//
//  ViewController.swift
//  NFCPart2
//
//  Created by tommys on 2024/08/13.
//

import UIKit
import CoreNFC

enum State {
    case standBy
    case read
    case write
}

class ViewController: UIViewController {

    
    @IBOutlet weak var textField: UITextField!
    
    
    var session: NFCNDEFReaderSession?
    var message: NFCNDEFMessage?
    var state: State = .standBy
    var text: String = ""
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }
    
    @IBAction func tapScreen(_ sender: Any) {
        print("exe tapScreen")
        textField.resignFirstResponder()
    }
    
    @IBAction func write(_ sender: Any) {
        print("exe write ")
        textField.resignFirstResponder()
        if textField.text == nil || textField.text!.isEmpty { return }
        text = textField.text!
        startSession(state: .write)
    }
    
    
    @IBAction func read(_ sender: Any) {
        print("exe read")
        startSession(state: .read)
    }
    
    func startSession(state: State) {
        print("startSession ; ")
        self.state = state
        guard NFCNDEFReaderSession.readingAvailable else {
            Swift.print("NFCはつかえない")
            return
        }
        session = NFCNDEFReaderSession(delegate: self, queue: nil, invalidateAfterFirstRead: false)
        session?.alertMessage = "Please hold the NFC tag near the top of your iPhone."

        session?.begin()
    }
    
    
    func stopSession(alert: String = "", error: String = "") {
        session?.alertMessage = alert
        print("exe stopSession 。alert = " + alert)
        if error.isEmpty {
            session?.invalidate()
        } else {
            session?.invalidate(errorMessage: error)
        }
        self.state = .standBy
    }
    
    func tagRemovalDetect(_ tag: NFCNDEFTag) {
        print("exe tagRemovalDetect .")
        session?.connect(to: tag) { (error: Error?) in
            if error != nil || !tag.isAvailable {
                self.session?.restartPolling()
                

                return
            }
            DispatchQueue.global().asyncAfter(deadline: DispatchTime.now() + .milliseconds(500), execute: {

                self.tagRemovalDetect(tag)
            })
        }
    }

    func updateMessage(_ message: NFCNDEFMessage) -> Bool {
        if message.records.isEmpty { return false }
        var results = [String]()
        for record in message.records {
            if let type = String(data: record.type, encoding: .utf8) {
                if type == "T" { //データ形式がテキストならば
                    let res = record.wellKnownTypeTextPayload()
                    if let text = res.0 {
                        print("updateMessage ; text" + text)
                        results.append("text: \(text)")
                    }
                } else if type == "U" { //データ形式がURLならば
                    let res = record.wellKnownTypeURIPayload()
                    if let url = res {
                        results.append("url: \(url)")
                    }
                    
                }
            }
        }
        stopSession(alert: "[" + results.joined(separator: ", ") + "]")
        return true
    }
}
    
    
extension ViewController: NFCNDEFReaderSessionDelegate {
        func readerSessionDidBecomeActive(_ session: NFCNDEFReaderSession) {
            //
            print("exe readerSessionDidBecomeActive")
            
        }

        func readerSession(_ session: NFCNDEFReaderSession, didInvalidateWithError error: Error) {
            Swift.print(error.localizedDescription)
            print("exe readerSession ")
        }
 
        func readerSession(_ session: NFCNDEFReaderSession, didDetectNDEFs messages: [NFCNDEFMessage]) {
            
            print("reader Session didDetectNDEFs")
            // not called
        }

        func readerSession(_ session: NFCNDEFReaderSession, didDetect tags: [NFCNDEFTag]) {
            
            print("reader Session didDetect")
            if tags.count > 1 {
                session.alertMessage = "読み込ませるNFCタグは1枚にしてください．"
                tagRemovalDetect(tags.first!)
                return
            }
            let tag = tags.first!
            session.connect(to: tag) { (error) in
                if error != nil {
                    session.restartPolling()
                    return
                }
            }

            tag.queryNDEFStatus { (status, capacity, error) in
                if status == .notSupported {
                    self.stopSession(error: "このNFCタグは対応していないみたい．")
                    return
                }
                if self.state == .write {
                    if status == .readOnly {
                        self.stopSession(error: "このNFCタグには書き込みできないぞ")
                        return
                    }
                    if let payload = NFCNDEFPayload.wellKnownTypeTextPayload(string: self.text, locale: Locale(identifier: "en")) {
                        

                        let urlPayload = NFCNDEFPayload.wellKnownTypeURIPayload(string: "https://kyome.io/")!
                        self.message = NFCNDEFMessage(records: [payload, urlPayload])
                        print("readerSession urlPayload です." )
                        if self.message!.length > capacity {
                            self.stopSession(error: "容量オーバーで書き込みできません。！\n容量は\(capacity)bytes．")
                            return
                        }
                        tag.writeNDEF(self.message!) { (error) in
                            if error != nil {
                                // self.printTimestamp()
                                self.stopSession(error: error!.localizedDescription)
                            } else {
                                self.stopSession(alert: "書き込み成功")
                            }
                        }
                    }
                } else if self.state == .read {
                    tag.readNDEF { (message, error) in
                        if error != nil || message == nil {
                            self.stopSession(error: error!.localizedDescription)
                            return
                        }
                        if !self.updateMessage(message!) {
                            self.stopSession(error: "このNFCタグは対応してません．")
                        }
                    }
                }
            }
        }

        func printTimestamp() {
            
            let df = DateFormatter()
            df.timeStyle = .long
            df.dateStyle = .long
            df.locale = Locale.current
            let now = Date()
            Swift.print("Timestamp: ", df.string(from: now))
        }
    

    
}