                        };
                        robot.turn_and_move(turn);
                        robot.state = RobotState::ReadyToPaint;
                    }
                }
            },
            MachineState::WaitingForInput => {
                machine.input.push(robot.read_color_at_current_position() as i64);
            },
            MachineState::ReadyToRun => {},
        }
        machine.resume()
    }
    let n_painted = robot.painted_boards.iter().count();
    println!("Number of painted boards: {}", n_painted);
    draw_call_sign(&robot.painted_boards);
}

fn draw_call_sign(painted_board: &HashMap<(i64, i64), Color>) {
    let min_x = painted_board.keys().fold(std::i64::MAX, |acc, k| std::cmp::min(acc, k.0));
    let max_x = painted_board.keys().fold(std::i64::MIN, |acc, k| std::cmp::max(acc, k.0));
    let min_y = painted_board.keys().fold(std::i64::MAX, |acc, k| std::cmp::min(acc, k.1));
    let max_y = painted_board.keys().fold(std::i64::MIN, |acc, k| std::cmp::max(acc, k.1));
    for y in min_y..=max_y {
        for x in min_x..=max_x {
            let color_char = match painted_board.get(&(x, y)) {
                Some(color) => char_for_color(color),
                None => char_for_color(&Color::Black)
            };
            print!("{}", color_char)
        }
        println!();
    }
}

fn char_for_color(color: &Color) -> char {
    match color {
        Color::White => '#',
        Color::Black => ' '
    }
}

enum Direction {
    Up = 0,
    Down = 1,
    Left = 2,
    Right = 3
}

enum TurnDirection {
    Left = 0,
    Right = 1
}

#[derive(Copy, Clone)]
enum Color {
    Black = 0,
    White = 1
}

enum RobotState {
    ReadyToPaint,
    ReadyToTurn
}

struct PaintingRobot {
    position: (i64, i64),
    state: RobotState,
    painted_boards: HashMap<(i64, i64), Color>,
    direction: Direction
}

impl PaintingRobot {
    fn read_color_at_current_position(&self) -> Color {
        match self.painted_boards.get(&self.position) {
            Some(color) => *color,
            None => Color::Black
        }
    }

    fn paint_at_current_position(&mut self, color: Color) {
        self.painted_boards.insert(self.position, color);
    }

    fn turn_and_move(&mut self, turn: TurnDirection) {
        self.direction = match self.direction {
            Direction::Up => {
                match turn {
                    TurnDirection::Left => Direction::Left, 
                    TurnDirection::Right => Direction::Right
                }
            },
            Direction::Down => {
                match turn {
                    TurnDirection::Left => Direction::Right, 
                    TurnDirection::Right => Direction::Left
                }

            },
            Direction::Left => {
                match turn {
                    TurnDirection::Left => Direction::Down, 
                    TurnDirection::Right => Direction::Up
                }

            },
            Direction::Right => {
                match turn {
                    TurnDirection::Left => Direction::Up, 
                    TurnDirection::Right => Direction::Down
                }
            }
        };
        let (x, y) = self.position;
        self.position = match self.direction {
            Direction::Up => (x, y - 1),
            Direction::Down => (x, y + 1),
            Direction::Left => (x - 1, y),
            Direction::Right => (x + 1, y)            
        }
    }
}