//
//  ChargedDeviceDetailView.swift
//  USB Meter
//
//  Created by Codex on 10/04/2026.
//

import SwiftUI

struct ChargedDeviceDetailView: View {
    @EnvironmentObject private var appData: AppData
    @Environment(\.dismiss) private var dismiss
    @State private var editorVisibility = false
    @State private var deleteConfirmationVisibility = false

    let chargedDeviceID: UUID

    var body: some View {
        Group {
            if let chargedDevice = appData.chargedDeviceSummary(id: chargedDeviceID) {
                ScrollView {
                    VStack(spacing: 18) {
                        headerCard(chargedDevice)
                        insightsCard(chargedDevice)

                        if chargedDevice.isCharger {
                            standbyPowerCard(chargedDevice)
                        }

                        if let activeSession = chargedDevice.activeSession {
                            activeSessionSummaryCard(activeSession, chargedDevice: chargedDevice)
                        }

                        if !chargedDevice.capacityHistory.isEmpty {
                            capacityEvolutionCard(chargedDevice)
                        }

                        if !chargedDevice.typicalCurve.isEmpty {
                            typicalCurveCard(chargedDevice)
                        }

                        if !closedSessions(for: chargedDevice).isEmpty {
                            sessionHistorySummaryCard(chargedDevice)
                        }
                    }
                    .padding()
                }
                .background(
                    LinearGradient(
                        colors: [tint(for: chargedDevice).opacity(0.18), Color.clear],
                        startPoint: .topLeading,
                        endPoint: .bottomTrailing
                    )
                    .ignoresSafeArea()
                )
                .navigationTitle(chargedDevice.name)
                .toolbar {
                    ToolbarItemGroup(placement: .primaryAction) {
                        Button("Edit") {
                            editorVisibility = true
                        }
                        Button(role: .destructive) {
                            deleteConfirmationVisibility = true
                        } label: {
                            Image(systemName: "trash")
                        }
                    }
                }
            } else {
                Text("This device is no longer available.")
                    .foregroundColor(.secondary)
                    .navigationTitle("Device")
            }
        }
        .sheet(isPresented: $editorVisibility) {
            if let chargedDevice = appData.chargedDeviceSummary(id: chargedDeviceID) {
                if chargedDevice.isCharger {
                    ChargerEditorSheetView(
                        appData: appData,
                        chargedDevice: chargedDevice
                    )
                } else {
                    ChargedDeviceEditorSheetView(
                        meterMACAddress: nil,
                        chargedDevice: chargedDevice
                    )
                    .environmentObject(appData)
                }
            }
        }
        .confirmationDialog("Delete \(deletionTitle)?", isPresented: $deleteConfirmationVisibility, titleVisibility: .visible) {
            Button("Delete", role: .destructive) {
                if appData.deleteChargedDevice(id: chargedDeviceID) {
                    dismiss()
                }
            }
            Button("Cancel", role: .cancel) {}
        } message: {
            Text(deletionMessage)
        }
    }

    private func headerCard(_ chargedDevice: ChargedDeviceSummary) -> some View {
        HStack(alignment: .top, spacing: 18) {
            ChargedDeviceQRCodeView(qrIdentifier: chargedDevice.qrIdentifier, side: 118)

            VStack(alignment: .leading, spacing: 10) {
                ChargedDeviceIdentityLabelView(
                    chargedDevice: chargedDevice,
                    iconPointSize: 22
                )
                .font(.title3.weight(.bold))

                Text(chargedDevice.identityTitle)
                    .font(.subheadline.weight(.semibold))
                    .foregroundColor(.secondary)

                if let meterMAC = chargedDevice.lastAssociatedMeterMAC {
                    Text("Default meter: \(meterMAC)")
                        .font(.caption)
                        .foregroundColor(.secondary)
                }

                Text(chargedDevice.qrIdentifier)
                    .font(.caption2.monospaced())
                    .foregroundColor(.secondary)
                    .textSelection(.enabled)
            }

            Spacer(minLength: 0)
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding(18)
        .meterCard(tint: tint(for: chargedDevice), fillOpacity: 0.20, strokeOpacity: 0.26, cornerRadius: 20)
    }

    private func insightsCard(_ chargedDevice: ChargedDeviceSummary) -> some View {
        MeterInfoCardView(title: "Insights", tint: tint(for: chargedDevice)) {
            if chargedDevice.isCharger {
                chargerInsights(chargedDevice)
            } else {
                deviceInsights(chargedDevice)
            }

            if let notes = chargedDevice.notes, !notes.isEmpty {
                Divider()
                Text(notes)
                    .font(.footnote)
                    .foregroundColor(.secondary)
                    .frame(maxWidth: .infinity, alignment: .leading)
            }
        }
    }

    @ViewBuilder
    private func deviceInsights(_ chargedDevice: ChargedDeviceSummary) -> some View {
        if chargedDevice.hasMultipleChargingStateModes {
            MeterInfoRowView(
                label: "Charge Modes",
                value: chargedDevice.chargingStateAvailability.title
            )
        }
        if chargedDevice.hasMultipleChargingTransports {
            MeterInfoRowView(
                label: "Charging Support",
                value: chargedDevice.supportedChargingModes.map(\.title).joined(separator: " + ")
            )
        }
        if chargedDevice.showsWirelessProfileDetails {
            MeterInfoRowView(
                label: "Wireless Profile",
                value: chargedDevice.wirelessChargingProfile.title
            )
        }

        ForEach(completionSessionKinds(for: chargedDevice), id: \.rawValue) { sessionKind in
            MeterInfoRowView(
                label: completionCurrentLabel(for: chargedDevice, sessionKind: sessionKind),
                value: completionCurrentDescription(for: chargedDevice, sessionKind: sessionKind)
            )
        }
        MeterInfoRowView(
            label: "Estimated Capacity",
            value: chargedDevice.estimatedBatteryCapacityWh.map { "\($0.format(decimalDigits: 2)) Wh" } ?? "Not enough data"
        )
        if let wiredCapacity = chargedDevice.wiredEstimatedBatteryCapacityWh {
            if chargedDevice.hasMultipleChargingTransports {
                MeterInfoRowView(
                    label: "Wired Capacity",
                    value: "\(wiredCapacity.format(decimalDigits: 2)) Wh"
                )
            }
        }
        if let wirelessCapacity = chargedDevice.wirelessEstimatedBatteryCapacityWh {
            if chargedDevice.hasMultipleChargingTransports {
                MeterInfoRowView(
                    label: "Wireless Capacity",
                    value: "\(wirelessCapacity.format(decimalDigits: 2)) Wh"
                )
            }
        }
        if let wirelessEfficiencyFactor = chargedDevice.wirelessChargerEfficiencyFactor,
           chargedDevice.showsWirelessProfileDetails {
            MeterInfoRowView(
                label: "Wireless Efficiency",
                value: "\(Int((wirelessEfficiencyFactor * 100).rounded()))%"
            )
        }
        MeterInfoRowView(
            label: "Charge Sessions",
            value: "\(chargedDevice.sessionCount)"
        )
    }

    @ViewBuilder
    private func chargerInsights(_ chargedDevice: ChargedDeviceSummary) -> some View {
        if let chargerType = chargedDevice.chargerType {
            MeterInfoRowView(
                label: "Type",
                value: chargerType.title
            )
        }
        if !chargedDevice.chargerObservedVoltageSelections.isEmpty {
            MeterInfoRowView(
                label: "Observed Voltages",
                value: chargedDevice.chargerObservedVoltageSelections
                    .map { "\($0.format(decimalDigits: 1)) V" }
                    .joined(separator: ", ")
            )
        }
        if let chargerIdleCurrentAmps = chargedDevice.chargerIdleCurrentAmps {
            MeterInfoRowView(
                label: "Idle Current",
                value: "\(chargerIdleCurrentAmps.format(decimalDigits: 2)) A"
            )
        }
        if let chargerEfficiencyFactor = chargedDevice.chargerEfficiencyFactor {
            MeterInfoRowView(
                label: "Efficiency",
                value: "\(Int((chargerEfficiencyFactor * 100).rounded()))%"
            )
        }
        if let chargerMaximumPowerWatts = chargedDevice.chargerMaximumPowerWatts {
            MeterInfoRowView(
                label: "Max Power",
                value: "\(chargerMaximumPowerWatts.format(decimalDigits: 2)) W"
            )
        }
        if let latestStandbyPowerMeasurement = chargedDevice.latestStandbyPowerMeasurement {
            MeterInfoRowView(
                label: "Standby Power",
                value: "\(latestStandbyPowerMeasurement.averagePowerWatts.format(decimalDigits: 3)) W"
            )
            MeterInfoRowView(
                label: "Standby Projection",
                value: standbyEnergyLabel(latestStandbyPowerMeasurement.projectedYearlyEnergyWh) + " / year"
            )
        }
        MeterInfoRowView(
            label: "Wireless Sessions",
            value: "\(chargedDevice.sessionCount)"
        )

        if chargedDevice.chargerIdleCurrentAmps == nil {
            Text("Idle current is missing. Wireless sessions that use this charger can still be recorded, but they cannot learn or auto-apply the wireless stop threshold yet.")
                .font(.caption2)
                .foregroundColor(.orange)
        }
    }

    private func standbyPowerCard(_ chargedDevice: ChargedDeviceSummary) -> some View {
        let latestMeasurement = chargedDevice.latestStandbyPowerMeasurement

        return MeterInfoCardView(
            title: "Standby Power",
            tint: .orange
        ) {
            if standbyMeasurementMeters.isEmpty {
                Text("Connect a meter first. Standby measurement is launched from a live meter feed, so only currently available meters can be selected here.")
                    .font(.footnote)
                    .foregroundColor(.secondary)
                    .frame(maxWidth: .infinity, alignment: .leading)
            } else {
                NavigationLink(
                    destination: ChargerStandbyPowerWizardView(
                        preferredChargerID: chargedDevice.id,
                        locksChargerSelection: true
                    )
                ) {
                    Label("New Measurement", systemImage: "plus.circle.fill")
                        .font(.subheadline.weight(.semibold))
                        .foregroundColor(.orange)
                }
                .buttonStyle(.plain)
            }

            if let latestMeasurement {
                Divider()

                NavigationLink(
                    destination: ChargerStandbyPowerMeasurementDetailView(
                        chargerID: chargedDevice.id,
                        measurementID: latestMeasurement.id
                    )
                ) {
                    VStack(alignment: .leading, spacing: 8) {
                        HStack {
                            Text("Latest Measurement")
                                .font(.subheadline.weight(.semibold))
                                .foregroundColor(.primary)
                            Spacer()
                            Text("\(latestMeasurement.averagePowerWatts.format(decimalDigits: 3)) W")
                                .font(.subheadline.weight(.bold))
                                .foregroundColor(.primary)
                                .monospacedDigit()
                        }

                        Text(
                            "\(latestMeasurement.endedAt.format()) • \(latestMeasurement.sampleCount) samples • \(standbyEnergyLabel(latestMeasurement.projectedYearlyEnergyWh)) / year"
                        )
                        .font(.caption)
                        .foregroundColor(.secondary)
                    }
                }
                .buttonStyle(.plain)
            }

            if chargedDevice.standbyPowerMeasurements.isEmpty == false {
                Divider()

                NavigationLink(
                    destination: ChargerStandbyPowerMeasurementsView(chargerID: chargedDevice.id)
                ) {
                    Label("View Saved Measurements", systemImage: "clock.arrow.trianglehead.counterclockwise.rotate.90")
                        .font(.subheadline.weight(.semibold))
                        .foregroundColor(.blue)
                }
                .buttonStyle(.plain)
            }
        }
    }

    private func activeSessionSummaryCard(
        _ activeSession: ChargeSessionSummary,
        chargedDevice: ChargedDeviceSummary
    ) -> some View {
        NavigationLink(
            destination: ChargedDeviceActiveSessionView(chargedDeviceID: chargedDevice.id)
        ) {
            VStack(alignment: .leading, spacing: 14) {
                HStack(alignment: .firstTextBaseline) {
                    VStack(alignment: .leading, spacing: 4) {
                        Text("Current Session")
                            .font(.headline)
                            .foregroundColor(.primary)
                        Text(activeSession.status.title)
                            .font(.caption.weight(.semibold))
                            .foregroundColor(statusTint(for: activeSession))
                    }

                    Spacer()

                    Image(systemName: "chevron.right")
                        .font(.caption.weight(.semibold))
                        .foregroundColor(.secondary)
                }

                LazyVGrid(columns: activeSessionSummaryColumns, spacing: 8) {
                    activeSessionMetricCell(
                        label: "Energy",
                        value: "\(activeSession.effectiveOrMeasuredEnergyWh.format(decimalDigits: 2)) Wh",
                        tint: .teal
                    )
                    activeSessionMetricCell(
                        label: "Duration",
                        value: sessionDurationText(activeSession),
                        tint: .orange
                    )
                    if let maximumObservedPowerWatts = activeSession.maximumObservedPowerWatts {
                        activeSessionMetricCell(
                            label: "Max Power",
                            value: "\(maximumObservedPowerWatts.format(decimalDigits: 2)) W",
                            tint: .blue
                        )
                    }
                    if let batteryPrediction = chargedDevice.batteryLevelPrediction(for: activeSession) {
                        activeSessionMetricCell(
                            label: "Battery",
                            value: "\(batteryPrediction.predictedPercent.format(decimalDigits: 0))%",
                            tint: .green
                        )
                    } else if let targetBatteryPercent = activeSession.targetBatteryPercent {
                        activeSessionMetricCell(
                            label: "Target",
                            value: "\(targetBatteryPercent.format(decimalDigits: 0))%",
                            tint: .indigo
                        )
                    }
                }

                Text("Started \(activeSession.startedAt.format())")
                    .font(.caption)
                    .foregroundColor(.secondary)
            }
        }
        .buttonStyle(.plain)
        .padding(18)
        .meterCard(tint: statusTint(for: activeSession), fillOpacity: 0.16, strokeOpacity: 0.22, cornerRadius: 18)
    }

    private var activeSessionSummaryColumns: [GridItem] {
        [
            GridItem(.flexible(minimum: 92), spacing: 8),
            GridItem(.flexible(minimum: 92), spacing: 8)
        ]
    }

    private func activeSessionMetricCell(label: String, value: String, tint: Color) -> some View {
        VStack(alignment: .leading, spacing: 4) {
            Text(label)
                .font(.caption2)
                .foregroundColor(.secondary)
            Text(value)
                .font(.footnote.weight(.semibold))
                .foregroundColor(.primary)
                .monospacedDigit()
                .lineLimit(1)
                .minimumScaleFactor(0.8)
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding(10)
        .meterCard(tint: tint, fillOpacity: 0.08, strokeOpacity: 0.12, cornerRadius: 12)
    }

    private func capacityEvolutionCard(_ chargedDevice: ChargedDeviceSummary) -> some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Capacity Evolution")
                .font(.headline)

            ForEach(chargedDevice.capacityHistory.suffix(6)) { point in
                HStack {
                    Text(point.timestamp.format())
                        .font(.caption)
                        .foregroundColor(.secondary)
                    Spacer()
                    if chargedDevice.shouldShowChargingTransport(point.chargingTransportMode) {
                        Text(point.chargingTransportMode.title)
                            .font(.caption2)
                            .foregroundColor(.secondary)
                        Text("•")
                            .foregroundColor(.secondary)
                    }
                    Text("\(point.capacityWh.format(decimalDigits: 2)) Wh")
                        .font(.footnote.weight(.semibold))
                }
            }
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding(18)
        .meterCard(tint: .orange, fillOpacity: 0.14, strokeOpacity: 0.20, cornerRadius: 18)
    }

    private func typicalCurveCard(_ chargedDevice: ChargedDeviceSummary) -> some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Typical Charge Curve")
                .font(.headline)

            ForEach(chargedDevice.typicalCurve) { point in
                HStack {
                    Text("\(point.percentBin)%")
                        .font(.footnote.weight(.semibold))
                    Spacer()
                    Text("\(point.averageEnergyWh.format(decimalDigits: 2)) Wh")
                        .font(.caption.weight(.semibold))
                    Text("•")
                        .foregroundColor(.secondary)
                    Text("\(point.sampleCount) sample\(point.sampleCount == 1 ? "" : "s")")
                        .font(.caption2)
                        .foregroundColor(.secondary)
                }
            }
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding(18)
        .meterCard(tint: .blue, fillOpacity: 0.14, strokeOpacity: 0.20, cornerRadius: 18)
    }

    private func sessionHistorySummaryCard(_ chargedDevice: ChargedDeviceSummary) -> some View {
        let sessions = closedSessions(for: chargedDevice)
        let latestSession = sessions.first
        let totalEnergyWh = sessions.reduce(0) { $0 + $1.effectiveOrMeasuredEnergyWh }

        return MeterInfoCardView(title: "Session History", tint: .teal) {
            MeterInfoRowView(label: "Closed Sessions", value: "\(sessions.count)")
            MeterInfoRowView(label: "Total Energy", value: "\(totalEnergyWh.format(decimalDigits: 2)) Wh")
            if let latestSession {
                MeterInfoRowView(label: "Latest", value: latestSession.startedAt.format())
            }

            NavigationLink(
                destination: ChargedDeviceSessionsView(chargedDeviceID: chargedDevice.id)
            ) {
                Label("Manage Sessions", systemImage: "clock.arrow.trianglehead.counterclockwise.rotate.90")
                    .font(.subheadline.weight(.semibold))
                    .frame(maxWidth: .infinity)
                    .padding(.vertical, 10)
                    .meterCard(tint: .teal, fillOpacity: 0.16, strokeOpacity: 0.22, cornerRadius: 14)
            }
            .buttonStyle(.plain)
        }
    }

    private func closedSessions(for chargedDevice: ChargedDeviceSummary) -> [ChargeSessionSummary] {
        chargedDevice.sessions.filter { !$0.status.isOpen }
    }

    private func wirelessSessionHint(for session: ChargeSessionSummary) -> String? {
        guard session.chargingTransportMode == .wireless else {
            return nil
        }

        var components: [String] = []
        if let wirelessEfficiencyFactor = session.wirelessEfficiencyFactor {
            components.append("Efficiency \(Int((wirelessEfficiencyFactor * 100).rounded()))%")
        }
        if session.usesEstimatedWirelessEfficiency {
            components.append("Estimated from wired baseline and checkpoints")
        }
        if session.shouldWarnAboutLowWirelessEfficiency {
            components.append("Low wireless efficiency, so capacity confidence is reduced")
        }

        return components.isEmpty ? nil : components.joined(separator: " • ")
    }

    private func tint(for chargedDevice: ChargedDeviceSummary) -> Color {
        switch chargedDevice.deviceClass {
        case .iphone:
            return .blue
        case .watch:
            return .green
        case .powerbank:
            return .orange
        case .charger:
            return .pink
        case .other:
            return .secondary
        }
    }

    private func statusTint(for session: ChargeSessionSummary) -> Color {
        switch session.status {
        case .active:
            return .green
        case .paused:
            return .orange
        case .completed:
            return .teal
        case .abandoned:
            return .secondary
        }
    }

    private func sessionDurationText(_ session: ChargeSessionSummary) -> String {
        let formatter = DateComponentsFormatter()
        let effectiveDuration = max(session.effectiveDuration, 0)
        formatter.allowedUnits = effectiveDuration >= 3600 ? [.hour, .minute] : [.minute, .second]
        formatter.unitsStyle = .abbreviated
        formatter.zeroFormattingBehavior = .dropAll
        return formatter.string(from: effectiveDuration) ?? "0m"
    }

    private func standbyEnergyLabel(_ wattHours: Double) -> String {
        if wattHours >= 1000 {
            return "\((wattHours / 1000).format(decimalDigits: 3)) kWh"
        }
        return "\(wattHours.format(decimalDigits: 2)) Wh"
    }

    private var standbyMeasurementMeters: [AppData.MeterSummary] {
        appData.meterSummaries.filter { $0.meter != nil }
    }

    private func completionCurrentDescription(
        for chargedDevice: ChargedDeviceSummary,
        sessionKind: ChargeSessionKind
    ) -> String {
        if let configuredCurrent = chargedDevice.configuredCompletionCurrentAmps(for: sessionKind) {
            if let learnedCurrent = chargedDevice.learnedCompletionCurrentAmps(for: sessionKind),
               abs(configuredCurrent - learnedCurrent) >= 0.01 {
                return "\(configuredCurrent.format(decimalDigits: 2)) A configured • \(learnedCurrent.format(decimalDigits: 2)) A learned"
            }
            return "\(configuredCurrent.format(decimalDigits: 2)) A configured"
        }

        if let learnedCurrent = chargedDevice.learnedCompletionCurrentAmps(for: sessionKind) {
            return "\(learnedCurrent.format(decimalDigits: 2)) A learned"
        }

        return "Learning"
    }

    private func completionCurrentLabel(
        for chargedDevice: ChargedDeviceSummary,
        sessionKind: ChargeSessionKind
    ) -> String {
        let showsTransport = chargedDevice.shouldShowChargingTransport(sessionKind.chargingTransportMode)
        let showsState = chargedDevice.shouldShowChargingStateMode(sessionKind.chargingStateMode)

        switch (showsTransport, showsState) {
        case (true, true):
            return "\(sessionKind.shortTitle) Stop Current"
        case (true, false):
            return "\(sessionKind.chargingTransportMode.title) Stop Current"
        case (false, true):
            return "\(sessionKind.chargingStateMode.title) Stop Current"
        case (false, false):
            return "Stop Current"
        }
    }

    private func completionSessionKinds(for chargedDevice: ChargedDeviceSummary) -> [ChargeSessionKind] {
        chargedDevice.supportedChargingModes.flatMap { chargingTransportMode in
            chargedDevice.supportedChargingStateModes.map { chargingStateMode in
                ChargeSessionKind(
                    chargingTransportMode: chargingTransportMode,
                    chargingStateMode: chargingStateMode
                )
            }
        }
    }

    private func autoStopDescription(for session: ChargeSessionSummary) -> String {
        if session.autoStopEnabled == false {
            return "Manual"
        }

        if let sessionWarning = sessionWarning(for: session),
           sessionWarning.contains("idle-current") {
            return "Blocked by charger setup"
        }

        if session.stopThresholdAmps > 0 {
            return "\(session.stopThresholdAmps.format(decimalDigits: 2)) A"
        }

        return "Learning"
    }

    private func sessionWarning(for session: ChargeSessionSummary) -> String? {
        guard session.chargingTransportMode == .wireless,
              let chargerID = session.chargerID,
              let charger = appData.chargedDeviceSummary(id: chargerID),
              charger.chargerIdleCurrentAmps == nil else {
            return nil
        }

        return "This charger has no idle-current measurement, so the wireless stop threshold cannot be learned or auto-applied for this session."
    }

    private var deletionTitle: String {
        appData.chargedDeviceSummary(id: chargedDeviceID)?.isCharger == true ? "charger" : "device"
    }

    private var deletionMessage: String {
        if appData.chargedDeviceSummary(id: chargedDeviceID)?.isCharger == true {
            return "This removes the charger from the library and unlinks it from wireless sessions that used it."
        }
        return "This removes the device and its stored charging history from the library."
    }

}