NetNewsWire/iOS/Settings/Account/SettingsFeedbinAccountView.swift

//
//  SettingsFeedbinAccountView.swift
//  NetNewsWire-iOS
//
//  Created by Maurice Parker on 6/11/19.
//  Copyright © 2019 Ranchero Software. All rights reserved.
//

import SwiftUI
import Combine
import Account
import RSWeb

struct SettingsFeedbinAccountView : View {
	@Environment(\.presentationMode) var presentation
	@ObservedObject var viewModel: ViewModel
	@State var busy: Bool = false
	@State var error: String = ""

	// This is a hack around the fact that onDismiss isn't being called by the sheet modifier.
	var onDismiss: () -> Void
	
	var body: some View {
		NavigationView {
			Form {
				Section(header:
					HStack {
						Spacer()
						SettingsAccountLabelView(accountImage: "accountFeedbin", accountLabel: "Feedbin").padding()
						Spacer()
					}
				)  {
					TextField("Email", text: $viewModel.email).textContentType(.emailAddress)
					SecureField("Password", text: $viewModel.password)
				}
				Section(footer:
					HStack {
						Spacer()
						Text(verbatim: error).foregroundColor(.red)
						Spacer()
					}
					) {
					HStack {
						Spacer()
						Button(action: { self.addAccount() }) {
							if viewModel.isUpdate {
								Text("Update Account")
							} else {
								Text("Add Account")
							}
						}
						.disabled(!viewModel.isValid)
						Spacer()
					}
				}
			}
			.disabled(busy)
			.navigationBarTitle(Text(""), displayMode: .inline)
			.navigationBarItems(leading:
				Button(action: { self.dismiss() }) { Text("Cancel") }
			)
		}
	}
	
	private func addAccount() {
		
		busy = true
		error = ""
		
		let emailAddress = viewModel.email.trimmingCharacters(in: .whitespaces)
		let credentials = Credentials.basic(username: emailAddress, password: viewModel.password)

		Account.validateCredentials(type: .feedbin, credentials: credentials) { result in
			
			self.busy = false
			
			switch result {
			case .success(let authenticated):
				
				if (authenticated != nil) {
					
					var newAccount = false
					let workAccount: Account
					if self.viewModel.account == nil {
						workAccount = AccountManager.shared.createAccount(type: .feedbin)
						newAccount = true
					} else {
						workAccount = self.viewModel.account!
					}
					
					do {
						
						do {
							try workAccount.removeCredentials()
						} catch {}
						try workAccount.storeCredentials(credentials)
						
						if newAccount {
							workAccount.refreshAll() { result in }
						}
						
						self.dismiss()
						
					} catch {
						self.error = "Keychain error while storing credentials."
					}
					
				} else {
					self.error = "Invalid email/password combination."
				}
				
			case .failure:
				self.error = "Network error. Try again later."
			}
			
		}
		
	}
	
	private func dismiss() {
		presentation.wrappedValue.dismiss()
		onDismiss()
	}
	
	class ViewModel: ObservableObject {
		
		let objectWillChange = ObservableObjectPublisher()
		var account: Account? = nil
		
		init() {
		}
		
		init(account: Account) {
			self.account = account
			if case .basic(let username, let password) = try? account.retrieveCredentials() {
				self.email = username
				self.password = password
			}
		}

		var email: String = "" {
			willSet {
				objectWillChange.send()
			}
		}
		
		var password: String = "" {
			willSet {
				objectWillChange.send()
			}
		}
		
		var isUpdate: Bool {
			return account != nil
		}
		
		var isValid: Bool {
			return !email.isEmpty && !password.isEmpty
		}
	}
	
}

#if DEBUG
struct SettingsFeedbinAccountView_Previews : PreviewProvider {
    static var previews: some View {
		SettingsFeedbinAccountView(viewModel: SettingsFeedbinAccountView.ViewModel(), onDismiss: {})
    }
}
#endif