package main

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

const FILE_PATH = "./input.txt"

//const FILE_PATH = "./sample.txt"

func LoadInput(filename string) ([]string, error) {
	file, err := os.Open(filename)
	if err != nil {
		return nil, err
	}
	defer file.Close()

	var lines []string
	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		lines = append(lines, scanner.Text())
	}

	if err := scanner.Err(); err != nil {
		return nil, err
	}

	return lines, nil
}

func TransformInput(lines []string) [2][]int {
	var result [2][]int

	for _, line := range lines {
		var numbs = strings.Split(line, "   ")
		var numb int
		numb, _ = strconv.Atoi(numbs[0])
		result[0] = append(result[0], numb)
		numb, _ = strconv.Atoi(numbs[1])
		result[1] = append(result[1], numb)
	}

	return result
}

func Sort(input []int) []int {
	var result []int = make([]int, len(input))
	var temp int
	copy(result, input)

	for i := 0; i < len(result)-1; i++ {
		for j := 0; j < len(result)-i-1; j++ {
			if result[j] > result[j+1] {
				temp = result[j]
				result[j] = result[j+1]
				result[j+1] = temp
			}
		}
	}

	return result
}

func Part1(input [2][]int) int {
	var result = 0
	var sorted [2][]int = [2][]int{Sort(input[0]), Sort(input[1])}
	for i := 0; i < len(sorted[0]); i++ {
		result += int(math.Abs((float64)(sorted[0][i] - sorted[1][i])))
	}
	return result
}

func Part2(input [2][]int) int {
	var sorted [2][]int = [2][]int{Sort(input[0]), Sort(input[1])}
	var result = 0
	var r = 0
	var l = 0
	var count_l = 0
	var count_r = 0

	for r < len(sorted[1]) && l < len(sorted[0]) {
		count_r = 0
		count_l = 1

		for r < len(sorted[1]) && sorted[1][r] < sorted[0][l] {
			r++
		}
		for r < len(sorted[1]) && sorted[1][r] == sorted[0][l] {
			count_r++
			r++
		}

		l++

		for l < len(sorted[0]) && sorted[0][l-1] == sorted[0][l] {
			count_l++
			l++
		}
		result += count_l * count_r * sorted[0][l-1]
	}

	return result
}

func main() {
	input, err := LoadInput(FILE_PATH)
	if err != nil {
		fmt.Println("Error loading input:", err)
		return
	}

	structuredInput := TransformInput(input)
	fmt.Println("Structured Input:", structuredInput)

	fmt.Println("Solution Part 1: ", Part1(structuredInput))
	fmt.Println("Solution Part 2: ", Part2(structuredInput))
}