//
//  UnitPerformanceTests.swift
//  KordantTests
//
//  Unit-level performance tests using manual timing and XCTMetric
//  for measuring view model operations, API serialization, cache
//  operations, and cryptographic primitives with mocked data.
//

import Testing
@testable import Kordant
import Foundation

// MARK: - JSON Deserialization Performance

struct DeserializationPerformanceTests {
    /// Measures the time to decode a full Alert array from JSON.
    /// Baseline: < 50ms for 1000 alerts on iPhone 12.
    @Test("Decode 1000 alerts under 50ms")
    func decodeAlerts() throws {
        let alertsJSON = generateAlertsJSON(count: 1000)
        let decoder = JSONDecoder()
        decoder.dateDecodingStrategy = .iso8601

        let start = Date()
        let data = try #require(alertsJSON.data(using: .utf8))
        let alerts = try decoder.decode([Alert].self, from: data)
        let elapsed = -start.timeIntervalSinceNow

        #expect(alerts.count == 1000, "Should decode 1000 alerts")
        #expect(elapsed < 0.05, "Decoding 1000 alerts took \(elapsed)s (expected < 50ms)")
    }

    /// Measures the time to decode a full Exposure array from JSON.
    /// Baseline: < 50ms for 1000 exposures on iPhone 12.
    @Test("Decode 1000 exposures under 50ms")
    func decodeExposures() throws {
        let exposuresJSON = generateExposuresJSON(count: 1000)
        let decoder = JSONDecoder()
        decoder.dateDecodingStrategy = .iso8601

        let start = Date()
        let data = try #require(exposuresJSON.data(using: .utf8))
        let exposures = try decoder.decode([Exposure].self, from: data)
        let elapsed = -start.timeIntervalSinceNow

        #expect(exposures.count == 1000, "Should decode 1000 exposures")
        #expect(elapsed < 0.05, "Decoding 1000 exposures took \(elapsed)s (expected < 50ms)")
    }

    /// Measures User JSON decoding performance.
    @Test("Decode user object under 5ms")
    func decodeUser() throws {
        let userJSON = """
        {
            "id": "user-1",
            "name": "Test User",
            "email": "test@kordant.com",
            "subscriptionTier": "premium",
            "createdAt": "2026-01-15T00:00:00Z",
            "updatedAt": "2026-06-01T00:00:00Z"
        }
        """
        let decoder = JSONDecoder()
        decoder.dateDecodingStrategy = .iso8601

        let start = Date()
        let data = try #require(userJSON.data(using: .utf8))
        let user = try decoder.decode(User.self, from: data)
        let elapsed = -start.timeIntervalSinceNow

        #expect(user.id == "user-1")
        #expect(elapsed < 0.005, "User deserialization took \(elapsed)s (expected < 5ms)")
    }

    // MARK: - Helpers

    private func generateAlertsJSON(count: Int) -> String {
        let alerts = (0..<count).map { i in
            """
            {
                "id": "alert-\(i)",
                "userId": "user-1",
                "type": \(i % 3 == 0 ? "\"exposure\"" : i % 3 == 1 ? "\"breach\"" : "\"login\""),
                "severity": \(i % 4 == 0 ? "\"critical\"" : i % 4 == 1 ? "\"high\"" : i % 4 == 2 ? "\"medium\"" : "\"low\""),
                "title": "Alert \(i)",
                "message": "This is alert number \(i)",
                "read": \(i % 2 == 0),
                "createdAt": "2026-06-0\(i % 9 + 1)T10:00:0\(i % 60)Z"
            }
            """
        }
        return "[\(alerts.joined(separator: ","))]"
    }

    private func generateExposuresJSON(count: Int) -> String {
        let exposures = (0..<count).map { i in
            """
            {
                "id": "exp-\(i)",
                "userId": "user-1",
                "source": \(i % 5 == 0 ? "\"darkWeb\"" : i % 5 == 1 ? "\"dataBreach\"" : i % 5 == 2 ? "\"socialMedia\"" : "\"publicRecord\""),
                "dataType": "Email Address",
                "exposedData": "user\(i)@example.com",
                "severity": \(i % 3 == 0 ? "\"high\"" : "\"medium\""),
                "status": \(i % 3 == 0 ? "\"new\"" : "\"reviewed\""),
                "discoveredAt": "2026-06-0\(i % 9 + 1)T00:00:00Z"
            }
            """
        }
        return "[\(exposures.joined(separator: ","))]"
    }
}

// MARK: - ViewModel Performance Tests

@MainActor
struct ViewModelPerformanceTests {
    /// Measures DashboardViewModel data loading time with mocked API.
    /// Baseline: < 100ms for full data load with 50 alerts, 50 exposures, 50 watchlist items.
    @Test("DashboardViewModel loads data under 100ms")
    func dashboardViewModelLoadTime() async throws {
        let mock = MockTRPCalling()
        mock.stubbedAlerts = generateMockAlerts(count: 50)
        mock.stubbedExposures = generateMockExposures(count: 50)
        mock.stubbedWatchlist = generateMockWatchlistItems(count: 50)

        let vm = DashboardViewModel(api: mock)

        let start = Date()
        await vm.loadDashboard()
        let elapsed = -start.timeIntervalSinceNow

        #expect(vm.alerts.count == 50)
        #expect(vm.exposures.count == 50)
        #expect(vm.watchlistItems.count == 50)
        #expect(elapsed < 0.1, "DashboardViewModel load took \(elapsed)s (expected < 100ms)")
    }

    /// Measures DarkWatchViewModel data loading time.
    /// Baseline: < 100ms for full data load.
    @Test("DarkWatchViewModel loads data under 100ms")
    func darkWatchViewModelLoadTime() async throws {
        let mock = MockTRPCalling()
        mock.stubbedWatchlist = generateMockWatchlistItems(count: 30)
        mock.stubbedExposures = generateMockExposures(count: 30)

        let vm = DarkWatchViewModel(api: mock)

        let start = Date()
        await vm.loadData()
        let elapsed = -start.timeIntervalSinceNow

        #expect(vm.watchlistItems.count == 30)
        #expect(vm.exposures.count == 30)
        #expect(elapsed < 0.1, "DarkWatchViewModel load took \(elapsed)s (expected < 100ms)")
    }

    /// Measures threat score calculation performance with large datasets.
    /// Baseline: < 10ms for 500 alerts + 500 exposures.
    @Test("Threat score calculation under 10ms with 1000 items")
    func threatScoreCalculationPerformance() async throws {
        let mock = MockTRPCalling()
        mock.stubbedAlerts = generateMockAlerts(count: 500)
        mock.stubbedExposures = generateMockExposures(count: 500)

        let vm = DashboardViewModel(api: mock)
        await vm.loadDashboard()

        // Measure threat score computation
        let start = Date()
        let _ = vm.threatScore
        let elapsed = -start.timeIntervalSinceNow

        #expect(elapsed < 0.01, "Threat score calculation took \(elapsed)s (expected < 10ms)")
    }

    // MARK: - Helpers

    private func generateMockAlerts(count: Int) -> [Alert] {
        (0..<count).map { i in
            Alert(
                id: "alert-\(i)",
                userId: "user-1",
                type: i % 3 == 0 ? .exposure : i % 3 == 1 ? .breach : .login,
                severity: i % 4 == 0 ? .critical : i % 4 == 1 ? .high : i % 4 == 2 ? .medium : .low,
                title: "Alert \(i)",
                message: "Alert message \(i)",
                read: i % 2 == 0,
                createdAt: Date().addingTimeInterval(-Double(i) * 3600)
            )
        }
    }

    private func generateMockExposures(count: Int) -> [Exposure] {
        (0..<count).map { i in
            Exposure(
                id: "exp-\(i)",
                userId: "user-1",
                source: i % 5 == 0 ? .darkWeb : i % 5 == 1 ? .dataBreach : i % 5 == 2 ? .socialMedia : .publicRecord,
                dataType: "Email",
                exposedData: "user\(i)@example.com",
                severity: i % 3 == 0 ? "high" : "medium",
                status: i % 3 == 0 ? .new : .reviewed,
                discoveredAt: Date().addingTimeInterval(-Double(i) * 7200)
            )
        }
    }

    private func generateMockWatchlistItems(count: Int) -> [WatchlistItem] {
        (0..<count).map { i in
            WatchlistItem(
                id: "watch-\(i)",
                userId: "user-1",
                term: "item\(i)@example.com",
                type: .email,
                status: "active",
                createdAt: Date().addingTimeInterval(-Double(i) * 86400)
            )
        }
    }
}

// MARK: - Keychain Performance Tests

struct KeychainPerformanceTests {
    /// Measures mock keychain store/retrieve performance.
    /// Baseline: < 0.1ms per operation.
    @Test("Keychain store/retrieve under 0.1ms per operation")
    func keychainStoreRetrievePerformance() throws {
        let keychain = MockKeychainService()
        let value = Data(repeating: 0x41, count: 1024) // 1KB value

        let start = Date()
        let count = 100
        for i in 0..<count {
            try keychain.store(key: "key-\(i)", value: value)
            let _ = try keychain.retrieve(key: "key-\(i)")
        }
        let elapsed = -start.timeIntervalSinceNow
        let perOp = elapsed / Double(count * 2) // store + retrieve per iteration

        #expect(perOp < 0.0001, "Keychain op took \(perOp * 1000)ms (expected < 0.1ms)")
    }
}

// MARK: - Security Manager Performance Tests

struct SecurityPerformanceTests {
    /// Measures jailbreak detector checks runtime.
    /// Baseline: < 10ms for full detection suite.
    @Test("Jailbreak detection completes under 10ms")
    func jailbreakDetectionPerformance() {
        let detector = JailbreakDetector.shared

        let start = Date()
        let _ = detector.isJailbroken
        let elapsed = -start.timeIntervalSinceNow

        // The check should be fast since it's checking file system paths
        #expect(elapsed < 0.01, "Jailbreak detection took \(elapsed)s (expected < 10ms)")
    }

    /// Measures RuntimeIntegrityMonitor checks performance.
    @Test("Runtime integrity check under 10ms")
    func runtimeIntegrityPerformance() {
        let monitor = RuntimeIntegrityMonitor.shared

        let start = Date()
        let _ = monitor.isRuntimeIntegrityCompromised
        let elapsed = -start.timeIntervalSinceNow

        #expect(elapsed < 0.01, "Runtime integrity check took \(elapsed)s (expected < 10ms)")
    }

    /// Measures SecureEnclave availability check performance.
    @Test("SecureEnclave availability check under 10ms")
    func secureEnclaveCheckPerformance() {
        let service = SecureEnclaveService.shared

        let start = Date()
        let _ = service.isAvailable
        let elapsed = -start.timeIntervalSinceNow

        #expect(elapsed < 0.01, "Secure Enclave check took \(elapsed)s (expected < 10ms)")
    }
}

// MARK: - Image Cache Metadata Performance Tests

struct ImageCacheMetadataPerformanceTests {
    /// Measures ImageCacheMetadata creation performance for bulk operations.
    @Test("ImageCacheMetadata creation under 0.1ms per item")
    func metadataCreationPerformance() {
        let start = Date()
        let count = 1000
        for i in 0..<count {
            _ = ImageCacheMetadata(
                url: "https://images.kordant.com/photo-\(i).jpg",
                contentType: "image/jpeg",
                fileSize: 1024 * 50,
                cachedAt: Date(),
                expirationDate: Date().addingTimeInterval(7 * 24 * 60 * 60)
            )
        }
        let elapsed = -start.timeIntervalSinceNow
        let perItem = elapsed / Double(count)

        #expect(perItem < 0.0001, "Metadata creation took \(perItem * 1000)ms (expected < 0.1ms)")
    }

    /// Measures CacheStats value type creation performance.
    @Test("CacheStats values created efficiently")
    func cacheStatsCreationPerformance() {
        let start = Date()
        let count = 10000
        for _ in 0..<count {
            _ = CacheStats(
                memoryUsage: 1024 * 1024,
                memoryCapacity: 50 * 1024 * 1024,
                diskUsage: 5 * 1024 * 1024,
                diskCapacity: 100 * 1024 * 1024,
                cachedEntries: 100,
                diskFiles: 50
            )
        }
        let elapsed = -start.timeIntervalSinceNow
        let perItem = elapsed / Double(count)

        #expect(perItem < 0.00001, "CacheStats creation took \(perItem * 1000)ms (expected < 0.01ms)")
    }
}

// MARK: - Sort Performance Tests

struct SortPerformanceTests {
    /// Measures alert sorting performance (alerts are sorted by createdAt).
    /// This is called every time the dashboard loads.
    @Test("Alert sorting under 5ms for 500 alerts")
    func alertSortingPerformance() {
        let alerts = (0..<500).map { i in
            Alert(
                id: "alert-\(i)",
                userId: "user-1",
                type: .exposure,
                severity: .medium,
                title: "Alert",
                message: "Message",
                read: i % 2 == 0,
                createdAt: Date().addingTimeInterval(Double(i) * 3600 - 500 * 3600)
            )
        }

        let start = Date()
        let sorted = alerts.sorted { ($0.createdAt ?? .distantPast) > ($1.createdAt ?? .distantPast) }
        let elapsed = -start.timeIntervalSinceNow

        #expect(sorted.count == 500)
        #expect(elapsed < 0.005, "Sorting 500 alerts took \(elapsed)s (expected < 5ms)")
    }
}

// MARK: - XCTMetric-Based Performance Tests (XCTestCase)

/// XCTestCase-based performance tests using XCTMetric for baseline recording.
/// These tests use `measure(metrics:)` which supports automatic baseline comparison
/// and 10% regression detection in Xcode.
///
/// Note: XCTMetric requires XCTestCase, not the Testing framework.
/// These tests are run via the KordantTests target alongside Testing-based tests.
final class XCTMetricPerformanceTests: XCTestCase {
    private static let encoder: JSONEncoder = {
        let enc = JSONEncoder()
        enc.dateEncodingStrategy = .iso8601
        return enc
    }()

    private static let decoder: JSONDecoder = {
        let dec = JSONDecoder()
        dec.dateDecodingStrategy = .iso8601
        return dec
    }()

    // MARK: - JSON Encoding Performance

    /// Measures JSON encoder performance for encoding Alert objects.
    /// XCTMetric captures clock, CPU, and memory.
    func testJSONEncodingPerformance() throws {
        let alerts = (0..<500).map { i in
            Alert(
                id: "alert-\(i)",
                userId: "user-1",
                type: .exposure,
                severity: .medium,
                title: "Test Alert \(i)",
                message: "This is a test alert message with some detail text that might appear in the actual app.",
                read: i % 2 == 0,
                createdAt: Date()
            )
        }

        measure(metrics: [XCTClockMetric(), XCTCPUMetric(), XCTMemoryMetric()]) {
            let encoder = Self.encoder
            for alert in alerts {
                _ = try? encoder.encode(alert)
            }
        }
    }

    // MARK: - JSON Decoding Performance

    /// Measures JSON decoder performance for decoding Alert array.
    func testJSONDecodingPerformance() throws {
        let alerts = (0..<500).map { i in
            Alert(
                id: "alert-\(i)",
                userId: "user-1",
                type: .exposure,
                severity: .medium,
                title: "Test Alert \(i)",
                message: "Test message",
                read: i % 2 == 0,
                createdAt: Date()
            )
        }

        let data = try Self.encoder.encode(alerts)

        measure(metrics: [XCTClockMetric(), XCTCPUMetric(), XCTMemoryMetric()]) {
            _ = try? Self.decoder.decode([Alert].self, from: data)
        }
    }

    // MARK: - ViewModel Data Processing Performance

    /// Measures threat score calculation performance with XCTMetric.
    func testThreatScoreCalculationPerformance() throws {
        let alerts = (0..<200).map { i in
            Alert(
                id: "alert-\(i)",
                userId: "user-1",
                type: i % 3 == 0 ? .breach : .exposure,
                severity: i % 5 == 0 ? .critical : .low,
                title: "Alert",
                message: "Message",
                read: i % 2 == 0,
                createdAt: Date().addingTimeInterval(-Double(i) * 3600)
            )
        }
        let exposures = (0..<100).map { i in
            Exposure(
                id: "exp-\(i)",
                userId: "user-1",
                source: .darkWeb,
                dataType: "Email",
                exposedData: "test@example.com",
                severity: i % 3 == 0 ? "high" : "medium",
                status: i % 2 == 0 ? .new : .reviewed,
                discoveredAt: Date()
            )
        }

        measure(metrics: [XCTClockMetric(), XCTCPUMetric(), XCTMemoryMetric()]) {
            let unreadCritical = alerts.filter { !$0.read && $0.isCritical }.count
            let newExposures = exposures.filter { $0.status == .new }.count
            let score = min(Double(unreadCritical * 25 + newExposures * 10), 100)
            _ = score / 100.0
        }
    }

    // MARK: - Image Cache Metadata Persistence Performance

    /// Measures metadata JSON persistence encoding/decoding performance.
    func testImageCacheMetadataPersistencePerformance() throws {
        let metadata = (0..<500).map { i in
            (
                key: "https://images.kordant.com/photo-\(i).jpg",
                value: ImageCacheMetadata(
                    url: "https://images.kordant.com/photo-\(i).jpg",
                    contentType: "image/jpeg",
                    fileSize: 1024 * (50 + i % 100),
                    cachedAt: Date(),
                    expirationDate: Date().addingTimeInterval(7 * 24 * 60 * 60)
                )
            )
        }

        let dict = Dictionary(uniqueKeysWithValues: metadata)

        measure(metrics: [XCTClockMetric()]) {
            if let encoded = try? Self.encoder.encode(dict) {
                _ = try? Self.decoder.decode([String: ImageCacheMetadata].self, from: encoded)
            }
        }
    }

    // MARK: - Alert Sorting Performance

    /// Measures the sorting performance of alerts (used by DashboardViewModel).
    func testAlertSortingPerformance() throws {
        let alerts = (0..<500).map { i in
            Alert(
                id: "alert-\(i)",
                userId: "user-1",
                type: .exposure,
                severity: .medium,
                title: "Alert",
                message: "Message",
                read: i % 2 == 0,
                createdAt: Date().addingTimeInterval(Double(i) * 3600 - 500 * 3600)
            )
        }

        measure(metrics: [XCTClockMetric()]) {
            let sorted = alerts.sorted { ($0.createdAt ?? .distantPast) > ($1.createdAt ?? .distantPast) }
            _ = sorted
        }
    }
}