package day15

import (
	"regexp"
	"strconv"
	"tools"
)

type Disc struct {
	posCount int
	initPos  int
}

func parseInput(inp []string, part2 bool) map[int]Disc {
	discs := make(map[int]Disc)
	parserRegex := regexp.MustCompile(".*has ([0-9]+) positions.*at position ([0-9]+).")
	for i, s := range inp {
		parts := parserRegex.FindStringSubmatch(s)
		pc, _ := strconv.Atoi(parts[1])
		ip, _ := strconv.Atoi(parts[2])
		discs[i] = Disc{pc, ip}
		if part2 {
			discs[i+1] = Disc{11, 0}
		}
	}

	return discs
}

func Part1(puzzle tools.AoCPuzzle) interface{} {
	discs := parseInput(puzzle.GetInputArray(), false)

	tIndex := -1
	for {
		tIndex++
		failed := false
		for i, d := range discs {
			if !((d.initPos+tIndex+i+1)%d.posCount == 0) {
				failed = true
				break
			}
		}
		if !failed {
			break
		}
	}

	return tIndex
}

func Part2(puzzle tools.AoCPuzzle) interface{} {
	discs := parseInput(puzzle.GetInputArray(), true)

	tIndex := -1
	for {
		tIndex++
		failed := false
		for i, d := range discs {
			if !((d.initPos+tIndex+i+1)%d.posCount == 0) {
				failed = true
				break
			}
		}
		if !failed {
			break
		}
	}

	return tIndex
}