perf(usage): cache reports across launches

Sources/TokPeek/TokPeekApp.swift

@@ -14,7 +14,8 @@ struct TokPeekApp: App {
     private var appDelegate
 
     @StateObject private var store = UsageStore(
-        loader: TokscaleClient()
+        loader: TokscaleClient(),
+        reportCache: FileUsageReportCache()
     )
     @StateObject private var settings = SettingsStore()
     @StateObject private var launchAtLogin = LaunchAtLoginController()

Sources/TokPeekKit/UsageReport.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-public struct UsageReport: Decodable, Sendable, Equatable {
+public struct UsageReport: Codable, Sendable, Equatable {
     public let meta: ReportMetadata
     public let summary: UsageSummary
     public let years: [YearSummary]
@@ -61,15 +61,15 @@ public struct UsageReport: Decodable, Sendable, Equatable {
     }
 }
 
-public struct ReportMetadata: Decodable, Sendable, Equatable {
+public struct ReportMetadata: Codable, Sendable, Equatable {
     public let generatedAt: String
     public let version: String
     public let dateRangeStart: String
     public let dateRangeEnd: String
     public let processingTimeMs: UInt32
 }
 
-public struct UsageSummary: Decodable, Sendable, Equatable {
+public struct UsageSummary: Codable, Sendable, Equatable {
     public let totalTokens: Int64
     public let totalCost: Double
     public let totalDays: Int
@@ -80,15 +80,15 @@ public struct UsageSummary: Decodable, Sendable, Equatable {
     public let models: [String]
 }
 
-public struct YearSummary: Decodable, Sendable, Equatable {
+public struct YearSummary: Codable, Sendable, Equatable {
     public let year: String
     public let totalTokens: Int64
     public let totalCost: Double
     public let rangeStart: String
     public let rangeEnd: String
 }
 
-public struct DailyContribution: Decodable, Sendable, Equatable, Identifiable {
+public struct DailyContribution: Codable, Sendable, Equatable, Identifiable {
     public var id: String { date }
 
     public let date: String
@@ -99,7 +99,7 @@ public struct DailyContribution: Decodable, Sendable, Equatable, Identifiable {
     public let activeTimeMs: Int64?
 }
 
-public struct HourlyContribution: Decodable, Sendable, Equatable, Identifiable {
+public struct HourlyContribution: Codable, Sendable, Equatable, Identifiable {
     public var id: String { hour }
 
     public let hour: String
@@ -120,21 +120,21 @@ public struct HourlyContribution: Decodable, Sendable, Equatable, Identifiable {
     }
 }
 
-public struct DailyTotals: Decodable, Sendable, Equatable {
+public struct DailyTotals: Codable, Sendable, Equatable {
     public let tokens: Int64
     public let cost: Double
     public let messages: Int
 }
 
-public struct TokenBreakdown: Decodable, Sendable, Equatable {
+public struct TokenBreakdown: Codable, Sendable, Equatable {
     public let input: Int64
     public let output: Int64
     public let cacheRead: Int64
     public let cacheWrite: Int64
     public let reasoning: Int64
 }
 
-public struct ClientContribution: Decodable, Sendable, Equatable, Identifiable {
+public struct ClientContribution: Codable, Sendable, Equatable, Identifiable {
     public var id: String {
         "\(client)|\(providerId)|\(modelId)"
     }

Sources/TokPeekKit/UsageReportCache.swift

@@ -0,0 +1,96 @@
+import Foundation
+
+public struct UsageReportSnapshot: Codable, Sendable, Equatable {
+    public let request: UsageRequest
+    public let report: UsageReport
+    public let refreshedAt: Date
+
+    public init(
+        request: UsageRequest,
+        report: UsageReport,
+        refreshedAt: Date
+    ) {
+        self.request = request
+        self.report = report
+        self.refreshedAt = refreshedAt
+    }
+}
+
+public protocol UsageReportCaching: Sendable {
+    func load() async -> UsageReportSnapshot?
+    func save(_ snapshot: UsageReportSnapshot) async
+}
+
+public actor FileUsageReportCache: UsageReportCaching {
+    private struct Envelope: Codable {
+        let version: Int
+        let snapshot: UsageReportSnapshot
+    }
+
+    private static let formatVersion = 1
+    private let fileURL: URL
+
+    public init() {
+        fileURL = Self.defaultFileURL()
+    }
+
+    public init(fileURL: URL) {
+        self.fileURL = fileURL
+    }
+
+    public func load() async -> UsageReportSnapshot? {
+        guard let data = try? Data(contentsOf: fileURL) else {
+            return nil
+        }
+
+        guard
+            let envelope = try? JSONDecoder().decode(
+                Envelope.self,
+                from: data
+            ),
+            envelope.version == Self.formatVersion
+        else {
+            try? FileManager.default.removeItem(at: fileURL)
+            return nil
+        }
+
+        return envelope.snapshot
+    }
+
+    public func save(_ snapshot: UsageReportSnapshot) async {
+        let envelope = Envelope(
+            version: Self.formatVersion,
+            snapshot: snapshot
+        )
+
+        do {
+            try FileManager.default.createDirectory(
+                at: fileURL.deletingLastPathComponent(),
+                withIntermediateDirectories: true
+            )
+            let data = try JSONEncoder().encode(envelope)
+            try data.write(to: fileURL, options: .atomic)
+        } catch {
+            // A disposable startup cache must never make a successful usage
+            // refresh look like a failure.
+        }
+    }
+
+    private static func defaultFileURL() -> URL {
+        let baseDirectory =
+            FileManager.default.urls(
+                for: .cachesDirectory,
+                in: .userDomainMask
+            ).first ?? FileManager.default.temporaryDirectory
+
+        return baseDirectory
+            .appendingPathComponent(
+                "com.tokpeek.app",
+                isDirectory: true
+            )
+            .appendingPathComponent(
+                "usage-report-v1.json",
+                isDirectory: false
+            )
+    }
+}

Sources/TokPeekKit/UsageRequest.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-public struct UsageRequest: Codable, Sendable, Equatable {
+public struct UsageRequest: Codable, Sendable, Hashable {
     public var homeDirectory: String?
     public var clients: [String]?
     public var since: String?