package Advent2018;

import AssemBunny.Command2018;
import AssemBunny.Operation;
import util.AdventOfCode;

import java.util.*;

public class Day21 extends AdventOfCode {

    public Day21(List<String> input) {
        super(input);
    }

    int pointer;
    int boundRegister;
    List<Operation> instr;
    Set<Integer> seen = new LinkedHashSet<>();

    int[] reg = new int[6];

    @Override
    public Object part1() {
        while (pointer < instr.size()) {
            if (runProgram()) break;
        }
        return seen.stream().findFirst().orElse(0);
    }

    boolean runProgram() {
        Operation op = instr.get(pointer);
        reg[boundRegister] = pointer;
        if (!op.cmd.firstReg) {
            op.aReg = reg[op.aVal];
        }
        if (!op.cmd.secondReg ) {
            op.bReg = reg[op.bVal];
        }
        reg[op.c] = op.cmd.opcode.applyAsInt(op);

        // found
        if (pointer == 28) {
            if (!seen.add(reg[1])) {
                return true;
            }
        }

        pointer = reg[boundRegister];
        pointer++;
        return false;
    }

    @Override
    public Object part2() {
        return seen.toArray()[seen.size() - 1];
    }

    @Override
    public void parse() {
        instr = new ArrayList<>();
        for (int i = 0; i < input.size(); i++) {
            String[] split = input.get(i).split(" ");
            if (i == 0) {
                boundRegister = Integer.parseInt(split[1]);
            } else {
                Command2018 cmd = Command2018.valueOf(split[0].toUpperCase());
                int a = Integer.parseInt(split[1]);
                int b = Integer.parseInt(split[2]);
                int c = Integer.parseInt(split[3]);
                Operation op = new Operation(a, a, b, b, c, cmd);
                instr.add(op);
            }
        }
    }

}