feat(history): implement rolling ring buffer, history store and Swift Charts trend view (Issue #23)

Sources/History/RollingRingBuffer.swift

@@ -0,0 +1,54 @@
+import Foundation
+
+public struct HistoricalSample<T>: Identifiable {
+    public let id: UUID
+    public let timestamp: Date
+    public let value: T
+    
+    public init(timestamp: Date = Date(), value: T) {
+        self.id = UUID()
+        self.timestamp = timestamp
+        self.value = value
+    }
+}
+
+public final class RollingRingBuffer<T> {
+    private var buffer: [HistoricalSample<T>]
+    private let capacity: Int
+    private let lock = NSLock()
+    
+    public init(capacity: Int = 60) {
+        self.capacity = max(1, capacity)
+        self.buffer = []
+        self.buffer.reserveCapacity(self.capacity)
+    }
+    
+    public func append(_ value: T, timestamp: Date = Date()) {
+        lock.lock()
+        defer { lock.unlock() }
+        
+        let sample = HistoricalSample(timestamp: timestamp, value: value)
+        if buffer.count >= capacity {
+            buffer.removeFirst()
+        }
+        buffer.append(sample)
+    }
+    
+    public var samples: [HistoricalSample<T>] {
+        lock.lock()
+        defer { lock.unlock() }
+        return buffer
+    }
+    
+    public var count: Int {
+        lock.lock()
+        defer { lock.unlock() }
+        return buffer.count
+    }
+    
+    public func clear() {
+        lock.lock()
+        defer { lock.unlock() }
+        buffer.removeAll(keepingCapacity: true)
+    }
+}

Sources/History/TelemetryHistoryStore.swift

@@ -0,0 +1,66 @@
+import Foundation
+import SwiftUI
+
+public struct TelemetrySnapshotRecord {
+    public let cpuLoad: Double
+    public let memoryUsedPercent: Double
+    public let networkInBps: Double
+    public let networkOutBps: Double
+    public let diskReadBps: Double
+    public let diskWriteBps: Double
+    public let cpuTemp: Double
+    public let systemPowerWatts: Double
+    public let timestamp: Date
+    
+    public init(
+        cpuLoad: Double = 0.0,
+        memoryUsedPercent: Double = 0.0,
+        networkInBps: Double = 0.0,
+        networkOutBps: Double = 0.0,
+        diskReadBps: Double = 0.0,
+        diskWriteBps: Double = 0.0,
+        cpuTemp: Double = 0.0,
+        systemPowerWatts: Double = 0.0,
+        timestamp: Date = Date()
+    ) {
+        self.cpuLoad = cpuLoad
+        self.memoryUsedPercent = memoryUsedPercent
+        self.networkInBps = networkInBps
+        self.networkOutBps = networkOutBps
+        self.diskReadBps = diskReadBps
+        self.diskWriteBps = diskWriteBps
+        self.cpuTemp = cpuTemp
+        self.systemPowerWatts = systemPowerWatts
+        self.timestamp = timestamp
+    }
+}
+
+@Observable
+public final class TelemetryHistoryStore {
+    public static let shared = TelemetryHistoryStore()
+    
+    public let cpuHistory = RollingRingBuffer<Double>(capacity: 60)
+    public let memoryHistory = RollingRingBuffer<Double>(capacity: 60)
+    public let networkInHistory = RollingRingBuffer<Double>(capacity: 60)
+    public let networkOutHistory = RollingRingBuffer<Double>(capacity: 60)
+    public let diskReadHistory = RollingRingBuffer<Double>(capacity: 60)
+    public let diskWriteHistory = RollingRingBuffer<Double>(capacity: 60)
+    public let cpuTempHistory = RollingRingBuffer<Double>(capacity: 60)
+    public let powerHistory = RollingRingBuffer<Double>(capacity: 60)
+    
+    public private(set) var sampleCounter: UInt64 = 0
+    
+    public init() {}
+    
+    public func record(snapshot: TelemetrySnapshotRecord) {
+        cpuHistory.append(snapshot.cpuLoad, timestamp: snapshot.timestamp)
+        memoryHistory.append(snapshot.memoryUsedPercent, timestamp: snapshot.timestamp)
+        networkInHistory.append(snapshot.networkInBps, timestamp: snapshot.timestamp)
+        networkOutHistory.append(snapshot.networkOutBps, timestamp: snapshot.timestamp)
+        diskReadHistory.append(snapshot.diskReadBps, timestamp: snapshot.timestamp)
+        diskWriteHistory.append(snapshot.diskWriteBps, timestamp: snapshot.timestamp)
+        cpuTempHistory.append(snapshot.cpuTemp, timestamp: snapshot.timestamp)
+        powerHistory.append(snapshot.systemPowerWatts, timestamp: snapshot.timestamp)
+        sampleCounter &+= 1
+    }
+}

Sources/UI/Charts/TelemetryTrendChartView.swift

@@ -0,0 +1,89 @@
+import SwiftUI
+import Charts
+
+public struct TelemetryTrendChartView: View {
+    public let title: String
+    public let unit: String
+    public let color: Color
+    public let samples: [HistoricalSample<Double>]
+    public let maxY: Double?
+    
+    public init(
+        title: String,
+        unit: String,
+        color: Color,
+        samples: [HistoricalSample<Double>],
+        maxY: Double? = nil
+    ) {
+        self.title = title
+        self.unit = unit
+        self.color = color
+        self.samples = samples
+        self.maxY = maxY
+    }
+    
+    private var currentValue: Double {
+        samples.last?.value ?? 0.0
+    }
+    
+    private var averageValue: Double {
+        guard !samples.isEmpty else { return 0.0 }
+        return samples.reduce(0.0) { $0 + $1.value } / Double(samples.count)
+    }
+    
+    private var maxValue: Double {
+        samples.map(\.value).max() ?? 0.0
+    }
+    
+    public var body: some View {
+        VStack(alignment: .leading, spacing: 10) {
+            HStack {
+                Text(title)
+                    .font(.headline)
+                Spacer()
+                HStack(spacing: 12) {
+                    Text(String(format: "Cur: %.1f %@", currentValue, unit))
+                        .font(.caption)
+                        .fontWeight(.semibold)
+                        .foregroundColor(color)
+                    Text(String(format: "Avg: %.1f %@", averageValue, unit))
+                        .font(.caption)
+                        .foregroundColor(.secondary)
+                    Text(String(format: "Max: %.1f %@", maxValue, unit))
+                        .font(.caption)
+                        .foregroundColor(.secondary)
+                }
+            }
+            
+            Chart {
+                ForEach(Array(samples.enumerated()), id: \.element.id) { index, sample in
+                    LineMark(
+                        x: .value("Sample", index),
+                        y: .value("Value", sample.value)
+                    )
+                    .interpolationMethod(.monotone)
+                    .foregroundStyle(color)
+                    
+                    AreaMark(
+                        x: .value("Sample", index),
+                        y: .value("Value", sample.value)
+                    )
+                    .interpolationMethod(.monotone)
+                    .foregroundStyle(
+                        LinearGradient(
+                            colors: [color.opacity(0.35), color.opacity(0.05)],
+                            startPoint: .top,
+                            endPoint: .bottom
+                        )
+                    )
+                }
+            }
+            .chartYScale(domain: 0...(maxY ?? max(1.0, maxValue * 1.15)))
+            .chartXAxis(.hidden)
+            .frame(height: 120)
+        }
+        .padding(14)
+        .background(Color(NSColor.controlBackgroundColor))
+        .cornerRadius(10)
+    }
+}

Tests/MMHistoryTests.swift

@@ -0,0 +1,54 @@
+import XCTest
+@testable import MacMonitor
+
+final class MMHistoryTests: XCTestCase {
+    
+    func testRollingRingBufferCapacityAndEviction() {
+        let buffer = RollingRingBuffer<Double>(capacity: 3)
+        XCTAssertEqual(buffer.count, 0)
+        
+        buffer.append(10.0)
+        buffer.append(20.0)
+        XCTAssertEqual(buffer.count, 2)
+        XCTAssertEqual(buffer.samples.map(\.value), [10.0, 20.0])
+        
+        buffer.append(30.0)
+        XCTAssertEqual(buffer.count, 3)
+        XCTAssertEqual(buffer.samples.map(\.value), [10.0, 20.0, 30.0])
+        
+        // 4th append should evict oldest (10.0)
+        buffer.append(40.0)
+        XCTAssertEqual(buffer.count, 3)
+        XCTAssertEqual(buffer.samples.map(\.value), [20.0, 30.0, 40.0])
+        
+        buffer.clear()
+        XCTAssertEqual(buffer.count, 0)
+        XCTAssertTrue(buffer.samples.isEmpty)
+    }
+    
+    func testTelemetryHistoryStoreRecord() {
+        let store = TelemetryHistoryStore()
+        let snapshot = TelemetrySnapshotRecord(
+            cpuLoad: 25.5,
+            memoryUsedPercent: 62.1,
+            networkInBps: 1024.0,
+            networkOutBps: 2048.0,
+            diskReadBps: 512.0,
+            diskWriteBps: 1024.0,
+            cpuTemp: 55.0,
+            systemPowerWatts: 18.5
+        )
+        store.record(snapshot: snapshot)
+        
+        XCTAssertEqual(store.sampleCounter, 1)
+        XCTAssertEqual(store.cpuHistory.count, 1)
+        XCTAssertEqual(store.cpuHistory.samples.first?.value, 25.5)
+        XCTAssertEqual(store.memoryHistory.samples.first?.value, 62.1)
+        XCTAssertEqual(store.networkInHistory.samples.first?.value, 1024.0)
+        XCTAssertEqual(store.networkOutHistory.samples.first?.value, 2048.0)
+        XCTAssertEqual(store.diskReadHistory.samples.first?.value, 512.0)
+        XCTAssertEqual(store.diskWriteHistory.samples.first?.value, 1024.0)
+        XCTAssertEqual(store.cpuTempHistory.samples.first?.value, 55.0)
+        XCTAssertEqual(store.powerHistory.samples.first?.value, 18.5)
+    }
+}