#!/usr/bin/swift
import Foundation

guard CommandLine.arguments.count >= 2 else {
    fatalError("Usage: ./Day_01 <input.txt>")
}

let moves = try! String(contentsOfFile: CommandLine.arguments[1], encoding: .utf8)
    .split(separator: "\n")
    .compactMap { line in
        guard let first = line.first,
              let magnitude = Int(line[line.index(after: line.startIndex)...])
        else { fatalError("L13 : [ERROR] Failed to read magnitude error") }
        let sign = (first == "R" ? 1 : -1)
        return sign * magnitude
    }

var dialValue = 50
var count = 0
for move in moves {
    dialValue = ((dialValue + move) % 100 + 100) % 100
    if dialValue == 0 {
        count += 1
    }
}
print("=======Part 1=======\n\(count)")

dialValue = 50
count = 0
for move in moves {
    let magnitude = abs(move)
    let effectivePosition = move > 0 ? dialValue : (100 - dialValue) % 100
    count += (effectivePosition + magnitude - 1) / 100
    dialValue = ((dialValue + move) % 100 + 100) % 100
    if dialValue == 0 {
        count += 1
    }
}
print("=======Part 2=======\n\(count)")