//
//  LoginController.swift
//  MastoSearchCore
//
//  Created by Shadowfacts on 7/3/22.
//

import Foundation
import AuthenticationServices

public class LoginController {
    private init() {}
    
    public static let shared = LoginController()
    
    private var authSession: ASWebAuthenticationSession?
    
    public func logIn(with instanceURL: URL, presentationContextProvider: ASWebAuthenticationPresentationContextProviding, completion: @escaping () -> Void) {
        LocalData.account = LocalData.AccountInfo(instanceURL: instanceURL, clientID: nil, clientSecret: nil, accessToken: nil)
        
        APIController.shared.register { response in
            guard case .success(let registration) = response else {
                fatalError()
            }
            
            LocalData.account!.clientID = registration.client_id
            LocalData.account!.clientSecret = registration.client_secret
            
            var authorizeComponents = URLComponents(url: instanceURL, resolvingAgainstBaseURL: false)!
            authorizeComponents.path = "/oauth/authorize"
            authorizeComponents.queryItems = [
                URLQueryItem(name: "client_id", value: LocalData.account!.clientID),
                URLQueryItem(name: "response_type", value: "code"),
                URLQueryItem(name: "scope", value: APIController.shared.scopes),
                URLQueryItem(name: "redirect_uri", value: APIController.shared.redirectURI),
            ]
            
            self.authSession = ASWebAuthenticationSession(url: authorizeComponents.url!, callbackURLScheme: "mastosearch", completionHandler: { url, error in
                guard error == nil,
                      let url = url,
                      let components = URLComponents(url: url, resolvingAgainstBaseURL: false),
                      let item = components.queryItems?.first(where: { $0.name == "code" }),
                      let authCode = item.value else {
                          fatalError()
                      }
                
                APIController.shared.getAccessToken(authCode: authCode) { response in
                    guard case .success(let settings) = response else {
                        fatalError()
                    }
                    
                    LocalData.account!.accessToken = settings.access_token
                    
                    DispatchQueue.main.async {
                        completion()
                    }
                }
            })
            DispatchQueue.main.async {
                self.authSession!.presentationContextProvider = presentationContextProvider
                self.authSession!.start()
            }
        }
    }
}