//

//  DataStore.swift

//  USB Meter

//

//  Created by Bogdan Timofte on 03/03/2020.

//  Copyright © 2020 Bogdan Timofte. All rights reserved.

//

import SwiftUI

import Combine

import CoreBluetooth

import UserNotifications

    let title: String

    let message: String

    var id: String {

        "\(title)\n\(message)"

    }

}

        let displayName: String

        let modelSummary: String

        let advertisedName: String?

        let lastSeen: Date?

        let lastConnected: Date?

        let meter: Meter?

        var id: String {

            macAddress

        }

    }

    private var meterStoreCloudObserver: AnyCancellable?

    private var chargeInsightsRemoteObserver: AnyCancellable?

    private let chargeNotificationCoordinator = ChargeNotificationCoordinator()

            .receive(on: DispatchQueue.main)

            .sink { [weak self] _ in

                self?.refreshMeterMetadata()

            }

        meterStoreCloudObserver = NotificationCenter.default.publisher(for: .meterNameStoreCloudStatusDidChange)

            .receive(on: DispatchQueue.main)

            .sink { [weak self] _ in

                self?.scheduleObjectWillChange()

            }

    var deviceSummaries: [ChargedDeviceSummary] {

        chargedDevices.filter { !$0.isCharger }

    }

    var chargerSummaries: [ChargedDeviceSummary] {

        chargedDevices.filter { $0.isCharger }

    }

    var cloudAvailability: MeterNameStore.CloudAvailability {

        meterStore.currentCloudAvailability

    }

        guard chargeInsightsStore == nil else {

            return

        }

        context.automaticallyMergesChangesFromParent = true

        chargeInsightsStoreObserver = NotificationCenter.default.publisher(

            for: .NSManagedObjectContextObjectsDidChange,

            object: context

        )

        .receive(on: DispatchQueue.main)

        .sink { [weak self] _ in

            self?.reloadChargedDevices()

        }

        chargeInsightsRemoteObserver = NotificationCenter.default.publisher(

            for: .NSPersistentStoreRemoteChange,

            object: nil

        )

        .receive(on: DispatchQueue.main)

        .sink { [weak self] _ in

            self?.reloadChargedDevices()

        }

        chargeNotificationCoordinator.ensureAuthorizationIfNeeded()

        reloadChargedDevices()

    }

        meterStore.name(for: macAddress)

    }

    func setMeterName(_ name: String, for macAddress: String) {

        meterStore.upsert(macAddress: macAddress, name: name, temperatureUnitRawValue: nil)

    }

    func temperatureUnitPreference(for macAddress: String) -> TemperatureUnitPreference {

        let rawValue = meterStore.temperatureUnitRawValue(for: macAddress) ?? TemperatureUnitPreference.celsius.rawValue

        return TemperatureUnitPreference(rawValue: rawValue) ?? .celsius

    }

    func setTemperatureUnitPreference(_ preference: TemperatureUnitPreference, for macAddress: String) {

        meterStore.upsert(macAddress: macAddress, name: nil, temperatureUnitRawValue: preference.rawValue)

        meterStore.registerMeter(macAddress: macAddress, modelName: modelName, advertisedName: advertisedName)

    func noteMeterSeen(at date: Date, macAddress: String) {

        meterStore.noteLastSeen(date, for: macAddress)

    }

    func noteMeterConnected(at date: Date, macAddress: String) {

        meterStore.noteLastConnected(date, for: macAddress)

    }

    func lastSeen(for macAddress: String) -> Date? {

        meterStore.lastSeen(for: macAddress)

    }

    func lastConnected(for macAddress: String) -> Date? {

        meterStore.lastConnected(for: macAddress)

    }

        chargedDevices.first(where: { $0.id == id })

    }

        for chargedDevice in chargedDevices {

            if let session = chargedDevice.sessions.first(where: { $0.id == id }) {

                return session

            }

        }

        return nil

    }

        let normalizedMAC = meterMACAddress.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()

        return chargedDevices.filter { chargedDevice in

            guard chargedDevice.isCharger == false else {

                return false

            }

            return chargedDevice.lastAssociatedMeterMAC == normalizedMAC

                || chargedDevice.sessions.contains(where: { $0.meterMACAddress == normalizedMAC })

        }

    }

    func chargers(for meterMACAddress: String) -> [ChargedDeviceSummary] {

        let normalizedMAC = meterMACAddress.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()

        return chargedDevices.filter { chargedDevice in

            guard chargedDevice.isCharger else {

                return false

            }

            return chargedDevice.lastAssociatedMeterMAC == normalizedMAC

                || chargedDevice.sessions.contains(where: { $0.meterMACAddress == normalizedMAC })

        }

    }

    func currentChargedDeviceSummary(for meterMACAddress: String) -> ChargedDeviceSummary? {

        let normalizedMAC = meterMACAddress.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()

        if let activeSession = activeChargeSessionSummary(for: normalizedMAC),

           let liveDevice = chargedDevices.first(where: {

               $0.id == activeSession.chargedDeviceID && $0.isCharger == false

           }) {

            return liveDevice

        }

        return chargedDevices.first(where: {

            $0.isCharger == false && $0.lastAssociatedMeterMAC == normalizedMAC

        })

    }

    func currentChargerSummary(for meterMACAddress: String) -> ChargedDeviceSummary? {

        let normalizedMAC = meterMACAddress.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()

        if let activeSession = activeChargeSessionSummary(for: normalizedMAC),

           let chargerID = activeSession.chargerID,

           let liveCharger = chargedDevices.first(where: {

               $0.id == chargerID && $0.isCharger

           }) {

            return liveCharger

        }

        return chargedDevices.first(where: {

            $0.isCharger && $0.lastAssociatedMeterMAC == normalizedMAC

        })

    }

    func activeChargeSessionSummary(for meterMACAddress: String) -> ChargeSessionSummary? {

        chargeInsightsStore?.activeChargeSessionSummary(forMeterMACAddress: meterMACAddress)

    }

    @discardableResult

        deviceClass: ChargedDeviceClass,

        supportsWirelessCharging: Bool,

        wirelessChargingProfile: WirelessChargingProfile,

        meterMACAddress: String?

    ) -> Bool {

            deviceClass: deviceClass,

            supportsWirelessCharging: supportsWirelessCharging,

            wirelessChargingProfile: wirelessChargingProfile,

            assignTo: meterMACAddress

        ) ?? false

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

    @discardableResult

        name: String,

        notes: String?,

        meterMACAddress: String?

    ) -> Bool {

        let didSave = chargeInsightsStore?.createCharger(

            name: name,

            notes: notes,

            assignTo: meterMACAddress

        ) ?? false

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

    @discardableResult

    func updateDevice(

        name: String,

        deviceClass: ChargedDeviceClass,

        supportsWirelessCharging: Bool,

        wirelessChargingProfile: WirelessChargingProfile,

    ) -> Bool {

            name: name,

            deviceClass: deviceClass,

            supportsWirelessCharging: supportsWirelessCharging,

            wirelessChargingProfile: wirelessChargingProfile,

        ) ?? false

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

    @discardableResult

        id: UUID,

        name: String,

        notes: String?

    ) -> Bool {

        let didSave = chargeInsightsStore?.updateCharger(

            id: id,

            name: name,

            notes: notes

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

    @discardableResult

    func assignChargedDevice(_ chargedDeviceID: UUID, to meterMACAddress: String) -> Bool {

        let didSave = chargeInsightsStore?.assignChargedDevice(id: chargedDeviceID, to: meterMACAddress) ?? false

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

    @discardableResult

    func assignCharger(_ chargerID: UUID, to meterMACAddress: String) -> Bool {

        let didSave = chargeInsightsStore?.assignCharger(id: chargerID, to: meterMACAddress) ?? false

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

        guard let activeSession = activeChargeSessionSummary(for: meter.btSerial.macAddress.description) else {

            return

        }

        guard activeSession.status == .active else {

            return

        }

        meter.restoreChargeMonitoringIfNeeded(from: activeSession)

    }

        for meter: Meter,

        chargedDeviceID: UUID,

        chargerID: UUID?,

        chargingTransportMode: ChargingTransportMode,

        chargingStateMode: ChargingStateMode,

        autoStopEnabled: Bool,

        startsFromFlatBattery: Bool

            return false

        }

            for: snapshot,

            chargedDeviceID: chargedDeviceID,

            chargerID: chargerID,

            chargingTransportMode: chargingTransportMode,

            chargingStateMode: chargingStateMode,

            autoStopEnabled: autoStopEnabled,

            startsFromFlatBattery: startsFromFlatBattery

        if didSave {

            reloadChargedDevices()

            if let activeSession = activeChargeSessionSummary(for: meter.btSerial.macAddress.description),

               meter.supportsRecordingThreshold,

               activeSession.stopThresholdAmps > 0 {

                meter.recordingTreshold = activeSession.stopThresholdAmps

            }

            restoreChargeMonitoringStateIfNeeded(for: meter)

        return didSave

    }

    @discardableResult

    func pauseChargeSession(sessionID: UUID, from meter: Meter? = nil) -> Bool {

        let observedAt = meter?.chargingMonitorSnapshot?.observedAt ?? Date()

        let didSave = chargeInsightsStore?.pauseSession(id: sessionID, observedAt: observedAt) ?? false

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

    @discardableResult

    func resumeChargeSession(sessionID: UUID, from meter: Meter? = nil) -> Bool {

        let snapshot = meter?.chargingMonitorSnapshot

        let didSave = chargeInsightsStore?.resumeSession(id: sessionID, snapshot: snapshot) ?? false

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

    @discardableResult

    func stopChargeSession(

        sessionID: UUID,

        finalBatteryPercent: Double,

        label: String? = "Final"

    ) -> Bool {

        let didSave = chargeInsightsStore?.stopSession(

            id: sessionID,

            finalBatteryPercent: finalBatteryPercent,

            label: label

        ) ?? false

            reloadChargedDevices()

        }

        return didSave

    }

    func observeChargeSnapshot(from meter: Meter, observedAt: Date = Date()) {

        guard let snapshot = meter.chargingMonitorSnapshot(at: observedAt) else {

            return

        }

        if chargeInsightsStore?.observe(snapshot: snapshot) == true {

            reloadChargedDevices()

        }

    }

    @discardableResult

    func addBatteryCheckpoint(percent: Double, label: String?, for meter: Meter) -> Bool {

        let activeSession = activeChargeSessionSummary(for: meter.btSerial.macAddress.description)

        let checkpointEnergyWh = activeSession.map { displayedSessionEnergyWh(for: $0, on: meter) }

        let checkpointChargeAh = activeSession.map { displayedSessionChargeAh(for: $0, on: meter) }

            percent: percent,

            label: label,

            measuredEnergyWh: checkpointEnergyWh,

            measuredChargeAh: checkpointChargeAh

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

    @discardableResult

    func addBatteryCheckpoint(percent: Double, label: String?, for sessionID: UUID) -> Bool {

        let didSave = chargeInsightsStore?.addBatteryCheckpoint(

            percent: percent,

            label: label,

            for: sessionID

        ) ?? false

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

        percent: Double,

        for sessionID: UUID

    ) -> BatteryCheckpointPlausibilityWarning? {

        guard let session = chargeSessionSummary(id: sessionID) else {

            return nil

        }

        return batteryCheckpointPlausibilityWarning(percent: percent, for: session)

    }

    @discardableResult

    func deleteBatteryCheckpoint(checkpointID: UUID, for sessionID: UUID) -> Bool {

        let didDelete = chargeInsightsStore?.deleteBatteryCheckpoint(

            id: checkpointID,

            from: sessionID

        ) ?? false

        if didDelete {

            reloadChargedDevices()

        }

        return didDelete

    }

    func flushChargeInsights() -> Bool {

        let didSave = chargeInsightsStore?.flushPendingChanges() ?? false

        reloadChargedDevices()

        return didSave

    }

    @discardableResult

    func setTargetBatteryPercent(_ percent: Double?, for meter: Meter) -> Bool {

        guard let activeSession = activeChargeSessionSummary(for: meter.btSerial.macAddress.description) else {

            return false

        }

        return setTargetBatteryPercent(percent, for: activeSession.id)

    }

    @discardableResult

    func setTargetBatteryPercent(_ percent: Double?, for sessionID: UUID) -> Bool {

        if percent != nil {

            chargeNotificationCoordinator.ensureAuthorizationIfNeeded()

        }

        let didSave = chargeInsightsStore?.setTargetBatteryPercent(percent, for: sessionID) ?? false

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

    @discardableResult

    func confirmChargeSessionCompletion(sessionID: UUID) -> Bool {

        let didSave = chargeInsightsStore?.confirmCompletion(for: sessionID) ?? false

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

    @discardableResult

    func continueChargeSessionMonitoring(sessionID: UUID) -> Bool {

        let didSave = chargeInsightsStore?.continueMonitoringDespiteCompletionContradiction(for: sessionID) ?? false

        if didSave {

            reloadChargedDevices()

        }

        return didSave

    }

    @discardableResult

    func deleteChargeSession(sessionID: UUID) -> Bool {

        let deletedSession = chargedDevices

            .flatMap(\.sessions)

            .first(where: { $0.id == sessionID })

        let didDelete = chargeInsightsStore?.deleteChargeSession(id: sessionID) ?? false

        guard didDelete else {

            return false

        }

           let liveMeter = meter(for: meterMACAddress) {

            liveMeter.resetChargeRecord()

        }

        reloadChargedDevices()

        return true

    }

    @discardableResult

    func deleteChargedDevice(id: UUID) -> Bool {

        let deletedDevice = chargedDeviceSummary(id: id)

        let didDelete = chargeInsightsStore?.deleteChargedDevice(id: id) ?? false

        guard didDelete else {

            return false

        }

        if deletedDevice?.isCharger == false,

           let liveMeter = meter(for: meterMACAddress) {

            liveMeter.resetChargeRecord()

        }

        reloadChargedDevices()

        return true

    }

    @discardableResult

    func createKnownMeter(

        macAddress: String,

        customName: String?,

        modelName: String,

        advertisedName: String?

    ) -> Bool {

        let normalizedMAC = Self.normalizedMACAddress(macAddress)

        guard Self.isValidMACAddress(normalizedMAC) else {

            return false

        }

        registerMeter(macAddress: normalizedMAC, modelName: modelName, advertisedName: advertisedName)

        if let customName = customName?.trimmingCharacters(in: .whitespacesAndNewlines), !customName.isEmpty {

            setMeterName(customName, for: normalizedMAC)

        }

        noteMeterSeen(at: Date(), macAddress: normalizedMAC)

        return true

    }

    @discardableResult

    func deleteMeter(macAddress: String) -> Bool {

        let normalizedMAC = Self.normalizedMACAddress(macAddress)

        guard Self.isValidMACAddress(normalizedMAC) else {

            return false

        }

        for meter in meters.values where meter.btSerial.macAddress.description == normalizedMAC {

            meter.disconnect()

        }

        meters = meters.filter { element in

            element.value.btSerial.macAddress.description != normalizedMAC

        }

        let didDelete = meterStore.remove(macAddress: normalizedMAC)

        if didDelete {

            scheduleObjectWillChange()

        }

        return didDelete

    }

        let recordsByMAC = Dictionary(uniqueKeysWithValues: meterStore.allRecords().map { ($0.macAddress, $0) })

        let macAddresses = Set(recordsByMAC.keys).union(liveMetersByMAC.keys)

        return macAddresses.map { macAddress in

            let liveMeter = liveMetersByMAC[macAddress]

            let record = recordsByMAC[macAddress]

                lastSeen: liveMeter?.lastSeen ?? record?.lastSeen,

                lastConnected: liveMeter?.lastConnectedAt ?? record?.lastConnected,

                meter: liveMeter

            )

        }

        .sorted { lhs, rhs in

                return true

            }

            if lhs.meter == nil && rhs.meter != nil {

                return false

            }

            if byName != .orderedSame {

                return byName == .orderedAscending

            }

            return lhs.macAddress < rhs.macAddress

        }

    }

        DispatchQueue.main.async { [weak self] in

            self?.objectWillChange.send()

        }

    }

        chargedDevices = chargeInsightsStore?.fetchChargedDeviceSummaries() ?? []

        chargeNotificationCoordinator.process(chargedDevices: deviceSummaries)

        for meter in meters.values {

            restoreChargeMonitoringStateIfNeeded(for: meter)

        }

    }

    private func meter(for meterMACAddress: String) -> Meter? {

        meters.values.first { meter in

            meter.btSerial.macAddress.description == meterMACAddress

        }

    }

        DispatchQueue.main.async { [weak self] in

            guard let self else { return }

            var didUpdateAnyMeter = false

            for meter in self.meters.values {

                let mac = meter.btSerial.macAddress.description

                let displayName = self.meterName(for: mac) ?? mac

                if meter.name != displayName {

                    meter.updateNameFromStore(displayName)

                    didUpdateAnyMeter = true

                }

                let previousTemperaturePreference = meter.tc66TemperatureUnitPreference

                meter.reloadTemperatureUnitPreference()

                if meter.tc66TemperatureUnitPreference != previousTemperaturePreference {

                    didUpdateAnyMeter = true

                }

            }

            if didUpdateAnyMeter {

                self.scheduleObjectWillChange()

            }

        }

    }

    private func batteryCheckpointPlausibilityWarning(

        percent: Double,

        for session: ChargeSessionSummary

    ) -> BatteryCheckpointPlausibilityWarning? {

        guard percent.isFinite, percent >= 0, percent <= 100 else {

            return nil

        }

        let sortedCheckpoints = session.checkpoints.sorted { lhs, rhs in

            if lhs.timestamp != rhs.timestamp {

                return lhs.timestamp < rhs.timestamp

            }

            if lhs.measuredEnergyWh != rhs.measuredEnergyWh {

                return lhs.measuredEnergyWh < rhs.measuredEnergyWh

            }

            return lhs.id.uuidString < rhs.id.uuidString

        }

        if let lastCheckpoint = sortedCheckpoints.last,

           percent < lastCheckpoint.batteryPercent - 1.5 {

            return BatteryCheckpointPlausibilityWarning(

                title: "Checkpoint Goes Backwards",

                message: "The latest checkpoint is \(lastCheckpoint.batteryPercent.format(decimalDigits: 0))% at \(lastCheckpoint.timestamp.format()). A new value of \(percent.format(decimalDigits: 0))% is unexpectedly lower while the session is still charging."

            )

        }

        guard let chargedDevice = chargedDeviceSummary(id: session.chargedDeviceID),

              let prediction = chargedDevice.batteryLevelPrediction(for: session)

        else {

            return nil

        }

        let predictionGap = percent - prediction.predictedPercent

        guard abs(predictionGap) >= 4 else {

            return nil

        }

        let direction = predictionGap > 0 ? "above" : "below"

        let gapText = abs(predictionGap).format(decimalDigits: 0)

        let predictedText = prediction.predictedPercent.format(decimalDigits: 0)

        if let lastCheckpoint = sortedCheckpoints.last {

            let effectiveEnergyWh = session.effectiveBatteryEnergyWh ?? session.measuredEnergyWh

            let energyDeltaWh = max(effectiveEnergyWh - lastCheckpoint.measuredEnergyWh, 0)

            return BatteryCheckpointPlausibilityWarning(

                title: "Checkpoint Looks Implausible",

                message: "This value is about \(gapText) percentage points \(direction) the predicted \(predictedText)% based on \(prediction.anchorDescription). Since the last checkpoint at \(lastCheckpoint.batteryPercent.format(decimalDigits: 0))%, only \(energyDeltaWh.format(decimalDigits: 2)) Wh were added."

            )

        }

        return BatteryCheckpointPlausibilityWarning(

            title: "Checkpoint Looks Implausible",

            message: "This value is about \(gapText) percentage points \(direction) the predicted \(predictedText)% based on \(prediction.anchorDescription). Save it only if the device gauge really jumped that much."

        )

    }

    private func displayedSessionEnergyWh(for session: ChargeSessionSummary, on meter: Meter) -> Double {

        let storedEnergyWh = session.effectiveOrMeasuredEnergyWh

        guard session.status.isOpen else {

            return storedEnergyWh

        }

        guard session.meterMACAddress == meter.btSerial.macAddress.description else {

            return storedEnergyWh

        }

        if let baselineEnergyWh = session.meterEnergyBaselineWh {

            return max(storedEnergyWh, max(meter.recordedWH - baselineEnergyWh, 0))

        }

        return storedEnergyWh

    }

    private func displayedSessionChargeAh(for session: ChargeSessionSummary, on meter: Meter) -> Double {

        let storedChargeAh = session.measuredChargeAh

        guard session.status.isOpen else {

            return storedChargeAh

        }

        guard session.meterMACAddress == meter.btSerial.macAddress.description else {

            return storedChargeAh

        }

        if let baselineChargeAh = session.meterChargeBaselineAh {

            return max(storedChargeAh, max(meter.recordedAH - baselineChargeAh, 0))

        }

        return storedChargeAh

    }

extension AppData.MeterSummary {

    var tint: Color {

        switch modelSummary {

        case "UM25C":

            return .blue

        case "UM34C":

            return .yellow

        case "TC66C":

            return Model.TC66C.color

        default:

            return .secondary

        }

    }

}

        if let liveName = liveMeter?.name.trimmingCharacters(in: .whitespacesAndNewlines), !liveName.isEmpty {

            return liveName

        }

        if let customName = record?.customName {

            return customName

        }

        if let advertisedName = record?.advertisedName {

            return advertisedName

        }

        if let recordModel = record?.modelName {

            return recordModel

        }

        if let liveModel = liveMeter?.deviceModelSummary {

            return liveModel

        }

        return "Meter"

    }

    static func normalizedMACAddress(_ macAddress: String) -> String {

        macAddress

            .trimmingCharacters(in: .whitespacesAndNewlines)

            .uppercased()

    }

    static func isValidMACAddress(_ macAddress: String) -> Bool {

        macAddress.range(

            of: #"^[0-9A-F]{2}(:[0-9A-F]{2}){5}$"#,

            options: .regularExpression

        ) != nil

    }

}

private final class ChargeNotificationCoordinator {

    private struct Payload {

        let id: String

        let title: String

        let body: String

        let threadIdentifier: String

    }

    private let notificationCenter = UNUserNotificationCenter.current()

    private let deliveredIDsDefaultsKey = "ChargeNotificationCoordinator.deliveredIDs"

    private let eventRecencyWindow: TimeInterval = 24 * 60 * 60

    private var inFlightEventIDs: Set<String> = []

    func ensureAuthorizationIfNeeded() {

        notificationCenter.getNotificationSettings { [weak self] settings in

            guard settings.authorizationStatus == .notDetermined else {

                return

            }

            self?.notificationCenter.requestAuthorization(options: [.alert, .badge, .sound]) { _, error in

                if let error {

                    track("Notification authorization request failed: \(error.localizedDescription)")

                }

            }

        }

    }

    func process(chargedDevices: [ChargedDeviceSummary]) {

        let now = Date()

        let pendingPayloads = chargedDevices.flatMap { chargedDevice in

            payloads(for: chargedDevice, now: now)

        }

        for payload in pendingPayloads {

            scheduleIfNeeded(payload)

        }

    }

    private func payloads(for chargedDevice: ChargedDeviceSummary, now: Date) -> [Payload] {

        chargedDevice.sessions.compactMap { session in

            if let triggeredAt = session.targetBatteryAlertTriggeredAt,

               now.timeIntervalSince(triggeredAt) <= eventRecencyWindow,

               let targetBatteryPercent = session.targetBatteryPercent {

                let estimatedPercent = chargedDevice.batteryLevelPrediction(for: session)?.predictedPercent

                    ?? session.endBatteryPercent

                    ?? targetBatteryPercent

                return Payload(

                    id: "target-\(session.id.uuidString)-\(Int(triggeredAt.timeIntervalSince1970))",

                    title: "Battery target reached",

                    body: "\(chargedDevice.name) reached about \(estimatedPercent.format(decimalDigits: 0))% on \(session.meterName ?? "USB Meter") (target \(targetBatteryPercent.format(decimalDigits: 0))%).",

                    threadIdentifier: session.id.uuidString

                )

            }

            if session.requiresCompletionConfirmation,

               let requestedAt = session.completionConfirmationRequestedAt,

               now.timeIntervalSince(requestedAt) <= eventRecencyWindow {

                let estimatedPercent = session.completionContradictionPercent

                    ?? chargedDevice.batteryLevelPrediction(for: session)?.predictedPercent

                let bodyPrefix = "\(chargedDevice.name) may have stopped too early on \(session.meterName ?? "USB Meter")."

                let detail = estimatedPercent.map {

                    " Estimated battery is only \($0.format(decimalDigits: 0))%."

                } ?? ""

                return Payload(

                    id: "completion-\(session.id.uuidString)-\(Int(requestedAt.timeIntervalSince1970))",

                    title: "Confirm charge completion",

                    body: bodyPrefix + detail,

                    threadIdentifier: session.id.uuidString

                )

            }

            return nil

        }

    }

    private func scheduleIfNeeded(_ payload: Payload) {

        guard deliveredEventIDs().contains(payload.id) == false else {

            return

        }

        guard inFlightEventIDs.contains(payload.id) == false else {

            return

        }

        inFlightEventIDs.insert(payload.id)

        notificationCenter.getNotificationSettings { [weak self] settings in

            guard let self else { return }

            guard settings.authorizationStatus == .authorized || settings.authorizationStatus == .provisional else {

                DispatchQueue.main.async {

                    self.inFlightEventIDs.remove(payload.id)

                }

                return

            }

            let content = UNMutableNotificationContent()

            content.title = payload.title

            content.body = payload.body

            content.sound = .default

            content.threadIdentifier = payload.threadIdentifier

            let request = UNNotificationRequest(

                identifier: payload.id,

                content: content,

                trigger: nil

            )

            self.notificationCenter.add(request) { error in

                DispatchQueue.main.async {

                    self.inFlightEventIDs.remove(payload.id)

                    if let error {

                        track("Failed scheduling local notification: \(error.localizedDescription)")

                        return

                    }

                    self.storeDeliveredEventID(payload.id)

                }

            }

        }

    }

    private func deliveredEventIDs() -> Set<String> {

        let values = UserDefaults.standard.stringArray(forKey: deliveredIDsDefaultsKey) ?? []

        return Set(values)

    }

    private func storeDeliveredEventID(_ id: String) {

        var values = deliveredEventIDs()

        values.insert(id)

        UserDefaults.standard.set(Array(values), forKey: deliveredIDsDefaultsKey)

    }