package main

import (
	"fmt"
	"regexp"
	"strconv"
	"strings"

	"git.mstar.dev/mstar/aoc24/util"
	"git.mstar.dev/mstar/goutils/other"
)

var mulRegex = regexp.MustCompile(`mul\((\d+),(\d+)\)`)
var doDontMulRegex = regexp.MustCompile(`mul\(\d+,\d+\)|do\(\)|don't\(\)`)

func dissectInstruction(inst string) int {
	stringElems := strings.TrimSuffix(strings.TrimPrefix(inst, "mul("), ")")
	elems := strings.Split(stringElems, ",")
	left := other.Must(strconv.Atoi(elems[0]))
	right := other.Must(strconv.Atoi(elems[1]))
	return left * right
}

func main() {
	data := util.LoadFileFromArgs()
	matches := mulRegex.FindAllString(string(data), -1)
	acc := 0
	for _, match := range matches {
		acc += dissectInstruction(match)
	}
	fmt.Printf("Part 1: %d\n", acc)
	doDontMatches := doDontMulRegex.FindAllString(string(data), -1)
	acc2 := 0
	active := true
	for _, match := range doDontMatches {
		switch {
		case strings.HasPrefix(match, "don't()"):
			active = false
		case strings.HasPrefix(match, "do()"):
			active = true
		default:
			if active {
				acc2 += dissectInstruction(match)
			}
		}
	}
	fmt.Printf("Part 2: %d\n", acc2)
}