package day23

import (
	"strconv"
	"strings"
	"tools"
)

func run(code []string, register map[string]int) map[string]int {
	index := 0
	for index < len(code) {
		//fmt.Println("Executing line", index, ":", code[index])
		instr := strings.Split(code[index], " ")
		switch instr[0] {
		case "cpy":
			value, err := strconv.Atoi(instr[1])
			if err != nil {
				register[instr[2]] = register[instr[1]]
			} else {
				register[instr[2]] = value
			}
			index++
		case "inc":
			register[instr[1]]++
			index++
		case "dec":
			register[instr[1]]--
			index++
		case "jnz":
			value, err := strconv.Atoi(instr[1])
			if err != nil {
				value = register[instr[1]]
			}
			if value == 0 {
				index++
			} else {
				jump, err := strconv.Atoi(instr[2])
				if err != nil {
					index += register[instr[2]]
				} else {
					index += jump
				}
			}
		case "tgl":
			toChange := index + register[instr[1]]
			if toChange < len(code) && toChange >= 0 {
				switch len(strings.Split(code[toChange], " ")) {
				case 2:
					if code[toChange][:3] == "inc" {
						code[toChange] = "dec" + code[toChange][3:]
					} else {
						code[toChange] = "inc" + code[toChange][3:]
					}
				case 3:
					if code[toChange][:3] == "jnz" {
						code[toChange] = "cpy" + code[toChange][3:]
					} else {
						code[toChange] = "jnz" + code[toChange][3:]
					}
				}
			}
			index++
		}
		/*
			fmt.Println("New registers", register)
			fmt.Println("New code", code)
			bufio.NewReader(os.Stdin).ReadBytes('\n')
		*/
	}

	return register
}

func Part1(puzzle tools.AoCPuzzle) interface{} {
	register := map[string]int{
		"a": 7,
		"b": 0,
		"c": 0,
		"d": 0,
	}

	register = run(puzzle.GetInputArray(), register)

	return register["a"]
}

func Part2(puzzle tools.AoCPuzzle) interface{} {
	register := map[string]int{
		"a": 12,
		"b": 0,
		"c": 1,
		"d": 0,
	}

	/*
		This could be optimized by closely looking at the input and finding the "inc x" loops
		and then replace them with multiplications.
		Also the code seems to resemble a factorial implementation which could lead to finding
		the solution without executing the code at all. Needs more analysis.
	*/
	register = run(puzzle.GetInputArray(), register)

	return register["a"]
}