Refactor applyLinks add events to link,usbank,aubecs (stripe#3471)

## Summary
Refactor applyLinks, add events to link,usbank,aubecs

## Motivation
Refactor was an old 'todo', which had an assert in 3 places. Moved this
to a single place.

## Testing
None

## Changelog
<!-- Is this a notable change that affects users? If so, add a line to
`CHANGELOG.md` and prefix the line with one of the following:
    - [Added] for new features.
    - [Changed] for changes in existing functionality.
    - [Deprecated] for soon-to-be removed features.
    - [Removed] for now removed features.
    - [Fixed] for any bug fixes.
    - [Security] in case of vulnerabilities.
-->

StripePaymentSheet/StripePaymentSheet/Source/Helpers/STPStringUtils.swift

@@ -7,11 +7,15 @@
 //
 
 import Foundation
+@_spi(STP) import StripeCore
 @_spi(STP) import StripePaymentsUI
 
 typealias STPTaggedSubstringCompletionBlock = (String?, NSRange) -> Void
 typealias STPTaggedSubstringsCompletionBlock = (String, [String: NSValue]) -> Void
 extension STPStringUtils {
+    enum Error: Swift.Error {
+        case tagMissing
+    }
     /// Takes a string with the named html-style tags, removes the tags,
     /// and then calls the completion block with the modified string and the range
     /// in it that the tag would have enclosed.
@@ -136,4 +140,28 @@ extension STPStringUtils {
 
         completion(modifiedString, tagsToRange)
     }
+
+    class func applyLinksToString(template: String, links: [String: URL]) -> NSMutableAttributedString {
+        let formattedString = NSMutableAttributedString()
+        STPStringUtils.parseRanges(from: template, withTags: Set<String>(links.keys)) { string, matches in
+            formattedString.append(NSAttributedString(string: string))
+            for (tag, range) in matches {
+                guard range.rangeValue.location != NSNotFound else {
+                    let errorAnalytic = ErrorAnalytic(event: .unexpectedPaymentSheetError,
+                                                      error: Error.tagMissing,
+                                                      additionalNonPIIParams: ["template": template,
+                                                                               "tag_missing": tag,
+                                                                              ])
+                    STPAnalyticsClient.sharedClient.log(analytic: errorAnalytic)
+                    stpAssertionFailure("Tag '<\(tag)>' not found")
+                    continue
+                }
+
+                if let url = links[tag] {
+                    formattedString.addAttributes([.link: url], range: range.rangeValue)
+                }
+            }
+        }
+        return formattedString
+    }
 }

StripePaymentSheet/StripePaymentSheet/Source/Internal/Link/Views/LinkLegalTermsView.swift

@@ -6,8 +6,10 @@
 //  Copyright © 2022 Stripe, Inc. All rights reserved.
 //
 
+@_spi(STP) import StripeCore
 @_spi(STP) import StripePaymentsUI
 @_spi(STP) import StripeUICore
+
 import UIKit
 
 protocol LinkLegalTermsViewDelegate: AnyObject {
@@ -109,24 +111,7 @@ final class LinkLegalTermsView: UIView {
                 )
             }
         }()
-
-        let formattedString = NSMutableAttributedString()
-
-        STPStringUtils.parseRanges(from: string, withTags: Set<String>(links.keys)) { string, matches in
-            formattedString.append(NSAttributedString(string: string))
-
-            for (tag, range) in matches {
-                guard range.rangeValue.location != NSNotFound else {
-                    assertionFailure("Tag '<\(tag)>' not found")
-                    continue
-                }
-
-                if let url = links[tag] {
-                    formattedString.addAttributes([.link: url], range: range.rangeValue)
-                }
-            }
-        }
-
+        let formattedString = STPStringUtils.applyLinksToString(template: string, links: links)
         let paragraphStyle = NSMutableParagraphStyle()
         paragraphStyle.lineSpacing = LinkUI.lineSpacing(
             fromRelativeHeight: Constants.lineHeight,
@@ -141,6 +126,9 @@ final class LinkLegalTermsView: UIView {
 }
 
 extension LinkLegalTermsView: UITextViewDelegate {
+    enum Error: Swift.Error {
+        case linkLegalTermsViewUITextViewDelegate
+    }
 
 #if !canImport(CompositorServices)
     func textView(
@@ -155,7 +143,11 @@ extension LinkLegalTermsView: UITextViewDelegate {
         }
 
         let handled = delegate?.legalTermsView(self, didTapOnLinkWithURL: URL) ?? false
-        assert(handled, "Link not handled by delegate")
+
+        let errorAnalytic = ErrorAnalytic(event: .unexpectedPaymentSheetError,
+                                          error: Error.linkLegalTermsViewUITextViewDelegate)
+        STPAnalyticsClient.sharedClient.log(analytic: errorAnalytic)
+        stpAssert(handled, "Link not handled by delegate")
 
         // If not handled by the delegate, let the system handle the link.
         return !handled

StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/USBankAccount/USBankAccountPaymentMethodElement.swift

@@ -97,6 +97,8 @@ final class USBankAccountPaymentMethodElement: Element {
             && configuration.defaultBillingDetails.name != nil
         let hasDefaultEmail = configuration.billingDetailsCollectionConfiguration.attachDefaultsToPaymentMethod
             && configuration.defaultBillingDetails.email != nil
+
+        // Fail loudly: This is an integration error
         assert(
             (collectingName || hasDefaultName) && (collectingEmail || hasDefaultEmail),
             "If name or email are not collected, they must be provided through defaults"
@@ -168,37 +170,18 @@ final class USBankAccountPaymentMethodElement: Element {
         } else if case .paymentSheet = configuration, !linkedBank.instantlyVerified {
             mandateText =  String.init(format: Self.MicrodepositCopy, merchantName) + "\n" + mandateText
         }
-        let formattedString = applyLinksToString(template: mandateText, links: links)
+        let formattedString = STPStringUtils.applyLinksToString(template: mandateText, links: links)
         applyStyle(formattedString: formattedString, theme: theme)
         return formattedString
     }
 
     class func attributedMandateTextSavedPaymentMethod(theme: ElementsUITheme = .default) -> NSMutableAttributedString {
         let mandateText = Self.ContinueMandateText
-        let formattedString = applyLinksToString(template: mandateText, links: links)
+        let formattedString = STPStringUtils.applyLinksToString(template: mandateText, links: links)
         applyStyle(formattedString: formattedString, theme: theme)
         return formattedString
     }
 
-    // TODO(wooj): Refactor this code to be common across multiple classes
-    private class func applyLinksToString(template: String, links: [String: URL]) -> NSMutableAttributedString {
-        let formattedString = NSMutableAttributedString()
-        STPStringUtils.parseRanges(from: template, withTags: Set<String>(links.keys)) { string, matches in
-            formattedString.append(NSAttributedString(string: string))
-            for (tag, range) in matches {
-                guard range.rangeValue.location != NSNotFound else {
-                    assertionFailure("Tag '<\(tag)>' not found")
-                    continue
-                }
-
-                if let url = links[tag] {
-                    formattedString.addAttributes([.link: url], range: range.rangeValue)
-                }
-            }
-        }
-        return formattedString
-    }
-
     private class func applyStyle(formattedString: NSMutableAttributedString, theme: ElementsUITheme = .default) {
         let style = NSMutableParagraphStyle()
         style.alignment = .center

StripePaymentSheet/StripePaymentSheet/Source/PaymentSheet/Views/AUBECSMandate.swift

@@ -62,25 +62,7 @@ final class AUBECSLegalTermsView: UIView {
             "Legal text shown when using AUBECS."
         )
         let string = String(format: template, configuration.merchantDisplayName)
-
-        let formattedString = NSMutableAttributedString()
-
-        STPStringUtils.parseRanges(from: string, withTags: Set<String>(links.keys)) { string, matches in
-            formattedString.append(NSAttributedString(string: string))
-
-            for (tag, range) in matches {
-                guard range.rangeValue.location != NSNotFound else {
-                    assertionFailure("Tag '<\(tag)>' not found")
-                    continue
-                }
-
-                if let url = links[tag] {
-                    formattedString.addAttributes([.link: url], range: range.rangeValue)
-                }
-            }
-        }
-
-        return formattedString
+        return STPStringUtils.applyLinksToString(template: string, links: links)
     }
 
 }