#if !hasFeature(Embedded)
import Foundation
#endif

@main
struct Day01 {
    static func run() {
        guard let input = realInput else {
            print("input sttring nil")
            return
        }
        print("Started...")
        let parsed = parseInput(input)
        part1(parsed)
        part2(parsed)
        print("Press Start to exit...")
    }

    static func parseInput(_ input: String) -> [(Direction, Int)] {
        input.split(separator: "\n").map({ line in
            return (
                Direction(line.first!),
                Int(line.dropFirst())!
            )
        })
    }

    static func part1(_ input: [(Direction, Int)]) {
        var cur = 50
        var count = 0
        for (dir, num) in input {
            cur = switch dir {
                case .Left: (cur - num) % 100
                case .Right: (cur + num) % 100
            }
            if (cur < 0) { cur += 100 }
            if (cur == 0) { count += 1 }
        }
        print("Part 1: \(count)")
    }

    static func part2(_ input: [(Direction, Int)]) {
        var cur = 50
        var count = 0
        for (dir, num) in input {
            let start = cur
            let fullCycles = num - (num % 100)
            count += fullCycles / 100

            cur = switch dir {
                case .Left: (cur - num) % 100
                case .Right: (cur + num) % 100
            }
            if (cur < 0) { cur += 100 }

            switch dir {
                case .Left:
                    if (start - (num % 100)) < 0 && start != 0 {
                        count += 1
                    }
                case .Right:
                    if (start + (num % 100)) >= 100 && start != 0 && cur != 0 {
                        count += 1
                    }
            }
            if (cur == 0) { count += 1 }
        }
        print("Part 2: \(count)")
    }


    #if hasFeature(Embedded)
    static func main() {
        gfxInitDefault()
        consoleInit(GFX_TOP, nil)
        guard romfsInit() == 0 else {
            print("Couldn't init RomFS")
            return
        }

        testInput = stringFromFile("romfs:/test.txt")
        realInput = stringFromFile("romfs:/input.txt")

        run()

        while aptMainLoop() {
            hidScanInput()
            let kDown = hidKeysDown()
            if kDown & KEY_START != 0 {
                break
            }

            gfxFlushBuffers()
            gfxSwapBuffers()
        }

        gfxExit()
    }

    static func stringFromFile(_ path: String) -> String {
        let file = fopen(path, "r")
        var ret = ""
        var buf = [CChar](repeating: 0, count: 100)
        while fgets(&buf, 100, file) != nil {
           ret += String(cString: buf)
        }
        guard feof(file) != 0 else {
            print("Error reading file \(path)")
            return ""
        }
        return ret
    }

    #else
    static func main() {
        testInput = try? String(contentsOfFile: "romfs/test.txt")
        realInput = try? String(contentsOfFile: "romfs/input.txt")
        run()
    }
    #endif

}


enum Direction {
    case Left
    case Right

    init(_ char: Character) {
        self = switch char {
            case "L": Direction.Left
            case "R": Direction.Right
            default: fatalError()
        }
    }
}

var testInput: String? = nil

var realInput: String? = nil