import AppKit
import MediaPlayer

@_cdecl("terebi_app_main")
@MainActor
public func checkAppStartup() {
    if let configuration = Bundle.main.url(forResource: "cli-check", withExtension: "json") {
        CLIInstanceCheck.run(configuration)
        return
    }
    AppStartupCheck.run()
}

@MainActor
private enum AppStartupCheck {
    static var model: PlayerModel?
    static var timer: Timer?
    static let deadline = ContinuousClock.now.advanced(by: .seconds(15))
    static let historyDomain = Bundle.main.bundleIdentifier! + ".history"

    static func run() {
        _ = NSApplication.shared
        NSApp.setActivationPolicy(.regular)
        let defaults = UserDefaults(suiteName: historyDomain)!
        model = PlayerModel(defaults: defaults)
        model!.setVolume(0)
        model!.open(URL(fileURLWithPath: CommandLine.arguments[2]).appendingPathComponent("av.mp4"))
        timer = Timer.scheduledTimer(withTimeInterval: 0.05, repeats: true) { _ in
            MainActor.assumeIsolated { finishWhenReady() }
        }
        NSApp.run()
    }

    static func finishWhenReady() {
        guard let model else { return }
        let ready = model.canTogglePlayback && model.state.status == PLAYER_PLAYING
        guard ready || model.state.status == PLAYER_ERROR || ContinuousClock.now >= deadline else { return }
        timer?.invalidate()
        let pid = ProcessInfo.processInfo.processIdentifier
        let application = NSRunningApplication.current
        let recognized = application.processIdentifier == pid &&
            NSWorkspace.shared.runningApplications.contains { $0.processIdentifier == pid && $0.bundleURL == Bundle.main.bundleURL }
        let result: [String: Any] = [
            "passed": ready && recognized && MPNowPlayingInfoCenter.default().playbackState == .playing,
            "pid": pid,
            "registeredPID": application.processIdentifier,
            "bundleIdentifier": application.bundleIdentifier ?? "nil",
            "playing": ready,
        ]
        do {
            let pipe = try FileHandle(forWritingTo: URL(fileURLWithPath: CommandLine.arguments[1]))
            try pipe.write(contentsOf: JSONSerialization.data(withJSONObject: result))
            try pipe.write(contentsOf: Data([10]))
            try pipe.close()
        } catch {
            FileHandle.standardError.write(Data("Startup check could not report: \(error)\n".utf8))
        }
        model.shutdown()
        UserDefaults(suiteName: historyDomain)!.removePersistentDomain(forName: historyDomain)
        self.model = nil
        NSApp.terminate(nil)
    }
}

@MainActor
private enum CLIInstanceCheck {
    static var timer: Timer?

    static func run(_ configuration: URL) {
        let settings = try! JSONSerialization.jsonObject(with: Data(contentsOf: configuration)) as! [String: String]
        let directory = URL(fileURLWithPath: settings["directory"]!, isDirectory: true)
        setenv("PATH", settings["path"]!, 1)
        _ = NSApplication.shared
        PlayerModel.shared.setVolume(0)
        // Exercise the real SwiftUI scene and delegate without displaying test windows.
        _ = NotificationCenter.default.addObserver(forName: NSWindow.didUpdateNotification, object: nil, queue: .main) { _ in
            MainActor.assumeIsolated { for window in NSApp.windows { window.alphaValue = 0 } }
        }
        timer = Timer.scheduledTimer(withTimeInterval: 0.05, repeats: true) { _ in
            MainActor.assumeIsolated {
                let model = PlayerModel.shared
                let pid = ProcessInfo.processInfo.processIdentifier
                let windows = NSApp.windows.filter { !($0 is NSPanel) && $0.contentView != nil }
                for window in windows { window.alphaValue = 0 }
                let applications = NSWorkspace.shared.runningApplications.filter {
                    !$0.isTerminated && $0.bundleURL == Bundle.main.bundleURL
                }
                let snapshot: [String: Any] = [
                    "pid": pid,
                    "pids": applications.map(\.processIdentifier).sorted(),
                    "media": model.fileName ?? "",
                    "status": model.state.status.rawValue,
                    "position": model.state.position,
                    "windows": windows.count,
                    "hasAudio": model.state.has_audio,
                    "hasVideo": model.state.has_video,
                    "error": model.errorText ?? "",
                ]
                do {
                    let data = try JSONSerialization.data(withJSONObject: snapshot)
                    try data.write(to: directory.appendingPathComponent("state-\(pid).json"), options: .atomic)
                } catch { fatalError("Could not publish CLI instance check: \(error)") }
            }
        }
        TerebiApp.main()
    }
}