//

//  ChargeInsightsModel.swift

//  USB Meter

//

//  Created by Codex on 10/04/2026.

//

import Foundation

    case charger

    var id: String { rawValue }

    var title: String {

        switch self {

        case .device:

            return "Device"

        case .charger:

            return "Charger"

        }

    }

    var pluralTitle: String {

        switch self {

        case .device:

            return "Devices"

        case .charger:

            return "Chargers"

        }

    }

    var symbolName: String {

        switch self {

        case .device:

            return "iphone"

        case .charger:

            return "bolt.horizontal.circle"

        }

    }

}

    case watch

    case powerbank

    case charger

    case other

    var id: String { rawValue }

        allCases.filter { $0 != .charger }

    }

    var kind: ChargedDeviceKind {

        self == .charger ? .charger : .device

    }

        switch self {

        case .iphone:

            return "iPhone"

        case .watch:

            return "Watch"

        case .powerbank:

            return "Powerbank"

        case .charger:

            return "Charger"

        case .other:

            return "Other"

        }

    }

    var symbolName: String {

        switch self {

        case .iphone:

            return "iphone"

        case .watch:

            return "applewatch"

        case .powerbank:

            return "battery.100.bolt"

        case .charger:

            return "bolt.badge.clock"

        case .other:

            return "shippingbox"

        }

    }

    var enforcedChargingSupport: (wired: Bool, wireless: Bool)? {

        switch self {

        case .watch:

            return (wired: false, wireless: true)

        case .powerbank:

            return (wired: true, wireless: false)

        case .charger:

            return (wired: false, wireless: true)

        case .iphone, .other:

            return nil

        }

    }

    var enforcedChargingStateAvailability: ChargingStateAvailability? {

        switch self {

        case .watch:

            return .onOnly

        case .powerbank:

            return .offOnly

        case .charger:

            return .onOnly

        case .iphone, .other:

            return nil

        }

    }

    func normalizedChargingSupport(

        supportsWiredCharging: Bool,

        supportsWirelessCharging: Bool

    ) -> (wired: Bool, wireless: Bool) {

        enforcedChargingSupport ?? (wired: supportsWiredCharging, wireless: supportsWirelessCharging)

    }

    func normalizedChargingStateAvailability(

        _ chargingStateAvailability: ChargingStateAvailability

    ) -> ChargingStateAvailability {

        enforcedChargingStateAvailability ?? chargingStateAvailability

    }

enum ChargeSessionStatus: String {

    case active

    case abandoned

    var title: String {

        case .active:

            return "Active"

        case .paused:

            return "Paused"

        case .completed:

            return "Completed"

        case .abandoned:

            return "Abandoned"

        }

    }

    var isOpen: Bool {

        switch self {

        case .active, .paused:

            return true

        case .completed, .abandoned:

            return false

        }

}

enum ChargeSessionSourceMode: String {

    case live

    case offline

    case blended

    var title: String {

        switch self {

        case .live:

            return "Live"

        case .offline:

            return "Offline Counters"

        case .blended:

            return "Blended"

        }

    }

}

    case wireless

    var id: String { rawValue }

    var title: String {

        switch self {

        case .wired:

            return "Wired"

        case .wireless:

            return "Wireless"

        }

    }

    var symbolName: String {

        switch self {

        case .wired:

            return "cable.connector"

        case .wireless:

            return "dot.radiowaves.left.and.right"

        }

    }

}

    case on

    case off

    var id: String { rawValue }

    var title: String {

        switch self {

        case .on:

            return "On"

        case .off:

            return "Off"

        }

    }

    var description: String {

        switch self {

        case .on:

            return "Device stays powered on while charging."

        case .off:

            return "Device is powered off while charging."

        }

    }

}

enum ChargingStateAvailability: String, CaseIterable, Identifiable, Codable {

    case onOnly

    case onOrOff

    case offOnly

    var id: String { rawValue }

    var title: String {

        switch self {

        case .onOnly:

            return "On Only"

        case .onOrOff:

            return "On or Off"

        case .offOnly:

            return "Off Only"

        }

    }

    var description: String {

        switch self {

        case .onOnly:

            return "The device can be recorded only while it is powered on."

        case .onOrOff:

            return "The session must specify whether the device is on or off."

        case .offOnly:

            return "The device can be recorded only while it is powered off."

        }

    }

    var supportedModes: [ChargingStateMode] {

        switch self {

        case .onOnly:

            return [.on]

        case .onOrOff:

            return [.on, .off]

        case .offOnly:

            return [.off]

        }

    }

    var supportsMultipleModes: Bool {

        supportedModes.count > 1

    }

    var supportsChargingWhileOff: Bool {

        self != .onOnly

    }

    static func fallback(for supportsChargingWhileOff: Bool) -> ChargingStateAvailability {

        supportsChargingWhileOff ? .onOrOff : .onOnly

    }

}

enum ChargeSessionKind: String, CaseIterable, Identifiable, Codable, Hashable {

    case wiredOn

    case wiredOff

    case wirelessOn

    case wirelessOff

    var id: String { rawValue }

    init(chargingTransportMode: ChargingTransportMode, chargingStateMode: ChargingStateMode) {

        switch (chargingTransportMode, chargingStateMode) {

        case (.wired, .on):

            self = .wiredOn

        case (.wired, .off):

            self = .wiredOff

        case (.wireless, .on):

            self = .wirelessOn

        case (.wireless, .off):

            self = .wirelessOff

        }

    }

    var chargingTransportMode: ChargingTransportMode {

        switch self {

        case .wiredOn, .wiredOff:

            return .wired

        case .wirelessOn, .wirelessOff:

            return .wireless

        }

    }

    var chargingStateMode: ChargingStateMode {

        switch self {

        case .wiredOn, .wirelessOn:

            return .on

        case .wiredOff, .wirelessOff:

            return .off

        }

    }

    var title: String {

        "\(chargingTransportMode.title) • \(chargingStateMode.title)"

    }

    var shortTitle: String {

        "\(chargingTransportMode.title) \(chargingStateMode.title)"

    }

}

    case genericQi

    var id: String { rawValue }

    var title: String {

        switch self {

        case .magsafe:

            return "MagSafe"

        case .genericQi:

            return "Generic Qi"

        }

    }

    var description: String {

        switch self {

        case .magsafe:

            return "Use separate wireless-efficiency calibration from devices that also have reliable wired capacity."

        case .genericQi:

            return "Use only automatic efficiency estimates and show a low-efficiency warning when needed."

        }

    }

}

    case systemSymbol

    case asset

}

struct ChargedDeviceTemplateIcon: Hashable, Codable {

    let type: ChargedDeviceTemplateIconSource

    let name: String

    let fallbackSystemName: String?

    static func systemSymbol(

        _ name: String,

        fallbackSystemName: String? = nil

    ) -> ChargedDeviceTemplateIcon {

        ChargedDeviceTemplateIcon(

            type: .systemSymbol,

            name: name,

            fallbackSystemName: fallbackSystemName

        )

    }

    func resolvedSystemSymbolName(fallbackSystemName: String) -> String {

        switch type {

        case .systemSymbol:

            return name

        case .asset:

            return self.fallbackSystemName ?? fallbackSystemName

        }

    }

}

struct ChargedDeviceTemplateDefinition: Identifiable, Hashable, Codable {

    let id: String

    let name: String

    let group: String

    let kind: ChargedDeviceKind

    let deviceClass: ChargedDeviceClass

    let icon: ChargedDeviceTemplateIcon

    let chargingStateAvailability: ChargingStateAvailability

    let supportsWiredCharging: Bool

    let supportsWirelessCharging: Bool

    let wirelessChargingProfile: WirelessChargingProfile

    let sortOrder: Int

    var chargingSupportSummary: String {

        switch (supportsWiredCharging, supportsWirelessCharging) {

        case (true, true):

            return "Wired + Wireless"

        case (true, false):

            return "Wired only"

        case (false, true):

            return "Wireless only"

        case (false, false):

            return "No charging transport"

        }

    }

    var capabilitySummary: String {

        var components = [chargingStateAvailability.title, chargingSupportSummary]

        if supportsWirelessCharging {

            components.append(wirelessChargingProfile.title)

        }

        return components.joined(separator: " • ")

    }

}

private struct ChargedDeviceTemplateDocument: Codable {

    let templates: [ChargedDeviceTemplateDefinition]

}

struct ChargedDeviceTemplateCatalog {

    static let shared = ChargedDeviceTemplateCatalog()

    let templates: [ChargedDeviceTemplateDefinition]

    private let templatesByID: [String: ChargedDeviceTemplateDefinition]

    private init(bundle: Bundle = .main) {

        let loadedTemplates: [ChargedDeviceTemplateDefinition]

        if let resourceURL = bundle.url(forResource: "ChargedDeviceTemplates", withExtension: "json"),

           let data = try? Data(contentsOf: resourceURL),

           let document = try? JSONDecoder().decode(ChargedDeviceTemplateDocument.self, from: data) {

            loadedTemplates = document.templates

        } else {

            loadedTemplates = []

        }

        self.templates = loadedTemplates.sorted { lhs, rhs in

            if lhs.group != rhs.group {

                return lhs.group < rhs.group

            }

            if lhs.sortOrder != rhs.sortOrder {

                return lhs.sortOrder < rhs.sortOrder

            }

            return lhs.name < rhs.name

        }

        self.templatesByID = Dictionary(uniqueKeysWithValues: self.templates.map { ($0.id, $0) })

    }

    func template(id: String?) -> ChargedDeviceTemplateDefinition? {

        guard let id else {

            return nil

        }

        return templatesByID[id]

    }

    func templates(for kind: ChargedDeviceKind) -> [ChargedDeviceTemplateDefinition] {

        templates.filter { $0.kind == kind }

    }

}

    let id: UUID

    let sessionID: UUID

    let chargedDeviceID: UUID

    let timestamp: Date

    let batteryPercent: Double

    let measuredEnergyWh: Double

    let measuredChargeAh: Double

    let currentAmps: Double

    let voltageVolts: Double?

    let label: String?

    var flag: ChargeCheckpointFlag {

        ChargeCheckpointFlag.fromStoredLabel(label)

    }

}

enum ChargeCheckpointFlag: String, CaseIterable {

    case initial

    case intermediate

    case final

    var title: String {

        switch self {

        case .initial:

            return "Initial"

        case .intermediate:

            return "Intermediate"

        case .final:

            return "Final"

        }

    }

    var anchorDescription: String {

        switch self {

        case .initial:

            return "initial checkpoint"

        case .intermediate:

            return "intermediate checkpoint"

        case .final:

            return "final checkpoint"

        }

    }

    static func fromStoredLabel(_ label: String?) -> ChargeCheckpointFlag {

        let normalized = label?

            .trimmingCharacters(in: .whitespacesAndNewlines)

            .lowercased()

        switch normalized {

        case "initial", "start":

            return .initial

        case "final", "end":

            return .final

        case "intermediate", nil, "":

            return .intermediate

        default:

            return .intermediate

        }

    }

struct ChargeSessionSampleSummary: Identifiable, Hashable {

    let sessionID: UUID

    let chargedDeviceID: UUID

    let bucketIndex: Int

    let timestamp: Date

    let averageCurrentAmps: Double

    let averageVoltageVolts: Double?

    let averagePowerWatts: Double

    let measuredEnergyWh: Double

    let measuredChargeAh: Double

    let sampleCount: Int

    var id: String {

        "\(sessionID.uuidString)-\(bucketIndex)"

    }

}

struct ChargeSessionSummary: Identifiable, Hashable {

    let id: UUID

    let chargedDeviceID: UUID

    let chargerID: UUID?

    let meterMACAddress: String?

    let meterName: String?

    let meterModel: String?

    let startedAt: Date

    let endedAt: Date?

    let lastObservedAt: Date

    let sourceMode: ChargeSessionSourceMode

    let chargingTransportMode: ChargingTransportMode

    let autoStopEnabled: Bool

    let effectiveBatteryEnergyWh: Double?

    let measuredChargeAh: Double

    let meterChargeBaselineAh: Double?

    let meterLastDurationSeconds: Double?

    let maximumObservedCurrentAmps: Double?

    let maximumObservedPowerWatts: Double?

    let maximumObservedVoltageVolts: Double?

    let selectedSourceVoltageVolts: Double?

    let completionCurrentAmps: Double?

    let stopThresholdAmps: Double

    let startBatteryPercent: Double?

    let endBatteryPercent: Double?

    let capacityEstimateWh: Double?

    let wirelessEfficiencyFactor: Double?

    let usesEstimatedWirelessEfficiency: Bool

    let shouldWarnAboutLowWirelessEfficiency: Bool

    let supportsChargingWhileOff: Bool

    let usedOfflineMeterCounters: Bool

    let targetBatteryPercent: Double?

    let targetBatteryAlertTriggeredAt: Date?

    let requiresCompletionConfirmation: Bool

    let completionConfirmationRequestedAt: Date?

    let completionContradictionPercent: Double?

    let selectedDataGroup: UInt8?

    let checkpoints: [ChargeCheckpointSummary]

    let aggregatedSamples: [ChargeSessionSampleSummary]

        ChargeSessionKind(

            chargingTransportMode: chargingTransportMode,

            chargingStateMode: chargingStateMode

        )

    }

        (endedAt ?? lastObservedAt).timeIntervalSince(startedAt)

    }

        guard let meterDurationBaselineSeconds, let meterLastDurationSeconds else {

            return nil

        }

        guard meterLastDurationSeconds >= meterDurationBaselineSeconds else {

            return nil

        }

        return meterLastDurationSeconds - meterDurationBaselineSeconds

    }

    var effectiveDuration: TimeInterval {

        meterObservedDuration ?? duration

    }

        effectiveBatteryEnergyWh ?? measuredEnergyWh

    }

    var batteryDeltaPercent: Double? {

              startBatteryPercent >= 0, endBatteryPercent >= 0 else { return nil }

    }

    var canAutoStop: Bool {

        autoStopEnabled && stopThresholdAmps > 0

    }

    var isPaused: Bool {

        status == .paused

    }

    var isOpen: Bool {

        status.isOpen

    }

struct BatteryLevelPrediction: Hashable {

    let predictedPercent: Double

    let estimatedCapacityWh: Double

    let anchorPercent: Double

    let anchorEnergyWh: Double

    let anchorDescription: String

}

    static let checkpointSettleDuration: TimeInterval = 10 * 60

    static func predictedPercent(

        anchorPercent: Double,

        anchorEnergyWh: Double,

        anchorTimestamp: Date,

        anchorIsCheckpoint: Bool,

        effectiveEnergyWh: Double,

        referenceTimestamp: Date,

        estimatedCapacityWh: Double

    ) -> Double {

        let energyDeltaWh = max(effectiveEnergyWh - anchorEnergyWh, 0)

        let rawGainPercent = (energyDeltaWh / estimatedCapacityWh) * 100

        let stabilizedGainPercent: Double

        if anchorIsCheckpoint {

            let elapsedSinceAnchor = max(referenceTimestamp.timeIntervalSince(anchorTimestamp), 0)

            let settleProgress = min(max(elapsedSinceAnchor / checkpointSettleDuration, 0), 1)

            stabilizedGainPercent = rawGainPercent * settleProgress

        } else {

            stabilizedGainPercent = rawGainPercent

        }

        return min(

            100,

            max(

                0,

                anchorPercent + stabilizedGainPercent

            )

        )

    }

}

    let sessionID: UUID

    let timestamp: Date

    let capacityWh: Double

    let chargingTransportMode: ChargingTransportMode

    var id: UUID { sessionID }

}

struct TypicalChargeCurvePoint: Identifiable, Hashable {

    let percentBin: Int

    let averageEnergyWh: Double

    let averageChargeAh: Double

    let sampleCount: Int

    var id: Int { percentBin }

}

    let timestamp: Date

    let powerWatts: Double

    let currentAmps: Double

    let voltageVolts: Double

    var id: TimeInterval {

        timestamp.timeIntervalSince1970

    }

}

struct ChargerStandbyPowerDistributionBin: Identifiable, Hashable {

    let index: Int

    let lowerBoundWatts: Double

    let upperBoundWatts: Double

    let count: Int

    let relativeFrequency: Double

    var id: Int { index }

}

struct ChargerStandbyPowerMeasurementStatistics: Hashable {

    let sampleCount: Int

    let observedDuration: TimeInterval

    let averagePowerWatts: Double

    let recentAveragePowerWatts: Double

    let medianPowerWatts: Double

    let minimumPowerWatts: Double

    let maximumPowerWatts: Double

    let standardDeviationPowerWatts: Double

    let coefficientOfVariation: Double

    let averageCurrentAmps: Double

    let averageVoltageVolts: Double

    let stabilityDeltaWatts: Double

    let stabilityToleranceWatts: Double

    let histogram: [ChargerStandbyPowerDistributionBin]

    var projectedDailyEnergyWh: Double {

        averagePowerWatts * 24

    }

    var projectedWeeklyEnergyWh: Double {

        averagePowerWatts * 24 * 7

    }

    var projectedMonthlyEnergyWh: Double {

        averagePowerWatts * 24 * 30

    }

    var projectedYearlyEnergyWh: Double {

        averagePowerWatts * 24 * 365

    }

    var stabilityDeltaMilliwatts: Double {

        stabilityDeltaWatts * 1000

    }

    var isStable: Bool {

        sampleCount >= ChargerStandbyPowerMeasurementAnalyzer.minimumStableSampleCount

        && stabilityDeltaWatts <= stabilityToleranceWatts

    }

}

struct ChargerStandbyPowerMeasurementSummary: Identifiable, Hashable, Codable {

    let id: UUID

    let chargerID: UUID

    let meterMACAddress: String

    let meterName: String?

    let meterModel: String?

    let startedAt: Date

    let endedAt: Date

    let sampleCount: Int

    let stabilizedAt: Date?

    let averagePowerWatts: Double

    let recentAveragePowerWatts: Double

    let medianPowerWatts: Double

    let minimumPowerWatts: Double

    let maximumPowerWatts: Double

    let standardDeviationPowerWatts: Double

    let coefficientOfVariation: Double

    let averageCurrentAmps: Double

    let averageVoltageVolts: Double

    let stabilityDeltaWatts: Double

    let stabilityToleranceWatts: Double

    let powerSamplesWatts: [Double]

    var duration: TimeInterval {

        endedAt.timeIntervalSince(startedAt)

    }

    var projectedDailyEnergyWh: Double {

        averagePowerWatts * 24

    }

    var projectedWeeklyEnergyWh: Double {

        averagePowerWatts * 24 * 7

    }

    var projectedMonthlyEnergyWh: Double {

        averagePowerWatts * 24 * 30

    }

    var projectedYearlyEnergyWh: Double {

        averagePowerWatts * 24 * 365

    }

    var isStable: Bool {

        stabilizedAt != nil

    }

    var histogram: [ChargerStandbyPowerDistributionBin] {

        ChargerStandbyPowerMeasurementAnalyzer.histogram(for: powerSamplesWatts)

    }

}

enum ChargerStandbyPowerMeasurementAnalyzer {

    static let minimumStableSampleCount = 45

    static let recentSampleWindow = 20

    static let minimumStabilityToleranceWatts = 0.003

    static let relativeStabilityTolerance = 0.01

    static func statistics(

        from samples: [ChargerStandbyPowerSample],

        startedAt: Date,

        referenceDate: Date = Date()

    ) -> ChargerStandbyPowerMeasurementStatistics? {

        guard !samples.isEmpty else {

            return nil

        }

        let powerValues = samples.map(\.powerWatts).filter(\.isFinite)

        let currentValues = samples.map(\.currentAmps).filter(\.isFinite)

        let voltageValues = samples.map(\.voltageVolts).filter(\.isFinite)

        guard powerValues.isEmpty == false else {

            return nil

        }

        let averagePower = mean(powerValues)

        let recentWindow = min(recentSampleWindow, max(1, powerValues.count))

        let recentAveragePower = mean(Array(powerValues.suffix(recentWindow)))

        let stabilityDelta = abs(averagePower - recentAveragePower)

        let stabilityTolerance = max(

            minimumStabilityToleranceWatts,

            abs(averagePower) * relativeStabilityTolerance

        )

        return ChargerStandbyPowerMeasurementStatistics(

            sampleCount: powerValues.count,

            observedDuration: max(referenceDate.timeIntervalSince(startedAt), 0),

            averagePowerWatts: averagePower,

            recentAveragePowerWatts: recentAveragePower,

            medianPowerWatts: median(powerValues),

            minimumPowerWatts: powerValues.min() ?? 0,

            maximumPowerWatts: powerValues.max() ?? 0,

            standardDeviationPowerWatts: standardDeviation(powerValues, mean: averagePower),

            coefficientOfVariation: coefficientOfVariation(powerValues, mean: averagePower),

            averageCurrentAmps: mean(currentValues),

            averageVoltageVolts: mean(voltageValues),

            stabilityDeltaWatts: stabilityDelta,

            stabilityToleranceWatts: stabilityTolerance,

            histogram: histogram(for: powerValues)

        )

    }

    static func measurementSummary(

        chargerID: UUID,

        meterMACAddress: String,

        meterName: String?,

        meterModel: String?,

        startedAt: Date,

        endedAt: Date,

        samples: [ChargerStandbyPowerSample],

        stabilizedAt: Date?

    ) -> ChargerStandbyPowerMeasurementSummary? {

        guard let statistics = statistics(from: samples, startedAt: startedAt, referenceDate: endedAt) else {

            return nil

        }

        return ChargerStandbyPowerMeasurementSummary(

            id: UUID(),

            chargerID: chargerID,

            meterMACAddress: meterMACAddress,

            meterName: meterName,

            meterModel: meterModel,

            startedAt: startedAt,

            endedAt: endedAt,

            sampleCount: statistics.sampleCount,

            stabilizedAt: stabilizedAt,

            averagePowerWatts: statistics.averagePowerWatts,

            recentAveragePowerWatts: statistics.recentAveragePowerWatts,

            medianPowerWatts: statistics.medianPowerWatts,

            minimumPowerWatts: statistics.minimumPowerWatts,

            maximumPowerWatts: statistics.maximumPowerWatts,

            standardDeviationPowerWatts: statistics.standardDeviationPowerWatts,

            coefficientOfVariation: statistics.coefficientOfVariation,

            averageCurrentAmps: statistics.averageCurrentAmps,

            averageVoltageVolts: statistics.averageVoltageVolts,

            stabilityDeltaWatts: statistics.stabilityDeltaWatts,

            stabilityToleranceWatts: statistics.stabilityToleranceWatts,

            powerSamplesWatts: samples.map(\.powerWatts)

        )

    }

    static func histogram(for values: [Double], preferredBinCount: Int? = nil) -> [ChargerStandbyPowerDistributionBin] {

        let finiteValues = values.filter(\.isFinite)

        guard finiteValues.isEmpty == false else {

            return []

        }

        let minimum = finiteValues.min() ?? 0

        let maximum = finiteValues.max() ?? 0

        let spread = maximum - minimum

        let binCount = preferredBinCount ?? min(18, max(8, Int(Double(finiteValues.count).squareRoot().rounded())))

        guard spread > 0 else {

            return [

                ChargerStandbyPowerDistributionBin(

                    index: 0,

                    lowerBoundWatts: minimum,

                    upperBoundWatts: maximum,

                    count: finiteValues.count,

                    relativeFrequency: 1

                )

            ]

        }

        let safeBinCount = max(1, binCount)

        let binWidth = spread / Double(safeBinCount)

        var counts = Array(repeating: 0, count: safeBinCount)

        for value in finiteValues {

            let normalizedIndex = Int(((value - minimum) / binWidth).rounded(.down))

            let safeIndex = min(max(normalizedIndex, 0), safeBinCount - 1)

            counts[safeIndex] += 1

        }

        return counts.enumerated().map { index, count in

            let lowerBound = minimum + (Double(index) * binWidth)

            let upperBound = index == safeBinCount - 1 ? maximum : lowerBound + binWidth

            return ChargerStandbyPowerDistributionBin(

                index: index,

                lowerBoundWatts: lowerBound,

                upperBoundWatts: upperBound,

                count: count,

                relativeFrequency: Double(count) / Double(finiteValues.count)

            )

        }

    }

    private static func mean(_ values: [Double]) -> Double {

        guard values.isEmpty == false else {

            return 0

        }

        return values.reduce(0, +) / Double(values.count)

    }

    private static func median(_ values: [Double]) -> Double {

        guard values.isEmpty == false else {

            return 0

        }

        let sorted = values.sorted()

        let middleIndex = sorted.count / 2

        if sorted.count.isMultiple(of: 2) {

            return (sorted[middleIndex - 1] + sorted[middleIndex]) / 2

        }

        return sorted[middleIndex]

    }

    private static func standardDeviation(_ values: [Double], mean: Double) -> Double {

        guard values.count > 1 else {

            return 0

        }

        let variance = values.reduce(0) { partialResult, value in

            let delta = value - mean

            return partialResult + (delta * delta)

        } / Double(values.count)

        return variance.squareRoot()

    }

    private static func coefficientOfVariation(_ values: [Double], mean: Double) -> Double {

        guard abs(mean) > 0.000_001 else {

            return 0

        }

        return standardDeviation(values, mean: mean) / abs(mean)

    }

}

    let id: UUID

    let qrIdentifier: String

    let name: String

    let deviceClass: ChargedDeviceClass

    let templateDefinition: ChargedDeviceTemplateDefinition?

    let supportsWirelessCharging: Bool

    let wirelessChargingProfile: WirelessChargingProfile

    let learnedCompletionCurrents: [ChargeSessionKind: Double]

    let wiredChargeCompletionCurrentAmps: Double?

    let wirelessChargeCompletionCurrentAmps: Double?

    let chargerObservedVoltageSelections: [Double]

    let chargerIdleCurrentAmps: Double?

    let chargerEfficiencyFactor: Double?

    let chargerMaximumPowerWatts: Double?

    let notes: String?

    let minimumCurrentAmps: Double?

    let estimatedBatteryCapacityWh: Double?

    let wiredMinimumCurrentAmps: Double?

    let wirelessMinimumCurrentAmps: Double?

    let wiredEstimatedBatteryCapacityWh: Double?

    let wirelessEstimatedBatteryCapacityWh: Double?

    let lastAssociatedMeterMAC: String?

    let createdAt: Date

    let updatedAt: Date

    let sessions: [ChargeSessionSummary]

    let capacityHistory: [CapacityTrendPoint]

    let typicalCurve: [TypicalChargeCurvePoint]

    var isCharger: Bool {

        deviceClass == .charger

    }

        deviceClass.kind

    }

    var identityTitle: String {

    }

        templateDefinition?.icon ?? .systemSymbol(fallbackIdentitySymbolName)

    }

    var identitySymbolName: String {

        identityIcon.resolvedSystemSymbolName(fallbackSystemName: fallbackIdentitySymbolName)

    }

    var recentCompletedSessions: [ChargeSessionSummary] {

        sessions.filter { $0.status == .completed }

    }

    var sessionCount: Int {

        sessions.count

    }

        standbyPowerMeasurements.first

    }

        var modes: [ChargingTransportMode] = []

        if supportsWiredCharging {

            modes.append(.wired)

        }

        if supportsWirelessCharging {

            modes.append(.wireless)

        }

        chargingStateAvailability.supportedModes

    }

        supportedChargingModes.count > 1

    }

    var hasMultipleChargingStateModes: Bool {

        supportedChargingStateModes.count > 1

    }

    var showsWirelessProfileDetails: Bool {

        supportsWirelessCharging

            && hasMultipleChargingTransports

            && deviceClass != .watch

    }

    var chargingSupportSummary: String {

        switch (supportsWiredCharging, supportsWirelessCharging) {

        case (true, true):

            return "Supports wired and wireless charging."

        case (true, false):

            return "Supports wired charging only."

        case (false, true):

            return "Supports wireless charging only."

        case (false, false):

            return "No charging method configured."

        }

    }

        if let matchingSession = sessions.first(where: {

            $0.status.isOpen && $0.chargingTransportMode == chargingTransportMode

        }) {

            return matchingSession.chargingStateMode

        }

        return chargingStateAvailability.supportedModes.first ?? .on

    }

    func sessionKind(

        for chargingTransportMode: ChargingTransportMode,

        chargingStateMode: ChargingStateMode? = nil

    ) -> ChargeSessionKind {

        ChargeSessionKind(

            chargingTransportMode: chargingTransportMode,

            chargingStateMode: chargingStateMode ?? defaultChargingStateMode(for: chargingTransportMode)

        )

    }

        switch chargingTransportMode {

        case .wired:

            return wiredEstimatedBatteryCapacityWh

        case .wireless:

            return wirelessEstimatedBatteryCapacityWh

        }

    }

    func minimumCurrentAmps(for chargingTransportMode: ChargingTransportMode) -> Double? {

        switch chargingTransportMode {

        case .wired:

            return wiredMinimumCurrentAmps

        case .wireless:

            return wirelessMinimumCurrentAmps

        }

    }

        hasMultipleChargingTransports

            || supportedChargingModes.contains(chargingTransportMode) == false

    }

    func shouldShowChargingStateMode(_ chargingStateMode: ChargingStateMode) -> Bool {

        hasMultipleChargingStateModes

            || supportedChargingStateModes.contains(chargingStateMode) == false

    }

        if let explicitCurrent = configuredCompletionCurrents[sessionKind] {

            return explicitCurrent

        }

        switch sessionKind.chargingTransportMode {

            return wiredChargeCompletionCurrentAmps

        case .wireless:

            return wirelessChargeCompletionCurrentAmps

        }

    }

        if let learnedCurrent = learnedCompletionCurrents[sessionKind] {

            return learnedCurrent

        }

        switch sessionKind.chargingTransportMode {

        case .wired:

            return wiredMinimumCurrentAmps ?? minimumCurrentAmps

        case .wireless:

            return wirelessMinimumCurrentAmps ?? minimumCurrentAmps

        }

    }

    func resolvedCompletionCurrentAmps(

        for chargingTransportMode: ChargingTransportMode,

        chargingStateMode: ChargingStateMode? = nil

    ) -> Double? {

        let sessionKind = sessionKind(

            for: chargingTransportMode,

            chargingStateMode: chargingStateMode

        )

        return configuredCompletionCurrentAmps(for: sessionKind)

            ?? learnedCompletionCurrentAmps(for: sessionKind)

            ?? minimumCurrentAmps

    }

        for session: ChargeSessionSummary,

        effectiveEnergyWhOverride: Double? = nil

    ) -> BatteryLevelPrediction? {

            ?? estimatedBatteryCapacityWh(for: session.chargingTransportMode)

            ?? estimatedBatteryCapacityWh

        guard let estimatedCapacityWh, estimatedCapacityWh > 0 else {

            return nil

        }

            ?? session.effectiveBatteryEnergyWh

            ?? session.measuredEnergyWh

        struct Anchor {

            let percent: Double

            let energyWh: Double

        var anchors: [Anchor] = []

                Anchor(

                    percent: startBatteryPercent,

                    energyWh: 0,

                    description: "session start",

                    isCheckpoint: false

            )

        }

        anchors.append(

            contentsOf: session.checkpoints

                .sorted { lhs, rhs in

                    if lhs.measuredEnergyWh != rhs.measuredEnergyWh {

                        return lhs.measuredEnergyWh < rhs.measuredEnergyWh

                    }

                    return lhs.timestamp < rhs.timestamp

                }

                    checkpoint.batteryPercent >= 0

                }

                    return Anchor(

                        percent: checkpoint.batteryPercent,

                        energyWh: checkpoint.measuredEnergyWh,

                }

        )

        guard !anchors.isEmpty else {

            return nil

        }

        let eligibleAnchors = anchors.filter { $0.energyWh <= effectiveEnergyWh + 0.05 }

        let anchor = eligibleAnchors.last ?? anchors.first!

            anchorPercent: anchor.percent,

            anchorEnergyWh: anchor.energyWh,

            anchorTimestamp: anchor.timestamp,

            anchorIsCheckpoint: anchor.isCheckpoint,

            effectiveEnergyWh: effectiveEnergyWh,

            referenceTimestamp: session.lastObservedAt,

            estimatedCapacityWh: estimatedCapacityWh

        return BatteryLevelPrediction(

            predictedPercent: predictedPercent,

            estimatedCapacityWh: estimatedCapacityWh,

            anchorPercent: anchor.percent,

            anchorEnergyWh: anchor.energyWh,

            anchorDescription: anchor.description

        )

    }

    func withStandbyPowerMeasurements(_ measurements: [ChargerStandbyPowerMeasurementSummary]) -> ChargedDeviceSummary {

        ChargedDeviceSummary(

            id: id,

            qrIdentifier: qrIdentifier,

            name: name,

            deviceClass: deviceClass,

            templateDefinition: templateDefinition,

            chargingStateAvailability: chargingStateAvailability,

            supportsWiredCharging: supportsWiredCharging,

            supportsWirelessCharging: supportsWirelessCharging,

            wirelessChargingProfile: wirelessChargingProfile,

            configuredCompletionCurrents: configuredCompletionCurrents,

            learnedCompletionCurrents: learnedCompletionCurrents,

            wirelessChargerEfficiencyFactor: wirelessChargerEfficiencyFactor,

            wiredChargeCompletionCurrentAmps: wiredChargeCompletionCurrentAmps,

            wirelessChargeCompletionCurrentAmps: wirelessChargeCompletionCurrentAmps,

            chargerObservedVoltageSelections: chargerObservedVoltageSelections,

            chargerIdleCurrentAmps: chargerIdleCurrentAmps,

            chargerEfficiencyFactor: chargerEfficiencyFactor,

            chargerMaximumPowerWatts: chargerMaximumPowerWatts,

            notes: notes,

            minimumCurrentAmps: minimumCurrentAmps,

            estimatedBatteryCapacityWh: estimatedBatteryCapacityWh,

            wiredMinimumCurrentAmps: wiredMinimumCurrentAmps,

            wirelessMinimumCurrentAmps: wirelessMinimumCurrentAmps,

            wiredEstimatedBatteryCapacityWh: wiredEstimatedBatteryCapacityWh,

            wirelessEstimatedBatteryCapacityWh: wirelessEstimatedBatteryCapacityWh,

            lastAssociatedMeterMAC: lastAssociatedMeterMAC,

            createdAt: createdAt,

            updatedAt: updatedAt,

            sessions: sessions,

            capacityHistory: capacityHistory,

            typicalCurve: typicalCurve,

            standbyPowerMeasurements: measurements

        )

    }

struct ChargingMonitorSnapshot {

    let meterMACAddress: String

    let meterName: String

    let meterModel: String

    let observedAt: Date

    let voltageVolts: Double

    let currentAmps: Double

    let powerWatts: Double

    let selectedDataGroup: UInt8?

    let meterChargeCounterAh: Double?

    let meterEnergyCounterWh: Double?

}