Switch Loop profiles from the Loop remote screen

LoopFollow/Controllers/Nightscout/ProfileManager.swift

@@ -123,6 +123,7 @@ final class ProfileManager {
 
         Storage.shared.teamId.value = profileData.teamID ?? Storage.shared.teamId.value ?? ""
         Storage.shared.remoteCommands.value = profileData.remoteCommands ?? []
+        Observable.shared.loopProfiles.set(LoopProfileSet(profileData))
     }
 
     func currentISF() -> HKQuantity? {
@@ -227,5 +228,6 @@ final class ProfileManager {
         units = .millimolesPerLiter
         timezone = TimeZone.current
         defaultProfile = ""
+        Observable.shared.loopProfiles.set(nil)
     }
 }

LoopFollow/Remote/LoopAPNS/LoopAPNSRemoteView.swift

@@ -7,6 +7,7 @@ struct LoopAPNSRemoteView: View {
     @Environment(\.presentationMode) var presentationMode
     @StateObject private var viewModel = RemoteSettingsViewModel()
     @ObservedObject private var activeOverrideNote = Observable.shared.override
+    @ObservedObject private var loopRemoteCommands = Storage.shared.loopRemoteCommands
 
     var body: some View {
         NavigationView {
@@ -22,6 +23,16 @@ struct LoopAPNSRemoteView: View {
                         CommandButtonView(command: "Meal", iconName: "fork.knife", destination: LoopAPNSCarbsView())
                         CommandButtonView(command: "Bolus", iconName: "syringe", destination: LoopAPNSBolusView())
                         CommandButtonView(command: "Overrides", iconName: "slider.horizontal.3", destination: OverridePresetsView(), isActive: activeOverrideNote.value != nil)
+                        if loopRemoteCommands.value.contains(LoopProfile.switchCommand) {
+                            CommandButtonView(command: "Profiles", iconName: "arrow.triangle.2.circlepath", destination: LoopProfilesView())
+                        } else {
+                            UnavailableCommandButtonView(
+                                command: "Profiles",
+                                iconName: "arrow.triangle.2.circlepath",
+                                title: "Profiles Not Available",
+                                message: "Switching Loop profiles from LoopFollow needs Loop built with the Profile Save & Load customization, added with the Loop and Learn Customization Select script."
+                            )
+                        }
                     }
                     .padding(.horizontal)
                 } else {

LoopFollow/Remote/LoopAPNS/LoopAPNSService.swift

@@ -92,7 +92,7 @@ class LoopAPNSService {
         return hasFullSetup
     }
 
-    private static let returnNotificationRequiredMessage = "Editing or deleting a carb entry needs LoopFollow's own APNS credentials so Loop can confirm the result. Configure them in App Settings → APN."
+    private static let returnNotificationRequiredMessage = "This command needs LoopFollow's own APNS credentials so Loop can confirm the result. Configure them in App Settings → APN."
 
     /// The return-notification block encrypted with the OTP, when LoopFollow's own credentials are configured.
     private func encryptedReturnNotification(otp: String) -> String? {
@@ -161,6 +161,12 @@ class LoopAPNSService {
         sendConfirmedCommand(payload, otp: otp, completion: completion)
     }
 
+    /// Switches Loop to the saved profile `name`. Requires the Loop remote profile patch.
+    func sendProfileSwitch(name: String, fingerprint: String, otp: String, completion: @escaping (Bool, String?) -> Void) {
+        LogManager.shared.log(category: .apns, message: "Sending profile switch to \(name) fingerprint=\(fingerprint)")
+        sendConfirmedCommand(LoopAPNSCommands.profileSwitchCommandPayload(name: name, fingerprint: fingerprint, otp: otp), otp: otp, completion: completion)
+    }
+
     /// Sends carbs via APNS push notification
     /// - Parameters:
     ///   - payload: The carbs payload to send

LoopFollow/Remote/LoopAPNS/LoopProfile.swift

@@ -0,0 +1,108 @@
+// LoopFollow
+// LoopProfile.swift
+
+import CryptoKit
+import Foundation
+import HealthKit
+
+/// A saved Loop profile from the Nightscout profile store, offered for a remote switch.
+struct LoopProfile: Identifiable, Equatable {
+    struct Item: Equatable {
+        let seconds: Int
+        let value: Double
+    }
+
+    struct RangeItem: Equatable {
+        let seconds: Int
+        let low: Double
+        let high: Double
+    }
+
+    /// Loop lists this in `remoteCommands` when it accepts remote profile switches.
+    static let switchCommand = "profile-switch"
+
+    let name: String
+    let units: HKUnit
+    let basal: [Item]
+    let carbRatio: [Item]
+    let sensitivity: [Item]
+    let correctionRange: [RangeItem]
+    /// Sent with the switch command. Loop only switches when its saved profile has the same fingerprint.
+    let fingerprint: String
+
+    var id: String { name }
+
+    init(name: String, store: NSProfile.Store) {
+        func items(_ entries: [(Double, Double)]) -> [Item] {
+            entries.map { Item(seconds: Int($0.0), value: $0.1) }
+        }
+        let basal = items(store.basal.map { ($0.timeAsSeconds, $0.value) })
+        let carbRatio = items(store.carbratio.map { ($0.timeAsSeconds, $0.value) })
+        let sensitivity = items(store.sens.map { ($0.timeAsSeconds, $0.value) })
+        let targetLow = items((store.target_low ?? []).map { ($0.timeAsSeconds, $0.value) })
+        let targetHigh = items((store.target_high ?? []).map { ($0.timeAsSeconds, $0.value) })
+
+        self.name = name
+        units = store.units.lowercased() == "mg/dl" ? .milligramsPerDeciliter : .millimolesPerLiter
+        self.basal = basal
+        self.carbRatio = carbRatio
+        self.sensitivity = sensitivity
+        correctionRange = zip(targetLow, targetHigh).map { RangeItem(seconds: $0.seconds, low: $0.value, high: $1.value) }
+        fingerprint = Self.fingerprint(basal: basal, carbRatio: carbRatio, sensitivity: sensitivity, targetLow: targetLow, targetHigh: targetHigh)
+    }
+
+    /// Scheduled basal over a full day, in units.
+    var basalTotal: Double {
+        basal.enumerated().reduce(0) { total, entry in
+            let end = entry.offset + 1 < basal.count ? basal[entry.offset + 1].seconds : 24 * 3600
+            return total + entry.element.value * Double(end - entry.element.seconds) / 3600
+        }
+    }
+
+    /// Saved profiles in a Loop profile document, by name. `Default` mirrors the active settings and is left out.
+    static func profiles(from profile: NSProfile) -> [LoopProfile] {
+        profile.store
+            .filter { $0.key != "Default" }
+            .map { LoopProfile(name: $0.key, store: $0.value) }
+            .sorted { $0.name.localizedStandardCompare($1.name) == .orderedAscending }
+    }
+
+    /// Matches Loop's fingerprint of a profile store entry:
+    /// `basal=<seconds>:<value>,...;carbratio=...;sens=...;target_low=...;target_high=...` with values to three
+    /// decimals, hashed with SHA-256, first 16 hex characters.
+    static func fingerprint(basal: [Item], carbRatio: [Item], sensitivity: [Item], targetLow: [Item], targetHigh: [Item]) -> String {
+        func encode(_ items: [Item]) -> String {
+            items.map { "\($0.seconds):" + String(format: "%.3f", $0.value) }.joined(separator: ",")
+        }
+        let canonical = [
+            "basal=" + encode(basal),
+            "carbratio=" + encode(carbRatio),
+            "sens=" + encode(sensitivity),
+            "target_low=" + encode(targetLow),
+            "target_high=" + encode(targetHigh),
+        ].joined(separator: ";")
+        let digest = SHA256.hash(data: Data(canonical.utf8))
+        return String(digest.map { String(format: "%02x", $0) }.joined().prefix(16))
+    }
+}
+
+/// The saved profiles from the latest Loop profile upload.
+struct LoopProfileSet: Equatable {
+    let profiles: [LoopProfile]
+    let activeName: String
+    let uploadedAt: Date?
+
+    init(profiles: [LoopProfile], activeName: String, uploadedAt: Date?) {
+        self.profiles = profiles
+        self.activeName = activeName
+        self.uploadedAt = uploadedAt
+    }
+
+    init(_ profile: NSProfile) {
+        self.init(
+            profiles: LoopProfile.profiles(from: profile),
+            activeName: profile.defaultProfile,
+            uploadedAt: profile.startDate.flatMap { NightscoutUtils.parseDate($0) }
+        )
+    }
+}