//
//  AppDelegate.swift
//  google_apps
//
//  Created by Dev Mac 1 on 27/03/2026.
//

import Cocoa
import Combine
import SwiftUI

@main
class AppDelegate: NSObject, NSApplicationDelegate, NSWindowDelegate {
    private var statusItem: NSStatusItem?
    private weak var launcherWindowReference: NSWindow?
    private var launcherWindowResignObserver: NSObjectProtocol?
    private var refocusLauncherObserver: NSObjectProtocol?
    private var appearanceChangedObserver: NSObjectProtocol?
    private var effectiveAppearanceObservation: NSKeyValueObservation?
    private var startupPaywallWindow: NSWindow?
    private var hasPresentedStartupPaywall = false
    private var premiumUnlockObservation: NSKeyValueObservation?
    private var premiumStateMonitorTask: Task<Void, Never>?

    private var launcherWindow: NSWindow? {
        if let launcherWindowReference, launcherWindowReference.contentViewController is ViewController {
            return launcherWindowReference
        }
        let resolved =
            NSApp.windows.first(where: { $0.contentViewController is ViewController }) ??
            NSApp.orderedWindows.first(where: { $0.contentViewController is ViewController }) ??
            NSApp.windows.first ??
            NSApp.orderedWindows.first
        launcherWindowReference = resolved
        return resolved
    }

    func applicationDidFinishLaunching(_ aNotification: Notification) {
        applyBundledAppIcon()
        configureMainWindowIfNeeded(centerOnLaunch: true)
        observeRefocusLauncherRequests()
        setupStatusBarItem()
        StatusBarAppIconsController.shared.start()
        presentLauncherAndPaywallOnLaunch()
    }

    private func observeRefocusLauncherRequests() {
        if let refocusLauncherObserver {
            NotificationCenter.default.removeObserver(refocusLauncherObserver)
            self.refocusLauncherObserver = nil
        }

        refocusLauncherObserver = NotificationCenter.default.addObserver(
            forName: .refocusLauncherWindowRequested,
            object: nil,
            queue: .main
        ) { [weak self] _ in
            guard let self else { return }
            // Defer a tick so window-close/miniaturize animations complete cleanly.
            DispatchQueue.main.async {
                self.showMainWindow()
            }
        }
    }

    private func presentLauncherAndPaywallOnLaunch() {
        // Bring the launcher up-front on cold launch, then show the paywall on top
        // for non-premium users. The paywall is presented as an AppKit child window
        // (instead of a SwiftUI .sheet) to avoid the resign-key observer below
        // tearing the window stack down the moment the sheet takes key focus.
        showMainWindow()

        Task { @MainActor in
            await PremiumStore.shared.refreshEntitlements()
            guard !PremiumStore.shared.isPremiumUnlocked else { return }
            self.presentStartupPaywallIfNeeded()
        }
    }

    @MainActor
    private func presentStartupPaywallIfNeeded() {
        guard !hasPresentedStartupPaywall else { return }
        guard !PremiumStore.shared.isPremiumUnlocked else { return }
        guard let parent = launcherWindow else { return }
        presentPremiumPaywall(over: parent, storeAsStartupPaywall: true)

        hasPresentedStartupPaywall = true

        observePremiumUnlockToAutoDismissPaywall()
    }

    /// Presents the premium paywall as a non-draggable, non-resizable child window that exactly covers `parent`.
    @MainActor
    func presentPremiumPaywall(over parent: NSWindow? = nil, storeAsStartupPaywall: Bool = false) {
        if storeAsStartupPaywall {
            // Startup paywall is only for non-premium users.
            guard !PremiumStore.shared.isPremiumUnlocked else { return }
        } else {
            // Allow showing the paywall for the yearly->lifetime upgrade flow.
            if PremiumStore.shared.isPremiumUnlocked && PremiumStore.shared.activePremiumProductID != .yearly {
                return
            }
        }
        guard let parentWindow = parent ?? launcherWindow else { return }

        if let existing = startupPaywallWindow, existing.isVisible {
            // Ensure it stays pinned to the parent’s current frame.
            existing.setFrame(PremiumPaywallWindowSizing.paywallFrame(forParentWindow: parentWindow), display: false)
            existing.makeKeyAndOrderFront(nil)
            NSApp.activate(ignoringOtherApps: true)
            return
        }

        let paywallFrame = PremiumPaywallWindowSizing.paywallFrame(forParentWindow: parentWindow)
        let paywallWindow = NSWindow(
            contentRect: paywallFrame,
            styleMask: [.borderless],
            backing: .buffered,
            defer: false
        )
        paywallWindow.isReleasedWhenClosed = false
        paywallWindow.delegate = self
        paywallWindow.isMovable = false
        paywallWindow.isMovableByWindowBackground = false
        paywallWindow.hasShadow = true
        paywallWindow.isOpaque = false
        paywallWindow.backgroundColor = .clear
        paywallWindow.level = .floating
        paywallWindow.minSize = paywallFrame.size
        paywallWindow.maxSize = paywallFrame.size

        let hosting = NSHostingController(
            rootView: PremiumFeaturesView(onDismissFromAppKitHost: { [weak self] in
                self?.closeStartupPaywall()
            })
            .environmentObject(PremiumStore.shared)
        )
        hosting.view.frame = NSRect(origin: .zero, size: paywallFrame.size)
        hosting.view.autoresizingMask = [.width, .height]
        paywallWindow.contentViewController = hosting

        if let layer = paywallWindow.contentView?.layer {
            paywallWindow.contentView?.wantsLayer = true
            layer.cornerRadius = 16
            if #available(macOS 11.0, *) {
                layer.cornerCurve = .continuous
            }
            layer.masksToBounds = true
        }

        paywallWindow.setFrame(paywallFrame, display: false)

        if storeAsStartupPaywall {
            startupPaywallWindow = paywallWindow
        } else {
            startupPaywallWindow = paywallWindow
        }
        parentWindow.addChildWindow(paywallWindow, ordered: .above)
        paywallWindow.makeKeyAndOrderFront(nil)
        NSApp.activate(ignoringOtherApps: true)
    }

    @MainActor
    private func closeStartupPaywall() {
        guard let window = startupPaywallWindow else { return }
        window.parent?.removeChildWindow(window)
        window.orderOut(nil)
        startupPaywallWindow = nil
        premiumStateMonitorTask?.cancel()
        premiumStateMonitorTask = nil
    }

    private func observePremiumUnlockToAutoDismissPaywall() {
        premiumStateMonitorTask?.cancel()
        premiumStateMonitorTask = Task { @MainActor [weak self] in
            for await unlocked in PremiumStore.shared.$isPremiumUnlocked.values {
                guard let self else { return }
                if unlocked {
                    self.closeStartupPaywall()
                    return
                }
            }
        }
    }

    private func applyBundledAppIcon() {
        if let assetAppIcon = NSImage(named: "AppIcon") {
            NSApp.applicationIconImage = assetAppIcon
            return
        }
        if let icnsURL = Bundle.main.url(forResource: "AppIcon", withExtension: "icns"),
           let icnsIcon = NSImage(contentsOf: icnsURL) {
            NSApp.applicationIconImage = icnsIcon
        }
    }

    private func setupStatusBarItem() {
        let item = NSStatusBar.system.statusItem(withLength: NSStatusItem.squareLength)
        statusItem = item

        guard let button = item.button else { return }
        updateStatusBarIconForCurrentAppearance()
        observeAppearanceChanges()
        button.imageScaling = .scaleProportionallyDown
        button.imagePosition = .imageOnly
        button.action = #selector(statusBarButtonClicked(_:))
        button.target = self
        button.sendAction(on: [.leftMouseUp, .rightMouseUp])
    }

    private func updateStatusBarIconForCurrentAppearance() {
        guard let button = statusItem?.button else { return }

        // Use a template image so macOS tints it appropriately (white on dark menu bar,
        // black on light menu bar), matching other status bar icons.
        if let menuBarIcon = NSImage(named: "menu_bar_dark_icon") ?? NSImage(named: "menu_bar_icon") {
            menuBarIcon.isTemplate = true
            button.image = menuBarIcon
            button.image?.isTemplate = true
            return
        }

        button.image = NSImage(systemSymbolName: "square.grid.2x2.fill", accessibilityDescription: "My Apps")
        button.image?.isTemplate = true
    }

    private func observeAppearanceChanges() {
        if let appearanceChangedObserver {
            DistributedNotificationCenter.default().removeObserver(appearanceChangedObserver)
            self.appearanceChangedObserver = nil
        }
        effectiveAppearanceObservation?.invalidate()
        effectiveAppearanceObservation = nil

        appearanceChangedObserver = DistributedNotificationCenter.default().addObserver(
            forName: NSNotification.Name("AppleInterfaceThemeChangedNotification"),
            object: nil,
            queue: .main
        ) { [weak self] _ in
            self?.updateStatusBarIconForCurrentAppearance()
        }

        effectiveAppearanceObservation = NSApp.observe(\.effectiveAppearance, options: [.new]) { [weak self] _, _ in
            self?.updateStatusBarIconForCurrentAppearance()
        }
    }

    @objc
    private func statusBarButtonClicked(_ sender: Any?) {
        guard let event = NSApp.currentEvent else {
            toggleMainWindowFromStatusBar()
            return
        }
        if event.type == .rightMouseUp {
            presentStatusBarShortcutsMenu()
        } else {
            toggleMainWindowFromStatusBar()
        }
    }

    private func presentStatusBarShortcutsMenu() {
        guard let button = statusItem?.button else { return }

        let menu = NSMenu()
        let openItem = NSMenuItem(
            title: "Open My Apps",
            action: #selector(openMainWindowFromStatusBar),
            keyEquivalent: ""
        )
        openItem.target = self
        menu.addItem(openItem)

        menu.addItem(.separator())
        let quitItem = NSMenuItem(
            title: "Quit",
            action: #selector(terminateApp),
            keyEquivalent: "q"
        )
        quitItem.target = self
        menu.addItem(quitItem)

        let location = NSPoint(x: 0, y: button.bounds.height)
        menu.popUp(positioning: nil, at: location, in: button)
    }

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

    @objc
    private func openMainWindowFromStatusBar() {
        showMainWindow()
    }

    @objc
    private func toggleMainWindowFromStatusBar() {
        configureMainWindowIfNeeded()
        guard let window = launcherWindow else { return }

        if window.isVisible && window.isKeyWindow {
            hideMainWindow()
            return
        }

        showMainWindow()
    }

    private func hideMainWindow() {
        guard let window = launcherWindow else { return }
        // Don't auto-hide while a modal-style child window (e.g. the paywall) is
        // attached; otherwise the launcher and its child get torn down together
        // the moment the child takes key focus.
        if windowHasAttachedChild(window) {
            return
        }
        if window.isMiniaturized {
            window.deminiaturize(nil)
        }
        window.orderOut(nil)
    }

    private func windowHasAttachedChild(_ window: NSWindow) -> Bool {
        if window.attachedSheet != nil { return true }
        if let children = window.childWindows, !children.isEmpty { return true }
        return false
    }

    private func showMainWindow() {
        configureMainWindowIfNeeded(centerOnLaunch: false)
        NSApp.setActivationPolicy(.regular)
        NSRunningApplication.current.activate(options: [.activateAllWindows, .activateIgnoringOtherApps])
        NSApp.activate(ignoringOtherApps: true)
        guard let window = launcherWindow else { return }
        if window.isMiniaturized {
            window.deminiaturize(nil)
        }
        window.orderFrontRegardless()
        window.makeKeyAndOrderFront(nil)
        // Re-assert key/front on next runloop; status-bar activations can race app focus handoff.
        DispatchQueue.main.async {
            window.orderFrontRegardless()
            window.makeKeyAndOrderFront(nil)
        }
    }

    private func configureMainWindowIfNeeded(centerOnLaunch: Bool = false) {
        guard let window = launcherWindow else { return }
        observeLauncherWindowResign(window)
        window.title = "My Apps"
        window.styleMask.insert(.titled)
        window.isOpaque = false
        window.backgroundColor = .clear
        applyRoundedCorners(to: window)
        window.titlebarAppearsTransparent = true
        window.titleVisibility = .hidden
        window.styleMask.insert(.fullSizeContentView)
        window.isMovableByWindowBackground = true
        window.minSize = NSSize(width: 760, height: 520)
        window.standardWindowButton(.closeButton)?.isHidden = true
        window.standardWindowButton(.miniaturizeButton)?.isHidden = true
        window.standardWindowButton(.zoomButton)?.isHidden = true

        let targetContentSize = NSSize(width: 980, height: 700)
        if window.contentRect(forFrameRect: window.frame).size.width < targetContentSize.width ||
            window.contentRect(forFrameRect: window.frame).size.height < targetContentSize.height {
            let currentCenter = NSPoint(x: window.frame.midX, y: window.frame.midY)
            var targetFrame = window.frameRect(forContentRect: NSRect(origin: .zero, size: targetContentSize))
            targetFrame.origin = NSPoint(
                x: currentCenter.x - (targetFrame.width / 2),
                y: currentCenter.y - (targetFrame.height / 2)
            )
            window.setFrame(targetFrame, display: true)
        }

        if centerOnLaunch {
            centerWindowOnCurrentOrPrimaryScreen(window)
        }
    }

    private func centerWindowOnCurrentOrPrimaryScreen(_ window: NSWindow) {
        // Prefer the screen the window is currently on; fall back to the primary screen.
        let screen = window.screen ?? NSScreen.main
        guard let visibleFrame = screen?.visibleFrame else { return }

        let frameSize = window.frame.size
        let unclampedX = visibleFrame.midX - (frameSize.width / 2)
        let unclampedY = visibleFrame.midY - (frameSize.height / 2)

        // Clamp so we don't move the window completely off-screen on small displays.
        let clampedX = min(max(unclampedX, visibleFrame.minX), visibleFrame.maxX - frameSize.width)
        let clampedY = min(max(unclampedY, visibleFrame.minY), visibleFrame.maxY - frameSize.height)

        window.setFrame(NSRect(origin: NSPoint(x: clampedX, y: clampedY), size: frameSize), display: false)
    }

    private func observeLauncherWindowResign(_ window: NSWindow) {
        if let observer = launcherWindowResignObserver {
            NotificationCenter.default.removeObserver(observer)
            launcherWindowResignObserver = nil
        }

        launcherWindowResignObserver = NotificationCenter.default.addObserver(
            forName: NSWindow.didResignKeyNotification,
            object: window,
            queue: .main
        ) { [weak self] _ in
            guard let self else { return }
            // Skip auto-hide while a child window (e.g. paywall) is attached;
            // the parent loses key when the child becomes key, but the user is
            // still interacting with our app's window stack.
            if let win = self.launcherWindow, self.windowHasAttachedChild(win) {
                return
            }
            self.hideMainWindow()
        }
    }

    private func applyRoundedCorners(to window: NSWindow) {
        let cornerRadius: CGFloat = 16
        window.hasShadow = true
        window.contentView?.wantsLayer = true
        window.contentView?.layer?.cornerRadius = cornerRadius
        window.contentView?.layer?.masksToBounds = true
    }

    func applicationWillTerminate(_ aNotification: Notification) {
        if let observer = launcherWindowResignObserver {
            NotificationCenter.default.removeObserver(observer)
            launcherWindowResignObserver = nil
        }
        if let observer = refocusLauncherObserver {
            NotificationCenter.default.removeObserver(observer)
            refocusLauncherObserver = nil
        }
        if let observer = appearanceChangedObserver {
            DistributedNotificationCenter.default().removeObserver(observer)
            appearanceChangedObserver = nil
        }
        effectiveAppearanceObservation?.invalidate()
        effectiveAppearanceObservation = nil
        premiumStateMonitorTask?.cancel()
        premiumStateMonitorTask = nil
        premiumUnlockObservation?.invalidate()
        premiumUnlockObservation = nil
    }

    func applicationDidResignActive(_ notification: Notification) {
        // Same guard as the resign-key observer: don't hide while the user is
        // looking at the paywall (or any other attached child window).
        if let win = launcherWindow, windowHasAttachedChild(win) {
            return
        }
        hideMainWindow()
    }

    func applicationShouldHandleReopen(_ sender: NSApplication, hasVisibleWindows flag: Bool) -> Bool {
        showMainWindow()
        return true
    }

    func windowWillClose(_ notification: Notification) {
        guard let closing = notification.object as? NSWindow else { return }
        if closing === startupPaywallWindow {
            closing.parent?.removeChildWindow(closing)
            startupPaywallWindow = nil
            premiumStateMonitorTask?.cancel()
            premiumStateMonitorTask = nil
        }
    }

    func applicationSupportsSecureRestorableState(_ app: NSApplication) -> Bool {
        return true
    }


}