package main

import (
	"bufio"
	"fmt"
	"log"
	"os"
	"strings"
)

type Graph struct {
	nodes map[string]*Node
}

type Node struct {
	name       string
	neighbours []string
}

func (g *Graph) addNode(location string) {
	if _, ok := g.nodes[location]; !ok {
		g.nodes[location] = &Node{location, make([]string, 0)}
	}
}

func (g *Graph) addNeighbour(location, neighbourLocation string) {
	node := g.nodes[location]
	node.neighbours = append(node.neighbours, neighbourLocation)
	node = g.nodes[neighbourLocation]
	node.neighbours = append(node.neighbours, location)
}

func (g *Graph) walk(n *Node, visited []string, target string, revisited bool) bool {
	if strings.ToLower(n.name) == n.name {
		for _, v := range visited {
			if v == n.name {
				if revisited || !partTwo {
					return false
				} else {
					revisited = true
				}
			}
		}
	}
	visited = append(visited, n.name)

	if n.name == target {
		total++
		return true
	}
	for _, neighbourLocation := range n.neighbours {
		if neighbourLocation == "start" {
			continue
		}
		node, ok := g.nodes[neighbourLocation]
		if !ok {
			return false
		}
		g.walk(node, visited, target, revisited)
	}
	return false
}

var total int
var partTwo bool

func main() {
	file, err := os.Open("input.txt")
	if err != nil {
		log.Fatal(err)
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	scanner.Split(bufio.ScanLines)

	graph := Graph{make(map[string]*Node)}

	for scanner.Scan() {
		line := scanner.Text()
		path := strings.Split(line, "-")
		graph.addNode(path[0])
		graph.addNode(path[1])
		graph.addNeighbour(path[0], path[1])
	}

	start := graph.nodes["start"]
	visited := []string{}
	graph.walk(start, visited, "end", false)
	fmt.Println(total)
	partTwo, total = true, 0
	graph.walk(start, visited, "end", false)
	fmt.Println(total)
}