//
//  PGPKeyArmorImportTableViewController.swift
//  pass
//
//  Created by Mingshen Sun on 17/2/2017.
//  Copyright © 2017 Bob Sun. All rights reserved.
//

import passKit
import UIKit

class PGPKeyArmorImportTableViewController: AutoCellHeightUITableViewController, UITextViewDelegate, QRScannerControllerDelegate {
    @IBOutlet var armorPublicKeyTextView: UITextView!
    @IBOutlet var armorPrivateKeyTextView: UITextView!
    @IBOutlet var scanPublicKeyCell: UITableViewCell!
    @IBOutlet var scanPrivateKeyCell: UITableViewCell!

    var armorPublicKey: String?
    var armorPrivateKey: String?

    class ScannedPGPKey {
        enum KeyType {
            case publicKey, privateKey
        }

        var keyType = KeyType.publicKey
        var segments = [String]()
        var message = ""

        func reset(keytype: KeyType) {
            keyType = keytype
            segments.removeAll()
            message = "LookingForStartingFrame.".localize()
        }

        func addSegment(segment: String) -> (accept: Bool, message: String) {
            let keyTypeStr = keyType == .publicKey ? "Public" : "Private"
            let theOtherKeyTypeStr = keyType == .publicKey ? "Private" : "Public"

            // Skip duplicated segments.
            guard segment != segments.last else {
                return (accept: false, message: message)
            }

            // Check whether we have found the first block.
            guard !segments.isEmpty || segment.contains("-----BEGIN PGP \(keyTypeStr.uppercased()) KEY BLOCK-----") else {
                // Check whether we are scanning the wrong key type.
                if segment.contains("-----BEGIN PGP \(theOtherKeyTypeStr.uppercased()) KEY BLOCK-----") {
                    message = "Scan\(keyTypeStr)Key.".localize()
                }
                return (accept: false, message: message)
            }

            // Update the list of scanned segment and return.
            segments.append(segment)
            if segment.contains("-----END PGP \(keyTypeStr.uppercased()) KEY BLOCK-----") {
                message = "Done".localize()
                return (accept: true, message: message)
            } else {
                message = "ScannedQrCodes(%d)".localize(segments.count)
                return (accept: false, message: message)
            }
        }
    }

    var scanned = ScannedPGPKey()

    override func viewDidLoad() {
        super.viewDidLoad()

        scanPublicKeyCell?.textLabel?.text = "ScanPublicKeyQrCodes".localize()
        scanPublicKeyCell?.selectionStyle = .default
        scanPublicKeyCell?.accessoryType = .disclosureIndicator

        scanPrivateKeyCell?.textLabel?.text = "ScanPrivateKeyQrCodes".localize()
        scanPrivateKeyCell?.selectionStyle = .default
        scanPrivateKeyCell?.accessoryType = .disclosureIndicator
    }

    @IBAction
    func save(_: Any) {
        armorPublicKey = armorPublicKeyTextView.text
        armorPrivateKey = armorPrivateKeyTextView.text
        saveImportedKeys()
    }

    func textView(_: UITextView, shouldChangeTextIn _: NSRange, replacementText text: String) -> Bool {
        if text == UIPasteboard.general.string {
            // user pastes something, do the copy here again and clear the pasteboard in 45s
            SecurePasteboard.shared.copy(textToCopy: text)
        }
        return true
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let selectedCell = tableView.cellForRow(at: indexPath)
        if selectedCell == scanPublicKeyCell {
            scanned.reset(keytype: ScannedPGPKey.KeyType.publicKey)
            performSegue(withIdentifier: "showPGPScannerSegue", sender: self)
        } else if selectedCell == scanPrivateKeyCell {
            scanned.reset(keytype: ScannedPGPKey.KeyType.privateKey)
            performSegue(withIdentifier: "showPGPScannerSegue", sender: self)
        }
        tableView.deselectRow(at: indexPath, animated: true)
    }

    // MARK: - QRScannerControllerDelegate Methods

    func checkScannedOutput(line: String) -> (accept: Bool, message: String) {
        return scanned.addSegment(segment: line)
    }

    // MARK: - QRScannerControllerDelegate Methods

    func handleScannedOutput(line _: String) {
        let key = scanned.segments.joined()
        switch scanned.keyType {
        case .publicKey:
            armorPublicKeyTextView.text += key
        case .privateKey:
            armorPrivateKeyTextView.text += key
        }
    }

    override func prepare(for segue: UIStoryboardSegue, sender _: Any?) {
        if segue.identifier == "showPGPScannerSegue" {
            if let navController = segue.destination as? UINavigationController {
                if let viewController = navController.topViewController as? QRScannerController {
                    viewController.delegate = self
                }
            } else if let viewController = segue.destination as? QRScannerController {
                viewController.delegate = self
            }
        }
    }
}

extension PGPKeyArmorImportTableViewController: PGPKeyImporter {
    static let keySource = KeySource.armor
    static let label = "AsciiArmorEncryptedKey".localize()

    func isReadyToUse() -> Bool {
        guard !armorPublicKeyTextView.text.isEmpty else {
            Utils.alert(title: "CannotSave".localize(), message: "SetPublicKey.".localize(), controller: self, completion: nil)
            return false
        }
        guard !armorPrivateKeyTextView.text.isEmpty else {
            Utils.alert(title: "CannotSave".localize(), message: "SetPrivateKey.".localize(), controller: self, completion: nil)
            return false
        }
        return true
    }

    func importKeys() throws {
        try KeyFileManager.PublicPgp.importKey(from: armorPublicKey ?? "")
        try KeyFileManager.PrivatePgp.importKey(from: armorPrivateKey ?? "")
    }

    func saveImportedKeys() {
        performSegue(withIdentifier: "savePGPKeySegue", sender: self)
    }
}