struct FDTHeader {
    let magic: UInt32            // 0xd00dfeed
    let totalsize: UInt32
    let off_dt_struct: UInt32
    let off_dt_strings: UInt32
    let off_mem_rsvmap: UInt32
    let version: UInt32
    let last_comp_version: UInt32
    let boot_cpuid_phys: UInt32
    let size_dt_strings: UInt32
    let size_dt_struct: UInt32
}

struct FDTProperty {
    let len: UInt32
    let nameoff: UInt32
}

enum FDTToken: UInt32 {
    case beginNode = 0x1
    case endNode   = 0x2
    case prop      = 0x3
    case nop       = 0x4
    case end       = 0x9
}

extension UInt32 {
    var fromBe: UInt32 {
        return self.byteSwapped
    }
}

func alignUp(_ value: Int, to: Int) -> Int {
    return (value + to - 1) & ~(to - 1)
}

let kFDTHeaderMagic = 0xd00dfeed

func parseDTB(at pointer: UnsafeRawPointer) {
    let header = pointer.bindMemory(to: FDTHeader.self, capacity: 1).pointee
    guard header.magic.byteSwapped == kFDTHeaderMagic else {
        return
    }

    let structOffset = Int(header.off_dt_struct.byteSwapped)
    let stringOffset = Int(header.off_dt_strings.byteSwapped)

    var structBase = pointer.advanced(by: structOffset)
    let stringsBase = pointer.advanced(by: stringOffset)

    var finished = false
    while !finished {
        let rawToken = structBase.load(as: UInt32.self).byteSwapped
        structBase = structBase.advanced(by: 4)

        if let token = FDTToken(rawValue: rawToken) {
            switch token {
                case .beginNode:
                    let namePointer = structBase.assumingMemoryBound(to: UInt8.self)
                    let name = String(cString: namePointer)
                    let nameLength = name.utf8.count + 1
                    structBase = structBase.advanced(by: alignUp(nameLength, to: 4))
                case .prop:
                    let propertyHeader = structBase.load(as: FDTProperty.self)
                    let dataLength = Int(propertyHeader.len.byteSwapped)
                    let nameOffset = Int(propertyHeader.nameoff.byteSwapped)

                    let namePointer = stringsBase.advanced(by: nameOffset).assumingMemoryBound(to: UInt8.self)

                    structBase = structBase.advanced(by: 8) // skip header
                    structBase = structBase.advanced(by: alignUp(dataLength, to: 4)) // skip data for now

                    // TODO: finish it :D
                case .endNode:
                    continue
                case .nop:
                    continue
                case .end:
                    finished = true
            }
        }
    }
}