package day02

import (
	"strings"

	"aoc2024/internal/common"
)

type Difference int

const (
	None Difference = iota
	Positive
	Negative
)

func (d Difference) IsTransitionOk(diff Difference) bool {
	if d == None && diff != None {
		return true
	}
	if d == diff && d != None {
		return true
	}
	return false
}

func Handle(input []string) (int, int) {
	safe := 0
	dampened := 0
	for _, line := range input {
		levels := strings.Split(line, " ")

		if isSafe(levels) {
			safe++
			dampened++
		} else if isSafeWithDeletion(levels) {
			dampened++
		}
	}
	return safe, dampened
}

func getTrend(diff int) Difference {
	if diff >= 1 && diff <= 3 {
		return Positive
	}
	if diff <= -1 && diff >= -3 {
		return Negative
	}
	return None
}

func isSafe(row []string) bool {
	trend := None
	for i := 0; i < len(row)-1; i++ {
		diff := common.StrToInt(row[i]) - common.StrToInt(row[i+1])
		newTrend := getTrend(diff)

		if !trend.IsTransitionOk(newTrend) {
			return false

		}
		trend = newTrend
	}
	return true
}

func isSafeWithDeletion(row []string) bool {
	safe := false
	for i := range row {
		copyRow := make([]string, len(row))
		copy(copyRow, row)
		if i == len(row)-1 {
			safe = isSafe(copyRow[:i])
		} else {
			safe = isSafe(append(copyRow[:i], copyRow[i+1:]...))
		}
		if safe {
			return safe
		}
	}
	return false
}