scripts: backend foundation/shape

ColourMeOKLABGame/Assets/Scripts/Backend.cs

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+using System;
+using System.Threading.Tasks;
+using Firebase;
+using Firebase.Auth;
+using Firebase.Database;
+using UnityEngine;
+
+/// <summary>
+///     the general managing class for handling communication with the firebase backend
+///     (to be initialised by GameManager)
+/// </summary>
+public class Backend : MonoBehaviour
+{
+    /// <summary>
+    ///     whether the backend is connected to the firebase backend
+    /// </summary>
+    public bool connected;
+
+    /// <summary>
+    ///     the firebase authentication object
+    /// </summary>
+    private FirebaseAuth _auth;
+
+    /// <summary>
+    ///     the firebase database reference
+    /// </summary>
+    private DatabaseReference _db;
+
+    /// <summary>
+    ///     callback function to be invoked when the user signs in
+    /// </summary>
+    private Action<FirebaseUser> _onSignInCallback = user => { Debug.Log("signed in as" + user.UserId); };
+
+    /// <summary>
+    ///     callback function to be invoked when the user signs out
+    /// </summary>
+    private Action<FirebaseUser> _onSignOutCallback = user => { Debug.Log("signed out" + user.UserId); };
+
+    /// <summary>
+    ///     the current user object, if authenticated
+    /// </summary>
+    private FirebaseUser _user;
+
+    /// <summary>
+    ///     script load function
+    /// </summary>
+    private void Awake()
+    {
+        Debug.Log("firing firebase Initialise() invocation");
+        Initialise();
+    }
+
+    /// <summary>
+    ///     deferred cleanup function
+    /// </summary>
+    private void OnDestroy()
+    {
+        SignOutUser();
+    }
+
+    /// <summary>
+    ///     variable initialisation function
+    /// </summary>
+    private void Initialise()
+    {
+        FirebaseApp.CheckAndFixDependenciesAsync().ContinueWith(task =>
+        {
+            switch (task.Result)
+            {
+                case DependencyStatus.Available:
+                    var app = FirebaseApp.DefaultInstance;
+                    _auth = FirebaseAuth.GetAuth(app);
+                    _auth.StateChanged += AuthStateChanged;
+                    _db = FirebaseDatabase.DefaultInstance.RootReference;
+                    connected = true;
+                    Debug.Log("firebase initialised");
+                    break;
+
+                case DependencyStatus.UnavailableDisabled:
+                case DependencyStatus.UnavailableInvalid:
+                case DependencyStatus.UnavilableMissing:
+                case DependencyStatus.UnavailablePermission:
+                    Debug.LogError("firebase error outside of our control");
+                    break;
+
+                case DependencyStatus.UnavailableUpdaterequired:
+                case DependencyStatus.UnavailableUpdating:
+                    Debug.LogError("firebase is updating");
+                    RetryInitialiseAfterDelay();
+                    break;
+
+                case DependencyStatus.UnavailableOther:
+                default:
+                    Debug.LogError("firebase ??? blew up or something," + task.Result);
+                    break;
+            }
+        });
+    }
+
+    /// <summary>
+    ///     function to handle the authentication state change event
+    /// </summary>
+    /// <param name="sender">the object that triggered the event</param>
+    /// <param name="eventArgs">the event arguments</param>
+    private void AuthStateChanged(object sender, EventArgs eventArgs)
+    {
+        if (_auth.CurrentUser == _user) return;
+        var signedIn = _user != _auth.CurrentUser && _auth.CurrentUser != null;
+        switch (signedIn)
+        {
+            case false when _user != null:
+                _onSignOutCallback(_user);
+                break;
+            case true:
+                _onSignInCallback(_auth.CurrentUser);
+                break;
+        }
+    }
+
+    /// <summary>
+    ///     function to register a callback for when the user signs in
+    /// </summary>
+    /// <param name="callback">callback function that takes in a FirebaseUser argument</param>
+    private void RegisterOnSignInCallback(Action<FirebaseUser> callback)
+    {
+        _onSignInCallback = callback;
+    }
+
+    /// <summary>
+    ///     function to register a callback for when the user signs out
+    /// </summary>
+    /// <param name="callback">callback function that takes in a FirebaseUser argument</param>
+    private void RegisterOnSignOutCallback(Action<FirebaseUser> callback)
+    {
+        _onSignOutCallback = callback;
+    }
+
+    /// <summary>
+    ///     async function to retry initialisation after a delay
+    /// </summary>
+    private async void RetryInitialiseAfterDelay()
+    {
+        await Task.Delay(TimeSpan.FromSeconds(10));
+        Initialise();
+    }
+
+    /// <summary>
+    ///     abstraction function to authenticate the user
+    /// </summary>
+    /// <param name="username">user name string</param>
+    /// <param name="password">user raw password string</param>
+    /// <param name="callback">callback function that takes in an AuthenticationResult argument</param>
+    /// <param name="registerUser">whether to treat authentication as registration</param>
+    private void AuthenticateUser(
+        string username,
+        string password,
+        Action<AuthenticationResult> callback,
+        bool registerUser = false)
+    {
+        throw new NotImplementedException();
+    }
+
+    /// <summary>
+    ///     abstraction function to retrieve the user
+    /// </summary>
+    /// <returns>the firebase user object</returns>
+    private FirebaseUser GetUser()
+    {
+        return _user;
+    }
+    
+    /// <summary>
+    ///     abstraction function to sign out the user
+    /// </summary>
+    private void SignOutUser()
+    {
+        _auth.SignOut();
+    }
+
+    /// <summary>
+    ///     abstraction function to submit a play to the database
+    /// </summary>
+    /// <param name="averageMatchAccuracy">the float percentage (0-100) of how accurate the user was when colour matching</param>
+    /// <param name="callback">callback function that takes in one DatabaseTransactionResult argument</param>
+    private void SubmitPlay(
+        float averageMatchAccuracy,
+        Action<DatabaseTransactionResult> callback)
+    {
+        throw new NotImplementedException();
+    }
+
+    /// <summary>
+    ///     abstraction function to get and calculate the user's rating from the database
+    ///     calculation is done locally, call UpdateUserRating to update the user's rating in the database
+    /// </summary>
+    /// <param name="callback">callback function that takes in a DatabaseTransactionResult and float (user rating) argument</param>
+    private void CalculateUserRating(
+        Action<DatabaseTransactionResult, float> callback)
+    {
+        throw new NotImplementedException();
+    }
+
+    /// <summary>
+    ///     abstraction function to update the user's rating in the database
+    /// </summary>
+    /// <param name="newRating">new user rating value as a float</param>
+    /// <param name="callback">callback function that takes in one DatabaseTransactionResult argument</param>
+    private void UpdateUserRating(
+        float newRating,
+        Action<DatabaseTransactionResult> callback)
+    {
+        throw new NotImplementedException();
+    }
+
+    /// <summary>
+    ///     abstraction function to get the leaderboard from the database
+    /// </summary>
+    /// <param name="callback"></param>
+    /// <exception cref="NotImplementedException"></exception>
+    private void GetLeaderboard(
+        Action<DatabaseTransactionResult, LeaderboardEntry[]> callback)
+    {
+        throw new NotImplementedException();
+    }
+
+    /// <summary>
+    ///     struct for a leaderboard entry
+    /// </summary>
+    // ReSharper disable once MemberCanBePrivate.Global
+    public struct LeaderboardEntry
+    {
+        public string Username;
+        public float Rating;
+        public int PlayCount;
+    }
+
+    /// <summary>
+    ///     enum for the result of the authentication process
+    /// </summary>
+    // ReSharper disable once MemberCanBePrivate.Global
+    public enum AuthenticationResult
+    {
+        Ok,
+        AlreadyAuthenticated,
+        NonExistentUser,
+        AlreadyExistingUser,
+        InvalidCredentials,
+        GenericError
+    }
+
+    /// <summary>
+    ///     generic enum for the result of a database transaction
+    /// </summary>
+    // ReSharper disable once MemberCanBePrivate.Global
+    public enum DatabaseTransactionResult
+    {
+        Ok,
+        Unauthenticated,
+        Error
+    }
+}

ColourMeOKLABGame/Assets/Scripts/Backend.cs.meta

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