//
//  MeterSettingsTabView.swift
//  USB Meter
//

import SwiftUI

struct MeterSettingsTabView: View {
    @EnvironmentObject private var appData: AppData
    @EnvironmentObject private var meter: Meter

    let isMacIPadApp: Bool
    let onBackToHome: () -> Void

    @State private var editingName = false
    @State private var editingScreenTimeout = false
    @State private var editingScreenBrightness = false
    @State private var deleteConfirmationVisibility = false

    var body: some View {
        VStack(spacing: 0) {
            if isMacIPadApp {
                settingsMacHeader
            }
            ScrollView {
                VStack(spacing: 14) {
                    settingsCard(title: "Name", tint: meter.color) {
                        HStack {
                            Spacer()
                            if !editingName {
                                Text(meter.name)
                                    .foregroundColor(.secondary)
                            }
                            ChevronView(rotate: $editingName)
                        }
                        if editingName {
                            MeterNameEditorView(editingName: $editingName, newName: meter.name)
                        }
                    }

                    if meter.operationalState == .dataIsAvailable && meter.supportsManualTemperatureUnitSelection {
                    settingsCard(
                        title: "Meter Temperature Unit",
                        infoMessage: "TC66 temperature is shown as degrees without assuming Celsius or Fahrenheit. Keep this matched to the unit configured on the device so you can interpret the reading correctly.",
                        tint: .orange
                    ) {
                            Picker("", selection: $meter.tc66TemperatureUnitPreference) {
                                ForEach(TemperatureUnitPreference.allCases) { unit in
                                    Text(unit.title).tag(unit)
                                }
                            }
                            .pickerStyle(SegmentedPickerStyle())
                        }
                    }

                    if meter.operationalState == .dataIsAvailable && meter.model == .TC66C {
                        settingsCard(
                            title: "Screen Reporting",
                            infoMessage: "TC66 is the exception: it does not report the current screen in the payload, so the app keeps this note here instead of showing it on the home screen.",
                            tint: .orange
                        ) {
                            MeterInfoRowView(label: "Current Screen", value: "Not Reported")
                        }
                    }

                    if meter.operationalState == .dataIsAvailable {
                        settingsCard(
                            title: meter.reportsCurrentScreenIndex ? "Screen Controls" : "Page Controls",
                            infoMessage: meter.reportsCurrentScreenIndex
                                ? "Use these controls when you want to change the screen shown on the device without crowding the main meter view."
                                : "Use these controls when you want to switch device pages without crowding the main meter view.",
                            tint: .indigo
                        ) {
                            MeterScreenControlsView(showsHeader: false)
                        }
                    }

                    if meter.operationalState == .dataIsAvailable && meter.supportsUMSettings {
                        settingsCard(title: "Screen Timeout", tint: .purple) {
                            HStack {
                                Spacer()
                                if !editingScreenTimeout {
                                    Text(meter.screenTimeout > 0 ? "\(meter.screenTimeout) Minutes" : "Off")
                                        .foregroundColor(.secondary)
                                }
                                ChevronView(rotate: $editingScreenTimeout)
                            }
                            if editingScreenTimeout {
                                ScreenTimeoutEditorView()
                            }
                        }

                        settingsCard(title: "Screen Brightness", tint: .yellow) {
                            HStack {
                                Spacer()
                                if !editingScreenBrightness {
                                    Text("\(meter.screenBrightness)")
                                        .foregroundColor(.secondary)
                                }
                                ChevronView(rotate: $editingScreenBrightness)
                            }
                            if editingScreenBrightness {
                                ScreenBrightnessEditorView()
                            }
                        }
                    }

                    settingsCard(
                        title: "Danger Zone",
                        infoMessage: "Delete this meter from the sidebar and clear its saved metadata. If the device is still nearby, it can appear again after a fresh Bluetooth discovery.",
                        tint: .red
                    ) {
                        Button("Delete Meter") {
                            deleteConfirmationVisibility = true
                        }
                        .frame(maxWidth: .infinity)
                        .padding(.vertical, 10)
                        .meterCard(tint: .red, fillOpacity: 0.16, strokeOpacity: 0.22, cornerRadius: 14)
                        .buttonStyle(.plain)
                    }
                }
                .padding()
            }
            .background(
                LinearGradient(
                    colors: [meter.color.opacity(0.14), Color.clear],
                    startPoint: .topLeading,
                    endPoint: .bottomTrailing
            )
            .ignoresSafeArea()
        )
        .alert("Delete Meter?", isPresented: $deleteConfirmationVisibility) {
            Button("Delete", role: .destructive) {
                if appData.deleteMeter(macAddress: meter.btSerial.macAddress.description) {
                    onBackToHome()
                }
            }
            Button("Cancel", role: .cancel) {}
        } message: {
            Text("This removes the saved meter entry and disconnects the live meter view.")
        }
    }
    }

    private var settingsMacHeader: some View {
        HStack(spacing: 12) {
            Button(action: onBackToHome) {
                HStack(spacing: 4) {
                    Image(systemName: "chevron.left")
                        .font(.body.weight(.semibold))
                    Text("Back")
                }
                .foregroundColor(.accentColor)
            }
            .buttonStyle(.plain)

            Text("Meter Settings")
                .font(.headline)
                .lineLimit(1)

            Spacer()

            if meter.operationalState > .notPresent {
                RSSIView(RSSI: meter.btSerial.averageRSSI)
                    .frame(width: 18, height: 18)
            }
        }
        .padding(.horizontal, 16)
        .padding(.vertical, 10)
        .background(
            Rectangle()
                .fill(.ultraThinMaterial)
                .ignoresSafeArea(edges: .top)
        )
        .overlay(alignment: .bottom) {
            Rectangle()
                .fill(Color.secondary.opacity(0.12))
                .frame(height: 1)
        }
    }

    private func settingsCard<Content: View>(
        title: String,
        infoMessage: String? = nil,
        tint: Color,
        @ViewBuilder content: () -> Content
    ) -> some View {
        VStack(alignment: .leading, spacing: 12) {
            HStack(spacing: 8) {
                Text(title)
                    .font(.headline)
                if let infoMessage {
                    ContextInfoButton(title: title, message: infoMessage)
                }
            }
            content()
        }
        .padding(18)
        .meterCard(tint: tint, fillOpacity: 0.18, strokeOpacity: 0.24)
    }
}