package day6

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func allDifferent(a string) bool {
	length := len(a)

	for i := 0; i < length; i++ {
		for j := i + 1; j < length; j++ {
			if a[i] == a[j] {
				return false
			}
		}
	}

	return true
}

func Run(filename string, problemStr string) {
	problem, err := strconv.Atoi(problemStr)
	if err != nil || !(problem == 4 || problem == 14) {
		fmt.Println("Didn't understand problem number", os.Args[2], "should be 4 or 14")
	}

	file, err := os.Open(filename)

	if err != nil {
		fmt.Println("Error opening file:", err)
		return
	}

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

	for scanner.Scan() {
		line := scanner.Text()

		if len(line) > 0 {
			var index int
			offset := problem - 1

			for index = offset; index < len(line); index++ {
				if allDifferent(line[index-offset : index+1]) {
					break
				}
			}

			fmt.Println("First marker after character", index+1)
		}
	}

	file.Close()
}