//
//  NFCHelper.swift
//
//  Created by Alexander Obi.
//  Copyright © 2017 Smartrac. All rights reserved.
//

import Foundation
import CoreNFC

class NFCHelper : NSObject {
  
  //getFormatName :: NFCTypeNameFormat -> String
  func getFormatName (_ format: NFCTypeNameFormat) -> String {
    switch format {
    case .empty:
      return "Empty"
    case .nfcWellKnown:
      return "NFC Well Known"
    case .media:
      return "Media"
    case .absoluteURI:
      return "Absolute URI"
    case .nfcExternal:
      return "NFC External"
    case .unchanged:
      return "Unchanged"
    default:
      return "Unknown"
    }
  }
  
  func getCode (_ char: Character) -> Bool {
    let charArray: [Character] = ["Q", "\u{01}", "&", "/", "(", ")"]
    return !charArray.contains(char)
  }
  
  // formatData :: [NFCNDEFMessage] -> [[String : String]]
  func formatData (_ nfcMessages : [NFCNDEFMessage]) -> [[String : String]] {
    return nfcMessages.map({ (message) -> [[String : String]] in
      let records = message.records
      return records.map({ (payload) -> [String : String] in
        var nfcData : [String : String] = [:]
        
        let format = getFormatName(payload.typeNameFormat)
        let payloadD = String(data: payload.payload, encoding: String.Encoding.ascii ) as String!
        let type = String(data: payload.type, encoding: String.Encoding.ascii ) as String!
        let identifier = String(data: payload.identifier, encoding: String.Encoding.ascii ) as String!
        let payloadM = (payloadD?.split(separator: "="))
        var tid: String
        
        if ((payloadM?.underestimatedCount ?? 0) > 1) {
          let tidString = String(payloadM![1])
          tid = String(tidString.prefix(while: getCode))
        } else {
          tid = String(payloadM![0])
        }

        nfcData["payload"] = payloadD
        nfcData["tid"] = tid
        nfcData["type"] = type
        nfcData["identifier"] = identifier
        nfcData["format"] = format
        
        return nfcData
        
      })
    }).flatMap{$0}
  }
  
  // formatError :: Error -> [String : String]
  func formatError (_ error: Error) -> [String : String] {
    var errorObj : [String : String] = [:]
    errorObj["message"] = error.localizedDescription
    return errorObj
  }
  
}