import Flutter
import UIKit
import AdSupport
import AppTrackingTransparency
import CFNetwork
import CoreTelephony
import Darwin

public class AnalyticsSdkPlugin: NSObject, FlutterPlugin, FlutterStreamHandler {
  private var proximityEventSink: FlutterEventSink?
  private var proximityMonitoringWasEnabled = false

  public static func register(with registrar: FlutterPluginRegistrar) {
    let channel = FlutterMethodChannel(name: "analytics_sdk", binaryMessenger: registrar.messenger())
    let instance = AnalyticsSdkPlugin()
    registrar.addMethodCallDelegate(instance, channel: channel)
    let proximityChannel = FlutterEventChannel(
      name: "analytics_sdk/proximity",
      binaryMessenger: registrar.messenger()
    )
    proximityChannel.setStreamHandler(instance)
  }

  public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
    switch call.method {
    case "getPlatformVersion":
      result("iOS " + UIDevice.current.systemVersion)
    case "getDeviceId":
      result(UIDevice.current.identifierForVendor?.uuidString ?? "")
    case "getSdkInitPlatformFields":
      result(sdkInitPlatformFields())
    default:
      result(FlutterMethodNotImplemented)
    }
  }

  public func onListen(
    withArguments arguments: Any?,
    eventSink events: @escaping FlutterEventSink
  ) -> FlutterError? {
    _ = onCancel(withArguments: nil)
    proximityEventSink = events
    proximityMonitoringWasEnabled = UIDevice.current.isProximityMonitoringEnabled
    UIDevice.current.isProximityMonitoringEnabled = true
    guard UIDevice.current.isProximityMonitoringEnabled else {
      proximityEventSink = nil
      return FlutterError(
        code: "proximity_unavailable",
        message: "Proximity monitoring unavailable",
        details: nil
      )
    }
    NotificationCenter.default.addObserver(
      self,
      selector: #selector(proximityStateDidChange),
      name: UIDevice.proximityStateDidChangeNotification,
      object: UIDevice.current
    )
    events(UIDevice.current.proximityState ? 1 : 0)
    return nil
  }

  public func onCancel(withArguments arguments: Any?) -> FlutterError? {
    NotificationCenter.default.removeObserver(
      self,
      name: UIDevice.proximityStateDidChangeNotification,
      object: UIDevice.current
    )
    UIDevice.current.isProximityMonitoringEnabled = proximityMonitoringWasEnabled
    proximityEventSink = nil
    return nil
  }

  @objc private func proximityStateDidChange() {
    proximityEventSink?(UIDevice.current.proximityState ? 1 : 0)
  }

  private func sdkInitPlatformFields() -> [String: Any] {
    var fields: [String: Any] = [
      "language": normalizedLocaleIdentifier(),
      "timezone": TimeZone.current.identifier,
      "bundle_id": Bundle.main.bundleIdentifier ?? "",
      "ios_device_model_raw": rawDeviceModel(),
      "idfv": UIDevice.current.identifierForVendor?.uuidString ?? "",
      "is_jailbroken": isJailbroken() ? 1 : 0,
      "cpu_cores": ProcessInfo.processInfo.activeProcessorCount,
      "device_memory_gb": bytesToGb(Int64(ProcessInfo.processInfo.physicalMemory)),
      "touch_support": 1
    ]

    fields.merge(screenFields()) { _, new in new }
    fields.merge(storageFields()) { _, new in new }
    fields.merge(batteryFields()) { _, new in new }
    fields.merge(telephonyFields()) { _, new in new }
    fields.merge(advertisingFields()) { _, new in new }
    fields.merge(networkStateFields()) { _, new in new }

    return fields
  }

  private func normalizedLocaleIdentifier() -> String {
    return Locale.current.identifier.replacingOccurrences(of: "_", with: "-")
  }

  private func rawDeviceModel() -> String {
    var systemInfo = utsname()
    uname(&systemInfo)
    let mirror = Mirror(reflecting: systemInfo.machine)
    let identifier = mirror.children.reduce(into: "") { value, element in
      guard let byte = element.value as? Int8, byte != 0 else { return }
      value.append(String(UnicodeScalar(UInt8(byte))))
    }
    return identifier
  }

  private func screenFields() -> [String: Any] {
    let screen = UIScreen.main
    let nativeBounds = screen.nativeBounds
    let scale = screen.scale
    return [
      "screen_width": Int(nativeBounds.width.rounded()),
      "screen_height": Int(nativeBounds.height.rounded()),
      "screen_dpi": Int((scale * 160).rounded()),
      "device_pixel_ratio": scale,
      "orientation": interfaceOrientation()
    ]
  }

  private func interfaceOrientation() -> String {
    if #available(iOS 13.0, *) {
      let orientation = UIApplication.shared.connectedScenes
        .compactMap { $0 as? UIWindowScene }
        .first?
        .interfaceOrientation
      if orientation?.isLandscape == true {
        return "landscape"
      }
      if orientation?.isPortrait == true {
        return "portrait"
      }
    } else {
      let orientation = UIApplication.shared.statusBarOrientation
      if orientation.isLandscape {
        return "landscape"
      }
      if orientation.isPortrait {
        return "portrait"
      }
    }
    return screenFallbackOrientation()
  }

  private func screenFallbackOrientation() -> String {
    let bounds = UIScreen.main.nativeBounds
    return bounds.width >= bounds.height ? "landscape" : "portrait"
  }

  private func storageFields() -> [String: Any] {
    do {
      let attributes = try FileManager.default.attributesOfFileSystem(forPath: NSHomeDirectory())
      let total = (attributes[.systemSize] as? NSNumber)?.int64Value ?? -1
      let free = (attributes[.systemFreeSize] as? NSNumber)?.int64Value ?? -1
      return [
        "storage": bytesToGb(total),
        "available_storage": bytesToGb(free)
      ]
    } catch {
      return ["storage": -1, "available_storage": -1]
    }
  }

  private func batteryFields() -> [String: Any] {
    UIDevice.current.isBatteryMonitoringEnabled = true
    let level = UIDevice.current.batteryLevel
    let batteryLevel = level >= 0 ? Int((level * 100).rounded()) : -1
    let charging: Int
    switch UIDevice.current.batteryState {
    case .charging, .full:
      charging = 1
    case .unplugged:
      charging = 0
    default:
      charging = -1
    }
    return ["battery_level": batteryLevel, "is_charging": charging]
  }

  private func telephonyFields() -> [String: Any] {
    var fields: [String: Any] = [
      "carrier": "",
      "mcc": "unknown",
      "mnc": "unknown",
      "has_sim": -1
    ]

    let info = CTTelephonyNetworkInfo()
    var carrier: CTCarrier?
    if #available(iOS 12.0, *) {
      carrier = info.serviceSubscriberCellularProviders?.values.first
    } else {
      carrier = info.subscriberCellularProvider
    }

    guard let carrier = carrier else {
      fields["has_sim"] = 0
      return fields
    }

    fields["carrier"] = carrier.carrierName ?? ""
    fields["mcc"] = carrier.mobileCountryCode ?? "unknown"
    fields["mnc"] = carrier.mobileNetworkCode ?? "unknown"
    fields["has_sim"] = 1
    return fields
  }

  private func advertisingFields() -> [String: Any] {
    if #available(iOS 14, *) {
      switch ATTrackingManager.trackingAuthorizationStatus {
      case .authorized:
        return [
          "idfa": ASIdentifierManager.shared().advertisingIdentifier.uuidString,
          "att_status": "authorized",
          "lat": 0
        ]
      case .denied:
        return ["idfa": "", "att_status": "denied", "lat": 1]
      case .restricted:
        return ["idfa": "", "att_status": "restricted", "lat": 1]
      case .notDetermined:
        return ["idfa": "", "att_status": "not_determined", "lat": -1]
      @unknown default:
        return ["idfa": "", "att_status": "unknown", "lat": -1]
      }
    } else {
      let manager = ASIdentifierManager.shared()
      let trackingEnabled = manager.isAdvertisingTrackingEnabled
      return [
        "idfa": trackingEnabled ? manager.advertisingIdentifier.uuidString : "",
        "att_status": "unknown",
        "lat": trackingEnabled ? 0 : 1
      ]
    }
  }

  private func networkStateFields() -> [String: Any] {
    return [
      "vpn_enabled": isVpnEnabled() ? 1 : 0,
      "proxy_enabled": isProxyEnabled()
    ]
  }

  private func isProxyEnabled() -> Int {
    guard
      let settings = CFNetworkCopySystemProxySettings()?.takeRetainedValue() as? [String: Any]
    else {
      return -1
    }

    let httpEnabled = (settings[kCFNetworkProxiesHTTPEnable as String] as? NSNumber)?.intValue == 1
    let httpsEnabled = (settings["HTTPSEnable"] as? NSNumber)?.intValue == 1
    return httpEnabled || httpsEnabled ? 1 : 0
  }

  private func isVpnEnabled() -> Bool {
    var addresses: UnsafeMutablePointer<ifaddrs>?
    guard getifaddrs(&addresses) == 0, let firstAddress = addresses else {
      return false
    }
    defer { freeifaddrs(firstAddress) }

    var pointer: UnsafeMutablePointer<ifaddrs>? = firstAddress
    while pointer != nil {
      if let name = pointer?.pointee.ifa_name {
        let interface = String(cString: name)
        if interface.hasPrefix("utun") ||
          interface.hasPrefix("ppp") ||
          interface.hasPrefix("ipsec") ||
          interface.hasPrefix("tap") ||
          interface.hasPrefix("tun") {
          return true
        }
      }
      pointer = pointer?.pointee.ifa_next
    }
    return false
  }

  private func isJailbroken() -> Bool {
    #if targetEnvironment(simulator)
    return false
    #else
    let paths = [
      "/Applications/Cydia.app",
      "/Library/MobileSubstrate/MobileSubstrate.dylib",
      "/bin/bash",
      "/usr/sbin/sshd",
      "/etc/apt",
      "/private/var/lib/apt/"
    ]
    if paths.contains(where: { FileManager.default.fileExists(atPath: $0) }) {
      return true
    }
    do {
      let path = "/private/analytics_sdk_jailbreak_test.txt"
      try "test".write(toFile: path, atomically: true, encoding: .utf8)
      try FileManager.default.removeItem(atPath: path)
      return true
    } catch {
      return false
    }
    #endif
  }

  private func bytesToGb(_ bytes: Int64) -> Int64 {
    if bytes <= 0 {
      return -1
    }
    return bytes / (1024 * 1024 * 1024)
  }
}