import CoreData
import SwiftUI
import Swinject

extension DataTable {
    struct RootView: BaseView {
        let resolver: Resolver
        @StateObject var state = StateModel()
        @State private var isRemoveHistoryItemAlertPresented: Bool = false
        @State private var alertTitle: String = ""
        @State private var alertMessage: String = ""
        @State private var alertTreatmentToDelete: Treatment?
        @State private var alertGlucoseToDelete: Glucose?

        @State private var showFutureEntries: Bool = false // default to hide future entries
        @State private var showManualGlucose: Bool = false
        @State private var isAmountUnconfirmed: Bool = true

        @Environment(\.colorScheme) var colorScheme

        /// fetch ALL glucose values, i.e. manual and non-manual
        @FetchRequest(
            fetchRequest: GlucoseStored.fetch(NSPredicate.predicateForOneDayAgo, ascending: false, fetchLimit: 288),
            animation: .bouncy
        ) var glucoseStored: FetchedResults<GlucoseStored>

        private var insulinFormatter: NumberFormatter {
            let formatter = NumberFormatter()
            formatter.numberStyle = .decimal
            formatter.maximumFractionDigits = 2
            return formatter
        }

        private var glucoseFormatter: NumberFormatter {
            let formatter = NumberFormatter()
            formatter.numberStyle = .decimal

            if state.units == .mmolL {
                formatter.maximumFractionDigits = 1
                formatter.roundingMode = .halfUp
            } else {
                formatter.maximumFractionDigits = 0
            }
            return formatter
        }

        private var manualGlucoseFormatter: NumberFormatter {
            let formatter = NumberFormatter()
            formatter.numberStyle = .decimal
            if state.units == .mmolL {
                formatter.maximumFractionDigits = 1
                formatter.roundingMode = .ceiling
            } else {
                formatter.maximumFractionDigits = 0
            }
            return formatter
        }

        private var dateFormatter: DateFormatter {
            let formatter = DateFormatter()
            formatter.timeStyle = .short
            return formatter
        }

        private var color: LinearGradient {
            colorScheme == .dark ? LinearGradient(
                gradient: Gradient(colors: [
                    Color.bgDarkBlue,
                    Color.bgDarkerDarkBlue
                ]),
                startPoint: .top,
                endPoint: .bottom
            )
                :
                LinearGradient(
                    gradient: Gradient(colors: [Color.gray.opacity(0.1)]),
                    startPoint: .top,
                    endPoint: .bottom
                )
        }

        var body: some View {
            ZStack(alignment: .center, content: {
                VStack {
                    Picker("Mode", selection: $state.mode) {
                        ForEach(
                            Mode.allCases.filter({ state.historyLayout == .twoTabs ? $0 != .meals : true }).indexed(),
                            id: \.1
                        ) { index, item in
                            if state.historyLayout == .threeTabs && item == .treatments {
                                Text("Insulin")
                                    .tag(index)
                            } else {
                                Text(item.name)
                                    .tag(index)
                            }
                        }
                    }
                    .pickerStyle(SegmentedPickerStyle())
                    .padding(.horizontal)

                    Form {
                        switch state.mode {
                        case .treatments: treatmentsList
                        case .glucose: glucoseList
                        case .meals: state.historyLayout == .threeTabs ? AnyView(mealsList) : AnyView(EmptyView())
                        }
                    }.scrollContentBackground(.hidden)
                        .background(color)
                }.blur(radius: state.waitForSuggestion ? 8 : 0)

                if state.waitForSuggestion {
                    CustomProgressView(text: progressText.rawValue)
                }
            })
                .background(color)
                .onAppear(perform: configureView)
                .onDisappear {
                    state.carbEntryDeleted = false
                    state.insulinEntryDeleted = false
                }
                .navigationTitle("History")
                .navigationBarTitleDisplayMode(.large)
                .toolbar {
                    ToolbarItem(placement: .topBarTrailing) {
                        addButton({
                            showManualGlucose = true
                            state.manualGlucose = 0
                        })
                    }
                }
                .sheet(isPresented: $showManualGlucose) {
                    addGlucoseView()
                }
        }

        @ViewBuilder func addButton(_ action: @escaping () -> Void) -> some View {
            Button(
                action: action,
                label: {
                    HStack {
                        Text("Add Glucose")
                        Image(systemName: "plus")
                            .font(.system(size: 20))
                    }
                }
            )
        }

        private var progressText: ProgressText {
            switch (state.carbEntryDeleted, state.insulinEntryDeleted) {
            case (true, false):
                return .updatingCOB
            case(false, true):
                return .updatingIOB
            default:
                return .updatingHistory
            }
        }

        private var treatmentsList: some View {
            List {
                HStack {
                    if state.historyLayout == .twoTabs {
                        Text("Treatments").foregroundStyle(.secondary)
                        Spacer()
                        filterEntriesButton
                    } else {
                        Text("Insulin").foregroundStyle(.secondary)
                        Spacer()
                        Text("Time").foregroundStyle(.secondary)
                    }
                }
                if !state.treatments.isEmpty {
                    ForEach(state.treatments.filter({ !showFutureEntries ? $0.date <= Date() : true })) { item in
                        treatmentView(item)
                    }
                } else {
                    HStack {
                        Text("No data.")
                    }
                }
            }.listRowBackground(Color.chart)
        }

        private var mealsList: some View {
            List {
                HStack {
                    Text("Type").foregroundStyle(.secondary)
                    Spacer()
                    filterEntriesButton
                }
                if !state.meals.isEmpty {
                    ForEach(state.meals.filter({ !showFutureEntries ? $0.date <= Date() : true })) { item in
                        mealView(item)
                    }
                } else {
                    HStack {
                        Text("No data.")
                    }
                }
            }.listRowBackground(Color.chart)
        }

        private var glucoseList: some View {
            List {
                HStack {
                    Text("Values").foregroundStyle(.secondary)
                    Spacer()
                    Text("Time").foregroundStyle(.secondary)
                }
                if !glucoseStored.isEmpty {
                    ForEach(glucoseStored) { glucose in
                        HStack {
                            Text(formatGlucose(glucose.glucose, isManual: glucose.isManual))

                            /// check for manual glucose
                            if glucose.isManual {
                                Image(systemName: "drop.fill").symbolRenderingMode(.monochrome).foregroundStyle(.red)
                            } else {
                                Text("\(glucose.direction ?? "--")")
                            }

                            Spacer()

                            Text(dateFormatter.string(from: glucose.date ?? Date()))
                        }
                    }
                } else {
                    HStack {
                        Text("No data.")
                    }
                }
            }.listRowBackground(Color.chart)
        }

        @ViewBuilder private func addGlucoseView() -> some View {
            let limitLow: Decimal = state.units == .mmolL ? 0.8 : 14
            let limitHigh: Decimal = state.units == .mmolL ? 40 : 720

            NavigationView {
                VStack {
                    Form {
                        Section {
                            HStack {
                                Text("New Glucose")
                                DecimalTextField(
                                    " ... ",
                                    value: $state.manualGlucose,
                                    formatter: manualGlucoseFormatter,
                                    autofocus: true,
                                    cleanInput: true
                                )
                                Text(state.units.rawValue).foregroundStyle(.secondary)
                            }
                        }.listRowBackground(Color.chart)

                        Section {
                            HStack {
                                Button {
                                    state.addManualGlucose()
                                    isAmountUnconfirmed = false
                                    showManualGlucose = false
                                }
                                label: { Text("Save") }
                                    .frame(maxWidth: .infinity, alignment: .center)
                                    .disabled(state.manualGlucose < limitLow || state.manualGlucose > limitHigh)
                            }
                        }
                        .listRowBackground(
                            state.manualGlucose < limitLow || state
                                .manualGlucose > limitHigh ? Color(.systemGray4) : Color(.systemBlue)
                        )
                        .tint(.white)
                    }.scrollContentBackground(.hidden).background(color)
                }
                .onAppear(perform: configureView)
                .navigationTitle("Add Glucose")
                .navigationBarTitleDisplayMode(.inline)
                .toolbar {
                    ToolbarItem(placement: .topBarLeading) {
                        Button("Close") {
                            showManualGlucose = false
                        }
                    }
                }
            }
        }

        private var filterEntriesButton: some View {
            Button(action: { showFutureEntries.toggle() }, label: {
                HStack {
                    Text(showFutureEntries ? "Hide Future" : "Show Future")
                        .foregroundColor(Color.secondary)
                    Image(systemName: showFutureEntries ? "calendar.badge.minus" : "calendar.badge.plus")
                }.frame(maxWidth: .infinity, alignment: .trailing)
            }).buttonStyle(.borderless)
        }

        @ViewBuilder private func treatmentView(_ item: Treatment) -> some View {
            HStack {
                Image(systemName: "circle.fill").foregroundColor(item.color)
                Text((item.isSMB ?? false) ? "SMB" : item.type.name)
                Text(item.amountText).foregroundColor(.secondary)

                if let duration = item.durationText {
                    Text(duration).foregroundColor(.secondary)
                }
                Spacer()
                Text(dateFormatter.string(from: item.date))
                    .moveDisabled(true)
            }
            .swipeActions {
                Button(
                    "Delete",
                    systemImage: "trash.fill",
                    role: .none,
                    action: {
                        alertTreatmentToDelete = item

                        if item.type == .carbs {
                            alertTitle = "Delete Carbs?"
                            alertMessage = dateFormatter.string(from: item.date) + ", " + item.amountText
                        } else if item.type == .fpus {
                            alertTitle = "Delete Carb Equivalents?"
                            alertMessage = "All FPUs of the meal will be deleted."
                        } else {
                            // item is insulin treatment; item.type == .bolus
                            alertTitle = "Delete Insulin?"
                            alertMessage = dateFormatter.string(from: item.date) + ", " + item.amountText

                            if item.isSMB ?? false {
                                // Add text snippet, so that alert message is more descriptive for SMBs
                                alertMessage += "SMB"
                            }
                        }

                        isRemoveHistoryItemAlertPresented = true
                    }
                ).tint(.red)
            }
            .disabled(item.type == .tempBasal || item.type == .tempTarget || item.type == .resume || item.type == .suspend)
            .alert(
                Text(NSLocalizedString(alertTitle, comment: "")),
                isPresented: $isRemoveHistoryItemAlertPresented
            ) {
                Button("Cancel", role: .cancel) {}
                Button("Delete", role: .destructive) {
                    guard let treatmentToDelete = alertTreatmentToDelete else {
                        debug(.default, "Cannot gracefully unwrap alertTreatmentToDelete!")
                        return
                    }

                    if state.historyLayout == .twoTabs, treatmentToDelete.type == .carbs || treatmentToDelete.type == .fpus {
                        state.invokeCarbDeletionTask(treatmentToDelete)
                    } else {
                        state.invokeInsulinDeletionTask(treatmentToDelete)
                    }
                }
            } message: {
                Text("\n" + NSLocalizedString(alertMessage, comment: ""))
            }
        }

        @ViewBuilder private func mealView(_ meal: Treatment) -> some View {
            HStack {
                Image(systemName: "circle.fill").foregroundColor(meal.color)
                Text(meal.type.name)
                Text(meal.amountText).foregroundColor(.secondary)

                if let duration = meal.durationText {
                    Text(duration).foregroundColor(.secondary)
                }

                Spacer()

                Text(dateFormatter.string(from: meal.date))
                    .moveDisabled(true)
            }.swipeActions {
                Button(
                    "Delete",
                    systemImage: "trash.fill",
                    role: .none,
                    action: {
                        alertTreatmentToDelete = meal

                        if meal.type == .carbs {
                            alertTitle = "Delete Carbs?"
                            alertMessage = dateFormatter.string(from: meal.date) + ", " + meal.amountText
                        } else if meal.type == .fpus {
                            alertTitle = "Delete Carb Equivalents?"
                            alertMessage = "All FPUs of the meal will be deleted."
                        } else {
                            // item is insulin treatment; item.type == .bolus
                            alertTitle = "Delete Insulin?"
                            alertMessage = dateFormatter.string(from: meal.date) + ", " + meal.amountText
                        }

                        isRemoveHistoryItemAlertPresented = true
                    }
                ).tint(.red)
            }
            .alert(
                Text(NSLocalizedString(alertTitle, comment: "")),
                isPresented: $isRemoveHistoryItemAlertPresented
            ) {
                Button("Cancel", role: .cancel) {}
                Button("Delete", role: .destructive) {
                    guard let treatmentToDelete = alertTreatmentToDelete else {
                        debug(.default, "Cannot gracefully unwrap alertTreatmentToDelete!")
                        return
                    }
                    state.invokeCarbDeletionTask(treatmentToDelete)
                }
            } message: {
                Text("\n" + NSLocalizedString(alertMessage, comment: ""))
            }
        }

//        @ViewBuilder private func glucoseView(_ item: Glucose, isManual: BloodGlucose) -> some View {
//            HStack {
//                Text(item.glucose.glucose.map {
//                    (
//                        isManual.type == GlucoseType.manual.rawValue ?
//                            manualGlucoseFormatter :
//                            glucoseFormatter
//                    )
//                    .string(from: Double(
//                        state.units == .mmolL ? $0.asMmolL : Decimal($0)
//                    ) as NSNumber)!
//                } ?? "--")
//                if isManual.type == GlucoseType.manual.rawValue {
//                    Image(systemName: "drop.fill").symbolRenderingMode(.monochrome).foregroundStyle(.red)
//                } else {
//                    Text(item.glucose.direction?.symbol ?? "--")
//                }
//                Spacer()
//
//                Text(dateFormatter.string(from: item.glucose.dateString))
//            }
//            .swipeActions {
//                Button(
//                    "Delete",
//                    systemImage: "trash.fill",
//                    role: .none,
//                    action: {
//                        alertGlucoseToDelete = item
//                        let valueText = (
//                            isManual.type == GlucoseType.manual.rawValue ?
//                                manualGlucoseFormatter :
//                                glucoseFormatter
//                        ).string(from: Double(
//                            state.units == .mmolL ? Double(item.glucose.value.asMmolL) : item.glucose.value
//                        ) as NSNumber)! + " " + state.units.rawValue
//                        alertTitle = "Delete Glucose?"
//                        alertMessage = dateFormatter.string(from: item.glucose.dateString) + ", " + valueText
//                        isRemoveHistoryItemAlertPresented = true
//                    }
//                ).tint(.red)
//            }
//            .alert(
//                Text(NSLocalizedString(alertTitle, comment: "")),
//                isPresented: $isRemoveHistoryItemAlertPresented
//            ) {
//                Button("Cancel", role: .cancel) {}
//                Button("Delete", role: .destructive) {
//                    guard let glucoseToDelete = alertGlucoseToDelete else {
//                        print("Cannot unwrap alertTreatmentToDelete!")
//                        return
//                    }
//                    state.deleteGlucose(glucoseToDelete)
//                }
//            } message: {
//                Text("\n" + NSLocalizedString(alertMessage, comment: ""))
//            }
//        }

        // MARK: - Format glucose

        private func formatGlucose(_ value: Int16, isManual: Bool) -> String {
            let formatter = isManual ? manualGlucoseFormatter : glucoseFormatter
            let formattedValue = formatter.string(from: NSNumber(value: value)) ?? "--"

            return state.units == .mmolL ? convertToMMOL(Double(value)) : formattedValue
        }

        private func convertToMMOL(_ value: Double) -> String {
            let mmolValue = value * 0.0555
            return "\(mmolValue) mmol/L"
        }
    }
}