package main

import (
	"fmt"
	"strings"

	"git.z1glr.de/advent-of-code-2025/pkg/aoc"
)

type Schematic struct {
	rows      []string
	timelines [][]int
	splits    int
}

func (s *Schematic) Calculate() {
	startIndex := strings.Index(s.rows[0], "S")

	s.timelines = make([][]int, len(s.rows))

	for ii, rr := range s.rows {
		s.timelines[ii] = make([]int, len(rr))
	}

	s.timelines[0][startIndex] = 1

	s.CalculateRow(0)
}

func (s *Schematic) CalculateRow(i int) {
	if i == len(s.rows)-1 {
		return
	}

	for ii, count := range s.timelines[i] {
		switch s.rows[i+1][ii] {
		case byte('^'):
			s.timelines[i+1][ii-1] += count
			s.timelines[i+1][ii+1] += count

			if s.timelines[i][ii] > 0 {
				s.splits++
			}
		default:
			s.timelines[i+1][ii] += count
		}
	}

	s.CalculateRow(i + 1)
}

func do(test bool) (int, int) {
	schematic := Schematic{
		rows: aoc.ReadFileRows(test),
	}

	schematic.Calculate()

	timelineCount := 0
	for _, cc := range schematic.timelines[len(schematic.timelines)-1] {
		timelineCount += cc
	}

	fmt.Println(schematic.splits)
	fmt.Println(timelineCount)

	return schematic.splits, timelineCount
}

func main() {
	if r1, r2 := do(true); r1 == 21 && r2 == 40 {
		do(false)
	}
}