/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * 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 android.service.autofill;

import android.annotation.Nullable;
import android.app.Activity;
import android.os.RemoteException;

/**
 * <p><code>FillCallback</code> handles autofill requests from the {@link AutofillService} into
 * the {@link Activity} being autofilled.
 *
 * <p>To learn about using Autofill services in your app, read
 * <a href="/guide/topics/text/autofill-services">Build autofill services</a>.
 */
public final class FillCallback {
    private final IFillCallback mCallback;
    private final int mRequestId;
    private boolean mCalled;

    /** @hide */
    public FillCallback(IFillCallback callback, int requestId) {
        mCallback = callback;
        mRequestId = requestId;
    }

    /**
     * Notifies the Android System that an
     * {@link AutofillService#onFillRequest(FillRequest, android.os.CancellationSignal,
     * FillCallback)} was successfully fulfilled by the service.
     *
     * @param response autofill information for that activity, or {@code null} when the activity
     * cannot be autofilled (for example, if it only contains read-only fields). See
     * {@link FillResponse} for examples.
     */
    public void onSuccess(@Nullable FillResponse response) {
        assertNotCalled();
        mCalled = true;

        if (response != null) {
            response.setRequestId(mRequestId);
        }

        try {
            mCallback.onSuccess(response);
        } catch (RemoteException e) {
            e.rethrowAsRuntimeException();
        }
    }

    /**
     * Notifies the Android System that an
     * {@link AutofillService#onFillRequest(FillRequest, android.os.CancellationSignal,
     * FillCallback)} could not be fulfilled by the service.
     *
     * @param message error message to be displayed to the user.
     */
    public void onFailure(@Nullable CharSequence message) {
        assertNotCalled();
        mCalled = true;
        try {
            mCallback.onFailure(mRequestId, message);
        } catch (RemoteException e) {
            e.rethrowAsRuntimeException();
        }
    }

    private void assertNotCalled() {
        if (mCalled) {
            throw new IllegalStateException("Already called");
        }
    }
}