#if !hasFeature(Embedded)
import Foundation
#endif

@main
struct Day03 {
    static func run() {
        guard let input = realInput else {
            print("input sttring nil")
            return
        }
        print("Parsing...")
        let parsed = parseInput(input)
        print("Running Part 1...")
        part1(parsed)
        //print("Running Part 2...")
        //part2(parsed)
        print("Finished!")
    }

    typealias ParsedInput = [String]

    static func parseInput(_ input: String) -> ParsedInput {
        return input
            .split(whereSeparator: { $0.isNewline })
            .map({ String($0) })
    }

    static func part1(_ input: ParsedInput) {
        var sum = 0
        for line in input {
            var firstMax: Character = "0"
            var lastMax: Character = "0"

            for char in line.dropLast() {
                if char > firstMax {
                    firstMax = char
                    lastMax = "0"
                    continue
                }
                if char > lastMax {
                    lastMax = char
                }
            }

            if line.last! > lastMax {
                lastMax = line.last!
            }

            sum += Int("\(firstMax)\(lastMax)")!
        }
        print("Part 1: \(sum)")
    }

    static func part2(_ input: ParsedInput) {
    }

    #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()
        }

        romfsExit()
        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 nil
        }
        while ret.first?.isNewline ?? false {
            ret.removeFirst()
        }
        while ret.last?.isNewline ?? false {
            ret.removeLast()
        }
        return ret
    }
    #else
    static func main() {
        testInput = try? String(contentsOfFile: "romfs/test.txt").trimmingCharacters(in: .whitespacesAndNewlines)
        realInput = try? String(contentsOfFile: "romfs/input.txt").trimmingCharacters(in: .whitespacesAndNewlines)

        run()
    }
    #endif

}

var testInput: String? = nil

var realInput: String? = nil