//
//  RecordsPage.swift
//  Food Ninja
//
//  Created by Albert on 2025/7/4.
//

import SwiftUI
import UserNotifications
import SwiftData
import UIKit


struct RecordsPage: View {
    @Query var records: [Record]
    @Environment(\.modelContext) private var modelContext
    @State private var selectedRecord: Record?
    @State private var searchText: String = ""
    @State private var draftRecord: Record?
    // Temporary state variables for editing/creating records
    @State private var tempName: String = ""
    @State private var tempEmoji: String = "🍽️"
    @State private var tempCategory: String = ""
    @State private var tempLocation: String = ""
    @State private var tempExpiration: Date = Date()
    @State private var tempNotifTime: Date = Date()
    @State private var tempNotes: String = ""

    var filteredRecords: [Record] {
        records
            .filter {
                searchText.isEmpty ||
                $0.name.localizedCaseInsensitiveContains(searchText) ||
                $0.location.localizedCaseInsensitiveContains(searchText) ||
                $0.category.localizedCaseInsensitiveContains(searchText)
            }
            .sorted {
                let now = Date()
                let isExpired0 = $0.expirationDate < now
                let isExpired1 = $1.expirationDate < now

                if isExpired0 != isExpired1 {
                    return isExpired0
                }

                if $0.expirationDate != $1.expirationDate {
                    return $0.expirationDate < $1.expirationDate
                } else {
                    return $0.name.localizedCaseInsensitiveCompare($1.name) == .orderedAscending
                }
            }
    }

    var body: some View {
        mainView
    }

    private var mainView: some View {
        NavigationSplitView {
            List(selection: $selectedRecord) {
                ForEach(filteredRecords, id: \.self) { record in
                    HStack(alignment: .top) {
                        VStack(alignment: .leading) {
                            HStack {
                                Text(record.emoji + " " + record.name)
                                    .font(.headline)
                                if record.isIncomplete {
                                    Image(systemName: "exclamationmark.circle.fill")
                                        .foregroundStyle(.red)
                                        .help("record_incomplete_tooltip".localized)
                                }
                            }
                            let daysDiff = Calendar.current.dateComponents([.day], from: Date(), to: record.expirationDate).day ?? 0
                            if Calendar.current.isDateInToday(record.expirationDate) {
                                Text("exp_today".localized)
                                    .font(.subheadline)
                                    .foregroundStyle(.orange)
                            } else if daysDiff < 0 {
                                Text("exp_already".localized(with: abs(daysDiff)))
                                    .font(.subheadline)
                                    .foregroundStyle(.red)
                            } else {
                                Text("exp_in".localized(with: daysDiff + 1))
                                    .font(.subheadline)
                                    .foregroundStyle(.orange)
                            }
                            let meta = [record.category, record.location].filter { !$0.isEmpty }.joined(separator: " • ")
                            if !meta.isEmpty {
                                Text(meta)
                                    .font(.caption)
                                    .foregroundStyle(.secondary)
                            }
                        }
                        .padding(.vertical, 4)
                        Spacer()
                    }
                    .tag(record)
                }
                .onDelete { indexSet in
                    for index in indexSet {
                        let record = filteredRecords[index]
                        removeNotifications(for: record)
                        modelContext.delete(record)
                    }
                }
            }
            .searchable(text: $searchText)
            .navigationTitle("tbrecords".localized)
            .toolbar {
                ToolbarItem(placement: .topBarTrailing) {
                    EditButton()
                }
                ToolbarItem(placement: .topBarTrailing) {
                    Button(action: {
                        let newExpiration = Date()
                        let newCategory = "cat_general".localized
                        let newDraft = Record(
                            name: "",
                            expirationDate: newExpiration,
                            category: newCategory,
                            location: "",
                            emoji: "🍽️",
                            notes: ""
                        )
                        newDraft.isIncomplete = true
                        draftRecord = newDraft
                        selectedRecord = newDraft
                        // Set temp variables for new draft
                        tempName = ""
                        tempEmoji = "🍽️"
                        tempCategory = newCategory
                        tempLocation = ""
                        tempExpiration = newExpiration
                        tempNotifTime = DateComponents(calendar: .current, hour: 8, minute: 0).date ?? Date()
                        tempNotes = ""
                    }) {
                        Image(systemName: "plus")
                    }
                }
            }
        } detail: {
            if let draft = draftRecord {
                Group {
                    recordForm(for: draft)
                        .onAppear {
                            // Copy values into temp variables if not already matching
                            if tempName != draft.name { tempName = draft.name }
                            if tempEmoji != draft.emoji { tempEmoji = draft.emoji }
                            if tempCategory != draft.category { tempCategory = draft.category }
                            if tempLocation != draft.location { tempLocation = draft.location }
                            if tempExpiration != draft.expirationDate { tempExpiration = draft.expirationDate }
                            // notificationTime may be nil, fallback to 8:00
                            let notifTime = draft.notificationTime ?? DateComponents(calendar: .current, hour: 8, minute: 0).date ?? Date()
                            if abs(tempNotifTime.timeIntervalSince1970 - notifTime.timeIntervalSince1970) > 1 {
                                tempNotifTime = notifTime
                            }
                            if tempNotes != draft.notes { tempNotes = draft.notes }
                        }
                }
                .navigationTitle("rec_edit_header".localized)
                .toolbar {
                    ToolbarItem(placement: .topBarTrailing) {
                        if !tempName.trimmingCharacters(in: .whitespaces).isEmpty,
                           !tempLocation.trimmingCharacters(in: .whitespaces).isEmpty,
                           Calendar.current.startOfDay(for: tempExpiration) >= Calendar.current.startOfDay(for: Date()) {
                            Button(action: {
                                if let dr = draftRecord {
                                    dr.name = tempName
                                    dr.emoji = tempEmoji
                                    dr.category = tempCategory
                                    dr.location = tempLocation
                                    dr.expirationDate = tempExpiration
                                    dr.notificationTime = tempNotifTime
                                    dr.notes = tempNotes
                                    if dr.isIncomplete, !dr.name.isEmpty, !dr.location.isEmpty, dr.expirationDate > Date.distantPast {
                                        dr.isIncomplete = false
                                    }
                                    // Insert into modelContext
                                    modelContext.insert(dr)
                                    scheduleNotifications(for: dr)
                                    draftRecord = nil
                                    selectedRecord = nil
                                }
                            }) {
                                Text("rec_save".localized)
                            }
                        }
                    }
                }
            } else if let record = selectedRecord {
                Group {
                    recordForm(for: record)
                        .onAppear {
                            tempName = record.name
                            tempEmoji = record.emoji
                            tempCategory = record.category
                            tempLocation = record.location
                            tempExpiration = record.expirationDate
                            tempNotifTime = record.notificationTime ?? DateComponents(calendar: .current, hour: 8, minute: 0).date ?? Date()
                            tempNotes = record.notes
                        }
                }
                .navigationTitle("rec_edit_header".localized)
                .toolbar {
                    ToolbarItem(placement: .topBarTrailing) {
                        if !tempName.trimmingCharacters(in: .whitespaces).isEmpty,
                           !tempLocation.trimmingCharacters(in: .whitespaces).isEmpty,
                           Calendar.current.startOfDay(for: tempExpiration) >= Calendar.current.startOfDay(for: Date()) {
                            Button(action: {
                                record.name = tempName
                                record.emoji = tempEmoji
                                record.category = tempCategory
                                record.location = tempLocation
                                record.expirationDate = tempExpiration
                                record.notificationTime = tempNotifTime
                                record.notes = tempNotes
                                if record.isIncomplete, !record.name.isEmpty, !record.location.isEmpty, record.expirationDate > Date.distantPast {
                                    record.isIncomplete = false
                                }
                                removeNotifications(for: record)
                                modelContext.insert(record)
                                scheduleNotifications(for: record)
                                selectedRecord = nil
                            }) {
                                Text("rec_save".localized)
                            }
                        }
                    }
                }
            } else {
                ContentUnavailableView("no_selected_rec".localized, systemImage: "doc.plaintext", description: Text("choose_rec".localized))
            }
        }
        .onAppear {
            requestNotificationPermissionIfNeeded()
        }
        .onReceive(NotificationCenter.default.publisher(for: .didTapNotification)) { notification in
            if let idString = notification.object as? String,
               let uuid = UUID(uuidString: idString) {
                selectedRecord = records.first(where: { $0.id == uuid })
            }
        }
    }
    // MARK: - Notification Scheduling
    func scheduleNotifications(for record: Record) {
        // Skip incomplete records (drafts)
        guard !record.isIncomplete else { return }
        let center = UNUserNotificationCenter.current()
        let content = UNMutableNotificationContent()
        content.sound = .default

        let templates = [
            "notif_template_7_12",
            "notif_template_3_5",
            "notif_template_1_2",
            "notif_template_today",
            "notif_template_expired",
            "notif_template_30_31",
            "notif_template_over30" // index 6
        ]

        // Calculate dayOffsets including monthly notifications (>30 days before)
        var dayOffsets: [Int] = [-1, 0, 1, 3, 7, 30]

        // Add additional monthly notifications for over 30 days before expiration
        let now = Calendar.current.startOfDay(for: Date())
        let expDate = Calendar.current.startOfDay(for: record.expirationDate)
        let diffInDays = Calendar.current.dateComponents([.day], from: now, to: expDate).day ?? 0

        if diffInDays >= 60 {
            var offset = 60
            while offset <= diffInDays {
                dayOffsets.append(offset)
                offset += 30
            }
        }

        for offset in dayOffsets {
            guard let triggerDate = Calendar.current.date(byAdding: .day, value: -offset, to: expDate),
                  triggerDate >= now else { continue }

            var triggerComponents = Calendar.current.dateComponents([.year, .month, .day], from: triggerDate)
            if let notifTime = record.notificationTime {
                let timeComponents = Calendar.current.dateComponents([.hour, .minute], from: notifTime)
                triggerComponents.hour = timeComponents.hour
                triggerComponents.minute = timeComponents.minute
            } else {
                triggerComponents.hour = 8
                triggerComponents.minute = 0
            }
            let trigger = UNCalendarNotificationTrigger(dateMatching: triggerComponents, repeats: false)

            let id = "exp_\(record.id.uuidString)_\(offset)"
            content.body = String(format: NSLocalizedString(templates[offsetToIndex(offset)], comment: ""), record.name)

            let request = UNNotificationRequest(identifier: id, content: content, trigger: trigger)
            center.add(request)
            // Debug print: show when the notification will be triggered
            if let scheduledDate = Calendar.current.date(from: trigger.dateComponents) {
                print("📆 Scheduled notification for \(record.name) at offset \(offset): \(scheduledDate)")
            }
        }
    }

    func removeNotifications(for record: Record) {
        let center = UNUserNotificationCenter.current()
        let ids = [-1, 0, 1, 3, 7, 30].map { "exp_\(record.id.uuidString)_\($0)" }
        center.removePendingNotificationRequests(withIdentifiers: ids)
    }

    private func offsetToIndex(_ offset: Int) -> Int {
        switch offset {
        case let x where x > 31: return 6 // New index for "over 30 days"
        case 30...31: return 5
        case 7...12: return 0
        case 3...5: return 1
        case 1...2: return 2
        case 0: return 3
        default: return 4
        }
    }
    // MARK: - Notification Permission Request
    func requestNotificationPermissionIfNeeded() {
        UNUserNotificationCenter.current().getNotificationSettings { settings in
            switch settings.authorizationStatus {
            case .notDetermined:
                UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) { granted, error in
                    if let error = error {
                        print("Notification auth error: \(error)")
                    } else {
                        print("Notification permission granted: \(granted)")
                    }
                }
            case .denied:
                DispatchQueue.main.async {
                    let alert = UIAlertController(title: "notif_denied_title".localized, message: "notif_denied_body".localized, preferredStyle: .alert)
                    alert.addAction(UIAlertAction(title: "notif_open_settings".localized, style: .default, handler: { _ in
                        if let settingsURL = URL(string: UIApplication.openSettingsURLString) {
                            UIApplication.shared.open(settingsURL)
                        }
                    }))
                    alert.addAction(UIAlertAction(title: "notif_cancel".localized, style: .cancel))

                    if let scene = UIApplication.shared.connectedScenes.first as? UIWindowScene,
                       let root = scene.windows.first?.rootViewController {
                        root.present(alert, animated: true)
                    }
                }
            case .authorized, .provisional, .ephemeral:
                break // Already authorized
            @unknown default:
                break
            }
        }
    }


    @ViewBuilder
    private func recordForm(for record: Record) -> some View {
        Form {
            Section("rec_product".localized) {
                TextField("rec_name".localized, text: $tempName)
                ScrollView(.horizontal, showsIndicators: false) {
                    HStack {
                        ForEach([
                            "🍽️", "🍇", "🍈", "🍉", "🍊", "🍋", "🍋‍🟩", "🍌", "🍍", "🥭", "🍎", "🍏", "🍐", "🍑", "🍒", "🍓", "🫐", "🥝", "🍅", "🫒", "🥥",
                            "🥑", "🍆", "🥔", "🥕", "🌽", "🌶️", "🫑", "🥒", "🥬", "🥦", "🧄", "🧅", "🥜", "🫘", "🌰", "🫚", "🫛", "🫜", "🍄‍🟫",
                            "🍞", "🥐", "🥖", "🫓", "🥨", "🥯", "🥞", "🧇", "🧀", "🍖", "🍗", "🥩", "🥓", "🍔", "🍟", "🍕", "🌭", "🥪", "🌮", "🌯", "🫔", "🥙", "🧆", "🥚", "🍳", "🥘", "🍲", "🫕", "🥗", "🍿", "🧈", "🧂", "🥫", "🍝",
                            "🍱", "🍘", "🍙", "🍚", "🍛", "🍜", "🍠", "🍢", "🍣", "🍤", "🍥", "🥮", "🍡", "🥟", "🥠",
                            "🍦", "🍧", "🍨", "🍩", "🍪", "🎂", "🍰", "🧁", "🥧", "🍫", "🍬", "🍭", "🍮", "🍯",
                            "🍼", "🥛", "☕", "🫖", "🍵", "🍶", "🍷", "🍸", "🍹", "🍺", "🥃", "🥤", "🧋", "🧃", "🧉",
                            "💊", "🤔"
                        ], id: \.self) { emoji in
                            Text(emoji)
                                .font(.largeTitle)
                                .padding(6)
                                .background(tempEmoji == emoji ? Color.accentColor.opacity(0.2) : Color.clear)
                                .clipShape(Circle())
                                .onTapGesture {
                                    tempEmoji = emoji
                                }
                        }
                    }
                }
            }

            Section("rec_details".localized) {
                Picker("rec_cat".localized, selection: $tempCategory) {
                    ForEach(["cat_general".localized, "cat_dairy".localized, "cat_veg".localized, "cat_fruit".localized, "cat_meat".localized, "cat_sea".localized, "cat_bakery".localized, "cat_grains".localized, "cat_drinks".localized, "cat_snacks".localized, "cat_frozen".localized, "cat_medic".localized, "cat_others".localized], id: \.self) {
                        Text($0)
                    }
                }
                TextField("rec_location".localized, text: $tempLocation)
                DatePicker("rec_exp".localized, selection: $tempExpiration, displayedComponents: .date)
                DatePicker("rec_notif_time".localized, selection: $tempNotifTime, displayedComponents: .hourAndMinute)
            }

            Section("rec_notes".localized) {
                TextEditor(text: $tempNotes)
            }
        }
    }
}

extension Notification.Name {
    static let didTapNotification = Notification.Name("didTapNotification")
}