import Combine
import FileChangeChecker
import GitHubCopilotService
import LaunchAgentManager
import Logger
import Preferences
import Service
import ServiceManagement
import Status
import SwiftUI
import UpdateChecker
import UserDefaultsObserver
import UserNotifications
import XcodeInspector
import XPCShared

let bundleIdentifierBase = Bundle.main
    .object(forInfoDictionaryKey: "BUNDLE_IDENTIFIER_BASE") as! String
let serviceIdentifier = bundleIdentifierBase + ".ExtensionService"

class ExtensionUpdateCheckerDelegate: UpdateCheckerDelegate {
    func prepareForRelaunch(finish: @escaping () -> Void) {
        Task {
            await Service.shared.prepareForExit()
            finish()
        }
    }
}

@main
class AppDelegate: NSObject, NSApplicationDelegate, NSWindowDelegate {
    let service = Service.shared
    var statusBarItem: NSStatusItem!
    var statusMenuItem: NSMenuItem!
    var authMenuItem: NSMenuItem!
    var xpcController: XPCController?
    let updateChecker =
        UpdateChecker(
            hostBundle: Bundle(url: locateHostBundleURL(url: Bundle.main.bundleURL)),
            checkerDelegate: ExtensionUpdateCheckerDelegate()
        )
    var xpcExtensionService: XPCExtensionService?
    private var cancellables = Set<AnyCancellable>()
    private var progressView: NSProgressIndicator?

    func applicationDidFinishLaunching(_: Notification) {
        if ProcessInfo.processInfo.environment["IS_UNIT_TEST"] == "YES" { return }
        _ = XcodeInspector.shared
        service.start()
        AXIsProcessTrustedWithOptions([
            kAXTrustedCheckOptionPrompt.takeRetainedValue() as NSString: true,
        ] as CFDictionary)
        setupQuitOnUpdate()
        setupQuitOnUserTerminated()
        xpcController = .init()
        Logger.service.info("XPC Service started.")
        NSApp.setActivationPolicy(.accessory)
        buildStatusBarMenu()
        watchServiceStatus()
        watchAXStatus()
        watchAuthStatus()
        setInitialStatusBarStatus()
    }

    @objc func quit() {
        Task { @MainActor in
            await service.prepareForExit()
            await xpcController?.quit()
            NSApp.terminate(self)
        }
    }

    @objc func openCopilotForXcode() {
        let task = Process()
        let appPath = locateHostBundleURL(url: Bundle.main.bundleURL)
        task.launchPath = "/usr/bin/open"
        task.arguments = [appPath.absoluteString]
        task.launch()
        task.waitUntilExit()
    }

    @objc func openGlobalChat() {
        Task { @MainActor in
            let serviceGUI = Service.shared.guiController
            serviceGUI.openGlobalChat()
        }
    }

    func setupQuitOnUpdate() {
        Task {
            guard let url = Bundle.main.executableURL else { return }
            let checker = await FileChangeChecker(fileURL: url)

            // If Xcode or Copilot for Xcode is made active, check if the executable of this program
            // is changed. If changed, quit this program.

            let sequence = NSWorkspace.shared.notificationCenter
                .notifications(named: NSWorkspace.didActivateApplicationNotification)
            for await notification in sequence {
                try Task.checkCancellation()
                guard let app = notification
                    .userInfo?[NSWorkspace.applicationUserInfoKey] as? NSRunningApplication,
                    app.isUserOfService
                else { continue }
                guard await checker.checkIfChanged() else {
                    Logger.service.info("Extension Service is not updated, no need to quit.")
                    continue
                }
                Logger.service.info("Extension Service will quit.")
                #if DEBUG
                #else
                quit()
                #endif
            }
        }
    }

    func setupQuitOnUserTerminated() {
        Task {
            // Whenever Xcode or the host application quits, check if any of the two is running.
            // If none, quit the XPC service.

            let sequence = NSWorkspace.shared.notificationCenter
                .notifications(named: NSWorkspace.didTerminateApplicationNotification)
            for await notification in sequence {
                try Task.checkCancellation()
                guard UserDefaults.shared.value(for: \.quitXPCServiceOnXcodeAndAppQuit)
                else { continue }
                guard let app = notification
                    .userInfo?[NSWorkspace.applicationUserInfoKey] as? NSRunningApplication,
                    app.isUserOfService
                else { continue }
                if NSWorkspace.shared.runningApplications.contains(where: \.isUserOfService) {
                    continue
                }
                quit()
            }
        }
    }

    func requestAccessoryAPIPermission() {
        AXIsProcessTrustedWithOptions([
            kAXTrustedCheckOptionPrompt.takeRetainedValue() as NSString: true,
        ] as NSDictionary)
    }

    @objc func checkForUpdate() {
        guard let updateChecker = updateChecker else {
            Logger.service.error("Unable to check for updates: updateChecker is nil.")
            return
        }
        updateChecker.checkForUpdates()
    }

    func getXPCExtensionService() -> XPCExtensionService {
        if let service = xpcExtensionService { return service }
        let service = XPCExtensionService(logger: .service)
        xpcExtensionService = service
        return service
    }

    func watchServiceStatus() {
        let notifications = NotificationCenter.default.notifications(named: .serviceStatusDidChange)
        Task { [weak self] in
            for await _ in notifications {
                guard let self else { return }
                self.updateStatusBarItem()
            }
        }
    }

    func watchAXStatus() {
        let osNotifications = DistributedNotificationCenter.default().notifications(named: NSNotification.Name("com.apple.accessibility.api"))
        Task { [weak self] in
            for await _ in osNotifications {
                guard let self else { return }
                self.updateStatusBarItem()
            }
        }
    }

    func watchAuthStatus() {
        let notifications = DistributedNotificationCenter.default().notifications(named: .authStatusDidChange)
        Task { [weak self] in
            for await _ in notifications {
                guard let self else { return }
                await self.forceAuthStatusCheck()
            }
        }
    }

    func setInitialStatusBarStatus() {
        Task {
            let authStatus = await Status.shared.getAuthStatus()
            if authStatus == .unknown {
                // temporarily kick off a language server instance to prime the initial auth status
                await forceAuthStatusCheck()
            }
            updateStatusBarItem()
        }
    }

    func forceAuthStatusCheck() async {
        do {
            let service = try GitHubCopilotService()
            _ = try await service.checkStatus()
            try await service.shutdown()
            try await service.exit()
        } catch {
            Logger.service.error("Failed to read auth status: \(error)")
        }
    }

    func updateStatusBarItem() {
        Task { @MainActor in
            let status = await Status.shared.getStatus()
            let image = status.icon.nsImage
            self.statusBarItem.button?.image = image
            self.authMenuItem.title = status.authMessage
            if let message = status.message {
                // TODO switch to attributedTitle to enable line breaks and color.
                self.statusMenuItem.title = message
                self.statusMenuItem.isHidden = false
                self.statusMenuItem.isEnabled = status.url != nil
            } else {
                self.statusMenuItem.isHidden = true
            }
            self.markAsProcessing(status.inProgress)
        }
    }

    func markAsProcessing(_ isProcessing: Bool) {
        if !isProcessing {
            // No longer in progress
            progressView?.removeFromSuperview()
            progressView = nil
            return
        }
        if progressView != nil {
            // Already in progress
            return
        }
        let progress = NSProgressIndicator()
        progress.style = .spinning
        progress.sizeToFit()
        progress.frame = statusBarItem.button?.bounds ?? .zero
        progress.isIndeterminate = true
        progress.startAnimation(nil)
        statusBarItem.button?.addSubview(progress)
        statusBarItem.button?.image = nil
        progressView = progress
    }
}

extension NSRunningApplication {
    var isUserOfService: Bool {
        [
            "com.apple.dt.Xcode",
            bundleIdentifierBase,
        ].contains(bundleIdentifier)
    }
}

func locateHostBundleURL(url: URL) -> URL {
    var nextURL = url
    while nextURL.path != "/" {
        nextURL = nextURL.deletingLastPathComponent()
        if nextURL.lastPathComponent.hasSuffix(".app") {
            return nextURL
        }
    }
    let devAppURL = url
        .deletingLastPathComponent()
        .appendingPathComponent("GitHub Copilot for Xcode Dev.app")
    return devAppURL
}