package day01

import (
	"adventofcode2025/utils"
	"fmt"
	"strings"
)

type Dir int

const (
	Left Dir = iota
	Right
	Safe
	Unsafe
)

type Instruction struct {
	Turn  Dir
	Steps int
}

func parseInput(input string) []Instruction {
	Instructions := make([]Instruction, 0)
	lines := strings.Split(input, "\n")
	for _, line := range lines {
		var steps int
		var dir Dir
		steps = utils.MustAtoi(line[1:])
		switch line[0] {
		case 'L':
			dir = Left
		case 'R':
			dir = Right
		default:
			fmt.Println("Invalid direction")
			continue
		}
		Instructions = append(Instructions, Instruction{Turn: dir, Steps: steps})
	}
	return Instructions
}

func Part1(input string) int {

	Instructions := parseInput(input)
	position := 50
	code := 0

	for _, instr := range Instructions {
		switch instr.Turn {
		case Left:
			position -= instr.Steps % 100
		case Right:
			position += instr.Steps % 100
		}
		if position < 0 {
			position += 100
		} else if position > 99 {
			position -= 100
		}
		if position == 0 {
			code++
		}
	}
	return code
}

func Part2(input string) int {
	Instructions := parseInput(input)
	position := 50
	code := 0
	new_position := position

	for _, instr := range Instructions {
		switch instr.Turn {
		case Left:
			new_position = position - instr.Steps%100
		case Right:
			new_position = position + instr.Steps%100
		}
		code += instr.Steps / 100
		if new_position == 0 {
			code++
		}
		if new_position < 0 {
			new_position += 100
			if position != 0 {
				code++
			}
		} else if new_position > 99 {
			new_position -= 100
			if position != 0 {
				code++
			}
		}
		position = new_position
	}
	return code
}