import AppKit
import SwiftUI

nonisolated func mctLog(_ format: String, _ args: CVarArg...) {
    let msg = String(format: format, arguments: args)
    let line = "\(msg)\n"
    // Write to both stderr and file
    fputs(line, stderr)
    guard let data = line.data(using: .utf8) else { return }
    let path = "/tmp/mct_debug.log"
    let fd = open(path, O_WRONLY | O_CREAT | O_APPEND, 0o644)
    if fd >= 0 {
        _ = data.withUnsafeBytes { write(fd, $0.baseAddress!, $0.count) }
        close(fd)
    }
}

@MainActor
final class AppDelegate: NSObject, NSApplicationDelegate {
    private let gestureProgressModel = GestureProgress()
    private lazy var overlayController = OverlayWindowController(gestureProgress: gestureProgressModel)
    private var hotKeyManager: HotKeyManager?
    private var gestureMonitor: GestureMonitor?
    private var settingsWindow: NSWindow?

    func applicationDidFinishLaunching(_ notification: Notification) {
        mctLog("[MCT] app launched")
        checkPermissions()
        syncLoginItem()
        setupHotKey()
        Task { await ThumbnailCapture.warmUp() }
        setupGestureMonitor()
    }

    func toggleOverlay() {
        overlayController.toggle()
    }

    func showSettings() {
        if let window = settingsWindow {
            window.makeKeyAndOrderFront(nil)
            NSApp.activate(ignoringOtherApps: true)
            return
        }

        let window = NSWindow(
            contentRect: NSRect(x: 0, y: 0, width: 450, height: 320),
            styleMask: [.titled, .closable],
            backing: .buffered,
            defer: false
        )
        window.title = "MCT Settings"
        window.contentView = NSHostingView(rootView: SettingsView())
        window.center()
        window.isReleasedWhenClosed = false
        window.makeKeyAndOrderFront(nil)
        NSApp.activate(ignoringOtherApps: true)
        settingsWindow = window
    }

    // MARK: - Private

    private func syncLoginItem() {
        // Only register from /Applications — SMAppService records the bundle
        // path it was registered from, so dev builds in ~/misc would otherwise
        // pin the login item to the wrong location.
        let bundlePath = Bundle.main.bundlePath
        guard bundlePath.hasPrefix("/Applications/") else {
            mctLog("[MCT] not registering login item — not running from /Applications (%@)", bundlePath)
            return
        }
        if Preferences.shared.launchAtLogin {
            LoginItemManager.setEnabled(true)
        }
    }

    private func checkPermissions() {
        if !AccessibilityBridge.hasPermission {
            let hasPromptedBefore = UserDefaults.standard.bool(forKey: "hasPromptedAccessibility")
            if !hasPromptedBefore {
                AccessibilityBridge.requestPermissionIfNeeded()
                UserDefaults.standard.set(true, forKey: "hasPromptedAccessibility")
            }
        }
    }

    private func setupHotKey() {
        let prefs = Preferences.shared
        hotKeyManager = HotKeyManager { [weak self] in
            self?.toggleOverlay()
        }
        hotKeyManager?.register(
            keyCode: prefs.hotKeyKeyCode,
            modifiers: prefs.hotKeyModifiers
        )
    }

    private func setupGestureMonitor() {
        gestureMonitor = GestureMonitor { [weak self] event in
            guard let self = self else { return }
            switch event {
            case .began:
                self.overlayController.gestureDidBegin()
            case .changed(let progress, let velocity):
                self.overlayController.gestureDidChange(rawDY: progress, rawVelocity: velocity)
            case .ended(let progress, let velocity):
                self.overlayController.gestureDidEnd(rawDY: progress, rawVelocity: velocity)
            case .cancelled:
                self.overlayController.gestureDidCancel()
            }
        }
        gestureMonitor?.start()
    }
}