import AppKit
import VoiceCatCore

// MARK: - Channel tree node

private final class ChannelNode: NSObject {
    let channel: Channel
    var children: [ChannelNode]
    init(_ channel: Channel, children: [ChannelNode] = []) {
        self.channel = channel
        self.children = children
    }
}

// MARK: - Window controller

final class MainWindowController: NSWindowController, NSWindowDelegate {

    // MARK: - Owned client
    private let client: VoiceCatClient
    private let selfUserId: UInt32
    private let nickname: String

    // MARK: - State
    private var currentChannelId: UInt32 = 0
    private var channels: [Channel] = []
    private var users: [UInt32: User] = [:]
    private var talkingUsers: Set<UInt32> = []
    private var ownPermissions = Permissions(canCreateTempChannel: false, canKick: false, canBan: false,
                                             canMoveUsers: false, canAdminAccounts: false, isAdmin: false)
    private var micStreamId: UInt32 = 0
    private var screenStreamId: UInt32 = 0
    private var pttKeyCode: UInt16 = 0x60  // F8
    private var pttMonitor: Any?
    private var serverMuted = false
    private var serverDeafened = false
    private var channelTree: [ChannelNode] = []
    private var activityLog: [String] = []
    private var displayedUsers: [User] = []
    private var displayedAccounts: [Account] = []
    private var adminMenuItem: NSMenuItem?

    // MARK: - UI components
    private let channelOutlineView = NSOutlineView()
    private let userTableView = NSTableView()
    private let chatTextView: NSTextView = {
        let tv = NSTextView()
        tv.isEditable = false
        tv.isSelectable = true
        return tv
    }()
    private let activityTableView = NSTableView()
    private let statusLabel = NSTextField(labelWithString: "")
    private let micToggleButton = NSButton()
    private let screenAudioButton = NSButton()
    private let muteCheckbox = NSButton(checkboxWithTitle: "Mute", target: nil, action: nil)
    private let deafenCheckbox = NSButton(checkboxWithTitle: "Deafen", target: nil, action: nil)
    private let inputModeControl = NSSegmentedControl(labels: ["VAD", "PTT", "Always On"],
                                                      trackingMode: .selectOne,
                                                      target: nil, action: nil)
    private let vadSlider: NSSlider = {
        let s = NSSlider(value: 50, minValue: 1, maxValue: 100, target: nil, action: nil)
        s.numberOfTickMarks = 0
        return s
    }()
    private let vadLabel = NSTextField(labelWithString: "Sensitivity:")
    private let pttKeyLabel = NSTextField(labelWithString: "(F8)")
    private let changePttButton = NSButton()
    private let devicePicker = NSPopUpButton()
    private let refreshDevicesButton = NSButton()
    private let levelMeter: NSProgressIndicator = {
        let p = NSProgressIndicator()
        p.style = .bar
        p.isIndeterminate = false
        p.minValue = 0
        p.maxValue = 100
        p.doubleValue = 0
        return p
    }()
    private let scopePicker = NSPopUpButton()
    private let composeField = NSTextField()
    private let sendButton = NSButton()

    // MARK: - Init

    init(client: VoiceCatClient, selfUserId: UInt32, nickname: String) {
        self.client = client
        self.selfUserId = selfUserId
        self.nickname = nickname
        let window = NSWindow(
            contentRect: NSRect(x: 0, y: 0, width: 900, height: 600),
            styleMask: [.titled, .closable, .miniaturizable, .resizable],
            backing: .buffered,
            defer: false
        )
        window.title = "VoiceCat — \(nickname)"
        window.minSize = NSSize(width: 640, height: 480)
        window.center()
        super.init(window: window)
        window.delegate = self

        buildUI()
        wireEvents()
        bootstrap()
    }

    required init?(coder: NSCoder) { fatalError() }

    // MARK: - UI construction

    private func buildUI() {
        guard let contentView = window?.contentView else { return }

        // Outer split: left panel (channels+users) | right panel (chat+activity)
        let outerSplit = NSSplitView()
        outerSplit.isVertical = true
        outerSplit.dividerStyle = .thin
        outerSplit.translatesAutoresizingMaskIntoConstraints = false

        // Left panel: channel outline + user table stacked vertically
        let innerSplit = NSSplitView()
        innerSplit.isVertical = false
        innerSplit.dividerStyle = .thin

        let channelPanel = buildChannelPanel()
        let userPanel = buildUserPanel()
        innerSplit.addArrangedSubview(channelPanel)
        innerSplit.addArrangedSubview(userPanel)
        innerSplit.setHoldingPriority(.defaultLow, forSubviewAt: 0)
        innerSplit.setHoldingPriority(.defaultLow + 1, forSubviewAt: 1)

        // Right panel: chat + activity stacked vertically
        let rightSplit = NSSplitView()
        rightSplit.isVertical = false
        rightSplit.dividerStyle = .thin
        let chatPanel = buildChatPanel()
        let activityPanel = buildActivityPanel()
        rightSplit.addArrangedSubview(chatPanel)
        rightSplit.addArrangedSubview(activityPanel)
        rightSplit.setHoldingPriority(.defaultLow + 1, forSubviewAt: 0)
        rightSplit.setHoldingPriority(.defaultLow, forSubviewAt: 1)

        outerSplit.addArrangedSubview(innerSplit)
        outerSplit.addArrangedSubview(rightSplit)
        outerSplit.setHoldingPriority(.defaultLow, forSubviewAt: 0)
        outerSplit.setHoldingPriority(.defaultLow + 1, forSubviewAt: 1)

        let statusBar = buildStatusBar()
        let voicePanel = buildVoicePanel()
        let composeBar = buildComposeBar()

        contentView.addSubview(outerSplit)
        contentView.addSubview(statusBar)
        contentView.addSubview(voicePanel)
        contentView.addSubview(composeBar)

        NSLayoutConstraint.activate([
            outerSplit.topAnchor.constraint(equalTo: contentView.topAnchor),
            outerSplit.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
            outerSplit.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
            outerSplit.bottomAnchor.constraint(equalTo: statusBar.topAnchor),

            statusBar.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
            statusBar.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
            statusBar.bottomAnchor.constraint(equalTo: voicePanel.topAnchor),
            statusBar.heightAnchor.constraint(equalToConstant: 24),

            voicePanel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
            voicePanel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
            voicePanel.bottomAnchor.constraint(equalTo: composeBar.topAnchor),

            composeBar.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
            composeBar.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
            composeBar.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
            composeBar.heightAnchor.constraint(equalToConstant: 36),
        ])
    }

    private func buildChannelPanel() -> NSView {
        let col = NSTableColumn(identifier: NSUserInterfaceItemIdentifier("channel"))
        channelOutlineView.addTableColumn(col)
        channelOutlineView.headerView = nil
        channelOutlineView.outlineTableColumn = col
        channelOutlineView.dataSource = self
        channelOutlineView.delegate = self
        channelOutlineView.doubleAction = #selector(channelDoubleClicked)
        channelOutlineView.target = self
        channelOutlineView.setAccessibilityLabel("Channel list")
        channelOutlineView.setAccessibilityRole(.outline)

        let sv = NSScrollView()
        sv.documentView = channelOutlineView
        sv.hasVerticalScroller = true
        sv.borderType = .noBorder
        sv.setAccessibilityLabel("Channel list")

        let menu = NSMenu()
        menu.delegate = self
        channelOutlineView.menu = menu

        return sv
    }

    private func buildUserPanel() -> NSView {
        let col = NSTableColumn(identifier: NSUserInterfaceItemIdentifier("user"))
        userTableView.addTableColumn(col)
        userTableView.headerView = nil
        userTableView.dataSource = self
        userTableView.delegate = self
        userTableView.doubleAction = #selector(userDoubleClicked)
        userTableView.target = self
        userTableView.setAccessibilityLabel("Users in current channel")
        userTableView.setAccessibilityRole(.table)

        let menu = NSMenu()
        menu.delegate = self
        userTableView.menu = menu

        let sv = NSScrollView()
        sv.documentView = userTableView
        sv.hasVerticalScroller = true
        sv.borderType = .noBorder
        sv.setAccessibilityLabel("Users in current channel")
        return sv
    }

    private func buildChatPanel() -> NSView {
        chatTextView.setAccessibilityLabel("Chat messages")
        chatTextView.setAccessibilityRole(.textArea)
        chatTextView.textContainerInset = NSSize(width: 4, height: 4)
        chatTextView.isAutomaticQuoteSubstitutionEnabled = false

        let sv = NSScrollView()
        sv.documentView = chatTextView
        sv.hasVerticalScroller = true
        sv.borderType = .noBorder
        sv.setAccessibilityLabel("Chat messages")
        return sv
    }

    private func buildActivityPanel() -> NSView {
        let col = NSTableColumn(identifier: NSUserInterfaceItemIdentifier("activity"))
        activityTableView.addTableColumn(col)
        activityTableView.headerView = nil
        activityTableView.dataSource = self
        activityTableView.delegate = self
        activityTableView.setAccessibilityLabel("Activity log")
        activityTableView.setAccessibilityRole(.table)

        let sv = NSScrollView()
        sv.documentView = activityTableView
        sv.hasVerticalScroller = true
        sv.borderType = .noBorder
        sv.setAccessibilityLabel("Activity log")
        return sv
    }

    private func buildStatusBar() -> NSView {
        let bar = NSView()
        bar.translatesAutoresizingMaskIntoConstraints = false
        statusLabel.translatesAutoresizingMaskIntoConstraints = false
        statusLabel.textColor = .secondaryLabelColor
        statusLabel.font = .systemFont(ofSize: NSFont.smallSystemFontSize)
        bar.addSubview(statusLabel)
        NSLayoutConstraint.activate([
            statusLabel.leadingAnchor.constraint(equalTo: bar.leadingAnchor, constant: 8),
            statusLabel.trailingAnchor.constraint(equalTo: bar.trailingAnchor, constant: -8),
            statusLabel.centerYAnchor.constraint(equalTo: bar.centerYAnchor),
        ])
        let sep = NSBox()
        sep.boxType = .separator
        sep.translatesAutoresizingMaskIntoConstraints = false
        bar.addSubview(sep)
        NSLayoutConstraint.activate([
            sep.topAnchor.constraint(equalTo: bar.topAnchor),
            sep.leadingAnchor.constraint(equalTo: bar.leadingAnchor),
            sep.trailingAnchor.constraint(equalTo: bar.trailingAnchor),
            sep.heightAnchor.constraint(equalToConstant: 1),
        ])
        return bar
    }

    private func buildVoicePanel() -> NSView {
        let panel = NSView()
        panel.translatesAutoresizingMaskIntoConstraints = false
        let sep = NSBox(); sep.boxType = .separator; sep.translatesAutoresizingMaskIntoConstraints = false
        panel.addSubview(sep)

        // Mic + Screen buttons
        micToggleButton.title = "Join Voice"
        micToggleButton.bezelStyle = .rounded
        micToggleButton.target = self; micToggleButton.action = #selector(micToggleClicked)
        micToggleButton.setAccessibilityLabel("Join Voice — start sending microphone audio")

        screenAudioButton.title = "Share Screen Audio"
        screenAudioButton.bezelStyle = .rounded
        screenAudioButton.target = self; screenAudioButton.action = #selector(screenAudioClicked)
        screenAudioButton.setAccessibilityLabel("Share Screen Audio")

        // Mute/Deafen
        muteCheckbox.target = self; muteCheckbox.action = #selector(muteChanged)
        muteCheckbox.setAccessibilityLabel("Mute microphone")
        muteCheckbox.isEnabled = false
        deafenCheckbox.target = self; deafenCheckbox.action = #selector(deafenChanged)
        deafenCheckbox.setAccessibilityLabel("Deafen — mute all incoming audio")
        deafenCheckbox.isEnabled = false

        // Input mode
        inputModeControl.target = self; inputModeControl.action = #selector(inputModeChanged)
        inputModeControl.selectedSegment = 0
        inputModeControl.setAccessibilityLabel("Input mode: VAD, PTT, or Always On")

        // VAD slider
        vadLabel.setAccessibilityLabel("VAD sensitivity")
        vadSlider.target = self; vadSlider.action = #selector(vadSliderChanged)
        vadSlider.setAccessibilityLabel("Voice activation sensitivity")
        vadSlider.setAccessibilityHelp("Drag right for more sensitive, left for less")

        // PTT
        pttKeyLabel.setAccessibilityLabel("Current PTT key")
        changePttButton.title = "Change…"
        changePttButton.bezelStyle = .rounded
        changePttButton.target = self; changePttButton.action = #selector(changePttClicked)
        changePttButton.setAccessibilityLabel("Change push-to-talk key")
        pttKeyLabel.isHidden = true
        changePttButton.isHidden = true

        // Device picker
        let deviceLabel = NSTextField(labelWithString: "Input:")
        devicePicker.setAccessibilityLabel("Input audio device")
        refreshDevicesButton.title = "↺"
        refreshDevicesButton.bezelStyle = .rounded
        refreshDevicesButton.target = self; refreshDevicesButton.action = #selector(refreshDevicesClicked)
        refreshDevicesButton.setAccessibilityLabel("Refresh device list")
        refreshDevicesButton.toolTip = "Refresh"

        // Level meter
        levelMeter.setAccessibilityLabel("Microphone input level")
        levelMeter.setAccessibilityHelp("Shows current microphone volume level")

        // Layout all voice controls
        let row1 = hstack([micToggleButton, screenAudioButton, muteCheckbox, deafenCheckbox])
        let row2 = hstack([inputModeControl, vadLabel, vadSlider, pttKeyLabel, changePttButton])
        let row3 = hstack([deviceLabel, devicePicker, refreshDevicesButton, levelMeter])

        [sep, row1, row2, row3].forEach { v in
            v.translatesAutoresizingMaskIntoConstraints = false
            panel.addSubview(v)
        }

        NSLayoutConstraint.activate([
            sep.topAnchor.constraint(equalTo: panel.topAnchor),
            sep.leadingAnchor.constraint(equalTo: panel.leadingAnchor),
            sep.trailingAnchor.constraint(equalTo: panel.trailingAnchor),
            sep.heightAnchor.constraint(equalToConstant: 1),

            row1.topAnchor.constraint(equalTo: sep.bottomAnchor, constant: 6),
            row1.leadingAnchor.constraint(equalTo: panel.leadingAnchor, constant: 8),
            row1.trailingAnchor.constraint(lessThanOrEqualTo: panel.trailingAnchor, constant: -8),

            row2.topAnchor.constraint(equalTo: row1.bottomAnchor, constant: 4),
            row2.leadingAnchor.constraint(equalTo: panel.leadingAnchor, constant: 8),
            row2.trailingAnchor.constraint(lessThanOrEqualTo: panel.trailingAnchor, constant: -8),

            row3.topAnchor.constraint(equalTo: row2.bottomAnchor, constant: 4),
            row3.leadingAnchor.constraint(equalTo: panel.leadingAnchor, constant: 8),
            row3.trailingAnchor.constraint(lessThanOrEqualTo: panel.trailingAnchor, constant: -8),
            row3.bottomAnchor.constraint(equalTo: panel.bottomAnchor, constant: -6),

            levelMeter.widthAnchor.constraint(equalToConstant: 100),
            devicePicker.widthAnchor.constraint(greaterThanOrEqualToConstant: 160),
        ])
        return panel
    }

    private func buildComposeBar() -> NSView {
        let bar = NSView()
        bar.translatesAutoresizingMaskIntoConstraints = false

        scopePicker.setAccessibilityLabel("Message scope — channel or private")
        composeField.placeholderString = "Type a message…"
        composeField.setAccessibilityLabel("Compose message")
        composeField.target = self; composeField.action = #selector(sendClicked)

        sendButton.title = "Send"
        sendButton.bezelStyle = .rounded
        sendButton.target = self; sendButton.action = #selector(sendClicked)
        sendButton.setAccessibilityLabel("Send message")
        sendButton.keyEquivalent = "\r"

        let sep = NSBox(); sep.boxType = .separator; sep.translatesAutoresizingMaskIntoConstraints = false
        [sep, scopePicker, composeField, sendButton].forEach { v in
            v.translatesAutoresizingMaskIntoConstraints = false
            bar.addSubview(v)
        }
        NSLayoutConstraint.activate([
            sep.topAnchor.constraint(equalTo: bar.topAnchor),
            sep.leadingAnchor.constraint(equalTo: bar.leadingAnchor),
            sep.trailingAnchor.constraint(equalTo: bar.trailingAnchor),
            sep.heightAnchor.constraint(equalToConstant: 1),

            scopePicker.leadingAnchor.constraint(equalTo: bar.leadingAnchor, constant: 8),
            scopePicker.centerYAnchor.constraint(equalTo: bar.centerYAnchor),

            composeField.leadingAnchor.constraint(equalTo: scopePicker.trailingAnchor, constant: 6),
            composeField.trailingAnchor.constraint(equalTo: sendButton.leadingAnchor, constant: -6),
            composeField.centerYAnchor.constraint(equalTo: bar.centerYAnchor),

            sendButton.trailingAnchor.constraint(equalTo: bar.trailingAnchor, constant: -8),
            sendButton.centerYAnchor.constraint(equalTo: bar.centerYAnchor),
            sendButton.widthAnchor.constraint(equalToConstant: 60),
        ])
        return bar
    }

    private func hstack(_ views: [NSView]) -> NSStackView {
        let s = NSStackView(views: views)
        s.orientation = .horizontal
        s.spacing = 8
        s.alignment = .centerY
        return s
    }

    // MARK: - Event wiring

    private func wireEvents() {
        client.onEvent = { [weak self] event in self?.handleEvent(event) }
        client.onLevel = { [weak self] streamId, rms in self?.handleLevel(streamId, rms) }

        pttMonitor = NSEvent.addLocalMonitorForEvents(matching: [.keyDown, .keyUp]) { [weak self] event in
            guard let self, self.inputModeControl.selectedSegment == 1,
                  self.micStreamId != 0, event.keyCode == self.pttKeyCode else { return event }
            self.client.setPushToTalk(event.type == .keyDown)
            return nil
        }
    }

    // MARK: - Bootstrap

    private func bootstrap() {
        channels = client.listChannels()
        let allUsers = client.listUsers()
        users.removeAll()
        for u in allUsers {
            users[u.id] = u
            if u.id == selfUserId { currentChannelId = u.channelId }
        }
        ownPermissions = client.getPermissions()

        refreshChannelTree()
        refreshUserList()
        rebuildScopePicker()
        updateStatusLabel()
        loadInputDevices()
        buildAdminMenu()
        addActivity("Connected to server as \(nickname)")
    }

    // MARK: - Event handling

    private func handleEvent(_ event: VoiceCatEvent) {
        switch event.type {
        case .channelList:
            channels = client.listChannels()
            let allUsers = client.listUsers()
            users.removeAll()
            for u in allUsers {
                users[u.id] = u
                if u.id == selfUserId { currentChannelId = u.channelId }
            }
            refreshChannelTree(); refreshUserList(); rebuildScopePicker()

        case .userJoined:
            let u = User(id: event.userId,
                         nickname: event.text ?? "User#\(event.userId)",
                         isGuest: true,
                         channelId: event.channelId,
                         selfMicMuted: false, selfDeafened: false,
                         serverMuted: false, serverDeafened: false)
            users[event.userId] = u
            refreshUserList(); rebuildScopePicker()
            if event.channelId == currentChannelId && event.userId != selfUserId {
                addActivity("\(u.nickname) joined the channel")
            }

        case .userLeft:
            let nick = users[event.userId]?.nickname ?? "User#\(event.userId)"
            let wasHere = users[event.userId]?.channelId == currentChannelId && event.userId != selfUserId
            users.removeValue(forKey: event.userId)
            talkingUsers.remove(event.userId)
            refreshUserList(); rebuildScopePicker()
            if wasHere { addActivity("\(nick) left the channel") }

        case .userUpdated:
            let allUsers = client.listUsers()
            users.removeAll()
            for u in allUsers {
                users[u.id] = u
                if u.id == selfUserId {
                    currentChannelId = u.channelId
                    applyServerMuteState(muted: u.serverMuted, deafened: u.serverDeafened)
                }
            }
            refreshChannelTree(); refreshUserList(); rebuildScopePicker()

        case .joinResult:
            if event.result == .ok {
                currentChannelId = event.channelId
                if let self_ = users[selfUserId] {
                    users[selfUserId] = User(id: self_.id, nickname: self_.nickname, isGuest: self_.isGuest,
                                            channelId: event.channelId,
                                            selfMicMuted: self_.selfMicMuted, selfDeafened: self_.selfDeafened,
                                            serverMuted: self_.serverMuted, serverDeafened: self_.serverDeafened)
                }
                refreshChannelTree(); refreshUserList(); updateStatusLabel()
                let name = channels.first(where: { $0.id == event.channelId })?.name ?? "Channel #\(event.channelId)"
                addActivity("Joined \(name)")
                NSAccessibility.post(element: activityTableView, notification: .announcementRequested,
                                     userInfo: [.announcement: "Joined \(name)", .priority: NSAccessibilityPriorityLevel.medium])
            } else {
                addActivity("Could not join channel: \(event.text ?? "\(event.result)")")
            }

        case .genericResult:
            let prefix = event.result == .ok ? "Success" : "Failed"
            let detail = event.text.map { ": \($0)" } ?? ""
            addActivity("\(prefix)\(detail) (\(event.result))")

        case .accountList:
            addActivity("Account list updated")

        case .textMessage:
            appendChatMessage(event)

        case .talkState:
            let talking = event.u32a == 1
            if talking { talkingUsers.insert(event.userId) } else { talkingUsers.remove(event.userId) }
            refreshUserList()
            if talking && event.userId != selfUserId,
               let u = users[event.userId], u.channelId == currentChannelId {
                addActivity("\(u.nickname) started talking")
                NSAccessibility.post(element: activityTableView, notification: .announcementRequested,
                                     userInfo: [.announcement: "\(u.nickname) started talking",
                                                .priority: NSAccessibilityPriorityLevel.medium])
            }

        case .streamStarted:
            guard let u = users[event.userId], u.channelId == currentChannelId else { break }
            let streams = client.listUserStreams(event.userId)
            let kind = streams.first(where: { $0.id == event.streamId })?.kind
            let kindStr = kind == .screenAudio ? "screen audio" : kind == .auxDevice ? "aux device" : "microphone"
            addActivity("\(u.nickname) started \(kindStr) stream")

        case .streamStopped:
            if let u = users[event.userId], u.channelId == currentChannelId {
                addActivity("\(u.nickname) stopped a stream")
            }

        case .disconnected:
            handleDisconnected(event)

        default:
            break
        }
    }

    private func handleLevel(_ streamId: UInt32, _ rms: Float) {
        guard streamId == micStreamId else { return }
        levelMeter.doubleValue = min(100, Double(rms * 400))
        levelMeter.setAccessibilityValue("\(Int(levelMeter.doubleValue)) percent")
    }

    // MARK: - Chat

    private func appendChatMessage(_ event: VoiceCatEvent) {
        let time: String
        if event.timestampUnixMs > 0 {
            let date = Date(timeIntervalSince1970: Double(event.timestampUnixMs) / 1000.0)
            time = DateFormatter.localizedString(from: date, dateStyle: .none, timeStyle: .short)
        } else {
            time = DateFormatter.localizedString(from: Date(), dateStyle: .none, timeStyle: .short)
        }
        let sender = nickname(for: event.userId)
        let prefix: String
        if event.textScope == .private {
            prefix = event.userId == selfUserId
                ? "(private to \(nickname(for: event.channelId))) "
                : "(private) "
        } else { prefix = "" }
        let line = "[\(time)] \(prefix)\(sender): \(event.text ?? "")\n"
        chatTextView.textStorage?.append(NSAttributedString(string: line))
        chatTextView.scrollToEndOfDocument(nil)
        if event.textScope == .private && event.userId != selfUserId {
            addActivity("Private message from \(sender)")
        }
    }

    // MARK: - Activity log

    private func addActivity(_ text: String) {
        let entry = "[\(DateFormatter.localizedString(from: Date(), dateStyle: .none, timeStyle: .short))] \(text)"
        activityLog.append(entry)
        if activityLog.count > 200 { activityLog.removeFirst() }
        activityTableView.reloadData()
        activityTableView.scrollRowToVisible(activityLog.count - 1)
    }

    // MARK: - UI refresh

    private func refreshChannelTree() {
        channelTree = buildChannelTree(channels)
        channelOutlineView.reloadData()
        channelOutlineView.expandItem(nil, expandChildren: true)
    }

    private func buildChannelTree(_ channels: [Channel]) -> [ChannelNode] {
        var nodeMap: [UInt32: ChannelNode] = [:]
        for ch in channels { nodeMap[ch.id] = ChannelNode(ch) }
        var roots: [ChannelNode] = []
        for ch in channels.sorted(by: { $0.name < $1.name }) {
            if ch.parentId == 0 {
                roots.append(nodeMap[ch.id]!)
            } else if let parent = nodeMap[ch.parentId] {
                parent.children.append(nodeMap[ch.id]!)
            }
        }
        return roots.sorted { $0.channel.name < $1.channel.name }
    }

    private func refreshUserList() {
        displayedUsers = users.values
            .filter { $0.channelId == currentChannelId }
            .sorted { $0.nickname < $1.nickname }
        userTableView.reloadData()
        updateStatusLabel()
    }

    private func rebuildScopePicker() {
        let prev = scopePicker.selectedItem?.representedObject as? UInt32
        scopePicker.removeAllItems()
        let chItem = NSMenuItem(title: "Channel", action: nil, keyEquivalent: "")
        chItem.representedObject = nil as UInt32?
        scopePicker.menu?.addItem(chItem)
        for u in users.values.sorted(by: { $0.nickname < $1.nickname }) where u.id != selfUserId {
            let item = NSMenuItem(title: "Private: \(u.nickname)", action: nil, keyEquivalent: "")
            item.representedObject = u.id
            scopePicker.menu?.addItem(item)
        }
        if let prev {
            for item in scopePicker.itemArray where (item.representedObject as? UInt32) == prev {
                scopePicker.select(item); break
            }
        } else {
            scopePicker.selectItem(at: 0)
        }
    }

    private func updateStatusLabel() {
        var suffix = ""
        if serverMuted { suffix += " [server muted]" }
        if serverDeafened { suffix += " [server deafened]" }
        if currentChannelId == 0 {
            statusLabel.stringValue = "Connected as \(nickname)\(suffix) — not in a channel."
            return
        }
        let chanName = channels.first(where: { $0.id == currentChannelId })?.name ?? "Channel #\(currentChannelId)"
        let count = users.values.filter { $0.channelId == currentChannelId }.count
        statusLabel.stringValue = "Connected as \(nickname)\(suffix) — \(chanName) (\(count) user\(count == 1 ? "" : "s"))"
    }

    private func applyServerMuteState(muted: Bool, deafened: Bool) {
        if muted && !serverMuted { addActivity("You have been server-muted") }
        if deafened && !serverDeafened { addActivity("You have been server-deafened") }
        if !muted && serverMuted { addActivity("Server mute cleared") }
        if !deafened && serverDeafened { addActivity("Server deafen cleared") }
        serverMuted = muted; serverDeafened = deafened
        updateStatusLabel()
    }

    private func handleDisconnected(_ event: VoiceCatEvent) {
        let msg = event.text.map { "Disconnected: \($0)" } ?? "Disconnected from server."
        statusLabel.stringValue = msg
        addActivity(msg)
        channelTree = []; channelOutlineView.reloadData()
        displayedUsers = []; userTableView.reloadData()
        users.removeAll(); talkingUsers.removeAll()
        currentChannelId = 0; micStreamId = 0; screenStreamId = 0
        composeField.isEnabled = false; sendButton.isEnabled = false
        micToggleButton.isEnabled = false; screenAudioButton.isEnabled = false
    }

    // MARK: - Admin menu

    private func buildAdminMenu() {
        guard ownPermissions.canAdminAccounts || ownPermissions.isAdmin else { return }
        let adminMenu = NSMenu(title: "Admin")
        let accountsItem = NSMenuItem(title: "Server accounts…", action: #selector(openAccounts), keyEquivalent: "")
        accountsItem.target = self
        adminMenu.addItem(accountsItem)
        let topItem = NSMenuItem(title: "Admin", action: nil, keyEquivalent: "")
        topItem.submenu = adminMenu
        adminMenuItem = topItem
        NSApp.mainMenu?.addItem(topItem)
    }

    @objc private func openAccounts() {
        presentSheet(AccountsSheet(client: client))
    }

    // MARK: - Channel actions

    @objc private func channelDoubleClicked() {
        guard let node = channelOutlineView.item(atRow: channelOutlineView.clickedRow) as? ChannelNode else { return }
        joinChannelRequest(node.channel.id)
    }

    private func joinChannelRequest(_ channelId: UInt32) {
        guard channelId != currentChannelId else { return }
        let channel = channels.first(where: { $0.id == channelId })
        if channel?.passwordProtected == true {
            let sheet = PasswordPromptSheet(prompt: "Password for channel \"\(channel!.name)\":")
            sheet.onComplete = { [weak self] pw in
                self?.client.joinChannel(channelId, password: pw)
            }
            presentSheet(sheet)
        } else {
            client.joinChannel(channelId, password: nil)
        }
    }

    // MARK: - User actions

    @objc private func userDoubleClicked() {
        openUserTuning(row: userTableView.clickedRow)
    }

    private func openUserTuning(row: Int) {
        guard row >= 0, row < displayedUsers.count else { return }
        let user = displayedUsers[row]
        presentSheet(PerUserTuningSheet(client: client, userId: user.id, nickname: user.nickname))
    }

    // MARK: - Voice controls

    @objc private func micToggleClicked() {
        if micStreamId == 0 {
            let (result, streamId) = client.startStream(StreamDescriptor(kind: .mic, deviceId: nil, label: "Microphone"))
            if result == .ok {
                micStreamId = streamId
                if let devId = selectedDeviceId(), !isDefaultDevice(devId) {
                    client.setInputDevice(streamId: streamId, deviceId: devId)
                }
                client.setInputMode(currentInputMode())
                if inputModeControl.selectedSegment == 0 {
                    client.setVadThreshold(vadThresholdFromSlider())
                }
                micToggleButton.title = "Leave Voice"
                micToggleButton.setAccessibilityLabel("Leave Voice — stop sending microphone audio")
                muteCheckbox.isEnabled = true; deafenCheckbox.isEnabled = true
                addActivity("Joined voice — microphone active")
                NSAccessibility.post(element: activityTableView, notification: .announcementRequested,
                                     userInfo: [.announcement: "Joined voice", .priority: NSAccessibilityPriorityLevel.medium])
            } else {
                addActivity("Failed to start microphone: \(result)")
            }
        } else {
            client.setPushToTalk(false)
            client.stopStream(micStreamId)
            micStreamId = 0
            levelMeter.doubleValue = 0
            micToggleButton.title = "Join Voice"
            micToggleButton.setAccessibilityLabel("Join Voice — start sending microphone audio")
            muteCheckbox.isEnabled = false; deafenCheckbox.isEnabled = false
            addActivity("Left voice")
        }
    }

    @objc private func screenAudioClicked() {
        if screenStreamId == 0 {
            let (result, streamId) = client.startStream(StreamDescriptor(kind: .screenAudio, deviceId: nil, label: "Desktop audio"))
            if result == .ok {
                screenStreamId = streamId
                screenAudioButton.title = "Stop Screen Audio"
                addActivity("Started sharing screen audio")
            } else {
                addActivity("Failed to start screen audio: \(result)")
            }
        } else {
            client.stopStream(screenStreamId)
            screenStreamId = 0
            screenAudioButton.title = "Share Screen Audio"
            addActivity("Stopped sharing screen audio")
        }
    }

    @objc private func muteChanged() {
        client.setSelfMute(micMuted: muteCheckbox.state == .on, deafened: deafenCheckbox.state == .on)
    }

    @objc private func deafenChanged() {
        client.setSelfMute(micMuted: muteCheckbox.state == .on, deafened: deafenCheckbox.state == .on)
    }

    @objc private func inputModeChanged() {
        let seg = inputModeControl.selectedSegment
        vadLabel.isHidden = seg != 0; vadSlider.isHidden = seg != 0
        pttKeyLabel.isHidden = seg != 1; changePttButton.isHidden = seg != 1
        if micStreamId != 0 {
            client.setInputMode(currentInputMode())
            if seg == 0 { client.setVadThreshold(vadThresholdFromSlider()) }
            if seg == 1 { client.setPushToTalk(false) }
        }
    }

    @objc private func vadSliderChanged() {
        if micStreamId != 0 && inputModeControl.selectedSegment == 0 {
            client.setVadThreshold(vadThresholdFromSlider())
        }
    }

    @objc private func changePttClicked() {
        let sheet = PttKeyCaptureSheet(currentKeyCode: pttKeyCode)
        sheet.onComplete = { [weak self] keyCode in
            guard let self, let keyCode else { return }
            self.pttKeyCode = keyCode
            self.pttKeyLabel.stringValue = "(\(keyCodeName(keyCode)))"
        }
        presentSheet(sheet)
    }

    @objc private func refreshDevicesClicked() { loadInputDevices() }

    private func loadInputDevices() {
        let devices = client.listDevices(.input)
        devicePicker.removeAllItems()
        for d in devices {
            let item = NSMenuItem(title: d.name, action: nil, keyEquivalent: "")
            item.representedObject = d.id
            devicePicker.menu?.addItem(item)
        }
        if let def = devices.first(where: { $0.isDefault }) {
            devicePicker.select(devicePicker.item(withTitle: def.name))
        } else if devicePicker.numberOfItems > 0 {
            devicePicker.selectItem(at: 0)
        }
    }

    private func selectedDeviceId() -> String? { devicePicker.selectedItem?.representedObject as? String }
    private func isDefaultDevice(_ id: String) -> Bool {
        client.listDevices(.input).first(where: { $0.id == id })?.isDefault == true
    }

    private func currentInputMode() -> VoiceCatInputMode {
        switch inputModeControl.selectedSegment {
        case 1:  return .pushToTalk
        case 2:  return .alwaysOn
        default: return .voiceActivation
        }
    }

    private func vadThresholdFromSlider() -> Float {
        0.1 * (1.0 - Float(vadSlider.doubleValue - 1.0) / 99.0)
    }

    // MARK: - Text send

    @objc private func sendClicked() {
        let msg = composeField.stringValue.trimmingCharacters(in: .whitespaces)
        guard !msg.isEmpty else { return }
        if let targetId = scopePicker.selectedItem?.representedObject as? UInt32 {
            client.sendText(scope: .private, targetId: targetId, text: msg)
        } else {
            guard currentChannelId != 0 else { return }
            client.sendText(scope: .channel, targetId: currentChannelId, text: msg)
        }
        composeField.stringValue = ""
    }

    // MARK: - M5: Moderation helpers

    private func moveUser(_ user: User) {
        let sheet = MoveUserSheet(channels: channels, currentChannelId: user.channelId)
        sheet.onComplete = { [weak self] channelId in
            guard let channelId else { return }
            self?.client.moveUser(user.id, toChannel: channelId)
        }
        presentSheet(sheet)
    }

    private func kickUser(_ user: User) {
        let sheet = InputSheet(title: "Kick user", prompt: "Reason:", defaultValue: "Kicked by admin")
        sheet.onComplete = { [weak self] reason in
            self?.client.kickUser(user.id, reason: reason)
        }
        presentSheet(sheet)
    }

    private func banUser(_ user: User) {
        let sheet = BanUserSheet(nickname: user.nickname)
        sheet.onComplete = { [weak self] (reason, expiresMs) in
            self?.client.banUser(user.id, reason: reason, expiresUnixMs: expiresMs)
        }
        presentSheet(sheet)
    }

    private func setPermissions(_ user: User) {
        let sheet = PermissionsSheet(nickname: user.nickname, current: Permissions(
            canCreateTempChannel: false, canKick: false, canBan: false,
            canMoveUsers: false, canAdminAccounts: false, isAdmin: false))
        sheet.onComplete = { [weak self] perms in
            guard let perms else { return }
            self?.client.setPermission(user.id, perms: perms)
        }
        presentSheet(sheet)
    }

    private func toggleServerMute(_ user: User) {
        client.setServerMute(user.id, muted: !user.serverMuted, deafened: user.serverDeafened)
    }

    private func toggleServerDeafen(_ user: User) {
        client.setServerMute(user.id, muted: user.serverMuted, deafened: !user.serverDeafened)
    }

    // MARK: - Helpers

    private func nickname(for userId: UInt32) -> String {
        if userId == selfUserId { return nickname }
        return users[userId]?.nickname ?? "User#\(userId)"
    }

    private func presentSheet(_ vc: NSViewController) {
        if let cvc = window?.contentViewController {
            cvc.presentAsSheet(vc)
        } else {
            let cvc = NSViewController()
            cvc.view = window!.contentView!
            window?.contentViewController = cvc
            cvc.presentAsSheet(vc)
        }
    }

    private func selectedUserInTable() -> User? {
        let row = userTableView.selectedRow
        guard row >= 0, row < displayedUsers.count else { return nil }
        return displayedUsers[row]
    }

    // MARK: - NSWindowDelegate

    func windowWillClose(_ notification: Notification) {
        if let mon = pttMonitor { NSEvent.removeMonitor(mon) }
        if let item = adminMenuItem { NSApp.mainMenu?.removeItem(item) }
        client.setPushToTalk(false)
        if screenStreamId != 0 { client.stopStream(screenStreamId) }
        if micStreamId != 0 { client.stopStream(micStreamId) }
        client.onLevel = nil
        client.onEvent = nil
        client.disconnect()
    }
}

// MARK: - NSOutlineView DataSource / Delegate

extension MainWindowController: NSOutlineViewDataSource, NSOutlineViewDelegate {
    func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int {
        if item == nil { return channelTree.count }
        return (item as! ChannelNode).children.count
    }

    func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any {
        if item == nil { return channelTree[index] }
        return (item as! ChannelNode).children[index]
    }

    func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool {
        !(item as! ChannelNode).children.isEmpty
    }

    func outlineView(_ outlineView: NSOutlineView, viewFor tableColumn: NSTableColumn?, item: Any) -> NSView? {
        let node = item as! ChannelNode
        let ch = node.channel
        var label = ch.name
        if ch.passwordProtected { label += " [pw]" }
        if ch.id == currentChannelId { label += " ►" }
        let id = NSUserInterfaceItemIdentifier("channelCell")
        let cell = outlineView.makeView(withIdentifier: id, owner: nil) as? NSTableCellView
                   ?? makeTextCellView(identifier: id)
        cell.textField?.stringValue = label
        cell.setAccessibilityLabel(label)
        return cell
    }

    func outlineView(_ outlineView: NSOutlineView, shouldSelectItem item: Any) -> Bool { true }
}

// MARK: - NSTableView DataSource / Delegate

extension MainWindowController: NSTableViewDataSource, NSTableViewDelegate {
    func numberOfRows(in tableView: NSTableView) -> Int {
        tableView === userTableView ? displayedUsers.count : activityLog.count
    }

    func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? {
        let id = NSUserInterfaceItemIdentifier("cell")
        let cell = tableView.makeView(withIdentifier: id, owner: nil) as? NSTableCellView
                   ?? makeTextCellView(identifier: id)
        if tableView === userTableView {
            let user = displayedUsers[row]
            var label = user.nickname
            if user.id == selfUserId { label += " (you)" }
            if talkingUsers.contains(user.id) { label += " (talking)" }
            if user.selfMicMuted || user.serverMuted { label += " (muted)" }
            if user.selfDeafened || user.serverDeafened { label += " (deafened)" }
            cell.textField?.stringValue = label
            cell.setAccessibilityLabel(label)
        } else {
            cell.textField?.stringValue = activityLog[row]
        }
        return cell
    }

    private func makeTextCellView(identifier: NSUserInterfaceItemIdentifier) -> NSTableCellView {
        let cell = NSTableCellView()
        cell.identifier = identifier
        let tf = NSTextField(labelWithString: "")
        tf.translatesAutoresizingMaskIntoConstraints = false
        cell.addSubview(tf); cell.textField = tf
        NSLayoutConstraint.activate([
            tf.leadingAnchor.constraint(equalTo: cell.leadingAnchor, constant: 4),
            tf.trailingAnchor.constraint(equalTo: cell.trailingAnchor, constant: -4),
            tf.centerYAnchor.constraint(equalTo: cell.centerYAnchor),
        ])
        return cell
    }
}

// MARK: - NSMenuDelegate (context menus)

extension MainWindowController: NSMenuDelegate {
    func menuNeedsUpdate(_ menu: NSMenu) {
        menu.removeAllItems()
        if menu === channelOutlineView.menu {
            buildChannelContextMenu(menu)
        } else if menu === userTableView.menu {
            buildUserContextMenu(menu)
        }
    }

    private func buildChannelContextMenu(_ menu: NSMenu) {
        let row = channelOutlineView.clickedRow
        if row >= 0, let node = channelOutlineView.item(atRow: row) as? ChannelNode {
            menu.addItem(withTitle: "Join", action: #selector(channelContextJoin), keyEquivalent: "").target = self
            menu.addItem(.separator())
            if ownPermissions.isAdmin {
                let edit = menu.addItem(withTitle: "Edit channel…", action: #selector(channelContextEdit), keyEquivalent: "")
                edit.target = self; edit.representedObject = node
                let del = menu.addItem(withTitle: "Delete channel…", action: #selector(channelContextDelete), keyEquivalent: "")
                del.target = self; del.representedObject = node
                menu.addItem(.separator())
            }
        }
        if ownPermissions.canCreateTempChannel || ownPermissions.isAdmin {
            menu.addItem(withTitle: "Create channel…", action: #selector(channelContextCreate), keyEquivalent: "").target = self
        }
    }

    private func buildUserContextMenu(_ menu: NSMenu) {
        let row = userTableView.clickedRow
        guard row >= 0, row < displayedUsers.count else { return }
        let user = displayedUsers[row]
        let isSelf = user.id == selfUserId

        menu.addItem(withTitle: "Adjust volume and noise settings…",
                     action: #selector(userContextTune), keyEquivalent: "").target = self

        if !isSelf {
            menu.addItem(.separator())
            if ownPermissions.canMoveUsers || ownPermissions.isAdmin {
                menu.addItem(withTitle: "Move to channel…", action: #selector(userContextMove), keyEquivalent: "").target = self
            }
            if ownPermissions.canKick || ownPermissions.isAdmin {
                menu.addItem(withTitle: "Kick…", action: #selector(userContextKick), keyEquivalent: "").target = self
            }
            if ownPermissions.canBan || ownPermissions.isAdmin {
                menu.addItem(withTitle: "Ban…", action: #selector(userContextBan), keyEquivalent: "").target = self
            }
            if ownPermissions.isAdmin {
                menu.addItem(.separator())
                menu.addItem(withTitle: user.serverMuted ? "Server unmute" : "Server mute",
                             action: #selector(userContextServerMute), keyEquivalent: "").target = self
                menu.addItem(withTitle: user.serverDeafened ? "Server undeafen" : "Server deafen",
                             action: #selector(userContextServerDeafen), keyEquivalent: "").target = self
                menu.addItem(withTitle: "Set permissions…", action: #selector(userContextPermissions), keyEquivalent: "").target = self
            }
        }
    }

    @objc private func channelContextJoin() {
        guard let node = channelOutlineView.item(atRow: channelOutlineView.clickedRow) as? ChannelNode else { return }
        joinChannelRequest(node.channel.id)
    }

    @objc private func channelContextCreate() {
        let sheet = ChannelEditSheet(channels: channels, editing: nil)
        sheet.onComplete = { [weak self] info in
            guard let info else { return }
            self?.client.createChannel(info)
        }
        presentSheet(sheet)
    }

    @objc private func channelContextEdit(_ sender: NSMenuItem) {
        guard let node = sender.representedObject as? ChannelNode else { return }
        let ch = node.channel
        let info = ChannelEdit(id: ch.id, parentId: ch.parentId, name: ch.name,
                               topic: ch.topic, passwordProtected: ch.passwordProtected,
                               password: nil, maxUsers: ch.maxUsers,
                               sortOrder: 0, audio: AudioConfig())
        let sheet = ChannelEditSheet(channels: channels, editing: info)
        sheet.onComplete = { [weak self] edited in
            guard let edited else { return }
            self?.client.editChannel(edited)
        }
        presentSheet(sheet)
    }

    @objc private func channelContextDelete(_ sender: NSMenuItem) {
        guard let node = sender.representedObject as? ChannelNode else { return }
        let alert = NSAlert()
        alert.messageText = "Delete channel?"
        alert.informativeText = "Delete \"\(node.channel.name)\"? This cannot be undone."
        alert.addButton(withTitle: "Delete"); alert.addButton(withTitle: "Cancel")
        alert.alertStyle = .warning
        guard let window else { return }
        alert.beginSheetModal(for: window) { [weak self] response in
            if response == .alertFirstButtonReturn {
                self?.client.deleteChannel(node.channel.id)
            }
        }
    }

    @objc private func userContextTune() { openUserTuning(row: userTableView.clickedRow) }
    @objc private func userContextMove() {
        guard let u = selectedUserAt(userTableView.clickedRow) else { return }
        moveUser(u)
    }
    @objc private func userContextKick() {
        guard let u = selectedUserAt(userTableView.clickedRow) else { return }
        kickUser(u)
    }
    @objc private func userContextBan() {
        guard let u = selectedUserAt(userTableView.clickedRow) else { return }
        banUser(u)
    }
    @objc private func userContextServerMute() {
        guard let u = selectedUserAt(userTableView.clickedRow) else { return }
        toggleServerMute(u)
    }
    @objc private func userContextServerDeafen() {
        guard let u = selectedUserAt(userTableView.clickedRow) else { return }
        toggleServerDeafen(u)
    }
    @objc private func userContextPermissions() {
        guard let u = selectedUserAt(userTableView.clickedRow) else { return }
        setPermissions(u)
    }

    private func selectedUserAt(_ row: Int) -> User? {
        guard row >= 0, row < displayedUsers.count else { return nil }
        return displayedUsers[row]
    }
}

// MARK: - PTT key name helper

private func keyCodeName(_ keyCode: UInt16) -> String {
    let map: [UInt16: String] = [
        0x60: "F5", 0x61: "F6", 0x62: "F7", 0x63: "F3", 0x64: "F8", 0x65: "F9",
        0x67: "F11", 0x69: "F13", 0x6A: "F16", 0x6B: "F14", 0x6D: "F10", 0x6F: "F12",
        0x71: "F15", 0x72: "Help", 0x73: "Home", 0x74: "PgUp", 0x75: "Del",
        0x76: "F4", 0x77: "End", 0x78: "F2", 0x79: "PgDn", 0x7A: "F1",
    ]
    return map[keyCode] ?? "Key\(keyCode)"
}