Merge pull request #78 from Hollister009/feature/migration-from-objc-…

…to-swift-guide

Add Guide on how to migrate code from Objective-C to Swift

docs/migration-objc-to-swift-guide.md

@@ -0,0 +1,343 @@
+# Objective-C to Swift Codebase Migration Guide
+
+## Introduction
+This document serves as a guide to migrate an existing codebase written in Objective-C to Swift. Migrating to Swift offers several benefits, including improved safety, readability, and maintainability of your code. This guide will provide an overview of the migration process and best practices to follow.
+
+**Note:** This guide assumes that you have a basic understanding of both Objective-C and Swift.
+
+## Table of Contents
+1. [Preparation](#preparation)
+2. [Xcode Project Configuration](#xcode-project-configuration)
+3. [Migration Steps](#migration-steps)
+    - [RNBraintree] (#RNBraintree)
+    - [RNBraintreeApplePay]
+4. [Common Migration Challenges](#common-migration-challenges)
+5. [Resources](#resources)
+
+## 1. Preparation <a name="preparation"></a>
+
+Before you start the migration, it's important to make sure you have the following in place:
+
+- **Back Up Your Code:** Create a backup of your Objective-C codebase to ensure you can return to it if needed.
+
+- **Version Control:** Ensure that your codebase is under version control (e.g., Git). This will help track changes and collaborate effectively.
+
+- **Latest Xcode Version:** Make sure you are using the latest version of Xcode with support for both Objective-C and Swift.
+
+## 2. Xcode Project Configuration <a name="xcode-project-configuration"></a>
+
+- Open your Xcode project.
+
+- Set your project's build settings to use Swift as the primary language.
+
+- Configure your project settings to use a Bridging Header for Objective-C to Swift interoperability.
+
+## 3. Migration Steps <a name="migration-steps"></a>
+
+### RNBrainTree <a name="RNBraintree"></a>
+
+Create new Swift file with the name `RNBrainTree.swift` and paste the migrated code:
+```swift
+//  RNBrainTree.swift
+import Foundation
+import React
+import BraintreeCore
+import BraintreeCard
+import BraintreeApplePay
+import BraintreePayPal
+
+@objc(RNBraintree)
+class RNBraintree: NSObject, BTViewControllerPresentingDelegate, BTThreeDSecureRequestDelegate {
+    private var apiClient: BTAPIClient?
+    private var dataCollector: BTDataCollector?
+
+    @objc
+    func showPayPalModule(
+        _ options: NSDictionary,
+        resolver resolve: @escaping RCTPromiseResolveBlock,
+        rejecter reject: @escaping RCTPromiseRejectBlock
+    ) {
+        guard let clientToken = options["clientToken"] as? String,
+              let amount = options["amount"] as? String,
+              let currencyCode = options["currencyCode"] as? String
+        else {
+            reject("INVALID_PARAMETERS", "Invalid parameters", nil)
+            return
+        }
+
+        // You may want to check if apiClient and dataCollector are already initialized.
+        if self.apiClient == nil {
+            self.apiClient = BTAPIClient(authorization: clientToken)
+            self.dataCollector = BTDataCollector(apiClient: self.apiClient!)
+        }
+
+        let payPalDriver = BTPayPalDriver(apiClient: self.apiClient!)
+        let request = BTPayPalCheckoutRequest(amount: amount)
+        request.currencyCode = currencyCode
+
+        payPalDriver.tokenizePayPalAccount(with: request) { tokenizedPayPalAccount, error in
+            if let error = error {
+                reject("ONE_TIME_PAYMENT_FAILED", error.localizedDescription, nil)
+                return
+            }
+
+            if tokenizedPayPalAccount == nil {
+                reject("ONE_TIME_PAYMENT_CANCELLED", "Payment has been cancelled", nil)
+                return
+            }
+
+            self.dataCollector.collectDeviceData { deviceData in
+                resolve(["deviceData": deviceData, "email": tokenizedPayPalAccount.email, "nonce": tokenizedPayPalAccount?.nonce])
+            }
+        }
+    }
+
+    @objc
+    func requestPayPalBillingAgreement(
+        _ options: NSDictionary,
+        resolver resolve: @escaping RCTPromiseResolveBlock,
+        rejecter reject: @escaping RCTPromiseRejectBlock
+    ) {
+
+        guard let clientToken = options["clientToken"] as? String,
+              let description = options["description"] as? String
+        else {
+            reject("INVALID_PARAMETERS", "Invalid parameters", nil)
+            return
+        }
+
+        // You may want to check if apiClient and dataCollector are already initialized.
+        if self.apiClient == nil {
+            self.apiClient = BTAPIClient(authorization: clientToken)
+            self.dataCollector = BTDataCollector(apiClient: self.apiClient!)
+        }
+
+        let payPalDriver = BTPayPalDriver(apiClient: self.apiClient!)
+        let request = BTPayPalVaultRequest()
+
+        if description {
+            request.billingAgreementDescription = description;
+        }
+
+        payPalDriver.tokenizePayPalAccount(with: request) { tokenizedPayPalAccount, error in
+            if let error = error {
+                reject("REQUEST_BILLING_AGREEMENT_FAILED", error.localizedDescription, nil)
+                return
+            }
+
+            if tokenizedPayPalAccount == nil {
+                reject("REQUEST_BILLING_AGREEMENT_CANCELLED", "Request billing agreement has been cancelled", nil)
+                return
+            }
+
+            self.dataCollector.collectDeviceData { deviceData in
+                resolve(["deviceData": deviceData, "nonce": tokenizedPayPalAccount.nonce])
+            }
+        }
+    }
+
+    @objc
+    func tokenizeCard(
+        _ parameters: NSDictionary,
+        resolver resolve: @escaping RCTPromiseResolveBlock,
+        rejecter reject: @escaping RCTPromiseRejectBlock
+    ) {
+        guard let clientToken = parameters["clientToken"] as? String,
+            let number = parameters["number"] as? String,
+            let expirationMonth = parameters["expirationMonth"] as? String,
+            let expirationYear = parameters["expirationYear"] as? String,
+            let cvv = parameters["cvv"] as? String
+        else {
+            reject("INVALID_PARAMETERS", "Invalid parameters", nil)
+            return
+        }
+
+        // Initialize the Braintree API client and data collector
+        self.apiClient = BTAPIClient(authorization: clientToken)
+        self.dataCollector = BTDataCollector(apiClient: self.apiClient!)
+
+        // Initialize the card client
+        let cardClient = BTCardClient(apiClient: self.apiClient)
+
+        // Create a BTCard instance and set its properties
+        let card = BTCard()
+        card.number = number
+        card.expirationMonth = expirationMonth
+        card.expirationYear = expirationYear
+        card.cvv = cvv
+        card.postalCode = parameters["postalCode"] as? String
+        card.shouldValidate = false
+
+        cardClient.tokenizeCard(card) { tokenizedCard, error in
+            if let error = error || tokenizedCard == nil {
+                reject("TOKENIZE_FAILED", error.localizedDescription, nil)
+                return
+            }
+
+            self.dataCollector.collectDeviceData { deviceData in
+                resolve(["deviceData": deviceData, "nonce": tokenizedCard.nonce])
+            }
+        }
+    }
+
+    @objc
+    func run3DSecureCheck(
+        _ parameters: NSDictionary,
+        resolver resolve: @escaping RCTPromiseResolveBlock,
+        rejecter reject: @escaping RCTPromiseRejectBlock
+    ) {
+        self.startPaymentFlow(parameters, resolver: resolve, rejecter: reject)
+    }
+
+    @objc
+    func getDeviceData(
+        _ clientToken: String,
+        resolver resolve: @escaping RCTPromiseResolveBlock,
+        rejecter reject: @escaping RCTPromiseRejectBlock
+    ) {
+        if self.apiClient == nil {
+            self.apiClient = BTAPIClient(authorization: clientToken)
+            self.dataCollector = BTDataCollector(apiClient: self.apiClient!)
+        }
+
+        self.dataCollector.collectDeviceData { deviceData in
+            resolve(deviceData)
+        }
+    }
+
+    // MARK:  - 3D Secure
+    private func startPaymentFlow(
+        _ parameters: NSDictionary,
+        resolver resolve: @escaping RCTPromiseResolveBlock,
+        rejecter reject: @escaping RCTPromiseRejectBlock
+    ) {
+        guard let clientToken = parameters["clientToken"] as? String
+        else {
+            reject("MISSING_CLIENT_TOKEN", "clientToken must be passed if Braintree methods weren't run before", nil)
+        }
+
+        if self.apiClient == nil {
+            self.apiClient = BTAPIClient(authorization: clientToken)
+            self.dataCollector = BTDataCollector(apiClient: self.apiClient!)
+        }
+
+        let threeDSecureRequest = BTThreeDSecureRequest()
+        threeDSecureRequest.amount = NSDecimalNumber(string: parameters["amount"] as? String ?? "")
+        threeDSecureRequest.nonce = parameters["nonce"] as? String
+        threeDSecureRequest.threeDSecureRequestDelegate = self
+        threeDSecureRequest.email = parameters["email"] as? String
+        threeDSecureRequest.versionRequested = .version2
+
+        let address = BTThreeDSecurePostalAddress()
+        address.givenName = parameters["firstname"] as? String // ASCII-printable characters required, else will throw a validation error
+        address.surname = parameters["lastname"] as? String // ASCII-printable characters required, else will throw a validation error
+        address.phoneNumber = parameters["phoneNumber"] as? String
+        address.streetAddress = parameters["streetAddress"] as? String
+        address.extendedAddress = parameters["streetAddress2"] as? String
+        address.locality = parameters["city"] as? String
+        address.region = parameters["region"] as? String
+        address.postalCode = parameters["postalCode"] as? String
+        address.countryCodeAlpha2 = parameters["countryCode"] as? String
+
+        let additionalInformation = BTThreeDSecureAdditionalInformation()
+        additionalInformation.shippingAddress = address
+
+        threeDSecureRequest.additionalInformation = additionalInformation
+        threeDSecureRequest.billingAddress = address
+
+        let paymentFlowDriver = BTPaymentFlowDriver(apiClient: apiClient)
+        paymentFlowDriver.viewControllerPresentingDelegate = self
+
+        paymentFlowDriver.startPaymentFlow(with: threeDSecureRequest) { result, error in
+            if let error = error {
+                reject("PAYMENT_FAILED", error.localizedDescription, nil)
+                return
+            }
+
+            if let threeDSecureResult = result as? BTThreeDSecureResult,
+               let tokenizedCard = threeDSecureResult.tokenizedCard,
+               let nonce = tokenizedCard.nonce {
+                if !tokenizedCard.threeDSecureInfo.liabilityShiftPossible && tokenizedCard.threeDSecureInfo.wasVerified {
+                    reject("3DSECURE_NOT_ABLE_TO_SHIFT_LIABILITY", "3D Secure liability cannot be shifted", nil)
+                    return
+                }
+                if !tokenizedCard.threeDSecureInfo.liabilityShifted && tokenizedCard.threeDSecureInfo.wasVerified {
+                    reject("3DSECURE_LIABILITY_NOT_SHIFTED", "3D Secure liability was not shifted", nil)
+                }
+                resolve(["deviceData": deviceData, "nonce": nonce])
+            } else {
+                reject("PAYMENT_3D_SECURE_FAILED", "Something went wrong", nil)
+            }
+        }
+    }
+
+    // MARK: - BTViewControllerPresentingDelegate
+    func paymentDriver(_ driver: Any, requestsPresentationOf viewController: UIViewController) {
+        reactRoot.present(viewController, animated: true, completion: nil)
+    }
+
+    func paymentDriver(_ driver: Any, requestsDismissalOf viewController: UIViewController) {
+        viewController.dismiss(animated: true, completion: nil)
+    }
+
+    // MARK: - BTThreeDSecureRequestDelegate
+    func onLookupComplete(_ request: BTThreeDSecureRequest, lookupResult result: BTThreeDSecureResult, next: @escaping () -> Void) {
+        next()
+    }
+
+    // MARK: - RootController
+    var reactRoot: UIViewController? {
+        var topViewController = UIApplication.shared.keyWindow?.rootViewController
+        if let presentedViewController = topViewController?.presentedViewController {
+            topViewController = presentedViewController
+        }
+        return topViewController
+    }
+}
+```
+
+Replace the content of `RNBraintree.m` with the following
+```objective-c
+// RNBraintree.m
+
+#import <React/RCTBridgeModule.h>
+
+// Export a native module
+@interface RCT_EXTERN_MODULE(RNBraintree, NSObject)
+
+// Export methods to a native module
+RCT_EXTERN_METHOD(showPayPalModule: (NSDictionary *)options
+                  resolver: (RCTPromiseResolveBlock)resolve
+                  rejecter: (RCTPromiseRejectBlock)reject)
+
+RCT_EXTERN_METHOD(requestPayPalBillingAgreement: (NSDictionary *)options
+                  resolver: (RCTPromiseResolveBlock)resolve
+                  rejecter: (RCTPromiseRejectBlock)reject)
+
+RCT_EXTERN_METHOD(tokenizeCard: (NSDictionary *)parameters
+                  resolver: (RCTPromiseResolveBlock)resolve
+                  rejecter: (RCTPromiseRejectBlock)reject)
+
+RCT_EXTERN_METHOD(run3DSecureCheck: (NSDictionary *)parameters
+                  resolver: (RCTPromiseResolveBlock)resolve
+                  rejecter: (RCTPromiseRejectBlock)reject)
+
+RCT_EXTERN_METHOD(getDeviceData: (NSString *) clientToken
+                  resolver: (RCTPromiseResolveBlock)resolve
+                  rejecter: (RCTPromiseRejectBlock)reject)
+@end
+```
+
+
+### RNBrainTreeApplePay
+- TODO
+
+## 4. Common Migration Challenges <a name="common-migration-challenges"></a>
+
+- TODO
+
+## 5. Resources <a name="resources"></a>
+
+- https://reactnative.dev/docs/native-modules-ios#exporting-swift
+- https://gist.github.com/JofArnold/31dfa8edcc3b8a42bbd86fbd44dad804
+- https://gaitatzis.medium.com/react-native-native-modules-in-ios-swift-97eb9073f5a2