import AppKit
import Combine
import Foundation
import Libbox
import Library

@MainActor
public class StatusBarController: NSObject, NSMenuDelegate {
    private var statusItem: NSStatusItem?
    private let environments: ExtensionEnvironments
    private var commandClient: CommandClient?
    private var cancellables = Set<AnyCancellable>()
    private var statusCancellable: AnyCancellable?
    private var speedMode: MenuBarExtraSpeedMode = .enabled

    private var menu: NSMenu?
    private var headerItem: NSMenuItem?
    private var headerView: StatusBarHeaderView?
    private var groupsItem: NSMenuItem?
    private var profilesItem: NSMenuItem?

    public init(environments: ExtensionEnvironments) {
        self.environments = environments
        super.init()
        observeProfile()
        Task {
            await initialize()
        }
    }

    private func initialize() async {
        let showMenuBarExtra = await SharedPreferences.showMenuBarExtra.get()
        speedMode = await MenuBarExtraSpeedMode(rawValue: SharedPreferences.menuBarExtraSpeedMode.get()) ?? .enabled
        updateVisibility(showMenuBarExtra)
    }

    public func updateVisibility(_ show: Bool) {
        if show {
            createStatusItem()
        } else {
            destroyStatusItem()
        }
    }

    public func updateSpeedMode(_ mode: Int) {
        speedMode = MenuBarExtraSpeedMode(rawValue: mode) ?? .enabled
        updateCommandClient()
    }

    private func createStatusItem() {
        guard statusItem == nil else { return }
        statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.variableLength)

        let button = statusItem!.button!
        button.image = NSImage(named: "MenuIcon")
        button.image?.isTemplate = true
        button.imagePosition = .imageTrailing

        menu = NSMenu()
        menu!.delegate = self
        statusItem!.menu = menu

        buildMenu()
        updateCommandClient()
    }

    private func destroyStatusItem() {
        if let statusItem {
            NSStatusBar.system.removeStatusItem(statusItem)
            self.statusItem = nil
        }
        menu = nil
        headerView = nil
        commandClient?.disconnect()
        commandClient = nil
    }

    private func buildMenu() {
        guard let menu else { return }
        menu.removeAllItems()

        headerView = StatusBarHeaderView(environments: environments)
        headerItem = NSMenuItem()
        headerItem!.view = headerView
        menu.addItem(headerItem!)

        groupsItem = NSMenuItem(title: NSLocalizedString("Group", comment: ""), action: nil, keyEquivalent: "")
        groupsItem!.submenu = NSMenu()
        groupsItem!.isHidden = true
        menu.addItem(groupsItem!)

        profilesItem = NSMenuItem(title: NSLocalizedString("Profile", comment: ""), action: nil, keyEquivalent: "")
        profilesItem!.submenu = NSMenu()
        menu.addItem(profilesItem!)

        menu.addItem(NSMenuItem.separator())

        let openItem = NSMenuItem(title: NSLocalizedString("Open", comment: ""), action: #selector(openApp), keyEquivalent: "")
        openItem.target = self
        menu.addItem(openItem)

        let quitItem = NSMenuItem(title: NSLocalizedString("Quit", comment: ""), action: #selector(quitApp), keyEquivalent: "")
        quitItem.target = self
        menu.addItem(quitItem)

        Task {
            await loadProfiles()
        }
    }

    private func observeProfile() {
        environments.$extensionProfile
            .receive(on: DispatchQueue.main)
            .sink { [weak self] profile in
                self?.headerView?.updateProfile(profile)
                self?.observeProfileStatus(profile)
                self?.updateCommandClient()
                self?.updateGroupsVisibility()
            }
            .store(in: &cancellables)

        environments.profileUpdate
            .receive(on: DispatchQueue.main)
            .sink { [weak self] _ in
                Task {
                    await self?.loadProfiles()
                }
            }
            .store(in: &cancellables)

        environments.selectedProfileUpdate
            .receive(on: DispatchQueue.main)
            .sink { [weak self] _ in
                Task {
                    await self?.loadProfiles()
                }
            }
            .store(in: &cancellables)

        environments.commandClient.$groups
            .receive(on: DispatchQueue.main)
            .sink { [weak self] groups in
                self?.updateGroupsMenu(groups)
            }
            .store(in: &cancellables)
    }

    private func observeProfileStatus(_ profile: ExtensionProfile?) {
        statusCancellable = nil
        guard let profile else { return }
        statusCancellable = profile.$status
            .receive(on: DispatchQueue.main)
            .sink { [weak self] _ in
                self?.updateCommandClient()
                self?.updateGroupsVisibility()
            }
    }

    private func updateGroupsVisibility() {
        let isConnected = environments.extensionProfile?.status.isConnected == true
        groupsItem?.isHidden = !isConnected
        if isConnected {
            environments.commandClient.connect()
        }
    }

    private func loadProfiles() async {
        guard let submenu = profilesItem?.submenu else { return }
        submenu.removeAllItems()

        let profileList: [ProfilePreview]
        do {
            profileList = try await ProfileManager.list().map { ProfilePreview($0) }
        } catch {
            return
        }

        if profileList.isEmpty {
            let emptyItem = NSMenuItem(title: NSLocalizedString("Empty profiles", comment: ""), action: nil, keyEquivalent: "")
            emptyItem.isEnabled = false
            submenu.addItem(emptyItem)
            return
        }

        var selectedProfileID = await SharedPreferences.selectedProfileID.get()
        if !profileList.contains(where: { $0.id == selectedProfileID }) {
            selectedProfileID = profileList[0].id
            await SharedPreferences.selectedProfileID.set(selectedProfileID)
        }

        for profile in profileList {
            let item = NSMenuItem(title: profile.name, action: #selector(selectProfile(_:)), keyEquivalent: "")
            item.target = self
            item.representedObject = profile.id
            item.state = profile.id == selectedProfileID ? .on : .off
            submenu.addItem(item)
        }
    }

    private func updateGroupsMenu(_ groups: [LibboxOutboundGroup]?) {
        guard let submenu = groupsItem?.submenu else { return }
        submenu.removeAllItems()

        guard let groups else { return }

        let selectableGroups = groups.filter { $0.selectable }
        if selectableGroups.isEmpty {
            groupsItem?.isHidden = true
            return
        }

        groupsItem?.isHidden = environments.extensionProfile?.status.isConnected != true

        let font = NSFont.menuFont(ofSize: 0)
        let attrs: [NSAttributedString.Key: Any] = [.font: font]

        for group in selectableGroups {
            let groupItem = NSMenuItem(title: group.tag, action: nil, keyEquivalent: "")
            let groupSubmenu = NSMenu()

            var outboundData: [(LibboxOutboundGroupItem, NSMenuItem)] = []
            var maxTagWidth: CGFloat = 0
            var maxDelayWidth: CGFloat = 0

            let items = group.getItems()!
            while items.hasNext() {
                let outbound = items.next()!
                let outboundItem = NSMenuItem(
                    title: outbound.tag,
                    action: #selector(selectOutbound(_:)),
                    keyEquivalent: ""
                )
                outboundItem.target = self
                outboundItem.representedObject = ["groupTag": group.tag, "outboundTag": outbound.tag]
                outboundItem.state = group.selected == outbound.tag ? .on : .off

                let tagWidth = (outbound.tag as NSString).size(withAttributes: attrs).width
                maxTagWidth = max(maxTagWidth, tagWidth)

                if outbound.urlTestDelay > 0 {
                    let delayText = "\(outbound.urlTestDelay)ms"
                    let delayWidth = (delayText as NSString).size(withAttributes: attrs).width
                    maxDelayWidth = max(maxDelayWidth, delayWidth)
                }

                outboundData.append((outbound, outboundItem))
            }

            let tabLocation = maxTagWidth + 20 + maxDelayWidth
            let tabStop = NSTextTab(textAlignment: .right, location: tabLocation)
            let style = NSMutableParagraphStyle()
            style.tabStops = [tabStop]

            for (outbound, outboundItem) in outboundData {
                let delay = outbound.urlTestDelay
                let delayText = delay > 0 ? "\(delay)ms" : ""
                let fullText = "\(outbound.tag)\t\(delayText)"
                let attrString = NSMutableAttributedString(
                    string: fullText,
                    attributes: [.font: font, .paragraphStyle: style]
                )
                if delay > 0 {
                    let color = NSColor.delayColor(for: UInt16(delay))
                    let delayStart = (fullText as NSString).length - (delayText as NSString).length
                    attrString.addAttribute(
                        .foregroundColor,
                        value: color,
                        range: NSRange(location: delayStart, length: (delayText as NSString).length)
                    )
                }
                outboundItem.attributedTitle = attrString
                groupSubmenu.addItem(outboundItem)
            }

            groupItem.submenu = groupSubmenu
            submenu.addItem(groupItem)
        }
    }

    @objc private func selectProfile(_ sender: NSMenuItem) {
        guard let profileID = sender.representedObject as? Int64 else { return }
        Task {
            await SharedPreferences.selectedProfileID.set(profileID)
            environments.selectedProfileUpdate.send()
            if environments.extensionProfile?.status.isConnected == true {
                do {
                    try await environments.extensionProfile?.reloadService()
                } catch {
                    showAlert(error: error)
                }
            }
            await loadProfiles()
        }
    }

    @objc private func selectOutbound(_ sender: NSMenuItem) {
        guard let info = sender.representedObject as? [String: String],
              let groupTag = info["groupTag"],
              let outboundTag = info["outboundTag"]
        else { return }

        Task {
            do {
                try await LibboxNewStandaloneCommandClient()!.selectOutbound(groupTag, outboundTag: outboundTag)
            } catch {
                showAlert(error: error)
            }
        }
    }

    @objc private func openApp() {
        NSApp.setActivationPolicy(.regular)
        if let window = NSApp.windows.first(where: { $0.identifier?.rawValue == "main" }) {
            window.makeKeyAndOrderFront(nil)
        }
        if let dockApp = NSRunningApplication.runningApplications(withBundleIdentifier: "com.apple.dock").first {
            dockApp.activate()
            DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(100)) {
                NSApp.activate(ignoringOtherApps: true)
            }
        }
    }

    @objc private func quitApp() {
        NSApp.terminate(nil)
    }

    private func updateCommandClient() {
        guard statusItem != nil else { return }
        let shouldConnect = speedMode != .disabled && environments.extensionProfile?.status.isConnectedStrict == true
        if shouldConnect {
            if commandClient == nil {
                commandClient = CommandClient(.status)
                commandClient!.$status
                    .receive(on: DispatchQueue.main)
                    .sink { [weak self] status in
                        self?.updateSpeedDisplay(status: status)
                    }
                    .store(in: &cancellables)
            }
            commandClient!.connect()
        } else {
            commandClient?.disconnect()
            updateSpeedDisplay(status: nil)
        }
    }

    private func updateSpeedDisplay(status: LibboxStatusMessage?) {
        guard let button = statusItem?.button else { return }
        if speedMode == .disabled || status == nil || !status!.trafficAvailable {
            button.title = ""
        } else if speedMode == .separate {
            button.title = "↑ \(LibboxFormatBytes(status!.uplink))/s ↓ \(LibboxFormatBytes(status!.downlink))/s  "
        } else {
            button.title = "\(LibboxFormatBytes(status!.uplink + status!.downlink))/s  "
        }
    }

    private func showAlert(error: Error) {
        let alert = NSAlert()
        alert.messageText = NSLocalizedString("Error", comment: "")
        alert.informativeText = error.localizedDescription
        alert.alertStyle = .warning
        alert.addButton(withTitle: NSLocalizedString("Ok", comment: ""))
        alert.runModal()
    }

    // MARK: - NSMenuDelegate

    public func menuWillOpen(_: NSMenu) {
        headerView?.refresh()
        Task {
            await loadProfiles()
        }
    }
}

// MARK: - StatusBarHeaderView

@MainActor
private class StatusBarHeaderView: NSView {
    private let environments: ExtensionEnvironments
    private let titleLabel: NSTextField
    private let statusSwitch: NSSwitch
    private let loadingIndicator: NSProgressIndicator
    private var cancellables = Set<AnyCancellable>()

    init(environments: ExtensionEnvironments) {
        self.environments = environments

        titleLabel = NSTextField(labelWithString: "sing-box")
        statusSwitch = NSSwitch()
        loadingIndicator = NSProgressIndicator()

        super.init(frame: NSRect(x: 0, y: 0, width: 250, height: 36))
        setupView()
        refresh()
    }

    @available(*, unavailable)
    required init?(coder _: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    private func setupView() {
        titleLabel.font = .boldSystemFont(ofSize: 13)
        titleLabel.translatesAutoresizingMaskIntoConstraints = false
        addSubview(titleLabel)

        statusSwitch.target = self
        statusSwitch.action = #selector(statusSwitchChanged)
        statusSwitch.translatesAutoresizingMaskIntoConstraints = false
        addSubview(statusSwitch)

        loadingIndicator.style = .spinning
        loadingIndicator.controlSize = .small
        loadingIndicator.translatesAutoresizingMaskIntoConstraints = false
        loadingIndicator.startAnimation(nil)
        addSubview(loadingIndicator)

        NSLayoutConstraint.activate([
            titleLabel.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 14),
            titleLabel.centerYAnchor.constraint(equalTo: centerYAnchor),

            statusSwitch.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -14),
            statusSwitch.centerYAnchor.constraint(equalTo: centerYAnchor),

            loadingIndicator.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -14),
            loadingIndicator.centerYAnchor.constraint(equalTo: centerYAnchor),
        ])
    }

    func refresh() {
        Task {
            if environments.extensionProfile == nil {
                await environments.reload()
            }
            updateProfile(environments.extensionProfile)
        }
    }

    func updateProfile(_ profile: ExtensionProfile?) {
        loadingIndicator.isHidden = profile != nil
        statusSwitch.isHidden = profile == nil

        if let profile {
            statusSwitch.isEnabled = profile.status.isEnabled
            statusSwitch.state = profile.status.isConnected ? .on : .off
            observeProfileStatus(profile)
        }
    }

    private func observeProfileStatus(_ profile: ExtensionProfile) {
        cancellables.removeAll()
        profile.$status
            .receive(on: DispatchQueue.main)
            .sink { [weak self] status in
                self?.statusSwitch.isEnabled = status.isEnabled
                self?.statusSwitch.state = status.isConnected ? .on : .off
            }
            .store(in: &cancellables)
    }

    @objc private func statusSwitchChanged() {
        let isOn = statusSwitch.state == .on
        Task {
            do {
                if isOn {
                    try await environments.extensionProfile?.start()
                } else {
                    try await environments.extensionProfile?.stop()
                }
            } catch {
                statusSwitch.state = isOn ? .off : .on
                let alert = NSAlert()
                alert.messageText = NSLocalizedString("Error", comment: "")
                alert.informativeText = error.localizedDescription
                alert.alertStyle = .warning
                alert.addButton(withTitle: NSLocalizedString("Ok", comment: ""))
                alert.runModal()
            }
        }
    }
}

// MARK: - NSColor Extension

extension NSColor {
    static func delayColor(for delay: UInt16) -> NSColor {
        switch delay {
        case 0:
            return .systemGray
        case ..<800:
            return .systemGreen
        case 800 ..< 1500:
            return .systemYellow
        default:
            return .systemOrange
        }
    }
}