/*
 * Copyright 2014, 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 com.android.managedprovisioning.preprovisioning;

import static com.android.internal.logging.nano.MetricsProto.MetricsEvent.PROVISIONING_WEB_ACTIVITY_TIME_MS;

import static java.net.HttpURLConnection.HTTP_FORBIDDEN;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.webkit.URLUtil;
import android.webkit.WebResourceRequest;
import android.webkit.WebResourceResponse;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;

import androidx.annotation.Nullable;

import com.android.managedprovisioning.ManagedProvisioningBaseApplication;
import com.android.managedprovisioning.ManagedProvisioningScreens;
import com.android.managedprovisioning.R;
import com.android.managedprovisioning.common.ProvisionLogger;
import com.android.managedprovisioning.common.SettingsFacade;
import com.android.managedprovisioning.common.SetupLayoutActivity;
import com.android.managedprovisioning.common.TransitionHelper;
import com.android.managedprovisioning.preprovisioning.terms.TermsActivity;

/**
 * This activity shows a web view, which loads the url indicated in the starting intent. By default
 * the user can click on links and load other urls. However, by passing the allowed url base, the
 * web view can be limited to urls that start with this base.
 *
 * <p>This activity is considered for using by
 * {@link TermsActivity} to display the support web pages
 * about provisioning concepts.
 */
public class WebActivity extends SetupLayoutActivity {
    private static final String EXTRA_URL = "extra_url";

    private WebView mWebView;
    private final SettingsFacade mSettingsFacade = new SettingsFacade();
    private final TransitionHelper mTransitionHelper = new TransitionHelper();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        String extraUrl = getIntent().getStringExtra(EXTRA_URL);
        if (extraUrl == null) {
            Toast.makeText(this, R.string.url_error, Toast.LENGTH_SHORT).show();
            ProvisionLogger.loge("No url provided to WebActivity.");
            mTransitionHelper.finishActivity(this);
        }

        mWebView = new WebView(this);
        // We need a custom WebViewClient. Without this an external browser will load the URL.
        mWebView.setWebViewClient(new WebViewClient() {
            @Override
            public WebResourceResponse shouldInterceptRequest(WebView view,
                    WebResourceRequest request) {
                String url = request.getUrl().toString();
                if (!URLUtil.isHttpsUrl(url)) {
                    ProvisionLogger.loge("Secure connection required, but insecure URL requested "
                            + "explicitly, or as a part of the page.");
                    return createNewSecurityErrorResponse();
                }
                return super.shouldInterceptRequest(view, request);
            }
        });
        mWebView.loadUrl(extraUrl);
        // Enable zoom gesture in web view.
        WebSettings webSettings = mWebView.getSettings();
        webSettings.setBuiltInZoomControls(true);
        webSettings.setDisplayZoomControls(false);
        webSettings.setJavaScriptEnabled(true);
        if (!mSettingsFacade.isUserSetupCompleted(this)) {
            // User should not be able to escape provisioning if user setup isn't complete.
            mWebView.setOnLongClickListener(v -> true);
        }
        getThemeHelper()
                .applyWebSettingsDayNight(getApplicationContext(), webSettings, getIntent());
        setContentView(mWebView);
    }

    private WebResourceResponse createNewSecurityErrorResponse() {
        WebResourceResponse response = new WebResourceResponse("text/plain", "UTF-8", null);
        response.setStatusCodeAndReasonPhrase(HTTP_FORBIDDEN, "Secure connection required");
        return response;
    }

    protected int getMetricsCategory() {
        return PROVISIONING_WEB_ACTIVITY_TIME_MS;
    }

    @Override
    public void onBackPressed() {
        if (mWebView.canGoBack()) {
            mWebView.goBack();
        } else {
            super.onBackPressed();
        }
    }

    /**
     * Creates an intent to launch the {@link WebActivity}.
     * @param url the url to be shown upon launching this activity
     */
    @Nullable
    public static Intent createIntent(Context context, String url) {
        if (URLUtil.isNetworkUrl(url)) {
            return new Intent(context, getWebActivityClass(context))
                    .putExtra(EXTRA_URL, url);
        }
        return null;
    }

    private static Class<? extends Activity> getWebActivityClass(Context context) {
        return getBaseApplication(context)
                .getActivityClassForScreen(ManagedProvisioningScreens.WEB);
    }

    private static ManagedProvisioningBaseApplication getBaseApplication(Context context) {
        return (ManagedProvisioningBaseApplication) context.getApplicationContext();
    }
}