import UIKit
import Flutter
import MobileNebula
import NetworkExtension
import SwiftyJSON

enum ChannelName {
    static let vpn = "net.defined.mobileNebula/NebulaVpnService"
}

func MissingArgumentError(message: String, details: Any?) -> FlutterError {
    return FlutterError(code: "missing_argument", message: message, details: details)
}

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
    private let dnUpdater = DNUpdater()
    private let apiClient = APIClient()
    private var sites: Sites?
    private var ui: FlutterMethodChannel?
    
    
    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
        GeneratedPluginRegistrant.register(with: self)
        
        
        dnUpdater.updateAllLoop { site in
            // Signal the site has changed in case the current site details screen is active
            let container = self.sites?.getContainer(id: site.id)
            if (container != nil) {
                // Update references to the site with the new site config
                container!.site = site
                container!.updater.update(connected: site.connected ?? false, replaceSite: site)
            }
            
            // Signal to the main screen to reload
            self.ui?.invokeMethod("refreshSites", arguments: nil)
        }
        
        guard let controller = window?.rootViewController as? FlutterViewController else {
            fatalError("rootViewController is not type FlutterViewController")
        }
        
        sites = Sites(messenger: controller.binaryMessenger)
        ui = FlutterMethodChannel(name: ChannelName.vpn, binaryMessenger: controller.binaryMessenger)
        
        ui!.setMethodCallHandler({(call: FlutterMethodCall, result: @escaping FlutterResult) -> Void in
            switch call.method {
            case "nebula.parseCerts": return self.nebulaParseCerts(call: call, result: result)
            case "nebula.generateKeyPair": return self.nebulaGenerateKeyPair(result: result)
            case "nebula.renderConfig": return self.nebulaRenderConfig(call: call, result: result)
            case "nebula.verifyCertAndKey": return self.nebulaVerifyCertAndKey(call: call, result: result)
                
            case "dn.enroll": return self.dnEnroll(call: call, result: result)
                
            case "listSites": return self.listSites(result: result)
            case "deleteSite": return self.deleteSite(call: call, result: result)
            case "saveSite": return self.saveSite(call: call, result: result)
            case "startSite": return self.startSite(call: call, result: result)
            case "stopSite": return self.stopSite(call: call, result: result)
                
            case "active.listHostmap": self.vpnRequest(command: "listHostmap", arguments: call.arguments, result: result)
            case "active.listPendingHostmap": self.vpnRequest(command: "listPendingHostmap", arguments: call.arguments, result: result)
            case "active.getHostInfo": self.vpnRequest(command: "getHostInfo", arguments: call.arguments, result: result)
            case "active.setRemoteForTunnel": self.vpnRequest(command: "setRemoteForTunnel", arguments: call.arguments, result: result)
            case "active.closeTunnel": self.vpnRequest(command: "closeTunnel", arguments: call.arguments, result: result)
                
            default:
                result(FlutterMethodNotImplemented)
            }
        })
        
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }
    
    func nebulaParseCerts(call: FlutterMethodCall, result: FlutterResult) {
        guard let args = call.arguments as? Dictionary<String, String> else { return result(NoArgumentsError()) }
        guard let certs = args["certs"] else { return result(MissingArgumentError(message: "certs is a required argument")) }
        
        var err: NSError?
        let json = MobileNebulaParseCerts(certs, &err)
        if (err != nil) {
            return result(CallFailedError(message: "Error while parsing certificate(s)", details: err!.localizedDescription))
        }
        
        return result(json)
    }
    
    func nebulaVerifyCertAndKey(call: FlutterMethodCall, result: FlutterResult) {
        guard let args = call.arguments as? Dictionary<String, String> else { return result(NoArgumentsError()) }
        guard let cert = args["cert"] else { return result(MissingArgumentError(message: "cert is a required argument")) }
        guard let key = args["key"] else { return result(MissingArgumentError(message: "key is a required argument")) }
        
        var err: NSError?
        var validd: ObjCBool = false
        let valid = MobileNebulaVerifyCertAndKey(cert, key, &validd, &err)
        if (err != nil) {  
            return result(CallFailedError(message: "Error while verifying certificate and private key", details: err!.localizedDescription))
        }
        
        return result(valid)
    }
    
    func nebulaGenerateKeyPair(result: FlutterResult) {
        var err: NSError?
        let kp = MobileNebulaGenerateKeyPair(&err)
        if (err != nil) {
            return result(CallFailedError(message: "Error while generating key pairs", details: err!.localizedDescription))
        }
        
        return result(kp)
    }
    
    func nebulaRenderConfig(call: FlutterMethodCall, result: FlutterResult) {
        guard let config = call.arguments as? String else { return result(NoArgumentsError()) }
        
        var err: NSError?
        let yaml = MobileNebulaRenderConfig(config, "<hidden>", &err)
        if (err != nil) {
            return result(CallFailedError(message: "Error while rendering config", details: err!.localizedDescription))
        }
        
        return result(yaml)
    }
    
    func dnEnroll(call: FlutterMethodCall, result: @escaping FlutterResult) {
        guard let code = call.arguments as? String else { return result(NoArgumentsError()) }
        
        do {
            let site = try apiClient.enroll(code: code)
            
            let oldSite = self.sites?.getSite(id: site.id)
            site.save(manager: oldSite?.manager) { error in
                if (error != nil) {
                    return result(CallFailedError(message: "Failed to enroll", details: error!.localizedDescription))
                }
                
                result(nil)
            }
        } catch {
            return result(CallFailedError(message: "Error from DN api", details: error.localizedDescription))
        }
    }
    
    func listSites(result: @escaping FlutterResult) {
        self.sites?.loadSites { (sites, err) -> () in
            if (err != nil) {
                return result(CallFailedError(message: "Failed to load site list", details: err!.localizedDescription))
            }

            let encoder = JSONEncoder()
            let data = try! encoder.encode(sites)
            let ret = String(data: data, encoding: .utf8)
            result(ret)
        }
    }
    
    func deleteSite(call: FlutterMethodCall, result: @escaping FlutterResult) {
        guard let id = call.arguments as? String else { return result(NoArgumentsError()) }
        //TODO: stop the site if its running currently
        self.sites?.deleteSite(id: id) { error in
            if (error != nil) {
                result(CallFailedError(message: "Failed to delete site", details: error!.localizedDescription))
            }
            
            result(nil)
        }
    }
    
    func saveSite(call: FlutterMethodCall, result: @escaping FlutterResult) {
        guard let json = call.arguments as? String else { return result(NoArgumentsError()) }
        guard let data = json.data(using: .utf8) else { return result(NoArgumentsError()) }
        
        guard let site = try? JSONDecoder().decode(IncomingSite.self, from: data) else {
            return result(NoArgumentsError())
        }
        
        let oldSite = self.sites?.getSite(id: site.id)
        site.save(manager: oldSite?.manager) { error in
            if (error != nil) {
                return result(CallFailedError(message: "Failed to save site", details: error!.localizedDescription))
            }

            self.sites?.loadSites { _, _ in
                result(nil)
            }
        }
    }
    
    func startSite(call: FlutterMethodCall, result: @escaping FlutterResult) {
        guard let args = call.arguments as? Dictionary<String, String> else { return result(NoArgumentsError()) }
        guard let id = args["id"] else { return result(MissingArgumentError(message: "id is a required argument")) }
        
#if targetEnvironment(simulator)
        let updater = self.sites?.getUpdater(id: id)
        updater?.update(connected: true)
#else
        let container = self.sites?.getContainer(id: id)
        let manager = container?.site.manager

        manager?.loadFromPreferences{ error in
            //TODO: Handle load error
            // This is silly but we need to enable the site each time to avoid situations where folks have multiple sites
            manager?.isEnabled = true
            manager?.saveToPreferences{ error in
                //TODO: Handle load error
                manager?.loadFromPreferences{ error in
                    //TODO: Handle load error
                    do {
                        container?.updater.startFunc = {() -> Void in
                            return self.vpnRequest(command: "start", arguments: args, result: result)
                        }
                        try manager?.connection.startVPNTunnel(options: ["expectStart": NSNumber(1)])
                    } catch {
                        return result(CallFailedError(message: "Could not start site", details: error.localizedDescription))
                    }
                }
            }
        }
#endif
    }
    
    func stopSite(call: FlutterMethodCall, result: @escaping FlutterResult) {
        guard let args = call.arguments as? Dictionary<String, String> else { return result(NoArgumentsError()) }
        guard let id = args["id"] else { return result(MissingArgumentError(message: "id is a required argument")) }
#if targetEnvironment(simulator)
        let updater = self.sites?.getUpdater(id: id)
        updater?.update(connected: false)
        
#else
        let manager = self.sites?.getSite(id: id)?.manager
        manager?.loadFromPreferences{ error in
            //TODO: Handle load error
            
            manager?.connection.stopVPNTunnel()
            return result(nil)
        }
#endif
    }
    
    func vpnRequest(command: String, arguments: Any?, result: @escaping FlutterResult) {
        guard let args = arguments as? Dictionary<String, Any> else { return result(NoArgumentsError()) }
        guard let id = args["id"] as? String else { return result(MissingArgumentError(message: "id is a required argument")) }
        let container = sites?.getContainer(id: id)
        
        if container == nil {
            // No site for this id
            return result(nil)
        }
        
        if !(container!.site.connected ?? false) {
            // Site isn't connected, no point in sending a command
            return result(nil)
        }

        if let session = container!.site.manager?.connection as? NETunnelProviderSession {
            do {
                try session.sendProviderMessage(try JSONEncoder().encode(IPCRequest(command: command, arguments: JSON(args)))) { data in
                    if data == nil {
                        return result(nil)
                    }
                    
                    //print(String(decoding: data!, as: UTF8.self))
                    guard let res = try? JSONDecoder().decode(IPCResponse.self, from: data!) else {
                        return result(CallFailedError(message: "Failed to decode response"))
                    }
                    
                    if res.type == .success {
                        return result(res.message?.object)
                    }
                    
                    return result(CallFailedError(message: res.message?.debugDescription ?? "Failed to convert error"))
                }
            } catch {
                return result(CallFailedError(message: error.localizedDescription))
            }
        } else {
            //TODO: we have a site without a manager, things have gone weird. How to handle since this shouldn't happen?
            result(nil)
        }
    }
}

func MissingArgumentError(message: String, details: Error? = nil) -> FlutterError {
    return FlutterError(code: "missingArgument", message: message, details: details)
}

func NoArgumentsError(message: String? = "no arguments were provided or could not be deserialized", details: Error? = nil) -> FlutterError {
    return FlutterError(code: "noArguments", message: message, details: details)
}

func CallFailedError(message: String, details: String? = "") -> FlutterError {
    return FlutterError(code: "callFailed", message: message, details: details)
}