New surface API and task-based GAC and SmartLock wrappers

Change-Id: I65f506d20df7fe7423e59df12e01be792d62b2e2

Author: Iain McGinniss

auth/src/main/java/com/firebase/ui/auth/AuthFlowFactory.java

@@ -0,0 +1,268 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.firebase.ui.auth;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.annotation.StyleRes;
+
+import com.firebase.ui.auth.api.CredentialsApiHelper;
+import com.firebase.ui.auth.choreographer.idp.provider.FacebookProvider;
+import com.firebase.ui.auth.choreographer.idp.provider.GoogleProvider;
+import com.firebase.ui.auth.choreographer.idp.provider.IDPProviderParcel;
+import com.firebase.ui.auth.ui.credentials.ChooseAccountActivity;
+import com.google.android.gms.common.api.Status;
+import com.google.android.gms.tasks.Continuation;
+import com.google.android.gms.tasks.Task;
+import com.google.firebase.FirebaseApp;
+import com.google.firebase.auth.EmailAuthProvider;
+import com.google.firebase.auth.FirebaseAuth;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * The entry point to the user authentication flow.
+ *
+ * <h1>IDP Provider configuration instructions</h1>
+ *
+ * <ul>
+ *
+ * <li>Enabling Google Sign In: If you're using the
+ * <a href="https://developers.google.com/android/guides/google-services-plugin">Google
+ * Services Gradle Plugin</a>, no additional configuration is required. If not, please override
+ * {@code R.string.default_web_client_id} to provide your
+ * <a href="https://developers.google.com/identity/sign-in/web/devconsole-project">Google OAuth
+ * web client id.</a>
+ * </li>
+ *
+ * <li>Enabling Facebook Sign In: Please override the
+ * {@code R.string.facebook_application_id} to provide the
+ * <a href="https://developers.facebook.com/docs/apps/register">App Id</a> from
+ * <a href="https://developers.facebook.com/apps">Facebook Developer Dashboard</a>.
+ * </li>
+ *
+ * </ul>
+ */
+public class AuthUI {
+
+    /**
+     * Provider identifier for email and password credentials, for use with
+     * {@link SignInIntentBuilder#setProviders}.
+     */
+    public static final String EMAIL_PROVIDER = "email";
+
+    /**
+     * Provider identifier for Google, for use with {@link SignInIntentBuilder#setProviders}.
+     */
+    public static final String GOOGLE_PROVIDER = "google";
+
+    /**
+     * Provider identifier for Facebook, for use with {@link SignInIntentBuilder#setProviders}.
+     */
+    public static final String FACEBOOK_PROVIDER = "facebook";
+
+    /**
+     * The set of authentication providers supported in Firebase Auth UI.
+     */
+    public static final Set<String> SUPPORTED_PROVIDERS =
+            Collections.unmodifiableSet(new HashSet<String>(Arrays.asList(
+                    EMAIL_PROVIDER,
+                    GOOGLE_PROVIDER,
+                    FACEBOOK_PROVIDER
+            )));
+
+    /**
+     * The theme identifier to use in {@link SignInIntentBuilder#setTheme(int)} if no theme
+     * customization is required.
+     */
+    public static final int DEFAULT_THEME = 0;
+
+    /**
+     * Signs the current user out, if one is signed in. The
+     * {@link FirebaseAuth} instance associated with the default {@link FirebaseApp} instance
+     * (as returned by {@code FirebaseApp.getInstance()}) will be used for this operation.
+     *
+     * @param activity The activity requesting the user be signed out.
+     * @return a task which, upon completion, signals that the user has been signed out
+     * ({@code result.isSuccess()}, or that the sign-out attempt failed unexpectedly
+     * ({@code !result.isSuccess()}).
+     */
+    public static Task<Void> signOut(@NonNull Activity activity) {
+        FirebaseApp firebaseApp = FirebaseApp.getInstance();
+        if (firebaseApp == null) {
+            throw new IllegalStateException("No FirebaseApp instance available");
+        }
+
+        FirebaseAuth firebaseAuth = FirebaseAuth.getInstance(firebaseApp);
+        if (firebaseAuth == null) {
+            throw new IllegalStateException(
+                    "No FirebaseAuth instance available for app" + firebaseApp.getName());
+        }
+
+        return signOut(activity, firebaseAuth);
+    }
+
+    /**
+     * Signs the current user out, if one is signed in to the context of the provided
+     * {@link FirebaseAuth} instance.
+     *
+     * @param activity The activity requesting the user be signed out.
+     * @param auth The auth instance from which the current user should be signed out.
+     * @return a task which, upon completion, signals that the user has been signed out
+     * ({@code result.isSuccess()}, or that the sign-out attempt failed unexpectedly
+     * ({@code !result.isSuccess()}).
+     */
+    public static Task<Void> signOut(@NonNull Activity activity, @NonNull FirebaseAuth auth) {
+        auth.signOut();
+        return CredentialsApiHelper.getInstance(activity).disableAutoSignIn()
+                .continueWith(new Continuation<Status, Void>() {
+                    @Override
+                    public Void then(@NonNull Task<Status> task) throws Exception {
+                        return null;
+                    }
+                });
+    }
+
+    /**
+     * Builder for the intent to start the user authentication flow.
+     */
+    public static final class SignInIntentBuilder {
+        private Context mContext;
+        private FirebaseApp mFirebaseApp;
+        private int mTheme = DEFAULT_THEME;
+        private List<String> mProviders = Collections.singletonList(EMAIL_PROVIDER);
+        private String mTosUrl;
+
+        /**
+         * Starts the process of creating a sign in intent, with the mandatory application
+         * context parameter.
+         */
+        public SignInIntentBuilder(@NonNull Context context) {
+            setContext(context);
+        }
+
+        /**
+         * Specifies the context to use in creating the sign-in intent.
+         */
+        public @NonNull SignInIntentBuilder setContext(@NonNull Context context) {
+            if (context == null) {
+                throw new IllegalArgumentException("context must not be null");
+            }
+            mContext = context;
+            return this;
+        }
+
+        /**
+         * Specifies the firebase app to use and update during the authentication flow.
+         * If {@code null} is provided, or this method is not called, the value returned by
+         * {@link FirebaseApp#getInstance()} will be used.
+         */
+        public SignInIntentBuilder setFirebaseApp(@Nullable FirebaseApp firebaseApp) {
+            if (firebaseApp == null) {
+                firebaseApp = getDefaultFirebaseApp();
+            }
+            mFirebaseApp = firebaseApp;
+            return this;
+        }
+
+        /**
+         * Specifies the theme to use for the application flow. If no theme is specified,
+         * {@link #DEFAULT_THEME} will be used.
+         */
+        public SignInIntentBuilder setTheme(@StyleRes int theme) {
+            mTheme = theme;
+            return this;
+        }
+
+        /**
+         * Specifies the terms-of-service URL for the application.
+         */
+        public SignInIntentBuilder setTosUrl(@Nullable String tosUrl) {
+            mTosUrl = tosUrl;
+            return this;
+        }
+
+        /**
+         * Specifies the set of supported authentication providers. At least one provider
+         * must be specified, and the set of providers must be a subset of
+         * {@link #SUPPORTED_PROVIDERS}.
+         *
+         * <p>If no providers are explicitly specified by calling this method, then
+         * {@link #EMAIL_PROVIDER email} is the default supported provider.
+         *
+         * @see #EMAIL_PROVIDER
+         * @see #FACEBOOK_PROVIDER
+         * @see #GOOGLE_PROVIDER
+         */
+        public SignInIntentBuilder setProviders(@NonNull String... providers) {
+            mProviders = Arrays.asList(providers);
+            for (String provider : mProviders) {
+                if (!SUPPORTED_PROVIDERS.contains(provider)) {
+                    throw new IllegalArgumentException("Unknown provider: " + provider);
+                }
+            }
+            return this;
+        }
+
+        public Intent build() {
+            if (mFirebaseApp == null) {
+                mFirebaseApp = getDefaultFirebaseApp();
+            }
+
+            ArrayList<IDPProviderParcel> providerParcels = new ArrayList<>();
+            for (String provider : mProviders) {
+                if (provider.equalsIgnoreCase(FACEBOOK_PROVIDER)) {
+                    providerParcels.add(FacebookProvider.createFacebookParcel(
+                            mContext.getString(R.string.facebook_application_id)));
+                } else if (provider.equalsIgnoreCase(GOOGLE_PROVIDER)) {
+                    providerParcels.add(GoogleProvider.createParcel(
+                            mContext.getString(R.string.default_web_client_id)));
+                } else if (provider.equalsIgnoreCase(EMAIL_PROVIDER)) {
+                    providerParcels.add(
+                            new IDPProviderParcel(EmailAuthProvider.PROVIDER_ID, new Bundle())
+                    );
+                }
+            }
+
+            return ChooseAccountActivity.createIntent(
+                    mContext,
+                    mFirebaseApp.getName(),
+                    mFirebaseApp.getOptions().getApiKey(),
+                    mFirebaseApp.getOptions().getApplicationId(),
+                    providerParcels,
+                    mTosUrl,
+                    mTheme);
+        }
+
+        private @NonNull FirebaseApp getDefaultFirebaseApp() {
+            FirebaseApp app = FirebaseApp.getInstance();
+            if (app == null) {
+                throw new IllegalStateException(
+                        "no FirebaseApp instance specified or available through "
+                                + "FirebaseApp.getInstance()");
+            }
+            return app;
+        }
+    }
+}