splits/Splits/DocsView.swift

//
//  DocsView.swift
//  Splits
//
//  Created by Isaac Greene on 6/3/22.
//

import SwiftUI
import LocalAuthentication
// this file will have some comments.
// Most of this code is considered simple enough
// to be human-readable without aid, as long as
// the reader has a basic understanding of
// Swift and/or SwiftUI.

let username = "admin"
let password = "123"

struct DocsView: View {
	enum Field: Hashable {
		case username
		case password
	}
	
	@State private var pass: String = ""
	@State private var user: String = ""
	@State private var isUnlocked = false
 	@FocusState private var focusedField: Field?
	
	var body: some View {
		NavigationView {
			List {
				NavigationLink("Help", destination: HelpView())
				NavigationLink("Change Log", destination: ChangeLog())
				
				Section(header: Text("Features")) {
					NavigationLink("New", destination: NewFeatures())
					NavigationLink("In Progress", destination: InProgressFeatures())
					NavigationLink("Deprecated", destination: DeprecatedFeatures())
				}
				Section(header: Text("Known Issues")) {
					NavigationLink("Recently Resolved", destination: RecentlyResolved())
					NavigationLink("High Priority", destination: HighPriority())
					NavigationLink("Medium Priority", destination: MediumPriority())
					NavigationLink("Low Priority", destination: LowPriority())
				}
				Section(header: Text("App Information")) {
					NavigationLink("Software License", destination: LicenseView())
					Text("Version: Release Candidate 2 (1.0.0)")
					Text("Release date: 2022-06-11")
					Text("Start date: 2022-03-25")
					Link("Built with SwiftUI \(Image(systemName: "swift"))", destination: URL(string: "https://developer.apple.com/xcode/swiftui")!)
				}
				Section(header: Text("Login")) {
					if (isUnlocked) {
						NavigationLink("Contacts", destination: SecretView())
						Button("Log out") {
							pass = ""
							user = ""
							isUnlocked = false
						}
					} else {
						if !isUnlocked {
							Button("Log in with biometrics") {
								authenticate()
							}
						}
						SecureField("Username", text: $user)
							.keyboardType(.alphabet)
							.textContentType(.username)
							.submitLabel(.next)
							.focused($focusedField, equals: .username)
						SecureField("Password", text: $pass)
							.keyboardType(.numbersAndPunctuation)
							.textContentType(.password)
							.submitLabel(.done)
							.focused($focusedField, equals: .password)
						if checkPassword() {
							NavigationLink("Contacts", destination: SecretView())
						}
					}
				}
			}
			.navigationTitle("Docs")
		}
		.onSubmit {
			switch focusedField {
				case .username:
					focusedField = .password
				default:
					()
			}
			if (pass == password && user == username) {
				isUnlocked = true
			}
		}
	}
	func checkPassword() -> Bool {
		if (pass == password && user == username) {
			return true
		} else {
			return false
		}
	}
	func checkIfUnlocked() {
		if !isUnlocked {
			authenticate()
		}
	}
	func authenticate() {
		let context = LAContext()
		var error: NSError?

		// check whether biometric authentication is possible
		if context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &error) {
			// it's possible, so go ahead and use it
			let reason = "We need authentication before we can show you sensitive data"

			context.evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, localizedReason: reason) { success, authenticationError in
				// authentication has now completed
				if success {
					isUnlocked = true
				} else {
					()
				}
			}
		} else {
			()
		}
	}
	// getting this to work came from
	// https://www.hackingwithswift.com/books/ios-swiftui/using-touch-id-and-face-id-with-swiftui
	// a truly epic website and it's helped me with
	// just about all of my code questions
}

struct DocsView_Previews: PreviewProvider {
    static var previews: some View {
        DocsView()
    }
}