/*
 * 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.datausage;

import android.app.Activity;
import android.content.Context;
import android.net.NetworkTemplate;
import android.telephony.SubscriptionInfo;
import android.telephony.SubscriptionPlan;
import android.text.TextUtils;
import android.util.Log;
import android.util.RecurrenceRule;

import androidx.annotation.VisibleForTesting;
import androidx.preference.Preference;

import com.android.internal.util.CollectionUtils;
import com.android.settings.R;
import com.android.settings.core.PreferenceControllerMixin;
import com.android.settings.datausage.lib.DataUsageLib;
import com.android.settings.network.ProxySubscriptionManager;
import com.android.settings.network.telephony.TelephonyBasePreferenceController;
import com.android.settingslib.net.DataUsageController;
import com.android.settingslib.utils.ThreadUtils;

import java.util.List;
import java.util.concurrent.Future;

/**
 * This is the controller for a data usage header that retrieves carrier data from the new
 * subscriptions framework API if available. The controller reads subscription information from the
 * framework and falls back to legacy usage data if none are available.
 */
public class DataUsageSummaryPreferenceController extends TelephonyBasePreferenceController
        implements PreferenceControllerMixin {

    private static final String TAG = "DataUsageController";
    private static final String KEY = "status_header";
    private static final long PETA = 1000000000000000L;

    protected DataUsageController mDataUsageController;
    protected DataUsageInfoController mDataInfoController;
    private NetworkTemplate mDefaultTemplate;
    private boolean mHasMobileData;

    /** Name of the carrier, or null if not available */
    private CharSequence mCarrierName;

    /** The number of registered plans, [0,N] */
    private int mDataplanCount;

    /** The time of the last update in milliseconds since the epoch, or -1 if unknown */
    private long mSnapshotTime;

    /**
     * The size of the first registered plan if one exists or the size of the warning if it is set.
     * -1 if no information is available.
     */
    private long mDataplanSize;
    /** The "size" of the data usage bar, i.e. the amount of data its rhs end represents */
    private long mDataBarSize;
    /** The number of bytes used since the start of the cycle. */
    private long mDataplanUse;
    /** The ending time of the billing cycle in ms since the epoch */
    private long mCycleEnd;

    private Future<Long> mHistoricalUsageLevel;

    public DataUsageSummaryPreferenceController(Activity activity, int subscriptionId) {
        super(activity, KEY);

        init(subscriptionId);
    }

    /**
     * Initialize based on subscription ID provided
     * @param subscriptionId is the target subscriptionId
     */
    public void init(int subscriptionId) {
        mSubId = subscriptionId;
        mHasMobileData = DataUsageUtils.hasMobileData(mContext);
        mDataUsageController = null;
    }

    protected void updateConfiguration(Context context,
            int subscriptionId, SubscriptionInfo subInfo) {
        mDataUsageController = createDataUsageController(context);
        mDataUsageController.setSubscriptionId(subscriptionId);
        mDataInfoController = new DataUsageInfoController();

        if (subInfo != null) {
            mDefaultTemplate = DataUsageLib.getMobileTemplate(context, subscriptionId);
        }
    }

    @VisibleForTesting
    DataUsageController createDataUsageController(Context context) {
        return new DataUsageController(context);
    }

    @VisibleForTesting
    DataUsageSummaryPreferenceController(
            DataUsageController dataUsageController,
            DataUsageInfoController dataInfoController,
            NetworkTemplate defaultTemplate,
            Activity activity,
            int subscriptionId) {
        super(activity, KEY);
        mDataUsageController = dataUsageController;
        mDataInfoController = dataInfoController;
        mDefaultTemplate = defaultTemplate;
        mHasMobileData = true;
        mSubId = subscriptionId;
    }

    @VisibleForTesting
    List<SubscriptionPlan> getSubscriptionPlans(int subscriptionId) {
        return ProxySubscriptionManager.getInstance(mContext).get()
                .getSubscriptionPlans(subscriptionId);
    }

    protected SubscriptionInfo getSubscriptionInfo(int subscriptionId) {
        if (!mHasMobileData) {
            return null;
        }
        return ProxySubscriptionManager.getInstance(mContext)
                .getAccessibleSubscriptionInfo(subscriptionId);
    }

    @Override
    public int getAvailabilityStatus(int subId) {
        return getSubscriptionInfo(subId) != null ? AVAILABLE : CONDITIONALLY_UNAVAILABLE;
    }

    @Override
    public void updateState(Preference preference) {
        DataUsageSummaryPreference summaryPreference = (DataUsageSummaryPreference) preference;

        final SubscriptionInfo subInfo = getSubscriptionInfo(mSubId);
        if (subInfo == null) {
            return;
        }
        if (mDataUsageController == null) {
            updateConfiguration(mContext, mSubId, subInfo);
        }

        mHistoricalUsageLevel = ThreadUtils.postOnBackgroundThread(() ->
                mDataUsageController.getHistoricalUsageLevel(mDefaultTemplate));

        final DataUsageController.DataUsageInfo info =
                mDataUsageController.getDataUsageInfo(mDefaultTemplate);

        long usageLevel = info.usageLevel;

        refreshDataplanInfo(info, subInfo);

        if (info.warningLevel > 0 && info.limitLevel > 0) {
            summaryPreference.setLimitInfo(TextUtils.expandTemplate(
                    mContext.getText(R.string.cell_data_warning_and_limit),
                    DataUsageUtils.formatDataUsage(mContext, info.warningLevel),
                    DataUsageUtils.formatDataUsage(mContext, info.limitLevel)));
        } else if (info.warningLevel > 0) {
            summaryPreference.setLimitInfo(TextUtils.expandTemplate(
                    mContext.getText(R.string.cell_data_warning),
                    DataUsageUtils.formatDataUsage(mContext, info.warningLevel)));
        } else if (info.limitLevel > 0) {
            summaryPreference.setLimitInfo(TextUtils.expandTemplate(
                    mContext.getText(R.string.cell_data_limit),
                    DataUsageUtils.formatDataUsage(mContext, info.limitLevel)));
        } else {
            summaryPreference.setLimitInfo(null);
        }

        if ((mDataplanUse <= 0L) && (mSnapshotTime < 0)) {
            Log.d(TAG, "Display data usage from history");
            mDataplanUse = displayUsageLevel(usageLevel);
            mSnapshotTime = -1L;
        }

        summaryPreference.setUsageNumbers(mDataplanUse, mDataplanSize, mHasMobileData);

        if (mDataBarSize <= 0) {
            summaryPreference.setChartEnabled(false);
        } else {
            summaryPreference.setChartEnabled(true);
            summaryPreference.setLabels(DataUsageUtils.formatDataUsage(mContext, 0 /* sizeBytes */),
                    DataUsageUtils.formatDataUsage(mContext, mDataBarSize));
            summaryPreference.setProgress(mDataplanUse / (float) mDataBarSize);
        }
        summaryPreference.setUsageInfo(mCycleEnd, mSnapshotTime, mCarrierName, mDataplanCount);
    }

    private long displayUsageLevel(long usageLevel) {
        if (usageLevel > 0) {
            return usageLevel;
        }
        try {
            usageLevel = mHistoricalUsageLevel.get();
        } catch (Exception ex) {
        }
        return usageLevel;
    }

    // TODO(b/70950124) add test for this method once the robolectric shadow run script is
    // completed (b/3526807)
    private void refreshDataplanInfo(DataUsageController.DataUsageInfo info,
            SubscriptionInfo subInfo) {
        // reset data before overwriting
        mCarrierName = null;
        mDataplanCount = 0;
        mDataplanSize = -1L;
        mDataBarSize = mDataInfoController.getSummaryLimit(info);
        mDataplanUse = info.usageLevel;
        mCycleEnd = info.cycleEnd;
        mSnapshotTime = -1L;

        if (subInfo != null && mHasMobileData) {
            mCarrierName = subInfo.getCarrierName();
            final List<SubscriptionPlan> plans = getSubscriptionPlans(mSubId);
            final SubscriptionPlan primaryPlan = getPrimaryPlan(plans);

            if (primaryPlan != null) {
                mDataplanCount = plans.size();
                mDataplanSize = primaryPlan.getDataLimitBytes();
                if (unlimited(mDataplanSize)) {
                    mDataplanSize = -1L;
                }
                mDataBarSize = mDataplanSize;
                mDataplanUse = primaryPlan.getDataUsageBytes();

                RecurrenceRule rule = primaryPlan.getCycleRule();
                if (rule != null && rule.start != null && rule.end != null) {
                    mCycleEnd = rule.end.toEpochSecond() * 1000L;
                }
                mSnapshotTime = primaryPlan.getDataUsageTime();
            }
        }
        Log.i(TAG, "Have " + mDataplanCount + " plans, dflt sub-id " + mSubId);
    }

    private static SubscriptionPlan getPrimaryPlan(List<SubscriptionPlan> plans) {
        if (CollectionUtils.isEmpty(plans)) {
            return null;
        }
        // First plan in the list is the primary plan
        SubscriptionPlan plan = plans.get(0);
        return plan.getDataLimitBytes() > 0
                && validSize(plan.getDataUsageBytes())
                && plan.getCycleRule() != null ? plan : null;
    }

    private static boolean validSize(long value) {
        return value >= 0L && value < PETA;
    }

    public static boolean unlimited(long size) {
        return size == SubscriptionPlan.BYTES_UNLIMITED;
    }
}