/*
 * 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 com.android.settings.datausage;

import static android.net.NetworkPolicyManager.POLICY_REJECT_METERED_BACKGROUND;

import android.app.Activity;
import android.app.LoaderManager;
import android.content.Context;
import android.content.Intent;
import android.content.Loader;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.graphics.drawable.Drawable;
import android.net.INetworkStatsSession;
import android.net.NetworkPolicy;
import android.net.NetworkStatsHistory;
import android.net.NetworkTemplate;
import android.net.TrafficStats;
import android.os.Bundle;
import android.os.RemoteException;
import android.os.UserHandle;
import android.support.annotation.VisibleForTesting;
import android.support.v14.preference.SwitchPreference;
import android.support.v7.preference.Preference;
import android.support.v7.preference.PreferenceCategory;
import android.text.format.Formatter;
import android.util.ArraySet;
import android.util.IconDrawableFactory;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;

import com.android.internal.logging.nano.MetricsProto.MetricsEvent;
import com.android.settings.R;
import com.android.settings.applications.AppInfoBase;
import com.android.settings.widget.EntityHeaderController;
import com.android.settingslib.AppItem;
import com.android.settingslib.net.ChartData;
import com.android.settingslib.net.ChartDataLoader;
import com.android.settingslib.net.UidDetail;
import com.android.settingslib.net.UidDetailProvider;
import com.android.settingslib.wrapper.PackageManagerWrapper;

public class AppDataUsage extends DataUsageBase implements Preference.OnPreferenceChangeListener,
        DataSaverBackend.Listener {

    private static final String TAG = "AppDataUsage";

    public static final String ARG_APP_ITEM = "app_item";
    public static final String ARG_NETWORK_TEMPLATE = "network_template";

    private static final String KEY_TOTAL_USAGE = "total_usage";
    private static final String KEY_FOREGROUND_USAGE = "foreground_usage";
    private static final String KEY_BACKGROUND_USAGE = "background_usage";
    private static final String KEY_APP_SETTINGS = "app_settings";
    private static final String KEY_RESTRICT_BACKGROUND = "restrict_background";
    private static final String KEY_APP_LIST = "app_list";
    private static final String KEY_CYCLE = "cycle";
    private static final String KEY_UNRESTRICTED_DATA = "unrestricted_data_saver";

    private static final int LOADER_CHART_DATA = 2;
    private static final int LOADER_APP_PREF = 3;

    private PackageManagerWrapper mPackageManagerWrapper;
    private final ArraySet<String> mPackages = new ArraySet<>();
    private Preference mTotalUsage;
    private Preference mForegroundUsage;
    private Preference mBackgroundUsage;
    private Preference mAppSettings;
    private SwitchPreference mRestrictBackground;
    private PreferenceCategory mAppList;

    private Drawable mIcon;
    private CharSequence mLabel;
    private String mPackageName;
    private INetworkStatsSession mStatsSession;
    private CycleAdapter mCycleAdapter;

    private long mStart;
    private long mEnd;
    private ChartData mChartData;
    private NetworkTemplate mTemplate;
    private NetworkPolicy mPolicy;
    private AppItem mAppItem;
    private Intent mAppSettingsIntent;
    private SpinnerPreference mCycle;
    private SwitchPreference mUnrestrictedData;
    private DataSaverBackend mDataSaverBackend;

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        mPackageManagerWrapper = new PackageManagerWrapper(getPackageManager());
        final Bundle args = getArguments();

        try {
            mStatsSession = services.mStatsService.openSession();
        } catch (RemoteException e) {
            throw new RuntimeException(e);
        }

        mAppItem = (args != null) ? (AppItem) args.getParcelable(ARG_APP_ITEM) : null;
        mTemplate = (args != null) ? (NetworkTemplate) args.getParcelable(ARG_NETWORK_TEMPLATE)
                : null;
        if (mTemplate == null) {
            Context context = getContext();
            mTemplate = DataUsageUtils.getDefaultTemplate(context,
                    DataUsageUtils.getDefaultSubscriptionId(context));
        }
        if (mAppItem == null) {
            int uid = (args != null) ? args.getInt(AppInfoBase.ARG_PACKAGE_UID, -1)
                    : getActivity().getIntent().getIntExtra(AppInfoBase.ARG_PACKAGE_UID, -1);
            if (uid == -1) {
                // TODO: Log error.
                getActivity().finish();
            } else {
                addUid(uid);
                mAppItem = new AppItem(uid);
                mAppItem.addUid(uid);
            }
        } else {
            for (int i = 0; i < mAppItem.uids.size(); i++) {
                addUid(mAppItem.uids.keyAt(i));
            }
        }
        addPreferencesFromResource(R.xml.app_data_usage);

        mTotalUsage = findPreference(KEY_TOTAL_USAGE);
        mForegroundUsage = findPreference(KEY_FOREGROUND_USAGE);
        mBackgroundUsage = findPreference(KEY_BACKGROUND_USAGE);

        mCycle = (SpinnerPreference) findPreference(KEY_CYCLE);
        mCycleAdapter = new CycleAdapter(getContext(), mCycle, mCycleListener, false);

        if (mAppItem.key > 0) {
            if (mPackages.size() != 0) {
                try {
                    ApplicationInfo info = mPackageManagerWrapper.getApplicationInfoAsUser(
                            mPackages.valueAt(0), 0, UserHandle.getUserId(mAppItem.key));
                    mIcon = IconDrawableFactory.newInstance(getActivity()).getBadgedIcon(info);
                    mLabel = info.loadLabel(mPackageManagerWrapper.getPackageManager());
                    mPackageName = info.packageName;
                } catch (PackageManager.NameNotFoundException e) {
                }
            }
            if (!UserHandle.isApp(mAppItem.key)) {
                removePreference(KEY_UNRESTRICTED_DATA);
                removePreference(KEY_RESTRICT_BACKGROUND);
            } else {
                mRestrictBackground = (SwitchPreference) findPreference(KEY_RESTRICT_BACKGROUND);
                mRestrictBackground.setOnPreferenceChangeListener(this);
                mUnrestrictedData = (SwitchPreference) findPreference(KEY_UNRESTRICTED_DATA);
                mUnrestrictedData.setOnPreferenceChangeListener(this);
            }
            mDataSaverBackend = new DataSaverBackend(getContext());
            mAppSettings = findPreference(KEY_APP_SETTINGS);

            mAppSettingsIntent = new Intent(Intent.ACTION_MANAGE_NETWORK_USAGE);
            mAppSettingsIntent.addCategory(Intent.CATEGORY_DEFAULT);

            PackageManager pm = getPackageManager();
            boolean matchFound = false;
            for (String packageName : mPackages) {
                mAppSettingsIntent.setPackage(packageName);
                if (pm.resolveActivity(mAppSettingsIntent, 0) != null) {
                    matchFound = true;
                    break;
                }
            }
            if (!matchFound) {
                removePreference(KEY_APP_SETTINGS);
                mAppSettings = null;
            }

            if (mPackages.size() > 1) {
                mAppList = (PreferenceCategory) findPreference(KEY_APP_LIST);
                getLoaderManager().initLoader(LOADER_APP_PREF, Bundle.EMPTY, mAppPrefCallbacks);
            } else {
                removePreference(KEY_APP_LIST);
            }
        } else {
            final Context context = getActivity();
            UidDetail uidDetail = new UidDetailProvider(context).getUidDetail(mAppItem.key, true);
            mIcon = uidDetail.icon;
            mLabel = uidDetail.label;
            mPackageName = context.getPackageName();

            removePreference(KEY_UNRESTRICTED_DATA);
            removePreference(KEY_APP_SETTINGS);
            removePreference(KEY_RESTRICT_BACKGROUND);
            removePreference(KEY_APP_LIST);
        }
    }

    @Override
    public void onDestroy() {
        TrafficStats.closeQuietly(mStatsSession);
        super.onDestroy();
    }

    @Override
    public void onResume() {
        super.onResume();
        if (mDataSaverBackend != null) {
            mDataSaverBackend.addListener(this);
        }
        mPolicy = services.mPolicyEditor.getPolicy(mTemplate);
        getLoaderManager().restartLoader(LOADER_CHART_DATA,
                ChartDataLoader.buildArgs(mTemplate, mAppItem), mChartDataCallbacks);
        updatePrefs();
    }

    @Override
    public void onPause() {
        super.onPause();
        if (mDataSaverBackend != null) {
            mDataSaverBackend.remListener(this);
        }
    }

    @Override
    public boolean onPreferenceChange(Preference preference, Object newValue) {
        if (preference == mRestrictBackground) {
            mDataSaverBackend.setIsBlacklisted(mAppItem.key, mPackageName, !(Boolean) newValue);
            updatePrefs();
            return true;
        } else if (preference == mUnrestrictedData) {
            mDataSaverBackend.setIsWhitelisted(mAppItem.key, mPackageName, (Boolean) newValue);
            return true;
        }
        return false;
    }

    @Override
    public boolean onPreferenceTreeClick(Preference preference) {
        if (preference == mAppSettings) {
            // TODO: target towards entire UID instead of just first package
            getActivity().startActivityAsUser(mAppSettingsIntent, new UserHandle(
                    UserHandle.getUserId(mAppItem.key)));
            return true;
        }
        return super.onPreferenceTreeClick(preference);
    }

    @VisibleForTesting
    void updatePrefs() {
        updatePrefs(getAppRestrictBackground(), getUnrestrictData());
    }

    private void updatePrefs(boolean restrictBackground, boolean unrestrictData) {
        if (mRestrictBackground != null) {
            mRestrictBackground.setChecked(!restrictBackground);
        }
        if (mUnrestrictedData != null) {
            if (restrictBackground) {
                mUnrestrictedData.setVisible(false);
            } else {
                mUnrestrictedData.setVisible(true);
                mUnrestrictedData.setChecked(unrestrictData);
            }
        }
    }

    private void addUid(int uid) {
        String[] packages = getPackageManager().getPackagesForUid(uid);
        if (packages != null) {
            for (int i = 0; i < packages.length; i++) {
                mPackages.add(packages[i]);
            }
        }
    }

    private void bindData() {
        final long backgroundBytes, foregroundBytes;
        if (mChartData == null || mStart == 0) {
            backgroundBytes = foregroundBytes = 0;
            mCycle.setVisible(false);
        } else {
            mCycle.setVisible(true);
            final long now = System.currentTimeMillis();
            NetworkStatsHistory.Entry entry = null;
            entry = mChartData.detailDefault.getValues(mStart, mEnd, now, entry);
            backgroundBytes = entry.rxBytes + entry.txBytes;
            entry = mChartData.detailForeground.getValues(mStart, mEnd, now, entry);
            foregroundBytes = entry.rxBytes + entry.txBytes;
        }
        final long totalBytes = backgroundBytes + foregroundBytes;
        final Context context = getContext();

        mTotalUsage.setSummary(Formatter.formatFileSize(context, totalBytes));
        mForegroundUsage.setSummary(Formatter.formatFileSize(context, foregroundBytes));
        mBackgroundUsage.setSummary(Formatter.formatFileSize(context, backgroundBytes));
    }

    private boolean getAppRestrictBackground() {
        final int uid = mAppItem.key;
        final int uidPolicy = services.mPolicyManager.getUidPolicy(uid);
        return (uidPolicy & POLICY_REJECT_METERED_BACKGROUND) != 0;
    }

    private boolean getUnrestrictData() {
        if (mDataSaverBackend != null) {
            return mDataSaverBackend.isWhitelisted(mAppItem.key);
        }
        return false;
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        String pkg = mPackages.size() != 0 ? mPackages.valueAt(0) : null;
        int uid = 0;
        if (pkg != null) {
            try {
                uid = mPackageManagerWrapper.getPackageUidAsUser(pkg,
                        UserHandle.getUserId(mAppItem.key));
            } catch (PackageManager.NameNotFoundException e) {
                Log.w(TAG, "Skipping UID because cannot find package " + pkg);
            }
        }

        final boolean showInfoButton = mAppItem.key > 0;

        final Activity activity = getActivity();
        final Preference pref = EntityHeaderController
                .newInstance(activity, this, null /* header */)
                .setRecyclerView(getListView(), getLifecycle())
                .setUid(uid)
                .setHasAppInfoLink(showInfoButton)
                .setButtonActions(EntityHeaderController.ActionType.ACTION_NONE,
                        EntityHeaderController.ActionType.ACTION_NONE)
                .setIcon(mIcon)
                .setLabel(mLabel)
                .setPackageName(pkg)
                .done(activity, getPrefContext());
        getPreferenceScreen().addPreference(pref);
    }

    @Override
    public int getMetricsCategory() {
        return MetricsEvent.APP_DATA_USAGE;
    }

    private AdapterView.OnItemSelectedListener mCycleListener =
            new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            final CycleAdapter.CycleItem cycle = (CycleAdapter.CycleItem) mCycle.getSelectedItem();

            mStart = cycle.start;
            mEnd = cycle.end;
            bindData();
        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {
            // ignored
        }
    };

    private final LoaderManager.LoaderCallbacks<ChartData> mChartDataCallbacks =
            new LoaderManager.LoaderCallbacks<ChartData>() {
        @Override
        public Loader<ChartData> onCreateLoader(int id, Bundle args) {
            return new ChartDataLoader(getActivity(), mStatsSession, args);
        }

        @Override
        public void onLoadFinished(Loader<ChartData> loader, ChartData data) {
            mChartData = data;
            mCycleAdapter.updateCycleList(mPolicy, mChartData);
            bindData();
        }

        @Override
        public void onLoaderReset(Loader<ChartData> loader) {
        }
    };

    private final LoaderManager.LoaderCallbacks<ArraySet<Preference>> mAppPrefCallbacks =
        new LoaderManager.LoaderCallbacks<ArraySet<Preference>>() {
            @Override
            public Loader<ArraySet<Preference>> onCreateLoader(int i, Bundle bundle) {
                return new AppPrefLoader(getPrefContext(), mPackages, getPackageManager());
            }

            @Override
            public void onLoadFinished(Loader<ArraySet<Preference>> loader,
                    ArraySet<Preference> preferences) {
                if (preferences != null && mAppList != null) {
                    for (Preference preference : preferences) {
                        mAppList.addPreference(preference);
                    }
                }
            }

            @Override
            public void onLoaderReset(Loader<ArraySet<Preference>> loader) {
            }
        };

    @Override
    public void onDataSaverChanged(boolean isDataSaving) {

    }

    @Override
    public void onWhitelistStatusChanged(int uid, boolean isWhitelisted) {
        if (mAppItem.uids.get(uid, false)) {
            updatePrefs(getAppRestrictBackground(), isWhitelisted);
        }
    }

    @Override
    public void onBlacklistStatusChanged(int uid, boolean isBlacklisted) {
        if (mAppItem.uids.get(uid, false)) {
            updatePrefs(isBlacklisted, getUnrestrictData());
        }
    }
}
