locktime.swift

import Foundation

/** Can be included after this time marker
 */
enum Locktime {
  case date(Date)
  case height(Int)
  
  /** Number of bytes
   */
  static let byteCount = 4

  /** Get the earliest possible lock time
   */
  static let genesis = Locktime.height(Int())
  
  /** Determine if a value refers to a block height
   */
  private static func isBlockHeight(value: Int) -> Bool {
    return value < maximalHeight
  }

  /** Height before which locktime values are treated as block heights
   */
  private static let maximalHeight = 500_000_000
  
  // MARK: - Init
  
  /** Create from little endian encoded data
   */
  init(from data: Data) {
    self.init(from: Int(UInt32(fromLittleEndian: data)))
  }
  
  /** Create from raw value
   */
  init(from value: Int) {
    switch type(of: self).isBlockHeight(value: value) {
    case false:
      self = .date(Date(timeIntervalSince1970: TimeInterval(value)))
      
    case true:
      self = .height(value)
    }
  }
}

// MARK: - UInt32
extension Locktime {
  /** Determine the serialized uint32 value
   */
  var asSerializedUint32: UInt32 {
    switch self {
    case .date(let date):
      return UInt32(date.timeIntervalSince1970)
      
    case .height(let height):
      return UInt32(height)
    }
  }
}