feat: Introduce ISODurationFormatter

RevenueCat.xcodeproj/project.pbxproj

@@ -626,6 +626,8 @@
 		575A8EE32922C5E100936709 /* AsyncTestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 575A8EE02922C56300936709 /* AsyncTestHelpers.swift */; };
 		575A8EE52922C9F300936709 /* MockStoreKit2TransactionListenerDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 575A8EE42922C9F300936709 /* MockStoreKit2TransactionListenerDelegate.swift */; };
 		575A8EE62922C9F300936709 /* MockStoreKit2TransactionListenerDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 575A8EE42922C9F300936709 /* MockStoreKit2TransactionListenerDelegate.swift */; };
+		575F19B42D5A27EF0089A64F /* ISODurationFormatter.swift in Sources */ = {isa = PBXBuildFile; fileRef = 575F19B32D5A27E70089A64F /* ISODurationFormatter.swift */; };
+		575F19B62D5A298F0089A64F /* ISODurationFormatterTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 575F19B52D5A29860089A64F /* ISODurationFormatterTests.swift */; };
 		5766AA3E283C750300FA6091 /* Operators+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5766AA3D283C750300FA6091 /* Operators+Extensions.swift */; };
 		5766AA42283C768600FA6091 /* OperatorExtensionsTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5766AA41283C768600FA6091 /* OperatorExtensionsTests.swift */; };
 		5766AA56283D4C5400FA6091 /* IgnoreHashable.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5766AA55283D4C5400FA6091 /* IgnoreHashable.swift */; };
@@ -1952,6 +1954,8 @@
 		575A17AA2773A59300AA6F22 /* CurrentTestCaseTracker.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CurrentTestCaseTracker.swift; sourceTree = "<group>"; };
 		575A8EE02922C56300936709 /* AsyncTestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AsyncTestHelpers.swift; sourceTree = "<group>"; };
 		575A8EE42922C9F300936709 /* MockStoreKit2TransactionListenerDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MockStoreKit2TransactionListenerDelegate.swift; sourceTree = "<group>"; };
+		575F19B32D5A27E70089A64F /* ISODurationFormatter.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ISODurationFormatter.swift; sourceTree = "<group>"; };
+		575F19B52D5A29860089A64F /* ISODurationFormatterTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ISODurationFormatterTests.swift; sourceTree = "<group>"; };
 		5766AA3D283C750300FA6091 /* Operators+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Operators+Extensions.swift"; sourceTree = "<group>"; };
 		5766AA41283C768600FA6091 /* OperatorExtensionsTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OperatorExtensionsTests.swift; sourceTree = "<group>"; };
 		5766AA55283D4C5400FA6091 /* IgnoreHashable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IgnoreHashable.swift; sourceTree = "<group>"; };
@@ -3663,6 +3667,7 @@
 		35272E1A26D0023400F22C3B /* Misc */ = {
 			isa = PBXGroup;
 			children = (
+				575F19B52D5A29860089A64F /* ISODurationFormatterTests.swift */,
 				576C8A9027D180540058FA6E /* __Snapshots__ */,
 				37E35B9AC7A350CA2437049D /* ISOPeriodFormatterTests.swift */,
 				37E35EEE7783629CDE41B70C /* SystemInfoTests.swift */,
@@ -4545,6 +4550,7 @@
 		57F3C0CC29B7A0F30004FD7E /* DateAndTime */ = {
 			isa = PBXGroup;
 			children = (
+				575F19B32D5A27E70089A64F /* ISODurationFormatter.swift */,
 				578DAA472948EEAD001700FD /* Clock.swift */,
 				37E3567189CF6A746EE3CCC2 /* DateExtensions.swift */,
 				0313FD40268A506400168386 /* DateProvider.swift */,
@@ -6311,6 +6317,7 @@
 				4DBC30962B1DFA97001D33C7 /* StoreKitVersion.swift in Sources */,
 				57DE807328074C76008D6C6F /* SK2Storefront.swift in Sources */,
 				57A17727276A721D0052D3A8 /* Set+Extensions.swift in Sources */,
+				575F19B42D5A27EF0089A64F /* ISODurationFormatter.swift in Sources */,
 				03C72FBE2D34949600297FEC /* PaywallIconComponent.swift in Sources */,
 				4DC546272AD44BBE005CDB35 /* EncodedAppleReceipt.swift in Sources */,
 				37E350C67712B9E054FEF297 /* AttributionData.swift in Sources */,
@@ -6367,6 +6374,7 @@
 				2DDF41CF24F6F4C3005BC22D /* ReceiptParsing+TestsWithRealReceipts.swift in Sources */,
 				57488C2329CB89CC0000EE7E /* OfflineEntitlementsManagerTests.swift in Sources */,
 				57FDAA962846BDE2009A48F1 /* PurchasesTransactionHandlingTests.swift in Sources */,
+				575F19B62D5A298F0089A64F /* ISODurationFormatterTests.swift in Sources */,
 				575A17AB2773A59300AA6F22 /* CurrentTestCaseTracker.swift in Sources */,
 				351B514326D449C100BD2BD7 /* MockSubscriberAttributesManager.swift in Sources */,
 				B300E4C026D4371200B22262 /* SKPaymentTransactionExtensionsTests.swift in Sources */,

Sources/Misc/DateAndTime/ISODurationFormatter.swift

@@ -0,0 +1,137 @@
+//
+//  Copyright RevenueCat Inc. All Rights Reserved.
+//
+//  Licensed under the MIT License (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      https://opensource.org/licenses/MIT
+//
+//  ISODurationFormatter.swift
+//
+//  Created by Facundo Menzella on 10/2/25.
+
+import Foundation
+
+/// A representation of an ISO 8601 duration.
+///
+/// This struct represents both date and time-based components of an ISO 8601 duration string.
+/// ISO 8601 durations use the format `PnYnMnWnDTnHnMnS`, where each part is optional:
+/// - `P` indicates the duration starts.
+/// - `nY` for years.
+/// - `nM` for months.
+/// - `nW` for weeks.
+/// - `nD` for days.
+/// - `T` separates the date part from the time part.
+/// - `nH` for hours.
+/// - `nM` for minutes.
+/// - `nS` for seconds.
+///
+/// Example duration strings:
+/// - `"P1Y2M3DT4H5M6S"`: 1 year, 2 months, 3 days, 4 hours, 5 minutes, 6 seconds.
+/// - `"P3W"`: 3 weeks.
+/// - `"PT15M"`: 15 minutes.
+struct ISODuration {
+    /// The number of years in the duration.
+    ///
+    /// Example: For `"P1Y"`, this will be `1`.
+    let years: Int
+
+    /// The number of months in the duration.
+    ///
+    /// Example: For `"P2M"`, this will be `2`.
+    let months: Int
+
+    /// The number of weeks in the duration.
+    ///
+    /// Weeks will be converted to days if calculating a `TimeInterval`.
+    /// Example: For `"P3W"`, this will be `3`.
+    let weeks: Int
+
+    /// The number of days in the duration.
+    ///
+    /// Example: For `"P4D"`, this will be `4`.
+    let days: Int
+
+    /// The number of hours in the duration.
+    ///
+    /// Example: For `"PT5H"`, this will be `5`.
+    let hours: Int
+
+    /// The number of minutes in the duration.
+    ///
+    /// Example: For `"PT6M"`, this will be `6`.
+    let minutes: Int
+
+    /// The number of seconds in the duration.
+    ///
+    /// Example: For `"PT7S"`, this will be `7`.
+    let seconds: Int
+}
+
+@available(iOS 11.2, macOS 10.13.2, tvOS 11.2, *)
+enum ISODurationFormatter {
+
+    // swiftlint:disable:next line_length
+    static let pattern = #"([-+]?)P(?:([-+]?\d+)Y)?(?:([-+]?\d+)M)?(?:([-+]?\d+)W)?(?:([-+]?\d+)D)?(?:T(?:([-+]?\d+)H)?(?:([-+]?\d+)M)?(?:([-+]?\d+)S)?)?"#
+
+    /// Parses an ISO 8601 duration string and returns an `ISODuration` object.
+    static func parse(from periodString: String) -> ISODuration? {
+        guard let regex = try? NSRegularExpression(pattern: pattern, options: .caseInsensitive) else {
+            return nil
+        }
+
+        let nsString = periodString as NSString
+        let match = regex.firstMatch(
+            in: periodString,
+            options: [],
+            range: NSRange(location: 0, length: nsString.length))
+
+        guard let match = match else {
+            print("Failed to parse ISO duration: \(periodString)")
+            return nil
+        }
+
+        let negate = nsString.substring(with: match.range(at: 1)) == "-" ? -1 : 1
+
+        let years = getIntValue(from: nsString, match: match, at: 2) * negate
+        let months = getIntValue(from: nsString, match: match, at: 3) * negate
+        let weeks = getIntValue(from: nsString, match: match, at: 4) * negate
+        let days = getIntValue(from: nsString, match: match, at: 5) * negate
+        let hours = getIntValue(from: nsString, match: match, at: 6) * negate
+        let minutes = getIntValue(from: nsString, match: match, at: 7) * negate
+        let seconds = getIntValue(from: nsString, match: match, at: 8) * negate
+
+        return ISODuration(
+            years: years,
+            months: months,
+            weeks: weeks,
+            days: days,
+            hours: hours,
+            minutes: minutes,
+            seconds: seconds)
+    }
+
+    /// Converts an `ISODuration` object back to an ISO 8601 duration string.
+    static func string(from duration: ISODuration) -> String {
+        var result = "P"
+        if duration.years != 0 { result += "\(duration.years)Y" }
+        if duration.months != 0 { result += "\(duration.months)M" }
+        if duration.weeks != 0 { result += "\(duration.weeks)W" }
+        if duration.days != 0 { result += "\(duration.days)D" }
+        if duration.hours != 0 || duration.minutes != 0 || duration.seconds != 0 {
+            result += "T"
+            if duration.hours != 0 { result += "\(duration.hours)H" }
+            if duration.minutes != 0 { result += "\(duration.minutes)M" }
+            if duration.seconds != 0 { result += "\(duration.seconds)S" }
+        }
+        return result
+    }
+
+    private static func getIntValue(from nsString: NSString, match: NSTextCheckingResult, at index: Int) -> Int {
+        guard match.range(at: index).location != NSNotFound else {
+            return 0
+        }
+        return Int(nsString.substring(with: match.range(at: index))) ?? 0
+    }
+}

Sources/Misc/DateAndTime/ISOPeriodFormatter.swift

@@ -19,24 +19,20 @@ import StoreKit
 enum ISOPeriodFormatter {
 
     static func string(fromProductSubscriptionPeriod period: SubscriptionPeriod) -> String {
-        let unitString = Self.period(fromUnit: period.unit)
-        let stringResult = "P\(period.value)\(unitString)"
-        return stringResult
+        ISODurationFormatter.string(from: period.isoDuration)
     }
+}
 
-    private static func period(fromUnit unit: SubscriptionPeriod.Unit) -> String {
-        switch unit {
-        case .day:
-            return "D"
-        case .week:
-            return "W"
-        case .month:
-            return "M"
-        case .year:
-            return "Y"
-        @unknown default:
-            fatalError("New SKProduct.PeriodUnit \(unit) unaccounted for")
-        }
+extension SubscriptionPeriod {
+    var isoDuration: ISODuration {
+        ISODuration(
+            years: unit == .year ? value : 0,
+            months: unit == .month ? value : 0,
+            weeks: unit == .week ? value : 0,
+            days: unit == .day ? value : 0,
+            hours: 0,
+            minutes: 0,
+            seconds: 0
+        )
     }
-
 }

Tests/UnitTests/Misc/ISODurationFormatterTests.swift

@@ -0,0 +1,109 @@
+//
+//  Copyright RevenueCat Inc. All Rights Reserved.
+//
+//  Licensed under the MIT License (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      https://opensource.org/licenses/MIT
+//
+//  ISODurationTests.swift
+//
+//  Created by Facundo Menzella on 10/2/25.
+
+import Nimble
+import XCTest
+
+@testable import RevenueCat
+
+final class ISODurationFormatterTests: TestCase {
+
+    func testParseFullDuration() {
+        let durationString = "P1Y2M3W4DT5H6M7S"
+        guard let duration = ISODurationFormatter.parse(from: durationString) else {
+            XCTFail("Failed to parse full duration")
+            return
+        }
+
+        expect(duration.years) == 1
+        expect(duration.months) == 2
+        expect(duration.weeks) == 3
+        expect(duration.days) == 4
+        expect(duration.hours) == 5
+        expect(duration.minutes) == 6
+        expect(duration.seconds) == 7
+    }
+
+    func testParseDaysOnly() {
+        let durationString = "P10D"
+        guard let duration = ISODurationFormatter.parse(from: durationString) else {
+            XCTFail("Failed to parse days-only duration")
+            return
+        }
+
+        expect(duration.years) == 0
+        expect(duration.months) == 0
+        expect(duration.weeks) == 0
+        expect(duration.days) == 10
+        expect(duration.hours) == 0
+        expect(duration.minutes) == 0
+        expect(duration.seconds) == 0
+    }
+
+    func testParseWeeksOnly() {
+        let durationString = "P5W"
+        guard let duration = ISODurationFormatter.parse(from: durationString) else {
+            XCTFail("Failed to parse weeks-only duration")
+            return
+        }
+
+        expect(duration.weeks) == 5
+        expect(duration.years) == 0
+        expect(duration.months) == 0
+        expect(duration.hours) == 0
+        expect(duration.minutes) == 0
+        expect(duration.seconds) == 0
+        expect(duration.days) == 0
+    }
+
+    func testParseTimeOnly() {
+        let durationString = "PT3H45M20S"
+        guard let duration = ISODurationFormatter.parse(from: durationString) else {
+            XCTFail("Failed to parse time-only duration")
+            return
+        }
+
+        expect(duration.weeks) == 0
+        expect(duration.years) == 0
+        expect(duration.months) == 0
+        expect(duration.hours) == 3
+        expect(duration.minutes) == 45
+        expect(duration.seconds) == 20
+        expect(duration.days) == 0
+    }
+
+    func testStringFromDuration() {
+        let duration = ISODuration(years: 1, months: 2, weeks: 0, days: 4, hours: 5, minutes: 6, seconds: 7)
+        let durationString = ISODurationFormatter.string(from: duration)
+
+        expect(durationString) == "P1Y2M4DT5H6M7S"
+    }
+
+    func testEmptyDuration() {
+        let durationString = "P"
+        let duration = ISODurationFormatter.parse(from: durationString)
+
+        expect(duration).toNot(beNil())
+        expect(duration?.years) == 0
+        expect(duration?.months) == 0
+        expect(duration?.days) == 0
+        expect(duration?.hours) == 0
+        expect(duration?.minutes) == 0
+        expect(duration?.seconds) == 0
+    }
+
+    func testInvalidDuration() {
+        let durationString = "InvalidString"
+        expect(ISODurationFormatter.parse(from: durationString)).to(beNil())
+    }
+}