Add shared usage history sync and observed timestamps

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ concurrency:
 jobs:
   test:
     name: Swift tests
-    runs-on: macos-14
+    runs-on: macos-15
     timeout-minutes: 10
     steps:
       - name: Check out repository

CONTEXT.md

@@ -51,3 +51,15 @@ _Avoid_: Worst case, guaranteed minimum
 **Burn-down chart**:
 A chart for the current usage window with time and remaining-budget axes. It shows the observed usage curve, a straight path from 100% to the safety buffer, the current projection, the historical projection, and the current point; earlier windows inform the historical projection but are not drawn individually.
 _Avoid_: Activity chart, task history
+
+**Usage sample**:
+A timestamped observation of the main limit's remaining budget and window reset. Its observation time is recorded locally; its remaining budget and window reset come from Codex.
+_Avoid_: Token bucket, activity event
+
+**Shared usage history**:
+The combined usage samples recorded by Macs connected through the same optional sync folder. It excludes preferences, launch settings, credentials, and raw Codex responses.
+_Avoid_: Shared app state, cloud backup
+
+**Sync folder**:
+An optional user-selected folder that connects the shared usage history of Macs signed in to the same Codex account. One sync folder represents one Codex account; the app does not identify or verify that account.
+_Avoid_: Account store, settings sync

Sources/CodexLimits/ForecastEngine.swift

@@ -11,16 +11,16 @@ enum ForecastEngine {
     ) -> Forecast {
         let daysLeft = max(window.resetsAt.timeIntervalSince(now) / 86_400, 0)
         let currentSamples = samples
-            .filter { $0.resetsAt == window.resetsAt && $0.date <= now }
-            .sorted { $0.date < $1.date }
+            .filter { $0.resetsAt == window.resetsAt && $0.observedAt <= now }
+            .sorted { $0.observedAt < $1.observedAt }
         let elapsedDays = max(now.timeIntervalSince(window.startsAt) / 86_400, 1 / 24)
         let windowRate = max((100 - window.remainingPercent) / elapsedDays, 0)
         let recentRate: Double
 
         if let first = currentSamples.first,
            let last = currentSamples.last,
-           last.date > first.date {
-            let days = last.date.timeIntervalSince(first.date) / 86_400
+           last.observedAt > first.observedAt {
+            let days = last.observedAt.timeIntervalSince(first.observedAt) / 86_400
             recentRate = max((first.remainingPercent - last.remainingPercent) / days, 0)
         } else {
             recentRate = windowRate
@@ -32,11 +32,11 @@ enum ForecastEngine {
         let historicalRates = Dictionary(grouping: samples.filter { $0.resetsAt != window.resetsAt }) {
             $0.resetsAt
         }.values.compactMap { windowSamples -> Double? in
-            let ordered = windowSamples.sorted { $0.date < $1.date }
+            let ordered = windowSamples.sorted { $0.observedAt < $1.observedAt }
             guard let first = ordered.first,
                   let last = ordered.last,
-                  last.date > first.date else { return nil }
-            let days = last.date.timeIntervalSince(first.date) / 86_400
+                  last.observedAt > first.observedAt else { return nil }
+            let days = last.observedAt.timeIntervalSince(first.observedAt) / 86_400
             return max((first.remainingPercent - last.remainingPercent) / days, 0)
         }
         let historicalRate: Double

Sources/CodexLimits/MenuContentView.swift

@@ -6,6 +6,7 @@ import SwiftUI
 struct MenuContentView: View {
     @ObservedObject var monitor: UsageMonitor
     @AppStorage(UsageMonitor.safetyBufferKey) private var safetyBuffer = 3.0
+    @Environment(\.openSettings) private var openSettings
 
     var body: some View {
         Group {
@@ -111,7 +112,14 @@ struct MenuContentView: View {
                 .font(.caption)
                 .foregroundStyle(.secondary)
                 Spacer()
-                SettingsLink {
+                Button {
+                    openSettings()
+                    DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
+                        NSApp.windows.first {
+                            $0.isVisible && $0.styleMask.contains(.titled)
+                        }?.orderFrontRegardless()
+                    }
+                } label: {
                     Image(systemName: "gearshape")
                 }
                 .buttonStyle(.borderless)
@@ -227,8 +235,8 @@ private struct BurnDownChart: View {
     private var observed: [BurnPoint] {
         let current = BurnPoint(date: fetchedAt, remaining: window.remainingPercent)
         let local = samples
-            .filter { $0.date > window.startsAt && $0.date < fetchedAt }
-            .map { BurnPoint(date: $0.date, remaining: $0.remainingPercent) }
+            .filter { $0.observedAt > window.startsAt && $0.observedAt < fetchedAt }
+            .map { BurnPoint(date: $0.observedAt, remaining: $0.remainingPercent) }
             .sorted { $0.date < $1.date }
         let firstKnown = local.first ?? current
         let buckets = tokenHistory
@@ -492,10 +500,37 @@ struct SettingsView: View {
                     .font(.caption)
                     .foregroundStyle(.secondary)
             }
+
+            Section("History sync") {
+                Text("Keep usage history in a folder available on your other Macs.")
+                    .foregroundStyle(.secondary)
+
+                if let folderName = monitor.syncFolderName {
+                    LabeledContent("Folder", value: folderName)
+                    Button("Stop Syncing") {
+                        Task { await monitor.stopHistorySync() }
+                    }
+                } else {
+                    Button("Choose Folder…", action: chooseHistoryFolder)
+                }
+
+                Text("Use this folder only on Macs signed in to the same Codex account.")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+                Text("Choose a private folder that isn’t shared with other people.")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+
+                if let syncErrorMessage = monitor.syncErrorMessage {
+                    Label(syncErrorMessage, systemImage: "exclamationmark.triangle")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                }
+            }
         }
         .formStyle(.grouped)
         .padding()
-        .frame(width: 320)
+        .frame(width: 380)
     }
 
     private func updateLaunchAtLogin(_ enabled: Bool) {
@@ -512,6 +547,17 @@ struct SettingsView: View {
             loginItemError = "Couldn’t update the login setting."
         }
     }
+
+    private func chooseHistoryFolder() {
+        let panel = NSOpenPanel()
+        panel.canChooseDirectories = true
+        panel.canChooseFiles = false
+        panel.allowsMultipleSelection = false
+        panel.canCreateDirectories = true
+        panel.prompt = "Choose"
+        guard panel.runModal() == .OK, let directory = panel.url else { return }
+        Task { await monitor.connectHistoryFolder(directory) }
+    }
 }
 
 enum LoginItem {