/*
 * Copyright (C) 2018 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.settings.network.telephony;

import android.app.ActionBar;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.provider.Settings;
import android.telephony.CarrierConfigManager;
import android.telephony.SubscriptionInfo;
import android.telephony.SubscriptionManager;
import android.telephony.ims.ImsRcsManager;
import android.text.TextUtils;

import androidx.annotation.NonNull;
import androidx.annotation.VisibleForTesting;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import com.android.internal.telephony.TelephonyIntents;
import com.android.internal.util.CollectionUtils;
import com.android.settings.R;
import com.android.settings.core.SettingsBaseActivity;
import com.android.settings.network.SubscriptionUtil;

import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

public class MobileNetworkActivity extends SettingsBaseActivity {

    private static final String TAG = "MobileNetworkActivity";
    @VisibleForTesting
    static final String MOBILE_SETTINGS_TAG = "mobile_settings:";
    @VisibleForTesting
    static final int SUB_ID_NULL = Integer.MIN_VALUE;

    @VisibleForTesting
    SubscriptionManager mSubscriptionManager;
    @VisibleForTesting
    int mCurSubscriptionId;
    @VisibleForTesting
    List<SubscriptionInfo> mSubscriptionInfos = new ArrayList<>();
    private PhoneChangeReceiver mPhoneChangeReceiver;

    private final SubscriptionManager.OnSubscriptionsChangedListener
            mOnSubscriptionsChangeListener
            = new SubscriptionManager.OnSubscriptionsChangedListener() {
        @Override
        public void onSubscriptionsChanged() {
            if (!Objects.equals(mSubscriptionInfos,
                    mSubscriptionManager.getActiveSubscriptionInfoList(true))) {
                int oldSubIndex = mCurSubscriptionId;
                updateSubscriptions(null);
                // Remove the dialog if the subscription associated with this activity changes.
                if (mCurSubscriptionId != oldSubIndex) {
                    removeContactDiscoveryDialog(oldSubIndex);
                }
            }
        }
    };

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        validate(intent);
        setIntent(intent);

        int updateSubscriptionIndex = SUB_ID_NULL;
        if (intent != null) {
            updateSubscriptionIndex = intent.getIntExtra(Settings.EXTRA_SUB_ID, SUB_ID_NULL);
        }
        int oldSubId = mCurSubscriptionId;
        updateSubscriptions(null);

        // If the subscription has changed or the new intent doesnt contain the opt in action,
        // remove the old discovery dialog. If the activity is being recreated, we will see
        // onCreate -> onNewIntent, so the dialog will first be recreated for the old subscription
        // and then removed.
        if (updateSubscriptionIndex != oldSubId || !doesIntentContainOptInAction(intent)) {
            removeContactDiscoveryDialog(oldSubId);
        }
        // evaluate showing the new discovery dialog if this intent contains an action to show the
        // opt-in.
        if (doesIntentContainOptInAction(intent)) {
            maybeShowContactDiscoveryDialog(updateSubscriptionIndex);
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.mobile_network_settings_container_v2);
        setActionBar(findViewById(R.id.mobile_action_bar));
        mPhoneChangeReceiver = new PhoneChangeReceiver(this, new PhoneChangeReceiver.Client() {
            @Override
            public void onPhoneChange() {
                // When the radio or carrier config changes (ex: CDMA->GSM), refresh the fragment.
                switchFragment(new MobileNetworkSettings(), mCurSubscriptionId,
                        true /* forceUpdate */);
            }

            @Override
            public int getSubscriptionId() {
                return mCurSubscriptionId;
            }
        });
        mSubscriptionManager = getSystemService(SubscriptionManager.class);
        mSubscriptionInfos = mSubscriptionManager.getActiveSubscriptionInfoList(true);
        final Intent startIntent = getIntent();
        validate(startIntent);
        mCurSubscriptionId = savedInstanceState != null
                ? savedInstanceState.getInt(Settings.EXTRA_SUB_ID, SUB_ID_NULL)
                : SUB_ID_NULL;

        final ActionBar actionBar = getActionBar();
        if (actionBar != null) {
            actionBar.setDisplayHomeAsUpEnabled(true);
        }
        updateSubscriptions(savedInstanceState);
        maybeShowContactDiscoveryDialog(mCurSubscriptionId);
    }

    @Override
    protected void onStart() {
        super.onStart();
        mPhoneChangeReceiver.register();
        mSubscriptionManager.addOnSubscriptionsChangedListener(mOnSubscriptionsChangeListener);
    }

    @Override
    protected void onStop() {
        super.onStop();
        mPhoneChangeReceiver.unregister();
        mSubscriptionManager.removeOnSubscriptionsChangedListener(mOnSubscriptionsChangeListener);
    }

    @Override
    protected void onSaveInstanceState(@NonNull Bundle outState) {
        super.onSaveInstanceState(outState);
        saveInstanceState(outState);
    }

    @VisibleForTesting
    void saveInstanceState(@NonNull Bundle outState) {
        outState.putInt(Settings.EXTRA_SUB_ID, mCurSubscriptionId);
    }

    @VisibleForTesting
    void updateSubscriptions(Bundle savedInstanceState) {
        // Set the title to the name of the subscription. If we don't have subscription info, the
        // title will just default to the label for this activity that's already specified in
        // AndroidManifest.xml.
        final SubscriptionInfo subscription = getSubscription();
        if (subscription != null) {
            setTitle(subscription.getDisplayName());
        }

        mSubscriptionInfos = mSubscriptionManager.getActiveSubscriptionInfoList(true);

        if (savedInstanceState == null) {
            switchFragment(new MobileNetworkSettings(), getSubscriptionId());
        }
    }

    /**
     * Get the current subscription to display. First check whether intent has {@link
     * Settings#EXTRA_SUB_ID} and if so find the subscription with that id. If not, just return the
     * first one in the mSubscriptionInfos list since it is already sorted by sim slot.
     */
    @VisibleForTesting
    SubscriptionInfo getSubscription() {
        final Intent intent = getIntent();
        if (intent != null) {
            final int subId = intent.getIntExtra(Settings.EXTRA_SUB_ID, SUB_ID_NULL);
            SubscriptionInfo info = getSubscriptionInfo(subId);
            if (info != null) return info;
        }
        if (CollectionUtils.isEmpty(mSubscriptionInfos)) {
            return null;
        }
        return mSubscriptionInfos.get(0);
    }

    /**
     * @return the subscription associated with a given subscription ID or null if none can be
     * found.
     */
    SubscriptionInfo getSubscriptionInfo(int subId) {
        if (subId == SUB_ID_NULL) {
            return null;
        }

        for (SubscriptionInfo subscription : SubscriptionUtil.getAvailableSubscriptions(this)) {
            if (subscription.getSubscriptionId() == subId) {
                return subscription;
            }
        }
        return null;
    }

    /**
     * Get the current subId to display.
     */
    @VisibleForTesting
    int getSubscriptionId() {
        final SubscriptionInfo subscription = getSubscription();
        if (subscription != null) {
            return subscription.getSubscriptionId();
        }
        return SubscriptionManager.INVALID_SUBSCRIPTION_ID;
    }

    @VisibleForTesting
    void switchFragment(Fragment fragment, int subscriptionId) {
        switchFragment(fragment, subscriptionId, false /* forceUpdate */);
    }

    @VisibleForTesting
    void switchFragment(Fragment fragment, int subscriptionId, boolean forceUpdate) {
        if (mCurSubscriptionId != SUB_ID_NULL && subscriptionId == mCurSubscriptionId
                && !forceUpdate) {
            return;
        }
        final FragmentManager fragmentManager = getSupportFragmentManager();
        final FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        final Bundle bundle = new Bundle();
        bundle.putInt(Settings.EXTRA_SUB_ID, subscriptionId);

        fragment.setArguments(bundle);
        fragmentTransaction.replace(R.id.main_content, fragment,
                buildFragmentTag(subscriptionId));
        fragmentTransaction.commit();
        mCurSubscriptionId = subscriptionId;
    }

    @VisibleForTesting
    private String buildFragmentTag(int subscriptionId) {
        return MOBILE_SETTINGS_TAG + subscriptionId;
    }

    @VisibleForTesting
    static class PhoneChangeReceiver extends BroadcastReceiver {
        private Context mContext;
        private Client mClient;

        interface Client {
            void onPhoneChange();
            int getSubscriptionId();
        }

        public PhoneChangeReceiver(Context context, Client client) {
            mContext = context;
            mClient = client;
        }

        public void register() {
            final IntentFilter intentFilter = new IntentFilter();
            intentFilter.addAction(TelephonyIntents.ACTION_RADIO_TECHNOLOGY_CHANGED);
            intentFilter.addAction(CarrierConfigManager.ACTION_CARRIER_CONFIG_CHANGED);
            mContext.registerReceiver(this, intentFilter);
        }

        public void unregister() {
            mContext.unregisterReceiver(this);
        }

        @Override
        public void onReceive(Context context, Intent intent) {
            if (isInitialStickyBroadcast()) {
                return;
            }
            if (intent.getAction().equals(CarrierConfigManager.ACTION_CARRIER_CONFIG_CHANGED)) {
                if (!intent.hasExtra(CarrierConfigManager.EXTRA_SUBSCRIPTION_INDEX) ||
                        intent.getIntExtra(CarrierConfigManager.EXTRA_SUBSCRIPTION_INDEX, -1)
                                != mClient.getSubscriptionId()) {
                    return;
                }
            }
            mClient.onPhoneChange();
        }
    }

    private void removeContactDiscoveryDialog(int subId) {
        ContactDiscoveryDialogFragment fragment = getContactDiscoveryFragment(subId);
        if (fragment != null) {
            fragment.dismiss();
        }
    }

    private ContactDiscoveryDialogFragment getContactDiscoveryFragment(int subId) {
        // In the case that we are rebuilding this activity after it has been destroyed and
        // recreated, look up the dialog in the fragment manager.
        return (ContactDiscoveryDialogFragment) getSupportFragmentManager()
                .findFragmentByTag(ContactDiscoveryDialogFragment.getFragmentTag(subId));
    }

    private void maybeShowContactDiscoveryDialog(int subId) {
        SubscriptionInfo info = getSubscriptionInfo(subId);
        CharSequence carrierName = "";
        if (info != null) {
            carrierName = info.getDisplayName();
        }
        // If this activity was launched using ACTION_SHOW_CAPABILITY_DISCOVERY_OPT_IN, show the
        // associated dialog only if the opt-in has not been granted yet.
        boolean showOptInDialog = doesIntentContainOptInAction(getIntent())
                // has the carrier config enabled capability discovery?
                && MobileNetworkUtils.isContactDiscoveryVisible(this, subId)
                // has the user already enabled this configuration?
                && !MobileNetworkUtils.isContactDiscoveryEnabled(this, subId);
        ContactDiscoveryDialogFragment fragment = getContactDiscoveryFragment(subId);
        if (showOptInDialog) {
            if (fragment == null) {
                fragment = ContactDiscoveryDialogFragment.newInstance(subId, carrierName);
            }
            // Only try to show the dialog if it has not already been added, otherwise we may
            // accidentally add it multiple times, causing multiple dialogs.
            if (!fragment.isAdded()) {
                fragment.show(getSupportFragmentManager(),
                        ContactDiscoveryDialogFragment.getFragmentTag(subId));
            }
        }
    }

    private boolean doesIntentContainOptInAction(Intent intent) {
        String intentAction = (intent != null ? intent.getAction() : null);
        return TextUtils.equals(intentAction,
                ImsRcsManager.ACTION_SHOW_CAPABILITY_DISCOVERY_OPT_IN);
    }

    private void validate(Intent intent) {
        // Do not allow ACTION_SHOW_CAPABILITY_DISCOVERY_OPT_IN without a subscription id specified,
        // since we do not want the user to accidentally turn on capability polling for the wrong
        // subscription.
        if (doesIntentContainOptInAction(intent)) {
            if (SubscriptionManager.INVALID_SUBSCRIPTION_ID == intent.getIntExtra(
                    Settings.EXTRA_SUB_ID, SubscriptionManager.INVALID_SUBSCRIPTION_ID)) {
                throw new IllegalArgumentException("Intent with action "
                        + "SHOW_CAPABILITY_DISCOVERY_OPT_IN must also include the extra "
                        + "Settings#EXTRA_SUB_ID");
            }
        }
    }
}