import SAPCAI
import SAPFoundation
import SwiftUI

/*
  Create the `CAIChannel` object by providing the channel id, channel token and channel slug which were created in CAI Platform.

  If you do not want to hardcode chanel information on the client then you can retrieve a list of channels for a given Application ID with `CAIChannelService`.
*/
let caiChannel = CAIChannel(id: "<channelId>", token: "<channelToken>", slug: "<channelSlug>").

 /*
  Create and attach OAuthObserver to `SAPURLSession`

  Example-specific extension for `CAIServiceConfig` to build OAuth observer (see next code snippet for implementation details)

  Use CAI OAuth credentials for prototyping & direct communication between iOS client and SAP Conversational AI *Community Edition* 
  
  Use Mobile Service OAuth credentials to connect indirectly with SAP Conversational AI *Enterprise Edition* through SAP Mobile Services. In this case you have to reuse the `SAPURLSession` instance used for authentication against Mobile Services.
*/
let session = SAPURLSession()
if let observer = CAIServiceConfig.buildOAuthObserver(systemBaseURL: URL(string: "<Example: https://sapcai-community.sap.eu10.hana.ondemand.com>")!,                                                  
                                                       authenticationBaseURL: URL(string: "<Example: https://sapcai-community.authentication.eu10.hana.ondemand.com>")!,                                
                                                       clientId: "<OAuth client id>",                                                       
                                                       clientSecret: "<OAuth client secret>") {
    session.register(observer)
}

// Create CAI service config for the provided SAPURLSession and URL pointing to CAI API endpoint
let serviceConfig = CAIServiceConfig(urlSession: session, host: URL(string:"<Example: https://api.cai.tools.sap>")!)
     
// Provide the message delivery object for polling
let polling: MessageDelivering = PollMessageDelivery(channelId: "<channelId>", serviceConfig: serviceConfig)
   
// Create CAIConversation object and use it as publisher
let dataPublisher = CAIConversation(config: serviceConfig, channel: caiChannel, messageDelivery: polling)

// Create view model for `AssistantView`
let viewModel = MessagingViewModel(publisher: dataPublisher)

extension CAIServiceConfig {
    public static func buildOAuthObserver(systemBaseURL: URL, authenticationBaseURL: URL, clientId: String, clientSecret: String) -> OAuth2Observer? {

        let compositeStore = CompositeStorage()
        do {
            let secureKeyValueStore = SecureKeyValueStore()
            try secureKeyValueStore.open(with: "cai_secure_store")
            try compositeStore.setPersistentStore(secureKeyValueStore)

            let params = OAuth2AuthenticationParameters(authorizationEndpointURL: authenticationBaseURL.appendingPathComponent("/oauth/authorize"),
                                                        clientID: clientId,
                                                        redirectURL: systemBaseURL.appendingPathComponent("login/callback"),
                                                        tokenEndpointURL: authenticationBaseURL.appendingPathComponent("/oauth/token"),
                                                        clientSecret: clientSecret)

            let authenticator = OAuth2Authenticator(authenticationParameters: params, webViewPresenter: WKWebViewPresenter())
            let oauthObserver = OAuth2Observer(authenticator: authenticator, tokenStore: OAuth2TokenStorage(store: compositeStore))

            return oauthObserver
        }
        catch  {
            // error handling
            return nil
        }
    }
}

AssistantView()
  .navigationBarTitle(Text("Chat"), displayMode: .inline) // if you are in navigation controller
  .environmentObject(viewModel)
  .environmentObject(ThemeManager.shared)
  .onDisappear {
    viewModel.cancelSubscriptions()
    dataPublisher.resetConversation()
  })

let vc = MessagingViewController(MessagingViewModel(publisher: dataPublisher))

self.navigationController?.pushViewController(vc, animated: true)

ThemeManager.shared.setCurrentTheme( .fiori(FioriColorPalette()) )

ThemeManager.shared.setCurrentTheme( .casual(CasualColorPalette()) )