package main

import (
	"fmt"
	"os"

	"git.annabunch.es/annabunches/adventofcode/2020/lib/util"
)

func countTrees(input []string, right, down int) int {
	x := 0
	total := 0
	for y, line := range input {
		if y == 0 || len(line) == 0 || y%down != 0 {
			continue
		}

		x = (x + right) % len(line)
		if line[x] == '#' {
			total += 1
		}
	}

	return total
}

func main() {
	step := os.Args[1]
	values := util.InputParserStrings(os.Args[2])

	switch step {
	case "1":
		total := countTrees(values, 3, 1)
		fmt.Println("Trees:", total)
	case "2":
		total := countTrees(values, 1, 1)
		total *= countTrees(values, 3, 1)
		total *= countTrees(values, 5, 1)
		total *= countTrees(values, 7, 1)
		total *= countTrees(values, 1, 2)
		fmt.Println("Tree Product:", total)
	}

}